Indicate by check mark whether the registrant files or will file annual reports under cover of
Form 20-F or Form 40F:
Form 20-F o Form 40-F þ
Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted
by Regulation S-T Rule 101(b)(1):
Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by
Regulation S-T Rule 101(b)(7):
Indicate by check mark whether by furnishing the information contained in this Form, the
registrant is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b)
under the Securities Exchange Act of 1934.
Yes o No þ
If “Yes” is marked, indicate below the file number assigned to the registrant in
connection with Rule 12g3-2(b): 82-
Generalized Stratigraphic Table for the Fort à la Corne Area
Table 3:
Kimberlite and Diamond Information Utilized in 2000 Prioritization Study
Table 4:
Prioritized Kimberlite Bodies
Table 5:
Macrodiamond Recoveries from 2000 Drillholes
Table 6:
Modeled Values and Revenue for Kimberlites 122 and 141
Table 7:
2001 Core Intersection Summary
Table 8:
2001 Summary of Minibulk Sampling
Table 9:
Summary of 2001 Initial Processing by Dense Media Separation
Table 10:
Minibulk Sample Grades for 2000 and 2001 Drillholes in Kimberlite 141
Table 11:
Summary of 2002 Core Drilling Program
Table 12:
Kimberlite Intersections and Sample Tonnages for 2002 Program
Table 13:
Summary of Final Macrodiamond Recovery Results and Grades for 2002 Program
Table 14:
Summary of Large Stone Recovery for 2002 Program
5
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
Table 15:
Raw Stone Values Based on the De Beers’ July 2003 Price Book
Table 16:
Total Microdiamond and Macrodiamond Stone Counts and Weights
Table 17:
2002 Evaluation Program – Actual and Modeled Grade and Revenue Data with
Comparison to 2001 Program
Table 18:
Preliminary Summary of 2003 Core Drilling at Fort à la Corne
Table 19:
Summary of 140/141 Microdiamond Results by Drillhole
Table 20:
Summary of 140/141 Microdiamond Results by Kimberlite Type
Table 21:
140/141 Microdiamond Recoveries by Sieve Category and Kimberlite Type
Table 22:
148 Microdiamond Results by Kimberlite Type
Table 23:
148 Microdiamond Results by Sieve Category and Kimberlite Type
Table 24:
Summary of 122 Microdiamond Results by Kimberlite Type
Table 25:
122 Microdiamond Recoveries by Sieve Category and Kimberlite Type
Table 26:
Comparison of Recent and Historical 122 Microdiamond Results by Area
Table 27:
150 Microdiamond Results by Kimberlite Type
Table 28:
KMDL 150 Microdiamond Results (>74 microns) by Sieve Category and Kimberlite Type
Table 29:
Fort à la Corne Kimberlite Units of Economic Interest
Table 30:
Summary of 2004 Core Drilling at Fort à la Corne
Table 31:
Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 120
Table 32:
Summary of 2004 and Historical Kimberlite 120 Microdiamond Results
Table 33:
Kimberlite 120 Microdiamond Recoveries by Drillhole and Sieve Category
Table 34:
Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 147
Table 35:
Summary of 2004 and Historical Kimberlite 147 Microdiamond Results
Table 36:
Kimberlite 147 Microdiamond Recoveries by Drillhole and Sieve Category
Table 37:
Summary of Historic Drillholes and Minibulk Macrodiamond on 147
Table 38:
Summary of 2004 and Historical Kimberlite 121 Microdiamond Results
Table 39:
Kimberlite 121 Microdiamond Recoveries by Drillhole and Sieve Category
Table 40:
Summary of 2004 and Historical Kimberlite 221 Microdiamond Results
Table 41:
Kimberlite 221 Microdiamond Recoveries by Drillhole and Sieve Category
Table 42:
Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 140
Table 43:
Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 141
Table 44:
140/141 Microdiamond Results by Kimberlite Type and Year Tested
Table 45:
Summary of 140/141 Microdiamond Results by Drillhole
Table 46:
140/141 Microdiamond Recoveries by Sieve Category and Kimberlite Type
Table 47:
Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-044
Table 48:
Summary of Macrodiamond Recovery by Sieve Size Category for Drillhole 04-140-044
Table 49:
Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-045
Table 50:
Summary of Macrodiamond Recovery by Sieve Size Category
Table 51:
Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-049
Table 52:
Summary of Macrodiamond Recovery by Sieve Size Category
Table 53:
Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-051
Table 54:
Summary of Macrodiamond Recovery from LDDH 04-140-051 by Sieve Size Category
Table 55:
Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-052
Table 56:
Summary of Macrodiamond Recovery by Sieve Size Category
Table 57:
Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 122
Table 58:
Summary of 122 Microdiamond Results by Drillhole
Table 59:
Summary of 2004 Microdiamond Results for 122 by Type and Year Sampled
Table 60:
2003-2004 Microdiamond Recoveries by Sieve Class and Kimberlite Type for 122
Table 61:
Summary of 122 Microdiamond Results from 2004 Pilot Hole Samples
Table 62:
Diamond Recovery by Sieve Category for the 2004 Pilot Holes
Table 63:
Actual 2004 Macrodiamond Recoveries from Kimberlite 122
Table 64:
Summary of 2004 Macrodiamond Recovery from Kimberlite 122 by Sieve Size Category
6
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
Table 65:
Comparison of Adjusted 2000 and 2004 Macrodiamond Recoveries from Kimberlite 122
Table 66:
Summary of Core Drilling on Geophysical Anomalies
Table 67:
Fort à la Corne Joint Venture Core Drilling Summary to August 31, 2005
Table 68:
Preliminary Core Drilling Summary on for the Star Kimberlite (drilling in progress)
Table 69:
Preliminary Core Drilling Summary for Kimberlite Body 134
Table 70:
Preliminary Core Drilling Summary for Kimberlite Body 145
Table 71:
Preliminary Core Drilling Summary for Kimberlite Body 219
Table 72:
Preliminary Core Drilling Summary for Kimberlite 119
Table 73:
Preliminary Core Drilling Summary for Kimberlite 133
Table 74:
Preliminary Core Drilling Summary for Kimberlite 158
Table 75:
Preliminary Core Drilling Summary for Kimberlite 216
Table 76:
Preliminary Core Drilling Summary for Kimberlite 116
Table 77:
Preliminary Core Drilling Summary for Kimberlite 118
Table 78:
Preliminary Core Drilling Summary for Kimberlite 218
Table 79:
Preliminary Core Drilling Summary for Kimberlite 123 (drilling in progress)
Table 80:
Preliminary Core Drilling Summary for Kimberlite 135 (drilling in progress)
7
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
Summary
The Fort à la Corne (FalC) Project is located in central Saskatchewan and is contained within
NTS map sheet 73H. The project is composed of legally surveyed claim blocks covering much of the
main trend of kimberlites with an area of 20,368 hectares that is located approximately 65
kilometres east of Prince Albert and extending northward from the Saskatchewan River to a few
kilometres north of Shipman. An additional smaller claim (also legally surveyed) with an area of
2,176 hectares covers magnetic anomalies near Snowden, located some 90 kilometres northeast of
Prince Albert.
The Fort à la Corne Project is a Joint Venture (FalC-JV) among Kensington Resources Ltd., a
wholly-owned subsidiary of Shore Gold Inc. (42.245%), De Beers Canada Inc. (formerly Monopros
Limited) (42.245%), Cameco Corporation (5.51%) and UEM Inc. (10%). Cameco Corporation and Cogema
Ltd. hold UEM’s North American interests. Neither UEM nor Cameco elected to fund exploration in
1999 or 2000, although Cameco did fund to their percentage interest in the FalC-JV during
subsequent programs. UEM retains a 10% free carried interest in the project. Monopros Limited
replaced Uranerz as operator of the FalC-JV in December 1998. At the end of November 2002,
participating interests (PI’s) in the FalC-JV were and remain as follows:
Kensington Resources Ltd.
42.245
%
De Beers Canada Inc. (operator)
42.245
%
Cameco Corporation
5.510
%
UEM Inc. (carried)
10.000
%
The Fort à la Corne Project consists of 52 drill-confirmed kimberlite bodies located in the main
northwesterly trend with an additional 11 drill-confirmed kimberlites in a satellite cluster
located 25 kilometres to the northeast. The Fort à la Corne kimberlite field is distinctive in
that it contains many of the world’s largest kimberlite bodies that have been remarkably
well-preserved since emplacement during Cretaceous time some 100 million years ago. The kimberlite
bodies range in size from 3 to >250 hectares with early estimates of individual mass as high as
675 million tonnes. In excess of 349 drillholes have either penetrated kimberlite or have been
terminated above a reasonable expectation of kimberlite. In general, the kimberlites are composed
of crater facies, volcaniclastic Type 1 kimberlite with irregular “champagne-glass” to disc-shaped
forms, typically described as thicker in the middle and attenuating towards the margins. The areal
outlines and estimated masses of the kimberlites are based on geophysical modeling of ground
magnetic data and drillhole intersections based on an outside 30 metre thickness cut-off. The
architecture of the kimberlite bodies ranges from simple to complex in terms of number of discrete
units or layers and occurrence and coalescence of proximal eruptive centres. The overall
horizontal to sub-horizontal attitude of the kimberlite units changes with proximity to eruptive
centres where more vertical kimberlite phase relationships are present. FalC kimberlites are
overlain by an average of 100 metres of overburden including glacial deposits and ancient shaly
mudstones. Kimberlite bodies range in thickness from a few centimetres to quasi-tabular lenses up
to 200 metres thick. Occasionally, intervals of kimberlite from 300 to 600 metres thick have been
intersected by drillholes located near, or within, the vertically-oriented feeder vents of the
body.
Some targets have become the focus of more detailed exploratory and evaluation work during the life
of the project (e.g., kimberlite bodies 120, 122, 140, 141, 145, 148, 169). Throughout the project,
various drilling methods ranging from small diameter core to large diameter reverse circulation
drilling have been utilized, while sampling protocols have evolved from single sample per drillhole
to interval testing with resolution as fine as several metres. In addition to testing for diamond
content, a series of geophysical surveys, geochemical, and petrologic studies have contributed to
understanding the architecture and emplacement history of the kimberlites.
Typically, diamonds are distributed sporadically throughout a kimberlite body or specific layer.
Not all bodies or layers are mineralized as this depends on several factors including source rock
and emplacement history of the kimberlite. Diamond recovery from FalC kimberlite samples show 70%
of the kimberlites are diamond
8
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
-bearing, and 50% are macrodiamond-bearing (based on recovery of stones >0.85 millimetres in one
dimension). These figures indicate Fort à la Corne to be the largest macrodiamond-bearing
kimberlite field in the world. This is a result of natural processes inherent to volcanic
eruptions and the occurrence of mixing and homogenization of the erupting magma or volcaniclastic
material. Diamonds are not usually localized unless there has been post-eruptive resedimentation
and sorting of the kimberlite.
In general, the project objective is to delineate mineable diamond resources from high-priority
kimberlite bodies in a methodical and step-wise approach. All exploration efforts during 1989–1999
contributed to characterizing the size, shape, internal structure and diamond content of the
kimberlites. This work provided the basis of which key targets could be identified for continued
work towards proving an economic resource. At the beginning of 2000, the De Beers’ Mineral Resource
Evaluation Department (MINRED) reviewed all available macrodiamond and microdiamond data and
re-prioritized the kimberlites. Priority targets 122 and 141 were selected for bulk sampling by
large-diameter (24-inch) reverse circulation drilling in the 2000 program. Results included the
recovery of 212 macrodiamonds from body 122, while body 141 yielded 275 macrodiamonds. De Beers
employed a statistical treatment of the results from the samples to estimate macrodiamond grades
(using a one millimetre cutoff size) between 8 and 13 carats per 100 tonne (cpht) for body 122, and
19 cpht for body 141. In addition, the 2000 drill program recovered sufficient stones to permit
preliminary revenue modeling. Modeled dollar per carat values take into account the expected
diamond size distribution from any potential, future production scenario. Modeled in situ value
estimates were expressed by utilizing conservative, best fit and optimistic models. Values ranged
from $US 90/carat to $US 178/carat (>1.5 millimetres) corresponding to in situ gross value
estimates from $US 16/tonne to $US 32/tonne for the 141 body. Similar modeling for stones greater
than 1.5 millimetres for 122 yielded model values between $US 144 and 147/carat with gross value
estimates between $US 11 and 18/tonne.
Encouraged by the results from the 2000 program, the FalC-JV approved a $4.79 million, two phase
2001 program with the main goal of obtaining additional carats from body 141 to improve confidence
in average diamond value modeling. In 2001, 16 core holes and 10 24-inch large diameter holes (LDD)
(nine in body 141 and one in body 150) were completed. A total of 890 theoretical tonnes of
kimberlite were sampled by the large diameter rig. Results from the 2001 sampling program recovered
an additional 45.6 carats of diamonds including a 3.335 carat stone. Based on this additional
sample set, modeled grade estimated for the 141 kimberlite were recast and ranged from 5 to 12 cpht
(>1.5 millimetres). Actual average parcel diamond values for the 2001 stones were posted at $US
52.60/carat, reflecting a substantial increase from $US 33.67/carat for the 2000 stones. Based on
the additional diamonds recovered from the 2001 program and the recognition of multiple-kimberlite
phases within kimberlite bodies an updated modeled revenue curve and diamond size distribution for
140/141 was developed. This, in turn, yielded updated dollar per carat value estimates. This gave
modeled values for macrodiamonds from 141 that ranged from $US 20 to $US 220/carat. Consequently,
ore value estimates were updated at a range between $US 1 and $US 26/tonne.
Valuation of the 2000/2001 diamonds was conducted during November 2002 by WWW International
Diamond Consultants Ltd. (WWW). WWW indicated an overall average value based on its open market
price book some 15-20% higher than that listed by De Beers for the same diamond parcels. The De
Beers valuations were made utilizing the Diamond Trading Company (DTC, the diamond marketing
company of De Beers) June 2002 price book. The single large stone measuring 3.335 carats was
given a value of $US 450/carat, then $US 580 the next year compared to $US 390/carat attributed by
De Beers. WWW also pointed out the technical difficulties of putting a realistic market value on
a relatively small geological sample.
Detailed core logging of the 140/141 kimberlite revealed distinct kimberlite units or phases, the
recognition of which has aided in the appreciation of variable diamond recoveries throughout
boreholes. Accordingly, the 2002 program involved drilling 25 NQ core holes to develop a better
understanding of the kimberlite geology. Based on this improved understanding, eight large diameter
mini-bulk drill holes were completed to provide
9
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
additional carats to increase confidence in grade
forecasts, valuation and revenue modeling. Three 36-inch LDDH holes were drilled in close-proximity
in the 141 portion of the body where higher stone recoveries were
expected. Five 24-inch LDDH holes were drilled in poorly sampled portions of the kimberlite, mostly
in the 140 portion of the complex.
Results from the 2002 LDD mini-bulk sampling of the 140/141 kimberlite complex included a total of
669 diamonds recovered from a sieve size of 1.5 millimetres. The stones had an aggregate weight of
93.76 carats. Importantly, the 24-inch LDDH holes recovered a number of large stones from the 140
portion of the kimberlite. These stones included a 10.23 carat stone with two dimensions of 14 and
10.5 millimetres along with stones weighing 3.61, 2.59, 2.57, and 1.82 carats. Breakdown of the
kimberlite into phases revealed discrete differences in grade. Grades from a ‘mega-graded bed’ unit
from the 141 body, sampled by three closely spaced 36-inch diameter LDD drill holes, had a
consistent recovered grade of about 6.6 cpht. In contrast, a distinctive breccia phase intersected
in two drill holes in the 140 portion of the 140/141 complex had recovered grades of 9.5 and 17.0
cpht respectfully, with an increase in the proportion of larger diamonds compared to the other
phases.
The average borehole sample grades ranged from 2.86–17.03 cpht, while grade forecasts based on
statistical extrapolation of combined micro- and macrodiamond recoveries show a range of averages
per kimberlite phase from 5 to 15 cpht. Corresponding modeled value figures derived from average
grades and actual values ranged from $US 67 to $US 97/carat. The kimberlite breccia phase which had
only been intersected in two 24-inch LDD drill holes in 2002, and thus has a relatively small
sample size, had the highest modeled grades of 15 cpht and a modeled value of $US 97/carat.
A considerable expansion of exploratory work was implemented in 2003 with the drilling of 49 HQ
coreholes (diameter of 2.5-inchs or 63.5 millimetres) over four different bodies. The southern
and western parts of 140/141 were targeted with 10 coreholes to test kimberlite phases with
perceived higher grades. The remainder of the program drilling was divided between kimberlites
122, 148, and 150. In each body the core was logged in detail to identify discrete phases and
contacts to guide sampling for diamond recovery using caustic dissolution methods. Diamond
recoveries for kimberlites 148, 140/141, and 122 totaled 3,545 stones (2,059, 1,159, and 327,
respectively). Diamond abundances for 148 and 140/141 were both exceptionally high compared to
historical results for those bodies, and for the kimberlite field as a whole. In addition to
caustic recoveries, a single white, clear 0.77 carat octahedroid macrodiamond was encountered while
splitting core from the top of kimberlite in drillhole 140-34. This stone was not incorporated in
the stone counts or dataset utilized for grade forecasts. Rather it stands alone as further proof
for the large stone potential of the 140/141 kimberlite.
In June of 2004 the FalC-JV had a significant revision to its strategy of investigating the Fort à
la Corne kimberlites. In the past, programs focused on assessing individual kimberlites as a whole.
This approach eventually led to the recognition of discrete phases within the kimberlites having
higher-grade and value potential. To this end, the new strategy considers the economic potential of
combined resources within higher-grade units within closely spaced kimberlites.
Exploratory work was implemented in 2004 with the drilling of 39 HQ coreholes over six different
bodies and five geophysical anomalies. Microdiamond recoveries from the six targeted kimberlites
included some of the highest stone counts (stone/10 kilograms) recovered from the Fort à la Corne
kimberlites. In each body the core was logged in detail to identify discrete phases and contacts to
guide sampling for microdiamond recovery using caustic dissolution methods. Eight coreholes on 120
provided a total of 962 microdiamonds which were recovered from 643.4 kilograms of kimberlite core,
while eight coreholes completed on 147 produced a total of 2,429 microdiamonds from 515.20
kilograms of core. Five coreholes on 121 revealed 326 microdiamonds from 295.25 kilograms of core,
with three coreholes on 221 providing 168 microdiamonds from 195.08 kilograms of core. Four HQ
coreholes (04-140-41, 42, 43, 50) were completed on the 140 portion of the 140/141 kimberlite
10
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
in order to provide geological control for five large diameter drillholes completed in the south
central portion of the 140/141 kimberlite body testing the diamond potential of an oscillating
kimberlite breccia unit. A total of 658 microdiamonds were recovered from 496 kilograms of core.
Similar to 2003 results, the “breccia beds”
yielded the better stone abundances. Four HQ coreholes were completed on 122 in order to provide
geological control for five large-diameter drillholes completed in the south central portion of the
122 kimberlite body. Sampling of the 2004 pilot holes resulted in the recovery of 212
microdiamonds from 309.44 kilograms of kimberlite. The average microdiamond abundance for all
122 samples from 2004 is 6.9 stones per 10 kilograms. Selected 2003 coreholes were re-sampled to
provide additional material for diamond recoveries utilizing caustic dissolution methods.
Additional kimberlite samples totaling 464 kilograms from eight 2003 coreholes located across the
body were submitted for diamond recovery utilizing caustic dissolution methods. A total of 269
additional microdiamonds were recovered for use in grade forecasting of specific kimberlite zones.
Five geophysical anomalies were tested with the objective of identifying new, low to non-magnetic
kimberlite bodies in the Fort à la Corne area. Kimberlite was not intersected in most of the holes
targeted on the anomalies, although approximately 27 metres of kimberlite was intersected in a
subtle magnetic anomaly located directly north of Kimberlite 147. More work is required on
integration and modeling of geophysical survey data.
As part of the 2004 program, five large diameter mini-bulk sampling holes were targeted on the
south part of Kimberlite 122 (MPK — South Kimberlite Unit) in order to expand the parcel of
diamonds from this body so that confidence levels in grade and revenue estimates could be
increased. The total estimated mass of kimberlite excavated from body 122 was 739.2 tonnes, of
which 318.1 tonnes of material greater than 1.5 millimetres in size was retained for macrodiamond
recoveries. All five drillholes primarily sampled the main, massive to bedded pyroclastic
kimberlite unit (MPK). A total of 248 macrodiamonds weighing 28.81 carats, including 23 stones
larger than 0.25 carats, were recovered from three 36-inch (914 millimetres) diameter drillholes
(two holes failed before reaching kimberlite). The recovery of many stones larger than 0.25 carats
plus two larger than one carat supports the model of a larger stone population in 122.
Five LDD mini-bulk sampling holes were targeted on the oscillating breccia beds unit located in the
south part of 140/141 in order to expand the parcel of diamonds from this body so that confidence
levels in grade and revenue estimates could be increased. The total estimated mass of kimberlite
excavated from body 140/141 in 2004 was 792.216 tonnes, of which 494.066 tonnes of material greater
than 1.5 millimetres in size was retained for macrodiamond recoveries. All five drillholes
primarily sampled the oscillating pyroclastic breccia group (OPKBGP). Total macrodiamond recovery
was 553 stones with a combined weight of 83.20 carats. Individual sample grades ranged from 1.68
cpht to 69.15 cpht, the latter grade being markedly influenced by recovery of the 10.23 carat
stone. Drillhole grades range from 7.05 to 12.20 cpht. Two large macrodiamonds weighing 10.53
carats and a 4.09 carats and 58 other stones larger than 0.25 carats were added to the inventory of
large macrodiamonds recovered from the 140/141 breccia beds during the 2004 program. These larger
stones and historical recoveries including diamonds weighing: 1.0, 1.16, 1.18, 1.26, 1.32, 1.39,
1.48, 1.5, 1.8, 2.57, 2.59, and 3.61 carats contribute significantly to the evidence supporting a
large stone distribution in the oscillating breccia unit.
Also in 2004, the FalC-JV released a preliminary summary of information from a detailed MRM report
(De Beers Mineral Resource Management Department) based on geological modeling and grade
forecasting for kimberlites 140/141, 148 and 122. Taken as a whole the high-interest zones in these
three kimberlite have an average grade of 10 cpht (>1.5 millimetres) and an estimated tonnage of
369 million tonnes. In detail, the combined units of higher interest in 140/141 have an estimated
mass of 134 million tonnes at a modeled average grade of 11 cpht with an estimated average value of
US$ 115/carat. Likewise, the higher grade part of 122 has a combined tonnage of 79 million tonnes
at an average grade of 13 cpht.
Consideration of the longer term view for the Fort á la Corne Project has provided the Joint
Venture Partners with a clear perspective on the way forward. Predicted supply, demand, and price
trends for rough diamonds
11
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
into the next decade provide a rationale for accelerating the present
rate of work on the project in order to be well positioned with respect to the favourable
forecasts. In late 2004, an overview perspective of the Fort á la Corne Project, from present day
to an assumed eventual mining operation, was examined and a time-line developed. The current phase
of the project was denoted as the Advanced Exploration and Evaluation Study
(AE&E) and was estimated to require three years in order to complete. The overall time-line for
the Fort á la Corne Project is considered to be aggressive, being driven by the need to favourably
position the commencement of mining operations in relation to the long term rough diamond supply
and demand predictions. A 2005 budget of CDN$25.6M applies to the period from 22 February 2005 to
15 December 2005.
Results from the historical programs have shown that the Fort à la Corne kimberlites contain
higher-grade zones. As such, it is possible that higher-grade units from a number of kimberlites,
when considered collectively, may form a resource which can be profitably mined. At present, some
35 million carats distributed over 369 tonnes and three different kimberlites have been identified
at a deposit level of confidence. The project strategy has now been revised to focus on the
higher-grade units within proximally-located priority kimberlite bodies and to consider them in
combination. This approach has the advantage of considerably increasing the size of the potential
resource and may permit significant economy of scale to be achieved for a large scale mining
operation.
The AE&E Program scope of work includes the following lines of investigation:
•
Project Administration
•
Resource (drilling and sampling program)
•
Geotechnical/Geohydrological
•
Mining
•
Metallurgy
•
Infrastructure
•
Waste Management
•
Socio-Economic
•
Environmental & Permitting
•
Government Liaison.
In general, the geological drilling program will be complete in 2005 and delineation drilling will
begin late in 2005. To support this, the bulk of geotechnical and geohydrology work will be done in
2005.
Delineation drilling, mini-bulk and supplemental bulk sampling will follow in years 2006 through
early 2008. Geological and delineation drilling will provide geological models and microdiamond
data for the targeted kimberlites. These results will be compared against the criteria established
in the revised conceptual study, following which a decision to proceed will be taken. In the
mini-bulk and supplemental large diameter drillhole (LDD) programs, samples will be treated and
diamonds recovered and valued. The geological model will be updated at the end of each component of
work. An MRM report will first be prepared based on the geological drilling results, then updated
as new data become available throughout the rest of the drill program.
Alongside the resource drilling program, both geotechnical domain and physical properties models
will be developed and mine geotechnical criteria prepared. Work is planned to construct both
geohydrology and water chemistry models, as well as perform geohydrology pumps tests to finalize
the geohydrology criteria and prepare preliminary dewatering criteria. The majority of this work is
planned to be undertaken once the initial geological and delineation drilling programs have
identified the priority targets to advance through to the components of the AE&E.
The AE&E Plan seeks to delineate a total of at least 70 million carats in the ground from the
higher-grade units within the larger kimberlites (greater than 20 hectares) in the south-central
cluster. Twenty primary kimberlite
12
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
targets have been identified to date, most within a radius of
five kilometres in the southern cluster of kimberlites. Four of the twenty targets were
investigated by evaluation and delineation drilling programs during 2000-2003, namely kimberlites
122, 140/141, 148 and 150. One of the four, kimberlite 150, was determined to be of no further
interest. Two kimberlites, 122 and 140/141, were determined to be of significant interest, and
mini-bulk sampling was conducted on them as part of the 2004 Exploration Program. Three more
bodies
including 120, 147 and 121/221 were drilled in the 2004 work program. The remaining bodies of
interest are in the process of being tested with up to 10 coreholes each to determine the existence
of higher-grade units.
A notable and relevant aspect of diamond resource evaluation at Fort à la Corne is that most
historical microdiamond recovery, all current macrodiamond recovery, and all diamond content
interpretation is conducted by De Beers or corporate affiliates/subsidiaries of De Beers
Consolidated Mines Limited of South Africa. De Beers is the operator of the project and a senior
participating partner of the FalC-JV Project. Hence, all analytical work, diamond recovery, and
interpretive diamond evaluation is done “within arm’s reach”, although Kensington Resources Ltd.
frequently monitors, audits, and reviews procedures and results utilizing both affiliated and
independent consultants.
The following points represent the major conclusions from exploration and evaluation work conducted
since 1989. The author considers the facts and information contained herein to be accurate,
representative, and complete. In light of the status of this project – that there is no properly
defined Inferred Resource or better — most of the conclusions given below are factual in nature and
there is a minimum of purely interpretative or speculative opinions. Rather, the opinions of the
author are embodied within the project and program recommendations that follow this section.
o
49 of the 69 tested (71%) bodies are diamondiferous (microdiamonds or macrodiamonds).
o
34 of the 69 (49%) kimberlites tested contain macrodiamonds. This frequency is exceptional
compared to other kimberlite fields.
o
A total of 2,774 macrodiamonds (minimum size of 0.85 millimetres in one dimension) with a
cumulative weight of 347.45 carats were recovered during exploration programs conducted from
1989 to 2004; over 10,000 microdiamonds have been recovered from all kimberlites to mid 2005.
o
Kimberlite body grades based on macrodiamond recovery alone range up to 7.7 cpht; these
values are considered to be significantly understated due to the limited amount of minibulk
sample from each body.
o
Grade estimates for individual bulk samples range up to 114.44 cpht; sample intervals range
from 12 to 194 metres.
o
Grades forecasts for commercial size stones modeled by De Beers range up to 16 cpht based
on size distributions of combined microdiamonds and macrodiamonds. A total of 17 kimberlite
bodies with sufficient diamond recoveries were prioritized in 2000. The best five of these
bodies have been the target of various stages of advanced exploration efforts during the last
5 years, and 17 bodies within the south central cluster are currently under investigation in
the first phase of the AE&E program.
o
Ongoing acquisition of large minibulk samples from prioritized bodies permits preliminary
revenue modeling and evaluation of the economic potential of select Fort à la Corne
diamondiferous kimberlites.
o
Modeled average macrodiamond values determined by De Beers for kimberlite ore from
Kimberlite 122 range from $US 133 to 147 per carat; best fit to optimistic modeled revenue
values range from $US 11 to 18 per tonne. These grades, values, and revenue figures are
based on recovery of approximately 23.3 carats from the 122 body to date.
13
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
o
Based on 2000 data only, modeled average macrodiamond values determined by De Beers for
kimberlite ore from body 141 ranged from $US 148 to 179 per carat; best fit to optimistic
modeled revenue values range from $US 28 to 33 per tonne. Modeled stone values and projected
revenue ranges for Kimberlites 122 and 141 have low confidence levels because of low numbers
of diamonds included in the evaluation.
o
The largest stone recovered to date is a high value, yellow, stone weighing 10.53 carats;
another high value diamond weighs 3.34 carats and has a value of $US 580/carat as determined
by De Beers and WWW International Diamond Consultants Ltd.; other large stones recovered
include ones weighing 10.23, 4.09, and 3.61 carats in size.
o
Interpretation of 2001 to 2002 data indicates that grades for specific parts of the 141
body are variable depending on diamond distribution and continuity of lithological facies,
and that a greater degree of testing is required to substantiate grade forecasts over the
entire body, and to permit higher levels of confidence in calculation of average of diamond
value; evaluation of small parcels of commercial-size stones shows preliminary indications
(considered low confidence until larger parcels are evaluated) that the average value of
diamonds from Kimberlite 140/141 range from $US 67 to 97 per carat and modeled revenue
figures range up to $US 14.65 per tonne depending on the phase (or type) of kimberlite.
Further work is ongoing to delineate all discrete kimberlite phases in this body and to model
estimated stone distributions and revenue per tonne.
o
Kimberlite body areas range from 2.7 to 250 hectares, typically based on a 30 metre
thickness cut-off.
o
The estimated mass of individual kimberlite bodies, based on geophysical modeling, ranges
from 3 million to 675 million tonnes. The integration of 140 and 141 indicates a combined
mass of 500+ million tonnes as derived from GEMCOM 3D digital modeling based on core drilling
in 2001 and 2002 with a minimum thickness threshold of 50 metres.
o
Age of emplacement of the various kimberlites occurred within the interval from
approximately 90-112 Ma, during Cretaceous time. The kimberlites range from simple
mono-eruptive bodies to multi-eruptive, multi-vent bodies characterized by complex stacking
and interlayering of multi-temporal kimberlite units. Ongoing studies of larger bodies
indicate discernible vertical and geographic (areal) zonation of kimberlite units and diamond
distribution.
o
Two of four high priority, potentially economic kimberlites (bodies 140/141, and 148,) are
located within a two mile radius in the central portion of the Fort à la Corne trend; the
total macro-diamondiferous kimberlite mass in this same radius (12 bodies), is some 3.6
billion tonnes. The other prioritized kimberlite, body 122, is located approximately five
kilometres to the west.
o
The Fort à la Corne Kimberlite Field has the largest concentration of diamondiferous
kimberlite in the world; the total modeled mass for the entire field is estimated at upwards
of 9 billion tonnes. Kimberlite 140/141, with an estimated mass of >500 million tonnes,
is the largest macrodiamond-bearing kimberlite in the world.
o
Fort à la Corne kimberlites are best categorized as very large tonnage, lower grade diamond
deposits overall, but with zones of higher grade potential.
o
Overall, the kimberlites remain insufficiently tested in consideration of their large size.
Only three bodies have minibulk testing for macrodiamonds to a level greater than 100
tonnes. Considerable effort was expended and significant costs were incurred simply to
reconnoiter the majority of kimberlite bodies in this field during the first 10 years of the
project. Since most of the minibulk sampling efforts in the past
14
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
were directed to testing to
some degree, each of the 69 targets, many of the larger bodies have very limited coverage in
an areal sense. Furthermore, vertical zonation has not been adequately tested in most of the
existing drillholes due to large sampling intervals. Due to the prevalence of the “nugget
effect” in kimberlites, average macrodiamond grades are expected to closely approach
forecasted grade levels as sample tonnage increases.
o
Evaluation work continues on Kimberlites 140/141, 122, and other high interest bodies in
order to better understand the location, extent and, continuity of high grade zones, to
determine an understanding of diamond distribution and diamond grade for mineable resources,
to upgrade confidence in determination of the average value of diamonds (in $/carat) and, to
determine the economic value of the body as represented by potential revenue calculations for
a diamond deposit given as an in-situ diamond value in $ per tonne (as per CIM
recommendations) compared to best initial estimates of capital and operating expenses.
o
The current components of drilling and sampling within the AE&E Plan involves core drilling
programs on the main part of the bodies to increase the understanding of the geology
(geometry and architecture) of the body and to identify higher potential zones. Higher grade
zones are then delineated in order to calculate a potentially mineable tonnage. This is then
followed by identifying a subset of coreholes that are suitable targets for minibulk sampling
in order to test diamond distribution and to provide a representative sample of kimberlites
from all prospective phases and across the vertical and areal extent of the kimberlite
bodies. A final inventory of some 100 to 300 carats will enable determination of a high
confidence grade forecast and a moderate level of confidence in the average value of
commercial sized stones. The bulk sample information coupled with the grid drilling and
sampling information should be adequate for at least a determination of inferred resource
over a significant part of the bodies. All lines of investigation from the AE&E will then be
integrated and evaluated in order to prioritize the potentially economic targets and to reach
a decision as to whether or not to proceed with a full pre-feasibility study as the next
phase of work.
o
Additional work is required to satisfy two main goals for each of the priority kimberlite
bodies. The AE&E encompasses a planned 43 months schedule of work to advance the project to a
major decision on pre-feasibility stage work. The plan is results driven and incorporates a
methodical, step-wise approach in the evaluation of 17 candidate kimberlite bodies for
higher-grade units that have potential to be economically mined. The overall goal of the
plan is to identify at least 70 million carats of commercial-sized stones in-ground in order
to reach a critical decision based on delineation of Inferred Resources on several kimberlite
bodies by 2008. The AE&E plan identified firm objectives and schedules to reach this goal.
o
The main objective for Kensington in this project is to delineate an economic diamond
resource at Fort à la Corne using a methodical stepwise approach.
On the basis of the information herein and the experience and expertise of the author, the
following recommendations for the Fort à la Corne Diamond Project are made to the owners and
management of Kensington Resources Ltd.:
o
The Fort à la Corne Diamond Field has shown strong, incontrovertible evidence supporting
the presence of kimberlite bodies hosting potentially economic diamond mineralization.
Furthermore, prospective kimberlites are characterized by high average diamond values, very
large tonnages, and the presence of coarse diamond populations. The information to date
definitely indicates the need for substantial exploration and evaluation work to delineate
the extent, magnitude of tonnage, grade, value, and mining potential of prospective
kimberlite bodies and zones in the south-central part of the main kimberlite trend.
15
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
o
The FalC Diamond Project should proceed according to the AE&E Plan as outlined in the FalC
Technical Report (and other more specific documents detailing the plan), but with the
following modifications:
o
The time line for the plan should be accelerated wherever possible, while
maintaining the integrity of the data and information collection, to define an
Inferred Resource on the property and to reach a decision point for pre-feasibility
stage activities. Acceleration of the program could come about by increasing the
magnitude of field operations and work force engaged in
core description, sampling, assay, and data management. Acceleration also could come
about by significantly overlapping the four components of field activities (core
drilling and mini-bulk sampling) and not relying on an inflexible step-wise approach
that relies on completion of each component before starting the next. The current
situation at FalC is amenable to this because several high-priority kimberlite bodies
are at more advanced stages of evaluation and that the plan is operated on a “best
bodies first” basis.
o
Bulk Sampling should be added to the AE&E Plan as part of the continuum
of evaluation required take prospective bodies or high grade zones to a
Feasibility-stage decision. Similarly to the point made above,
suitably prospective
bodies could be advanced to bulk sampling while core drilling and mini-bulk sampling
are underway on neighbouring bodies.
o
The postulated total FalC-JV budget of CND $91,347,436 for the AE&E program activities as
defined by De Beers, the project operator, for the time period from February 2005 through the
second quarter of 2008 should be accepted as a reasonable expenditure dedicated to defining a
NI 43-101 compliant Inferred Resource at Fort à la Corne. Kensington’s share of this
expenditure would be CND $46,792,758 (46.94% funding interest).
Reports and diamond results received from De Beers for the project are reviewed and utilized by
Shore Gold Inc. under the supervision of Brent C. Jellicoe, P.Geo., who is the recognized
Qualified Person for the Company in regard to this project.
16
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
1.0 Introduction and Terms of Reference
A technical report detailing exploration and evaluation of the Fort à la Corne Kimberlite
Field in east-central Saskatchewan was prepared for Kensington Resources Ltd. for various
informational uses, though primarily for an updated description of technical work carried out by
the Fort à la Corne Joint Venture (FalC-JV) and results reported by the operators of the FalC-JV.
In addition, some results are included from independent consultants working for the Company. This
report was prepared by Brent C. Jellicoe, P. Geo., an employee of Shore Gold Inc.. Mr. Jellicoe is
a professional geoscientist, registered in the Province of Saskatchewan, who also operates a sole
proprietorship consulting business, focused on project management, drilling, kimberlite exploration
and evaluation, and regional subsurface geology. Mr. Jellicoe is currently working with Kensington
Resources Ltd. and Shore Gold Inc. under the title of Project Manager, and periodically as the
onsite Drilling Manager for the FalC-JV partners during implementation of field programs. From
time to time, the consultant also conducts independent geological investigations and drilling
programs for other companies operating in the Fort à la Corne vicinity.
Sources of data for this report include:
—
public reports issued by Saskatchewan Industry and Resources (SIR), typically in the
form of Assessment Reports and Open File Reports,
—
non-proprietary descriptions and results released by the FalC-JV,
—
information derived from various journals and scientific papers, and
—
data and interpretations collected by, and formed by the author during an extended
period of time intimately associated with the project area (1992-2002).
The author has worked in and around the Fort à la Corne area since 1992 as a consultant and
employee, both in the office and in the field, for several different organizations including those
considered to be junior exploration companies and for senior mining companies. In addition, the
author has previous experience garnered from 5 years of research concerning geochemical and
stratigraphic concepts of the kimberlite host rocks within the Western Canada Sedimentary Basin,
and most particularly within Saskatchewan.
The purpose of the report is to summarize historical investigations into the geology, size, and
diamond content of the Fort à la Corne kimberlites and to document recent results, particularly
those relevant to the current focus of attention. This report is to be updated as required and
utilized as the technical basis for legal, financial, and securities related business of Kensington
Resources Ltd. It should be recognized that a few inconsistencies and variances are apparent
between subsequent reports of yearly exploration activities and results. This Technical Report is
updated on an annual basis to add new information and little effort is made to revise and update
older sections in order to preserve, to some extent, the essence and direction of those programs.
2.0 Disclaimer
Sources of information on prior exploration work in the Fort à la Corne area are available as
technical reports filed with Saskatchewan Industry and Resources in fulfillment of annual
assessment requirements that become non-confidential after 3 years. These reports, dating from
1989, do not necessarily provide a complete record of exploration work. Assessment reports have
not been filed for the last two years because sufficient assessment credits remain available to the
FalC–JV to retain claim to most of the land base for the maximum allowable time period. Other
sources are peer-reviewed papers which contain data deemed to be accurate, along with
interpretations which may be subject to change.
The Phanerozoic stratigraphy in the Fort à la Corne area and the processes of kimberlite
emplacement, erosion and preservation are topics of on-going research by the Geological Survey of
Canada (GSC), Saskatchewan Geological Survey, and the FalC-JV. Detailed stratigraphic correlations
have not been attempted within the
17
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
present report, and inferences drawn from previously reported
stratigraphy may be subject to revision, pending a compilation of available information.
Property descriptions and land status were provided for this report by Barbara Stehwien, a
consultant in Saskatoon, tasked with maintaining the land records of the project by De Beers Canada
Inc.
Results and interpretations for the 2001 diamond recovery program were summarized from a report
signed by Wynand Kleingeld (identified as the De Beers Qualified Person) and a team of
geoscientists working for De Beers Mineral Resource Services (MRS). This report comments on
statistical grade forecasts, modeled diamond valuations, and correlation of described lithology
with distribution of diamond size frequency models. These interpretive results are very important
for providing indicators of economic potential and for influencing exploration strategy. Results
from the MRS Report are considered contentious at this time and a third party opinion of the report
assertions was sought from an independent Qualified Person. Reports from the independent QP
indicated assertions concerning certain concepts and associations included in the interpretive
results were premature, or not well supported.
In November 2002, the FalC-JV partners initiated a Conceptual Modeling Study for the Fort à la
Corne diamond property through the operator, De Beers Canada Inc. The main objectives of the study
were to determine the ore values ($/t) that would be needed to reach minimum hurdle rates for a
number of diamond mining scenarios. Also tasked in the study was identification of critical
information that would be needed if the project proceeds to more detailed engineering studies and
to identify high-risk areas, which require planning of mitigation measures as the project evolves.
Most information comprising the bulk of the investigation was available through the operator,
derived from expertise gained in similar mining ventures elsewhere in the world, from local
sources, and from multi-disciplinary input from AMEC experts and the FalC-JV partners. No
engineering designs were produced and assumptions and estimates were made in many areas given the
generic sense of the report and that the project is still in the early phase of evaluation.
Consequently, grades and diamond values were not utilized in calculating revenue streams, nor was
any reference given to an inferred resource, which as yet, does not exist. The study was
facilitated by framing the mine modeling after the basic characteristics of some of the larger Fort
à la Corne kimberlite bodies, primarily the 140/141 kimberlite, which is the focus of current
exploration by the FalC-JV partners. The primary use of the financial models and results from the
study is to indicate resource and revenue criteria that would be required to meet the stated
FalC-JV pre-tax hurdle rate. Hence, the study is primarily an internal tool designed to provide
direction for further exploration and evaluation in the project area.
3.0 Property Description and Location
The Fort à la Corne Project is located in central Saskatchewan and is contained within NTS map
sheet 73H. A legally surveyed claim block covering much of the main trend of kimberlites lies
approximately 65 kilometres east of Prince Albert and extends northward from the Saskatchewan River
to a few kilometres north of Shipman. An additional smaller claim (also legally surveyed) covers
magnetic anomalies near Snowden, located some 120 kilometres northeast of Prince Albert.
Claims which fall within the surveyed (southern) portion of the province are defined in terms of
legal sections or subdivisions. Road allowances, typically 20 metres in width, fall between
sections and are separate legal entities. In November 2001, Saskatchewan Energy and Mines (now
Saskatchewan Industry and Resources or SIR) amended the description of mineral claims in the
surveyed portion of the province to allocate road allowances to adjacent claim holders so that
claim coverage can be seamless. The FalC-JV land holdings are spread across portions of township
blocks from T.49 to T.52 and R.18 to R.21. Approximately 70% of the claims are within the
boundaries of the Fort à la Corne Provincial Forest Reserve (Government of Saskatchewan crown
lands) and the remainder is under private landholder’s surface rights, but without freehold mineral
rights. Surface access to private land is by negotiation usually resulting in payment of an access
fee. A map indicating
18
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
kimberlite outlines and the FalC-JV’s land holdings is shown in Figure 1. A
total of 63 kimberlite bodies are held by the FalC-JV at this time.
After ten years, the annual expenditure requirement to maintain good standing for claims increases
from $12 to $25 per hectare. Grouping of contiguous claims is allowed to a maximum block size of
10,000 hectares. Reports submitted in support of assessment fillings are held confidential by
Saskatchewan Industry and Resources for a period of 3 years.
In agricultural areas, surface access must be negotiated with individual landholders, and with the
approval of the Rural Municipality (in this case, the RM of Torch River, with offices in White Fox,
Saskatchewan). The Rural Municipalities commonly impose heavy vehicle restrictions (road bans)
during spring thaw (2-3 weeks). Permits for all exploration field activities are administered by
Saskatchewan Environment and Resource Management (SERM), in this case from their Prince Albert
office. No part of the project lands are subject to specific environmental liabilities above or
beyond those responsibilities assumed under permitting of exploration programs.
As of September 1, 2005, land holdings held under the joint-venture agreement included 121 claims
totaling 22,544 hectares that are divided into four groups for assessment purposes. The property
status for the FalC-JV land holdings is shown in Table 1. All claims were acquired during the
period 1988-1990 and are subject to assessment rates proscribed for claims older than 10 years.
All disposition groups are protected until at least 2009, with the main claims of interest in group
FalC (E) protected until at least 2021. Assessment credits for Group 44961 (known as FalC East)
were not applied for in 2002 for the 2001 expenditures given consideration of the new Saskatchewan
Mining legislation that puts a maximum on the number of years to hold an exploration disposition
(21 years total, from 2002 onwards). Assessment reports were prepared for exploration work
conducted in 2002 and 2003 and credits were received and applied to the appropriate claim groups.
Suitability of application for assessment credits will be reviewed by the FalC-JV partners on a
yearly basis.
The Fort à la Corne Project is a Joint Venture among Kensington Resources Ltd., a wholly-owned
subsidiary of Shore Gold Inc. (42.245%), De Beers Canada Inc. (formerly Monopros Limited)
(42.245%), Cameco Corporation (5.51%) and UEM Inc. (10%). Cameco Corporation and Cogema Ltd hold
UEM’s North American interests. Neither UEM nor Cameco elected to fund exploration in 1999 or
2000, although Cameco did fund to their percentage interest in the FalC-JV during subsequent
programs. UEM retains a 10% free carried interest in the project. Monopros Limited replaced
Uranerz as operator of the FalC-JV in December 1998. At the end of November 2002, participating
interests (PI’s) in the FalC-JV were and remain as follows:
Kensington Resources Ltd.
42.245
%
De Beers Canada Inc. (operator)
42.245
%
Cameco Corporation
5.510
%
UEM Inc. (carried)
10.000
%
19
Technical
Report For the Fort à la Corne Diamond Project — November 09, 2005
All relevant permits required for surface exploration (drilling, geophysics, etc.) in this
area are obtained on a program basis from Saskatchewan Environment (SE) by the project operator,
De Beers Canada Inc. Saskatchewan Environment provides a “one stop shop” service facilitating the
acquisition of specific permits including those necessary for environmental approvals, water
consumption, and felling of timber. In addition, Saskatchewan Industry and Resources is alerted
to the type, size, and duration of exploration programs on a yearly basis.
At the project level, De Beers submits a detailed exploration/evaluation program plan to SE prior
to the field program which includes all anticipated impacts caused by the drilling activities in
the Fort à la Corne Forest (road construction, pad preparation, water sources and rehabilitation).
Approval for site access and drill pad construction for the drillholes is through a Timber Permit
issued separately by SE. Authority for the project to withdraw surface water for drilling is
covered by a Temporary Water Rights Licence issued by the Saskatchewan Watershed Authority. The
Department of Fisheries and Oceans (DFO) is advised by letter of the program and typically
responds with a list of guidelines.
Prior to mobilization, a field visit is conducted by a SE conservation officer to inspect each of
the proposed drill sites. Photographs are taken at each site so that rehabilitation can be checked
against original land surface features after drilling is completed.
In 2004 and 2005, Golder Associates Ltd. of Saskatoon, Saskatchewan was contracted to undertake a
flora and fauna survey of the focus areas as well a heritage resource review of proposed drillsite
areas in accordance with the provincial Heritage Property Act. Once reports of the findings of the
various surveys were submitted and reviewed by the Cultural and Heritage Branch (Heritage Resource
Review) and Saskatchewan Environment (Flora and Fauna Survey), approval or recommendations were
granted by the various regulatory bodies for drilling activity.
3.1 Historical Landmarks for the Fort à la Corne Diamond Project
o
In August of 1988, spurred by rumours of kimberlite discoveries near Prince Albert, the presence of kimberlite-type
intrusions in and around the Fort à la Corne Provincial Forest were interpreted by Uranerz Exploration and Mining Ltd.
using published aeromagnetic maps of the area compiled by the Geological Survey of Canada (GSC).
o
In June of 1989, the Fort à la Corne joint-venture project was created between Uranerz Exploration and Mining Ltd. and
Cameco Corporation; Uranerz remained as project operator until 1998. Kimberlite was successfully intersected in each
of 7 drillholes targeted on geophysical anomalies.
o
De Beers Canada Inc. joined the FalC-JV in 1992 under a three-year earning-in period, after which time, the three
partners each held a 331/3% equity in the project. De Beers Canada Inc. satisfied earn-in requirements by
the end of 1994.
o
Kensington Resources Ltd., a junior exploration company involved in the search for diamonds in Saskatchewan, was
invited to the FalC-JV in 1995 under a three-year earning-in period, after which time the four partners each held a
25% equity in the project. Kensington satisfied earn-in requirements by the end of 1997.
o
Cameco Corporation acquired Uranerz Exploration and Mining Ltd. during the third quarter of 1998. Cameco assumed the
10% carried participating interest held by Uranerz and became interim operator of the project.
20
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
o
De Beers Canada Inc. became operator of the project effective December 1998.
o
Review of available data in a desktop study during 1999-2000 delineated four most high-priority targets
(140/141,122,148,150);
o
Kensington and De Beers have actively funded exploration throughout their involvement in the project, while the
participating interests of Uranerz and Cameco have been reduced due to periods of non-funding from 1992 to 1999 (not
including periods of time when new Joint Venture partners were earning-in).
o
During 2001, the FalC-JV sold a block of 4 claims located near Weirdale (1024 ha in area) which contain 2 drilled
kimberlite bodies,
o
During 2002, the FalC-JV sold a block of 12 claims near Foxford (1088 ha), which contain 2 drilled kimberlite bodies,
and a block of 5 claims located northeast of Birchbark Lake (320 ha) which contains a single drilled kimberlite body
to Shore Gold Inc.
o
All FalC-JV partners funded exploration and evaluation programs during 2001 — 2005 except for UEM (carried interest).
o
In late 2004 strategic refocusing resulted in the development of an Advanced Exploration and Evaluation program (AE&E)
to advance the project to pre-feasibility within a three year timeframe based on identification and evaluation of 70
million carats from high-grade zones in the central cluster of kimberlites.
o
In October, 2005, Kensington Resources Ltd. and Shore Gold Inc. were approved to merge their businesses to create a
combined mineral resources company. This resulted in Kensington Resources Ltd. becoming a wholly-owned subsidiary of
Shore Gold Inc., while maintaining their 42.245% interest in the FalC-JV Diamond Project.
4.0 Accessibility, Climate, Local Resources, Infrastructure and Physiography
The property lies 65 kilometres northeast of the City of Prince Albert, population 42,000,
which is served by road, rail and scheduled air links. The closest settlements are a series of
villages located along Provincial Highway 55, which link Prince Albert and the town of Nipawin.
The highway roughly marks the northern margin of an agricultural belt which extends to the White
Fox River in the south. This region is close to the northern limit of arable agriculture in this
segment of the province. The nearest point of juncture for power and phone lines is 25 kilometres
towards the town of Smeaton.
A network of logging roads and 4-wheel drive trails provides access within the forested areas. The
best of these sand roads are open all year and are maintained by area logging companies and by the
FalC-JV during field operations. Provincial Highway 55 traverses the Snowden claims and also is a
main trunk road from which gravel grid roads surround the northern claims situated under cultivated
land.
The Fort à la Corne Forest and this portion of the Northern Provincial Forest fall within the
boreal transition eco-region which defines the gradation from the grasslands and aspen groves of
the south to the true boreal forest of the north. The Forests are mature, with a predominance of
jack pine. Aspen, alder, white and black spruce, poplar and tamarack are found in local stands.
The average elevation of the area is 450 metres above
sea level, with local relief of less than 50 metres in narrow creek valleys. The immediate area of
the main
21
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
exploration/evaluation focus around kimberlite 140/141 has local relief of less than 20
metres and is predominantly flat with subtle hills.
Climate data has recently been compiled by the University of Saskatchewan Geography Department as
part of the Atlas of Saskatchewan Project (1999). The climate of the Prince Albert region is
described as humid continental, cool summers (Köppen temperature and precipitation classification).
The annual mean temperature (100 year average) is 0.8°C. Monthly mean temperatures vary from
-19°C (January) to +17°C (July). The average annual number of hot days (30°C or higher) is 6. The
average annual number of very cold days (-30°C or lower) is 29. The annual mean precipitation is
406 millimetres, with precipitation (0.2 millimetres or greater) in 21 days per year, on average.
The operating season for exploration and evaluation programs in the field is year-round.
The uranium and gold mining operations of northern Saskatchewan are serviced in part by Prince
Albert area businesses, and draw skilled labour from this area. Electrical power is generated
nearby (the E.B. Campbell Hydro Generating Station on the Saskatchewan River east of Nipawin) and
telecommunications infrastructure is in place.
5.0 History
All dispositions currently held by the FalC JV were staked in 1988-89. Prior ownership of
lands is not relevant in this report as there are no disputes and there was no specific, previous
diamond exploration in this area.
The area has not been explored for the occurrence of kimberlites previously, although there are
reports of a prospector having found as many as five diamonds in the Melfort-Nipawin area sometime
prior to the Second World War. The story however, remains unsubstantiated as the diamonds were
reportedly lost in a fire. A prospector hoping to follow-up on this report requested a permit from
the provincial government in 1948 for exclusive diamond prospecting within Saskatchewan. The
venture was abandoned because the government was only willing to grant a permit area of 259
kilometres2.
The next report of diamond related activity was in 1961 when several stones were reportedly
discovered in gravels downstream from Sturgeon Lake (northwest of Prince Albert). However, nothing
of any substance developed as a result. At around the same time, a subsidiary of De Beers was
reportedly conducting a regional exploration program throughout southern Saskatchewan. A full
description of exploration activities leading up to the discovery of diamondiferous kimberlites in
the Fort à la Corne area is given in Lehnert-Thiel et al. (1992). To date, no formal mineral
resource or mineral reserve estimates for diamond have been made in the Fort à la Corne area.
Other than several aggregate deposits, no economic occurrences of minerals, oil or gas are known in
the project area. Zones of banded iron formation in the Precambrian basement near Choiceland were
investigated in 1955 by IREX and IPSCO. The IREX-Zone (155 Mt grading 28% Fe) and the IPSCO-Zone
(55 Mt grading 27% to 29% Fe) were found to be uneconomic. A third body, the Kelsey Lake Zone
investigated in 1975 (390 Mt at 34% Fe), was also found to be uneconomic. These deposits lie
approximately 600 metres below surface and were found to consist of interlayered bands of magnetite
and hematite dipping 65 to 70 degrees to the east.
22
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 1: Map showing Fort à la Corne Joint Venture Land Boundaries and Kimberlite Outlines
23
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Oil and gas exploration wells have been drilled throughout the area, but none currently produce
hydrocarbons. Groundwater exploration holes, water well, and oil and gas exploration holes are the
main sources of information on the sub-Quaternary geology within the project area. Notably, none
of these holes was ever reported to have encountered kimberlite.
The uranium and gold mining operations of northern Saskatchewan are serviced in part by Prince
Albert area businesses, and draw skilled labour from this area. Electrical power is generated
nearby (the E.B. Campbell Hydro Generating Station on the Saskatchewan River east of Nipawin) and
telecommunications infrastructure is in place.
5.0 History
All dispositions currently held by the FalC JV were staked in 1988-89. Prior ownership of
lands is not relevant in this report as there are no disputes and there was no specific, previous
diamond exploration in this area.
The area has not been explored for the occurrence of kimberlites previously, although there are
reports of a prospector having found as many as five diamonds in the Melfort-Nipawin area sometime
prior to the Second World War. The story however, remains unsubstantiated as the diamonds were
reportedly lost in a fire. A prospector hoping to follow-up on this report requested a permit from
the provincial government in 1948 for exclusive diamond prospecting within Saskatchewan. The
venture was abandoned because the government was only willing to grant a permit area of 259
kilometres2.
The next report of diamond related activity was in 1961 when several stones were reportedly
discovered in gravels downstream from Sturgeon Lake (northwest of Prince Albert). However, nothing
of any substance developed as a result. At around the same time, a subsidiary of De Beers was
reportedly conducting a regional exploration program throughout southern Saskatchewan. A full
description of exploration activities leading up to the discovery of diamondiferous kimberlites in
the Fort à la Corne area is given in Lehnert-Thiel et al. (1992). To date, no formal mineral
resource or mineral reserve estimates for diamond have been made in the Fort à la Corne area.
Other than several aggregate deposits, no economic occurrences of minerals, oil or gas are known in
the project area. Zones of banded iron formation in the Precambrian basement near Choiceland were
investigated in 1955 by IREX and IPSCO. The IREX-Zone (155 Mt grading 28% Fe) and the IPSCO-Zone
(55 Mt grading 27% to 29% Fe) were found to be uneconomic. A third body, the Kelsey Lake Zone
investigated in 1975 (390 Mt at 34% Fe), was also found to be uneconomic. These deposits lie
approximately 600 metres below surface and were found to consist of interlayered bands of magnetite
and hematite dipping 65 to 70 degrees to the east.
Oil and gas exploration wells have been drilled throughout the area, but none currently produce
hydrocarbons. Groundwater exploration holes, water well, and oil and gas exploration holes are the
main sources of information on the sub-Quaternary geology within the project area. Notably, none
of these holes was ever reported to have encountered kimberlite.
Geological information on the area is available from groundwater test holes and oil and gas
exploration wells. Geological maps of Quaternary deposits and other Phanerozoic units are
available at a scale of 1:250,000. Information on the Precambrian basement within the project area
is largely restricted to inferences gathered from airborne magnetic surveys. Data from a 1969 GSC
airborne magnetic survey is available on 1:253,440 scale map sheets.
24
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
5.1 Activities by Competitors in the Fort à la Corne Area
Spurred by the public interest generated both by the results obtained from the Fort à la Corne
Project and by the activities of the large number of companies actively exploring for diamonds
across much of Canada, an area in excess of 100 kilometres north-south x 80 kilometres east-west,
centered on the FalC-JV dispositions, is almost completely staked by in excess of 20 different
companies. (NTS map sheets 63L, 73G, H, I, and J).
Great Western Minerals Group (GWG) holds two claim blocks , termed the Candle Lake properties, at
the north end of the Fort à la Corne kimberlite field. The southern block of claims is adjacent to
the Rampton/Consolidated Pine Channel/United Carina Smeaton Property and contains the Candle Lake
#28 kimberlite body. In all, and including a block of claims registered to Northmin Development,
Great Western Minerals Group control 48 claims for a total of 22,882 ha. GWG conducted
delineation drilling on Kimberlites 28, 29, and 30 during the mid 1990’s and was joined by
Kennecott Canada in a joint venture to bulk sample Kimberlite 28. Kennecott collected a small
minibulk kimberlite sample from drilling, but experienced severe drilling difficulties due to poor
ground conditions. Kennecott eventually withdrew from the earn-in agreement for corporate reasons.
During 2003, a new core drilling program was implemented and results have not yet been released by
GWG.
United Carina Resources and Consolidated Pine Channel Gold were major participants in the
exploration boom of 1993-94, with programs of aeromagnetic and follow-up ground magnetic surveys
and drilling in the Montreal Lake – Wapawekka Lake area to the north, and the Torch River area east
of Fort à la Corne. These companies recently renewed their kimberlite exploration programs by
acquiring sizeable properties in the wider Fort à la Corne area and claims adjacent to the
Cameco/De Beers Canada Inc./Kensington kimberlite 122 on the west side of the main kimberlite
cluster, during 2000. United Carina and Consolidated Pine Channel currently hold 55,147 hectares
in 259 claims in the Fort à la Crone area.
A very large land position was acquired by Buckshot Holdings and Commando Holdings during 2001, and
was expanded upon during 2002. The 597 claims cover 237,388 ha and extend from the Paddockwood
area north of Prince Albert to Choiceland and Highway 6 in the east, surrounding the FalC-JV land
on all sides except south of the Saskatchewan River.
Two more large land positions were acquired in December 2001. Twin Oaks Management staked most of
3 townships near Foxford and northeast of Birchbark Lake. The 30 claims cover 24,736 ha. General
Resources Inc. acquired 46,694 ha in 100 claims, which incorporate most of 5 townships and parts of
2 more, extending north and northwest of the Rampton/Consolidated Pine Channel/United Carina
Smeaton Property towards Candle Lake and also in the Weirdale area. In addition, Geodex and Forest
Gate Resources each have claims located south and east of the FalC-JV lands, respectively.
Up to 2003, some limited drilling has been completed in the immediate vicinity of the FalC
Kimberlite Field as well as further to the north (Smeaton, Wapawekka, and Candle Lake), although
much of the work is of a speculative and promotional nature. These activities have indicated the
presence of three kimberlites north of the Fort à la Corne area and two kimberlites (anomalies 137
and 139) in the former Crown Reserve along the southeast margin of the joint-venture land holdings.
Shore Gold Inc. continues to maintain an interest in these southern-most bodies, and has
extensively drilled the Star Kimberlite Body (anomaly #139) including core drilling and one 24 inch
diameter, reverse circulation drillhole. On the basis of extensive work to produce a geological
model for the Star Kimberlite by the GSC, the Saskatchewan Geological Survey, Dr. John Bowles of
Mineral Science Ltd., and consultants with ACA Howe, Shore Gold planned and initiated a bulk sample
program to sample up to 30,000 tonnes of kimberlite for diamond recovery. A 4.5 metre diameter
shaft was excavated during 2003 and 2004, and work continues on sampling the vertical and
horizontal extent of kimberlite near the interpreted main vent of the Star Kimberlite. The shaft
extends to a depth of 250 metres and extensive horizontal drifting and limited underground
delineation drilling are ongoing. Kimberlite samples are
25
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
processed through a 10 tonne per hour
Dense Media Separation facility with final diamond recovery from DMS
concentrate in a procedure combining x-ray sorting, grease table technology, and hand-picking. An
additional 10,000 tonnes of kimberlite was excavated during 2005 to provide an additional 1,500
carats to the 4,000+ carats already recovered to date. An extensive drillhole program was
initiated during the summer of 2005 with two rigs drilling PQ (3-inch) coreholes in a 100 to 200
metre grid across the body. Large diameter drillholes targeted on a subset of the coreholes will
provide representative samples from the central part of the body. These samples will be run
through the processing plant onsite and diamond results will be integrated with subsurface
correlation in the geological model to develop a 43-101 and CIM compliant Indicated Resource for
the Star Kimberlite.
In addition to the Weirdale, Foxford, and Birchbark Lake claims recently purchased from the
FalC-JV, Shore Gold Inc. have progressively increased their land holdings at the southern margin of
the Fort à la Corne area since 1995. Their most recent staking acquisitions were 3 small claims
(60 ha) located at the junction of the North and South Saskatchewan Rivers. Shore Gold Inc.
currently holds 138 claims for a total of 23,952 ha. Under an earn-in agreement with Shore Gold,
Skeena Resources drilled two NQ coreholes into two different kimberlites within the Weirdale
cluster. Both holes intersected kimberlite and core samples were submitted for diamond recovery.
The evaluation program did not continue due to low diamond recoveries and Skeena withdrew from the
earn-in agreement.
IPSCO maintains a small, scattered land base within a few 10’s of kilometres of the FalC-JV land
holdings. A core-drilling program, reputed to include 3-4 drillholes, was conducted during the
third quarter of 1999 on claims located east of the FalC-JV land holdings and close to Highway #6,
which bisects the Fort à la Corne Forest Reserve from north to south. Results from these
drillholes have not been reported yet.
Shane Resources Ltd. and a small consortium of companies have several coreholes in the vicinity of
Smeaton, in the southern part of the Fort à la Corne Forest, and immediately west of the FalC-JV
holdings near the 122 kimberlite body. Drilling in the Smeaton area intersected thin kimberlite
stringers on the margin of a known kimberlite body and a few, thin kimberlitic horizons were
interpreted from the more recent drillholes (2001) located near the 122 kimberlite. The latter
claims are now being managed by Forest Gate Resources Inc.
Forest Gate Resources Inc. drilled a small geophysical anomaly east of the FalC-JV landholdings
approximately 2 kilometres from kimberlite body 119 during the 2nd quarter of 2003.
Their first NQ drillhole intersected kimberlite, but the hole was lost after intersecting some 26
metres of kimberlite. Subsequent attempts to intersect kimberlite by NQ and HQ coreholes were
defeated due to bad ground conditions in the glacial overburden causing the holes to be lost above
kimberlite. Forest Gate resumed investigation of the Dizzy Kimberlite during November 2003. Five
NQ holes were targeted on the central part of the magnetic anomaly, all within some 50 metres of
the discovery hole. Details and results of the drilling program have not yet been released by
Forest Gate. Core drilling continued on the property during 2004 and 2005 and a second kimberlite
(Duke) was discovered during June 2005 located on their south boundary with Shore Gold Inc..
Additional drilling during the summer of 2005 re-tested ground adjacent to the eastern boundary of
the FalC-JV property in the vicinity of Kimberlite 121 and 119. An unknown thickness of
resedimented kimberlite hosted within the Cretaceous mudstones was intersected.
In early 2004, Casavant Mining Kimberlite International (CMKX) drilled a known, small kimberlite
body (the “Smeaton Kimberlite”) located approximately 10 kilometres north of the northwestern end
of the main FalC kimberlite trend. Their drillhole encountered kimberlite, but the extent of
sampling currently is unknown. Historically, the Smeaton Kimberlite has been penetrated during at
least three other drilling programs by junior exploration companies including Shane Resources Ltd.
Meager recovery of microdiamonds has previously been reported, but no effort has been made to
substantially sample the kimberlite. In 2004, Casavant drilled coreholes located northeast of
kilometre 54 of the Division Road in the FalC Forest Reserve based on airborne geophysical
anomalies and did not intersect kimberlite.
26
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
During April of 2004, Garnet Point Resources Corp. and Global Prospecting Ventures Inc. created a
joint venture to evaluate potential for small-scale mining of the Sturgeon Lake glacially-rafted
kimberlite block located west of Prince Albert. The companies also mobilized a drill at their
Candle Lake Claims located east of the narrow Hills Provincial Park for a 5 hole NQ drilling
program. Geophysical anomalies identified in a ground geophysical program by contractor, Spectra
management Corp., were targeted by the holes, but no kimberlite was intersected. The target
anomalies occur in a broad tract of land that was thought to be in line with the northwest trend of
the main FalC Kimberlite Field.
6.0 Geological Setting
6.1 Basement Geology
The project area lies near the northeastern rim of the Interior Platform of North America.
The platform is covered by a series of sedimentary rocks over Precambrian basement in a 600 to
1,200 kilometres wide belt between the Rocky Mountains to the west, and the Canadian Shield, which
crops out towards the northeast. Little is known of the metamorphic basement underlying the
kimberlite area except from 1950’s- and 1960’s era exploration work at the nearby Choiceland banded
iron formation deposit. Aeromagnetic and gravity data suggest that crystalline basement in the
Fort à la Corne area is geologically similar to the Glennie Domain, which is exposed further to the
north in the vicinity of Lac La Ronge (Lewry, 1981; Green et al., 1985 Collerson et al., 1989;
Kjarsgaard, 1995; Leclair and Lucas, 1995). The Glennie Domain is part of the Reindeer Zone of the
1.8 Ga Trans-Hudson Orogen (Lewry et al., 1994) and is composed of Paleoproterozoic island arc
volcanogenic successions separated by reworked Archean granitoids and granitic gneisses (McNichol
et al., 1992). Recent integration of field mapping, radiometric dating and LITHOPROBE seismic
investigations, summarized by Chiarenzelli et al. (1996), indicates that the Glennie Domain
blankets the apex of a largely buried Archean microcontinent (see also, Ashton et al., 1997;
Ansdell et al., 1995), which has been named the Sask Craton (Chiarenzelli et al., 1996).
The shape and size of the Sask Craton is poorly understood; however it has been described as a
roughly 500 kilometres long by 200 kilometres wide westward convex bow bounded on the west by (and
dipping under) the La Ronge belt and on the east by the Flin Flon belt and Caisson Domain
(Chiarenzelli et al. 1996; Green et al., 1985). It is suggested that the Sask Craton provided a
thick lithospheric keel, which is a feature of diamondiferous kimberlite provinces elsewhere. A
recent teleseismic study of south-central Saskatchewan (Bank et al., 1997) supports this model.
6.2 Phanerozoic Geological Setting
Throughout much of Phanerozoic time, most of Saskatchewan was the site of episodic marine
deposition, with periodic intervals of erosion brought about both by craton uplift and by
regression of marginal and epeiric seas which extended over much of the North American continent
(Kauffman and Caldwell, 1993).
The central Saskatchewan region is underlain by over 700 metres of Phanerozoic sedimentary rocks.
The basal 440 metres consist of Cambro-Ordovician to Devonian sandstones and carbonates, followed
by 150-170 metres of Cretaceous shale and sandstone which are overlain by up to 130 metres of
unconsolidated Quaternary deposits. Paleozoic and Mesozoic strata dip gently toward the southwest.
In central Saskatchewan, this results in successively lower strata being exposed at the
sub-Quaternary interface towards the northeast. Within the project area, subcrops of Cretaceous
Colorado Group and Mannville Group strata underlie the topographically irregular basal
Tertiary/Quaternary unconformity.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Potential diamond-bearing strata in Saskatchewan are dominantly of Cretaceous age and were emplaced
along the northeastern margin of a broad sedimentary basin known as the “Western Canada Sedimentary
Basin” during a time of broadly oscillating sea level, affecting a variously embayed to confluent
seaway cutting north-
south through the Prairie region. This feature was bound to the east by the Precambrian Shield and
to the west by the Jura-Cretaceous Rocky Mountain geosyncline. In Saskatchewan, deposition of
generally fine-grained and laterally continuous Lower Cretaceous sedimentary strata occurred within
or proximal to the seaway during a series of cyclic transgressive-regressive sequences. Complete
stratigraphic sections of the Colorado Group lithostratigraphy, as determined in cored drillholes,
show this area to be closely comparable to the west-central Saskatchewan stratigraphic column.
The regional Quaternary geology consists of several till sheets of diverse origin and variable
areal continuity from several glacial episodes as well as interglacial fluvial and lacustrine
sediments. As a first approximation, the Quaternary section can be described as alternating layers
of predominantly shale-derived, impermeable till, and sandy to gravelly aquifers (Schreiner, 1990;
Christiansen and Sauer, 1993). In some areas, these aquifers are exploited for potable water.
6.3 Cretaceous Bedrock Stratigraphy
In a regional stratigraphic section, a sequence of Quaternary tills and outwash gravels
overlie light grey, non-calcareous mudstones of the Pierre Shale and a thin interval of Gammon
Member carbonaceous mudstone. Both bedrock units form the lower part of the Montana Group. Dark
grey, calcareous, shaley mudstones and shales of the Single White Speckled Shale are separated from
the overlying Pierre Shale by an unconformity of regional extent. The presence of only a single
white-speckled zone (dominantly the Upper White-Speckled Shale) corresponds to a regional
unconformity at the base of the unit and probably represents the exclusion of all or most of the
Lower White Speckled Shale and the intervening Morden Formation. Where both speckled shales are
present, the base of the Lower White-Speckled Shale overlies another major unconformity of regional
extent representing loss of the middle to uppermost portion of the Cenomanian Belle Fourche
Formation. Upper and Middle Cretaceous sedimentary units are preserved only sporadically in the
areas of kimberlite and are much more continuously preserved to the immediate northwest of the Fort
à la Corne area.
Partially preserved intervals of sandy and shaley mudstones of the Belle Fourche Formation are
chronologically equivalent in part to the Belle Fourche Shale Member of the Ashville Formation in
Manitoba (McNeil and Caldwell, 1981) and to the upper portion of the Big River Formation in central
Saskatchewan (Simpson, 1982). The base of this formation is delineated by the regionally extensive
Fish Scale Marker, a vaguely expressed lithologic zone of slightly higher organic carbon content,
silty interbeds, and comminuted fish debris including fish scales. The Fish Scale Marker separates
nearly identical mudstones of the Westgate Formation below from those of the Belle Fourche
formation above. Sandy and shaley mudstones of the Westgate Formation are equivalent to the
Westgate Member of the Ashville Formation (McNeil and Caldwell, 1981) and the lower portion of the
Big River Formation (Simpson, 1982). The Westgate Formation is interrupted by silty and sandy
units of the southward extending St. Walburg Sandstone and terminates above the Flotten Lake
Sandstone.
Siltstones, sandstones, and sandy mudstones of the Flotten Lake Sandstone in central Saskatchewan
are the stratigraphic equivalent to the Viking Formation found throughout the subsurface of
southern Saskatchewan and eastern Alberta (Simpson, 1982). Following the paleogeographic
propositions made by Koziol (1988), a shaley fine-grained equivalent of the westward attenuating
Newcastle Member may be present between the Flotten Lake Sandstone and St. Walburg Sandstone east
of Shipman.
Below the Flotten Lake Sandstone, laminated to thinly bedded shaley mudstones of the Joli Fou
Formation encase an interval of glauconitic sandstones and mudstones of the Spinney Hill Member.
Generally, the Spinney Hill is a westward attenuating wedge of coarser clastics marked by
emerald-green glauconite clusters in mudstone and carbonate-cemented lenses of pale green
glauconitic sandstone. The lower portion of the Joli
28
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Fou Formation (informally, the Lower Joli Fou
in this report) is characterized by glauconitic mudstones and often includes areally disjunct,
thin, bimodal, muddy sandstones related to the Basal Colorado Sandstone (informally, the Basal
Colorado in this report), a unit that is thicker and better developed basinward in Alberta
(Banerjee etal., 1994). Stratigraphic variability of these distinctive muddy
sandstones is related to episodic
shallowing and reworking of sandstones during the initial Colorado transgression. As such,
delineation of the muddy sandstones as a separate stratigraphic entity is not always practical and
the Lower Joli Fou and Basal Colorado sandstone are combined.
Approx.
Basal
Depth
Boundary
Period/Epoch/Stage
Group/Formation
(m)
Age (Ma)
QUATERNARY
Holocene
post-glacial sediments
0.011
Pleistocene
Saskatoon Group
Sutherland Group
Empress Group
100
1.6
CRETACEOUS
Late Cretaceous
Campanian
Montana Group
84.0
Santonian
Upper Colorado Subgroup
87.5
Coniacian
Upper Colorado Subgroup
88.5
Early Cretaceous
Turonian
Upper Colorado Subgroup
91
Cenomanian
Lower Colorado Subgroup
98.5
Albian
Lower Colorado Subgroup
102*
Mannville Group
200
112
Aptian
Mannville Group
119
DEVONIAN
Middle Devonian
Manitoba Group
300
Elk Point Group
400
387
SILURIAN
Early Silurian
Interlake Group
500
438
ORDOVICIAN
Late Ordovician
Big Horn Group
458
Middle Ordovician
Big Horn Group
600
478
Early Ordovician
Winnipeg Formation
505
CAMBRIAN
Late Cambrian
Deadwood Formation
700
523
PRECAMBRIAN
Palaeoproterozoic
Glennie Domain
720+
2100-1800
*Approximate age for the base of the Colorado group
Table 2: Generalized Stratigraphic Table for the Fort à la Corne Area
29
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Beneath a thin basal tongue of Joli Fou black shale, underlying the Spinney Hill, is the regional
unconformity separating the shale dominated Colorado Group from the Mannville Group characterized
by interbedded nearshore marine and terrestrial sands, silts, and mudstones. Dominantly marine
mudstones and sandstones of the Pense Formation form a variably thick veneer over a thick interval
of sandstone-shale bedding sequences comprising the six members of the Cantuar Formation including
the Waseca, Sparky, General Petroleums, Rex,
Lloydminster, Cummings, and Dina at the base of the formation (Christopher, 1983). The Pense
Formation is equivalent to the combined Colony and McLaren formations, both of which are prevalent
in west-central Saskatchewan. Some portion of the upper Cantuar Formation is correlatable to the
Swan River Formation, a distinctive northeastern-derived facies of quartzose-dominated, stacked
fluvial and fluviodeltaic sequences, which is present in the northeastern and north-central
Saskatchewan.
7.0 Deposit Types
The mineral deposit type under investigation is diamondiferous kimberlite. The main group of
kimberlites is located within the Fort à la Corne Provincial Forest and forms a north-northwest
elongated cluster approximately 32 kilometres in length, extending from the Saskatchewan River to
Highway 55 near Shipman. Smaller outlying kimberlite clusters occur near Weirdale in the west,
near Foxford in the north and near Snowden in the northeast. A main grouping of very large
kimberlite bodies occurs in the southern part of the trend. The basis of all exploration and
evaluation in this area is that large horizontally-oriented layers of potential diamondiferous
kimberlite are located between depths of 100 and 300 metres. The kimberlites must be tested
sufficiently to ascertain appropriate geological models, the extent and degree of mineralization,
as well as the average value of the diamonds so that revenue models can be determined. The scope
of work for the project at the present-time is to determine whether a NI 43-101 compliant Inferred
Resource of diamonds exists in the Fort à la Corne Diamond Field and to what extent it may be
economically viable utilizing economy of scale open pit mining methods.
The footprint sizes of 69 kimberlite bodies originally held by the FalC-JV were estimated from
geophysical models to fall in the 2.7 to 184 hectare range. The mass of kimberlite at each body
was also estimated, using a conservative density value of 2.5 gm/cc, and was reported to range from
3 to 675 million tonnes. From the same report, the cumulative surface area of the kimberlite
bodies contained within the FalC-JV was estimated to be 2,818 hectares, and the total mass of these
kimberlites was estimated at 9 billion tonnes. More recently, the 140 and 141 kimberlites were
shown to be part of a single large structure with estimated footprint of 250 hectares and >500
million tonnes, based on a density value of approximately 2.2 gm/cc.
Kimberlite Emplacement and Post-depositional Modification
During Cretaceous time, kimberlite volcanoes erupted into the sedimentary basin in the Weirdale,
Foxford, White Fox, Snowden, and Fort à la Corne areas. Stratigraphic constraints on kimberlite
emplacement and radiometric ages suggest that formation of the main bodies was likely in the range
of 112 to 98.5 Ma (Kjarsgaard et al., 1995). Rb/Sr age dates of 94-96 Ma were acquired from
phlogopite separates analyzed by the Anglo American Research Laboratory (1991 UEM Seasonal Report).
Significant precursor kimberlites were also deposited at the base, middle and top of the Mannville
Group beneath the base of the main kimberlite sequences. If the base of the Mannville Group is 119
Ma, and the youngest kimberlite was transgressed over during the waning stages of eruption at about
94 Ma during deposition of the St. Walburg Sandstone, then kimberlite activity in Fort à la Corne
area spanned some 25 Ma.
In general, most episodes or pulses of kimberlite volcanism occurred during intervals of
sedimentary deposition over a time span of about eight million years corresponding to middle to
late Albian time. At this time, central Saskatchewan was either proximal to-, or covered by
shallow Cretaceous epeiric seas during an extended period of oscillatory transgressive-regressive
conditions that helped to preserve the volcanic and sedimentary facies. Since the exact time of
each kimberlite eruption is loosely constrained, only broad interpretations of the prevalent
depositional environments can be made. Older precursor kimberlites encased within brownish-grey
30
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
sands and mudstones of the Mannville Group were deposited in dominantly regressive/
fluvial/deltaic/terrigenous-dominated, terrestrial to nearshore shallow marine sedimentary regimes.
Kimberlite is also found as thinly bedded ashfalls throughout much of the Mannville Group section.
Younger kimberlites which are thought to have erupted during deposition of the Lower Colorado Group
are interpreted to have formed in dominantly subaerial conditions; however, some evidence indicates
deposition of
water-lain and resedimented kimberlite. Cretaceous sediments preserved above the main kimberlites
are often sand- and silt-dominated facies, which are associated with one of the regressive seaway
episodes that deposited the St. Walburg, Newcastle, or Viking/Flotten Lake coarser terrigenous
units. However, some kimberlite bodies have a preserved upper transitional sequence of interbedded
kimberlitic siltstones, marine mudstones, and ashfall tuffs. Furthermore, interbedded marine
mudstones and kimberlitic mudstones are common towards the margins of some kimberlite bodies.
These younger kimberlites are thought to have erupted into shallow seaway conditions subject to
periodic strandline migration.
Geologically, the Fort à la Corne kimberlites are somewhat unique in that they apparently consist
only of crater volcaniclastic material (Scott-Smith, 1996). Texturally, these rocks are classified
as pyroclastic kimberlites, which may have accumulated within shallow blast-excavated craters that
built upwards into low-relief tuff-cones. Many of the kimberlites appear to have formed in a two
stage process including initial excavation of a relatively shallow and wide crater followed by
infilling by both primary pyroclastic kimberlite and slumping of kimberlitic material from the
margins of the crater. In general, the kimberlites have geometries ranging from narrow steep-sided
pseudo-pipes to moderately steeply dipping funnel shapes to large irregular “champagne-glass” to
disc-shaped forms, typically described as thicker in the middle and attenuating towards the
margins. The architecture of the kimberlite bodies ranges from simple to complex in terms of
number of discrete units or layers and occurrence and coalescence of proximal eruptive centres.
The overall horizontal to sub-horizontal attitude of the kimberlite units changes with proximity to
eruptive centres where more vertical kimberlite phase relationships and vent margins are
anticipated. Feeders for the kimberlite bodies are probably small in area and steep. Some drill
holes penetrate what are thought to be feeder zones filled with crater and pipe volcaniclastic
material. Diatreme volcaniclastic kimberlite has only tentatively been identified from the deepest
of these intersections.
Pyroclastic airfall kimberlites composed of variable proportions of olivine and juvenile lapilli
formed subtly graded beds resulting from physical separation of grain components within high energy
eruptive columns. These columns were the product of rapid degassing of volatile-rich magma at the
vent and may be considered to be the extrusive equivalent of diatremes in other kimberlites
(Scott-Smith et al., 1994). The fine ash component of these eruptive columns may have reached up
to 15 kilometres high and been effectively removed by wind action, allowing concentration of
distinct grain size and density populations dependent on local weather conditions and proximity to
the vent (Scott Smith et al., 1994). Olivine-dominated crystal tuffs with absent to rare lapilli
are thought to have formed through extreme examples of this process or possibly by the
disintegration of lapilli followed by winnowing of fines in a sedimentary environment. Juvenile
lapilli form as the result of fragmentation of fluidal magmas in explosive to relatively passive
eruptive conditions, and may be most concentrated in areas proximal to eruptive vents. Some
lapilli are vesicular, but scoriaceous clasts are extremely rare. Up to four distinct generations
of lapilli have been observed to coexist in the same rock type in some Fort à la Corne kimberlites,
indicating that material from old eruptions is recycled to a limited extent during later eruptions
in some bodies (Scott Smith et al., 1994).
The internal geology of each kimberlite body varies considerably. Pyroclastic airfall and
lava-spattering are interpreted as the principle modes of kimberlite accumulation and are likely
the result of several styles of eruption due to variations in volatile content and degree of
interaction with groundwater. Reworked kimberlite and intervening fine-grained sediments occur
occasionally and provide time markers within the pyroclastic piles. These markers are thought to
record times of erosion, transgression, and/or shallow marine deposition. Changes in eruptive
style, both within and between discrete pulses of kimberlite volcanism ultimately resulted
31
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
in complex layering of stratigraphically distinct kimberlite lithotypes during late Mannville time and
throughout much of early Colorado time. The specific physical setting of each of the bodies would
impact the formation and character of graded and massive bedded lapilli tuffs and olivine-dominated
crystal tuffs. Some factors to consider include the location of eruptive centres, depositional
environment, original magma composition, and morphology of the crater-cone development. Within a
single pulse, progressive loss of abundant, primal volatile content (CO2 and
H2O) and an increase in magma viscosity would have dampened the escape of pyroclastic
material from the vent, allowing the formation of thicker mega-graded beds and lapilli-rich
lithotypes characteristic of lava-spattering. Collectively, these deposits may have overfilled the
shallow crater allowing a period of cone development dependent on the volume of material extruded
and the size of the crater. Cone-margin deposits formed and were composed of coarse-grained
xenolith-rich base surge and airfall deposits overlain by distal, finer-grained, xenolith-poor,
airfall facies (Leckie et al., 1997). Different eruptive styles ranging from explosive
Strombolian-type ash columns to more passive Hawaiian-style lava fountaining which are thought to
be appropriate for the Fort à la Corne eruptions based on petrographic examination of kimberlite
core and chips (Scott-Smith et al., 1994; Leckie et al., 1997). The close stratigraphic and
spatial association of kimberlites produced from different eruptive styles indicates some
alternation of styles or perhaps the presence of a composite eruptive mode.
The morphologies and resulting pyroclastic assemblages of the Fort à la Corne kimberlites are the
product of the local geology. In contrast to kimberlites elsewhere in the world, the broad,
initially shallow craters and low-relief cones are the result of having been emplaced within
several hundred metres of poorly consolidated sediments, which could not effectively cap or contain
the volatile-rich magmas. The bodies began as craters, which were explosively excavated into the
Mannville Group and Lower Colorado Group sediments. The base of the kimberlite bodies appear to
flare upwards at either the Mannville/Paleozoic carbonate contact or within the uppermost portion
of the Mannville Group, just below the contact with the Colorado Group. Synthesis of petrographic
information, interpretations of body geometry, and internal correlation of kimberlite and marker
strata indicate kimberlite body architectures that range from simple, mono-eruptive, essentially
stratiform bodies to stratigraphically complex, temporally diverse, multi-centered, multi-eruptive
edifices marked by stacking of lensoidal to pancake shaped eruptive deposits. Correlation of
internal marker beds and erosive horizons indicate the very common occurrence of stacked severely
beveled kimberlite masses at several stratigraphic levels. In larger bodies, coalescence of
kimberlite lenses sourced from proximal eruptive centres produced clusters of intercalated
kimberlites.
Subsequent to each eruption, terrestrial or marine depositional and erosional processes may have
affected the exposed portions of the body causing truncation of beds and accumulation of reworked
kimberlites. Furthermore, continued eruption from the current vent or proximal new vents may have
locally truncated existing beds. The bulk of petrographic evidence suggests that most of the
kimberlites accumulated in dominantly subaerial conditions as crater-fill pyroclastic deposits
(Scott-Smith et al., 1994), however, it is not known to what extent positive-relief cone building
occurred above the plane of the surrounding surface. Some vent-distal deposits indicate deposition
of water-lain kimberlite, but drillhole control is typically poor away from the centres of the
kimberlite bodies. Lower Colorado Group sediments preserved above the top of the main kimberlites
are often sand- and silt-dominated facies which were associated with one of several regressive
seaway episodes coeval with deposition of the St. Walburg, Newcastle, or Viking/Flotten Lake
coarser terrigenous units. However, some kimberlite bodies have a preserved upper transitional
sequence of interbedded kimberlitic siltstones, marine mudstones, and ashfall tuffs. Furthermore,
interbedded marine mudstones and kimberlitic mudstones are common towards the margins of some
kimberlite bodies. These particular kimberlites are thought to have erupted into nearshore
terrestrial to shallow marine seaway conditions subject to periodic strandline migration and
erosion.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
8.0 Mineralization
Diamond recovery from kimberlite samples from the tested bodies indicate approximately 70% of
the kimberlites are diamond-bearing (diamondiferous) , and 50% are macrodiamond-bearing (based on
recovery of stones >0.85 millimetres in one dimension). These figures indicate Fort à la Corne
to be the largest macrodiamond-bearing kimberlite field in the world. Many of the kimberlites have
been tested by few drill holes and, given the number of very large and heterogeneous kimberlites in
this field, coupled with the chaotic occurrence of diamonds, only small, poorly representative
samples have been acquired from most of the bodies. Regardless, best efforts were made to
categorize the kimberlites based on size, petrography, and diamond content. Typically resolution
of discrete mineralized zones within the kimberlite bodies has not been attempted except for those
bodies prioritized by the FalC-JV in 2000, due to time and cost restraints. The estimated size of
the three prioritized prospective diamondiferous kimberlites range from 126 to 250 hectares, and
discrete high grade zones have estimated tonnages of 29 to 156 million tonnes (see Table 29). The
depth of the top of these zones ranges from 90 to 120 metres depth and can extend vertically to a
depths between 150 to 275 metres. For prioritized bodies such as 140/141, grid drilling is now
providing information for detailed geological modeling and evidence of patterns in areal and
vertical diamond distribution patterns. De Beers Canada Inc. provided all information on the size
of the mineralized kimberlites and this information is readily available in historic Assessment
Reports (1996-1999) for the project submitted to Saskatchewan Industry and Resources (SIR). These
reports are available to the public, although more recent Assessment Reports will become available
to the public in 2007.
8.1 Petrographic Characteristics of Fort à la Corne Kimberlite
The Fort à la Corne bodies are classified as Group 1 kimberlites based upon a composition
including two generations of olivine (phenocrysts and macrocrysts) and a groundmass of
monticellite, spinel, perovskite, mica, primary serpentine and carbonate (Scott Smith et al.,
1994). Most bodies also contain rare amounts of mantle-derived, xenocrystic/xenolithic
constituents including garnet, ilmenite, and olivine macro- and megacrysts, as well as eclogites
and coarse grained, garnet-bearing peridotites. Basement rocks, Paleozoic carbonates and
Cretaceous terrigenous and marine lithologies may also be found as fine to very coarse xenolithic
fragments within the kimberlites. The Fort à la Corne kimberlites are dominated by olivine/lapilli
pyroclastics of variable composition with rare to common country rock and mantle xenoliths, minor
very fine-grained inter-clast matrix, and rare garnet, ilmenite, and chromite.
Texturally, these rocks are classified as pyroclastic kimberlites, however, reworked kimberlite
sediments occur occasionally throughout the sequence, but are usually found in the upper few tens
of metres of the body.
The main rock type end-members are juvenile lapilli-dominated kimberlites and olivine-dominated
crystal tuffs. While pure end-member rock types do occur, they are rare with olivine/lapilli
kimberlite of variable composition being most common. Clast sizes range from <1 millimetres to
10 centimetres, although most rocks are dominated by fine to medium-grained textures ranging from
0.5 to 5 millimetres with a notable paucity of fines or material less than 0.2 millimetres in size.
The pyroclastic components are dominated by varying sizes and proportions of juvenile lapilli and
single crystals of olivine. Lapilli vary in shape from spherical to ovoid, to more commonly
fluidal, irregular amoeboid forms and are composed of olivine grains and rare garnet and black
macrocrysts set within very fine-grained matrix. Lapilli generally show definable edges and subtle
to striking differences in colour compared to the inter-clast matrix or cement.
Olivine occurs in two significantly different populations, which often coexist in varying
proportions (and seemingly were both present in the postulated precursor magma and in hypabyssal
equivalents) that were controlled by physical separation processes either prior to, or during
eruption. A finer grained population is composed of euhedral to subhedral olivine phenocrysts
generally <2 millimetres in size and most probably crystallized from the precursor kimberlitic
magma. A second, coarser-grained population consists of subhedral
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
to anhedral olivine macrocrysts
usually >2 millimetres in size and is xenolithic in nature, having been derived
from either the kimberlite magma source or from mantle wallrocks during ascent. Olivine-dominated
crystal tuffs with absent to rare lapilli are thought to have formed through the physical
separation of discrete crystals from fine and coarse ash during violently explosive eruptions, or
possibly by the disintegration of lapilli followed by winnowing of fines in a sedimentary
environment.
The inter-clast matrix of the rock and intra-lapilli matrix are composed of dense, often massive
serpentine, carbonate, magnetite and a highly variable assortment of very fine grains including
spinel, apatite, monticellite, perovskite, mica, primary carbonate and coarse ash-sized olivine
microphenocrysts (Scott Smith et al., 1994). Inter-clast matrix or cement may form through the
crystallization of minerals from kimberlitic fluids derived from subsequent eruptions, or may be
the alteration product of fine ash deposited coevally with the coarser grains. Scott-Smith noted
the common absence of matrix fines in many of the kimberlites. As these fines may be
representative of the pre-eruptive kimberlite “magma”, their absence indicates syn-eruptive sorting
and removal. Multiple and sequential phases of identifiable cementation show that lithification
occurred early on, but with modification of the cementing components during subsequent eruptive
pulses, subsidence and compaction (Scott Smith et al., 1994). Hence, the matrix of the kimberlite
is highly variable in appearance and composition. In comparison, the presence of very fine,
microphenocrysts of olivine, and what is thought to be spinel, perovskite, mica, and monticellite
often characterize intra-lapilli matrix and may represent preserved fines and ash derived from
explosive eruption of the original, highly-fragmented “magma”.
8.2 Indicator Mineral Geochemistry
Major and trace element geochemistry of garnets can be used in conjunction with garnet
Ni-thermometry to synthesize an interpretation of the mantle source rocks for kimberlite (Gurney et
al., 1993; Griffin and Ryan, 1995). Garnet geochemical data from Fort à la Corne kimberlites
indicate a predominantly lherzolitic population with lesser harzburgitic, websteritic, megacrystic
and eclogitic components. Ni-thermometry data are trimodal, which is a strong indication that
mantle material at three separate depths was sampled by the ascending kimberlitic magma.
Geochemical analyses of ilmenite and chromite also have provided clues to the potential for
diamonds and the magmatic history of the kimberlites.
The main mantle sampling interval or depth straddles the lower threshold of the diamond window
based on application of a cratonic geotherm of 40 mWm-2. Most of the kimberlites are
dominated by G9 lherzolitic garnets, but also include other peridotitic, eclogitic and macrocrystic
garnets. Garnet Ni-thermometry data indicates a common triple sampling pattern or entrainment of
lithospheric mantle material variably split between the 700-800°C, 950°C, and 1150-1200°C
temperature regimes. The middle sampling interval (950°C) is the dominant peak in the temperature
distributions and it lies just within the lower threshold of the diamond stability field. The
abundance of high-TiO2 lherzolitic garnets close to 1200°C suggests that this
temperature marks the base of the lithosphere and the lower depth of diamond entrainment.
Prospective harzburgitic G10 garnets are present in most of the kimberlites, but generally in low
abundance (<7 percent of total garnet, averaging 3.4 percent) and are usually associated with
sampling in the 950°C range. Sampling of the mantle was dominantly at or near 950°C, however, the
source rocks seem to have been fertile lherzolites (i.e. not melt-fractionated), thus diamond
grades could be low. Where material was entrained over the lower temperature interval (700-800°C),
the mantle also was fertile and consequently of low diamond potential. Mantle material from the
upper temperature interval (1200-1400°C) was enriched by melt-metasomatic processes and is
considered to have low diamond preservation potential.
Chrome spinel is common in most of the kimberlites tested. On a plot of weight percent MgO vs
Cr2O3, chrome spinels often plot in an inverted U pattern or portion thereof,
representing entrainment of material from a number of different mantle sources. High interest
spinels have very high Cr2O3 contents (>61 percent), which may place them
within the diamond inclusion field at appropriate MgO contents (11.5-16.5 wt. percent).
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Generally,
Fort à la Corne kimberlites may contain only a few percent chrome spinel grains that plot in the
diamond inclusion window, but a few bodies range up to 8 percent. Picroilmenite is also common in
most of
the kimberlite bodies. Most of the ilmenites have major chemistry signatures indicative of the
megacryst suit, although distinct populations are seen in some Cr2O3 vs. MgO
plots that probably reflect sampling from several different sources in the lithosphere. Some
kimberlite bodies have ilmenite subpopulations characterized by low MgO contents (<7 wt.
percent). In general, Gurney et al. (1993) consider the presence of picroilmenites with low MgO
compositions to be indicative of exposure to conditions promoting low diamond preservation
potential. In the past, De Beers considered these low MgO and low Cr2O3
ilmenites simply to be non-kimberlitic.Recently, Schulze et al. (in press) found no
evidence to support the hypothesis that oxidized ilmenite populations were indicative of increased
potential for diamond resorption in kimberlites.
Although many Fort à la Corne kimberlites incorporated mantle material from within the diamond
stability field, the contribution of diamonds from depleted, harzburgitic mantle and eclogitic
mantle appears to have been diluted by potentially diamond-poor, fertile and enriched lherzolites.
An understanding of the relative contribution of xenocrysts (including picroilmenite, chrome
spinel, and diamonds) to the kimberlite magma from distinct mantle lithosphere sources including
harzburgite, lherzolite, websterite, and eclogite from within distinct temperature ranges,
contributes to the explanation of why the diamond contents of the Fort à la Corne kimberlites are
highly variable. However, for many of the Fort à la Corne kimberlites, major and minor element
chemistry have identified abundant peridotitic garnets potentially from diamondiferous mantle
source rocks (G1, G9, G10, and G11), which justifies continued exploration interest.
9.0 Exploration
Exploration activities in the field were conducted every year since 1989, except 1998, and
included local and regional geophysical surveys, drilling, and sampling for the recovery of
macrodiamonds, microdiamonds, and indicator minerals.
9.1 Geophysical Exploration
A total of 88 magnetic targets were obtained from 15,500 line-kilometres of airborne magnetic
survey. Seventy-one anomalies were interpreted as kimberlite-type signatures. Extensive ground
magnetic surveys were utilized to refine the area and estimated thickness of each of the anomalies
and in many cases further work was done subsequent to discovery drilling of the kimberlite bodies.
While the geophysical emphasis has been on magnetics and gravity, several other methods including
CSAMT, seismic, and GEOTEM have been tested. Information and results of geophysical surveys are
briefly described in this section, but more detail is provided in the year by year summaries
described in section 9.2.
9.2.1 Magnetic Survey Coverage
The Fort à la Corne kimberlite bodies lie beneath 75 to 150 metres of overburden and have no
surface expression. During the 1988 staking rush, Uranerz Exploration and Mining Limited acquired
a large land position in the Fort à la Corne area, some 60 kilometres east of Prince Albert. The
ground was chosen on the basis of aeromagnetic anomalies which were thought to resemble
kimberlite-type targets in the available GSC regional aeromagnetic coverage. Twenty-eight isolated
contour highs were identified and staked. Since the known kimberlite bodies were discovered from
aeromagnetics, all are magnetic to some degree. Apparent magnetite contents for the kimberlites
range from 0.1% to 4%, in contrast to the non-magnetic Phanerozoic sediments, which host the
kimberlites. Magnetic responses from crystalline basement, which is greater than 600 metres below
the ground surface, are sufficiently longer in wavelength to be clearly differentiated from the
sharper signatures of the kimberlite bodies. The cost effectiveness of magnetic surveys in
delineating the kimberlites was recognized at an early stage, although some refinements in
interpretation and modeling have been necessary to comply with the unusual geometry of these bodies
as subsequently revealed by drilling.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Additional geophysical coverage of the 140/141 kimberlite was completed during the Fall of 2002,
including new ground magnetic survey, ground gravity survey, and magneto-telluric methods. Results
will be submitted as they are finalized by the operator of the FalC-JV.
In 2003, work commenced with a fixed-wing airborne tri-sensor magnetic gradiometer survey over the
entire FalC-JV project claim area that was run by Goldak Airborne Surveys. The survey had some
over-run beyond the claim boundaries. Two blocks were flown for a total of 3,090 line kilometres
at 150 metre line spacing. The airborne survey provides a much improved magnetic dataset compared
to previous airborne data acquired in 1989 and 1990. The survey results were evaluated for new
potential kimberlite targets, and where necessary, higher-priority kimberlites will be re-modeled
to update body outlines based on a 30 metre thickness cut-off.
9.1.2 3D Models from Magnetic Survey Coverage
A working model for the Fort à la Corne kimberlite bodies, up until late 1990, consisted of a
vertical, near-circular pipe based on the published and widely accepted diatreme-type occurrences
of Southern Africa (Gerryts, 1970, Macnae, 1979), although quite significantly under 100 metres of
overburden in this case. Magnetic signatures, particularly over some smaller bodies, were found to
be reasonably consistent with this model. The larger magnetic features were assumed to be
aggregates of coalesced pipes. Drilling in 1989 had sampled only the top few tens of metres of
seven kimberlite bodies. More intensive drilling, beginning in 1990, soon revealed that many of
the kimberlite bodies were limited to +/- 100 metres in thickness. Revised geophysical modelling
confirmed that the typical pipe-like magnetic signatures could also be caused by lensoidal magnetic
bodies, which would be somewhat larger in footprint area than the prior pipe-type models.
Grid-style ground magnetic coverage over most kimberlite bodies in the central Fort à la Corne
Forest area also revealed irregular shaped outlines, implying that a considerable amount of
detailed ground magnetic survey work would be necessary to fully define the outlines of the seventy
or so suspected kimberlite bodies.
A further refinement to modelling was in recognizing that many bodies appear to have a weakly
magnetic halo, which commonly seems to be developed more extensively towards the south or southwest
of the main magnetic feature. This could represent a reworked peripheral apron of kimberlite, or
perhaps distally deposited material, which might be down-current or down-wind from a volcanic
centre. The working geophysical model at this point could be described in terms of a central thick
kimberlite block, 100 metres to 200 metres in thickness, with an irregular, peripheral apron
perhaps 30 metres to 50 metres in thickness. The apron areas of many of the kimberlite bodies can
be quite large and contributes significantly to overall footprint areas, requiring more extensive
ground magnetic coverage to assess. Ultimately, in support of mapping these bodies in detail,
almost 1000 kilometres of ground magnetic profiles were completed over the 71 kimberlite targets,
much of it with 100 metres line spacing and 25 metres stations.
The sizes of the kimberlite bodies, estimated according to current geophysical models for each
body, fall in the range 2.7 to 184 hectares. The mass of kimberlite at each body has also been
estimated, using a conservative density value of 2.5 gm/cc, and ranges from 3 to 675 million
tonnes. The total kimberlite footprint area for the 71 bodies is estimated to be 2818 ha. The
total mass of kimberlite is estimated at close to 9 billion tonnes.
The “puck and apron” model is recognized to be inadequate for many of the larger kimberlite bodies,
where kimberlite thicknesses are difficult to predict from magnetics due to uneven distribution of
magnetite. Many bodies contain multiple magnetic peaks, which do not correspond to thick
kimberlite segments but which are more likely caused by zones of strongly magnetic kimberlite near
the top of the kimberlite section. A more complex but probably more realistic working model is to
simulate each kimberlite body by a stack of horizontal disks of varying dimensions, corresponding
to stratigraphically discrete kimberlite layers. This is supported by geological evidence of
sub-horizontal stratification, which is thought to be caused by sequences of kimberlite
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
deposition separated by erosional intervals. Models of this complexity need control from drilling
and detailed stratigraphic input. However, several of the Fort à la Corne kimberlites are already
at this stage of exploration.
9.1.3 Magnetic Susceptibility Logging
Magnetic susceptibility measurements were completed on core from 16 drillholes obtained from
11 different kimberlites. In all, over 7,500 magnetic susceptibility measurements were acquired.
The data were used to establish reasonable average magnetic susceptibility values for the
kimberlites for comparison with model-derived values from ground magnetic data and to assess the
variability of magnetic properties within each body. Magnetic susceptibility logging indicates
that some segments of some kimberlites are essentially non-magnetic. Whether wholly non-magnetic
kimberlites might exist is conjectural, and none have been detected, thus far. However, gravity,
resistivity (airborne and ground surveys) and seismic might be employed if such targets were
suspected. Recent gravity surveys conducted in 2002 and 2003 indicate the presence of potential
kimberlite anomalies that have subtle or no significant associated magnetic signature. Follow-up
interpretation of these data is on-going by the operator. Magnetic susceptibility measurements
were routinely taken on all kimberlite and host rock core acquired during the 2001, 2002, and 2003
field programs. This information is utilized in interpretation of recent ground magnetic surveys
conducted on the 140/141 kimberlite and other high priority bodies in 2002 and 2003.
9.1.4 Gravity Coverage
Since kimberlite can have significantly higher density than the Phanerozoic sediments (i.e.
perhaps 2.6 gm/cc versus 2.4 gm/cc), gravity surveys have proved to be effective. Gravity surveys
were completed in 1989, ’90, ’91 and ’93 with a total of 219 kilometres of profiles. The surveys
provide gravity signatures from 29 of the kimberlite targets, which are all positive peak anomalies
ranging from 0.1 to over 1.0 milliGals in amplitude. The gravity data provides assistance in
modelling some of the larger kimberlite bodies, where kimberlite thicknesses are difficult to
predict from magnetics. Also, some weak magnetic anomalies have been screened by gravity coverage
to ascertain their cause, since magnetite concentrations in till or within the Phanerozoic
sediments are possible sources of false anomalies. Three large bodies in the central Fort à la
Corne Forest area provided the highest amplitude gravity signatures (1.0 milliGal), and drilling
has confirmed that thick (>200 metres) kimberlite segments are present.
A more detailed and extensive gravity survey of Kimberlite 140/141 was completed in October 2002.
In addition to expanding the footprint of the kimberlite body, two new anomalies were discovered
close to the 140/141 body, but lacking any substantial anomalous magnetic signature (compared to
background).
Gravity coverage was acquired in 2003 for the 148, 150, and 122 kimberlite bodies. The individual
surveys around 150, 148, and 140/141 were extended to provide unbroken coverage in the central part
of the main kimberlite trend.
9.1.5 Galvanic Resistivity Surveys
In comparison to the enclosing Phanerozoic sediments, which are largely mudstones and shales,
the kimberlite bodies should tend to be more resistive, although contrast between the two rock
types is minimal. This tends to reduce the utility of electro-magnetic data in highlighting
kimberlite based anomalies, and more specifically, in delineating geometry of the kimberlite
bodies. The 100 metres-thick overburden comprises various interbedded sands and sandy tills
grading to clayey tills that average 10 to 20 ohm-metres in resistivity. Bedrock is composed of
the Phanerozoic Colorado Group shales with resistivity of perhaps 5 ohm-metres, overlying Mannville
Group sandstone units, which might have resistivities in the 100 ohm-metre range. Kimberlite
resistivities can be highly variable, depending on the degree of alteration and porosity. From
test survey data over a low number of bodies it seems that these kimberlites fall in the range 20
to 100 ohm-metres.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Ground resistivity surveys were conducted at 4 sites in 1990. Dipole-dipole array tests were not
successful, presumably due to the thick, conductive overburden. However, a gradient array survey
provided clear, high resistivity anomaly signatures at two of the four sites. Dipole-dipole array
and gradient array coverage was tested over Kimberlite 219. The gradient array resistivity peak
corresponds with the centre of the 219 kimberlite as defined by magnetic and gravity coverage and
as also confirmed by drilling. At the two other sites, the resistivity profiles did not extend
beyond the kimberlite outlines as presently recognized.
9.1.6 GEOTEM Test Survey
Resistivity mapping can also be performed from the air using electromagnetics. A time domain
EM and aeromagnetic survey (GEOTEM) was flown over a 12 kilometres x 4 kilometres block in 1996.
The line spacing for this work was 300 metres. The survey area contained 10 known kimberlite
bodies and a variety of surficial conditions ranging from cultivated farmland to forest, with a
belt of swamp along the White Fox River. Overburden thicknesses range from 130 metres in the north
to 90 metres at the White Fox River and increasing again to 110 metres in the south.
All of the known kimberlite bodies are represented by prominent magnetic anomalies in the GEOTEM
aeromagnetic coverage. Coincident EM data are presented as apparent resistivity contours. Nine of
the 10 kimberlites are detected as high resistivity anomalies, and one (target 326) is associated
with a low resistivity anomaly. Kimberlite 326 is also one of the most strongly magnetic features
at Fort à la Corne, with an estimated magnetite content of over 2%. Analysis of borehole logging
data from a nearby kimberlite body by the GSC indicated a strong correlation of lower kimberlite
resistivities with higher magnetic responses (Richardson et al., 1995), presumably due to the high
metallic magnetite content. However, an equally strongly magnetic anomaly located 4 kilometres
further west (Kimberlite 126) is represented by a conductivity low. An alternative possible cause
of the high conductivity feature is an overlying conductive zone, which might mask the kimberlite
response. A prominent east-west conductivity low which traverses the north part of the GEOTEM
survey correlates with deeper overburden (up to 130 metres in drilling) and is probably a glacial
erosion feature.
Overall, the EM-derived resistivity background is quite active, which might tend to mask kimberlite
signatures. Nevertheless, the combination of aeromagnetics and coincident EM data provided by the
GEOTEM system is a powerful exploration tool in this environment.
9.1.7 TEM In-loop Soundings
As a follow-up to the GEOTEM survey, three profiles of in-loop time domain electromagnetic
(TEM) depth soundings were obtained at Kimberlite 169. Instrumentation for this work was a Geonics
EM-37 unit using 100 metres x 100 metres transmitter loop and a 30 Hz pulse repetition rate, with
the receiver at the centre of the loop. Soundings were obtained at 100 metres intervals on each
profile. This work confirmed that a reasonable resistivity target exists and can be detected by
this method. A benefit of in-loop TEM soundings is that 1D inversions may be performed to image
the ground resistivity in a pseudo-depth section format, producing a conductivity-depth image
section.
The 169 image begins at around bedrock level. A 100 metre-thick layer of high conductivity
material (0.2 Siemens/metre) represents the Lower Colorado shales. The underlying Mannville
sandstones are less conductive (0.02 Siemens/metre). A prominent 300 metre-wide disruption in the
horizontally stratified conductivity section correlates with the shallowest and thickest portion of
the 169 kimberlite body. The kimberlite conductivity seems to be less than the Lower Colorado
shales and greater than the Mannville sandstones.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.1.8 Seismic Test
During 1992 and 1993, high resolution reflection seismic data were obtained over Kimberlite
169 in farm land near Smeaton. This work was performed under the supervision of Don Gendzwill of
the University of Saskatchewan in collaboration with the GSC (Matieshin, 1998; Gendzwill and
Matieshin, 1996). Seismic data complemented a suite of studies including multi-parameter borehole
logging also conducted by the GSC on a corehole at the same kimberlite target. The strong velocity
and density contrasts between kimberlite and host sediments, and the normally horizontal
stratification of the Phanerozoic sediments provided a favourable setting for seismic imaging.
After suitable processing, the upper kimberlite surface and two possible intra-kimberlite horizons
were well-resolved. The base of kimberlite is not distinctly imaged and appears to diverge from
drill-indicated data in some regions. The overall size of the kimberlite body indicated by the
seismic coverage is considerably larger than that from magnetic modelling, apparently due to an
extensively developed, thin apron zone, which was not fully identified in magnetics. Kimberlite
169 is enclosed and overlain by Colorado Group sediments and displays subdued topographic relief on
the upper surface with a domal feature at its centre. Many other kimberlite bodies seem to be
eroded to a flat upper surface, which is commonly at the subcrop level of the Colorado Group strata
below glacial overburden. The sub-horizontal intra-kimberlite reflectors were interpreted as
erosion surfaces separating distinct eruptive packages (Matieshin and Gendzwill, 1995). This
multi-temporal, multi-erosional genetic model has since been confirmed by intra-body petrographic
comparisons and stratigraphic correlations derived from drilling sections from numerous bodies.
A similar, but more detailed 2D seismic survey was completed on Kimberlite 140/141 body late in
2002 by a combined effort of the GSC and the Saskatchewan Geological Survey. Processing of data is
ongoing and results are expected during 2003.
9.1.9 GSC Downhole Geophysical Logging
During 1992, the GSC funded drilling of a 242 metre vertical corehole near the centre of
Kimberlite 169, which intersected approximately 100 metres of kimberlite. Borehole geophysical
measurements were obtained in the drillhole with a near comprehensive suite of logs acquired
including seismic velocity, density, natural gamma-ray spectroscopy, and magnetic susceptibility,
which complemented ground geophysical surveys in the area. The wide range of geophysical
parameters investigated assisted in characterization of the physical properties of the kimberlites
and in the interpretation of other, geophysical measurements (Richardson et al., 1995; Mwenifumbo
et al., 1996).
A second study of multi-parameter downhole geophysical logging was completed on four additional
coreholes on the 140/141 kimberlite body in 2001. This work was associated with the
multi-disciplinary Targeted Geoscience Initiative (TGI) project mounted in 2001-2002 which
encompassed petrographic logging, geochemistry, and 2-dimensional seismic on the 140/141
kimberlite. More details of this work are discussed in the section of this report concerned with
2002 exploration activities.
A total of 349 drillholes have been completed to the end of 2004-2005 program using various
methods to produce core or chips from boreholes ranging from small to very large diameter (64 to
914 millimetres). As of 1997, 69 of the original 71 (98.6%) targets in the project area were
tested by drilling. Of these, all but one of the 45 anomalies with estimated areas >20 ha have
been drilled. The FalC-JV currently retains 63 kimberlite bodies after selling several lower
priority satellite kimberlite clusters. At least 5,600 tonnes of kimberlite have been tested for
macrodiamond content and thousands of samples for complete diamond recovery were completed using
caustic fusion or jigging procedures and continue to be run to present-day. Close to half of this
mass of kimberlite has come from Kimberlite 140/141. Other investigations have included: grade
estimate studies, diamond valuations, diamond breakage studies, tracer studies, core and chip
logging, microscopic
39
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
petrography, sedimentary and volcanological studies, stratigraphic studies, radiometric age dating,
zonation studies, downhole geophysical logging, caliper logging, lithogeochemistry,
micropaleontology studies, magnetic susceptibility measurements, specific gravity measurements, and
drillhole location surveys. A historical accounting of exploration activities and results from
1988 to 1997 is available in Jellicoe et al. (1998) and Lehnert-Thiel et al. (1992). During 1999
and the early part of 2000, an in-depth evaluation and synthesis of all available information for
each kimberlite body was conducted separately by De Beers Canada Inc. and Kensington staff. Based
on these studies, De Beers Canada Inc. identified 17 kimberlites having sufficient information on
which to prioritize their diamond resource potential. From this list, five targets were selected
for continued evaluation of diamond content and value.
9.2.1 1988 Exploration and Sampling Program
In August, spurred by rumours of kimberlite discoveries near Prince Albert, the possible
presence of kimberlite-type intrusions in and around the Fort à la Corne Provincial Forest were
interpreted by UEM using published GSC aeromagnetic maps of the area. Ground-magnetic
investigations of several anomalies in the area indicated that they were caused by sources in the
Phanerozoic sediment cover, and not sources in the metamorphic basement. A detailed airborne
magnetic survey completed over the main cluster of GSC anomalies resulted in the identification of
29 discrete anomalies.
9.2.2 1989 Exploration and Sampling Program
In June, the FalC-JV Project was created between UEM and Cameco. Exploration consisted of 7
shallow 120.65 millimetres diameter rotary testholes, airborne magnetic surveys by Terraquest Ltd.
(10,254 kilometres), ground magnetic surveys (108.7 kilometres), and gravity surveys (17.5
kilometres). Kimberlite was intersected in all seven drillholes and microdiamonds were recovered
in five of the seven drill-chip samples (<100 kilograms) submitted to C.F. Minerals. The
recovered stones were small, but of generally gem quality. A total of seven macrodiamonds were
recovered having an aggregate weight of 0.0155 carats. The largest individual stone had a diameter
of 1.27 millimetres and weighed 0.0035 carats. Geophysical surveys showed the Fort à la Corne
kimberlite field to consist of three clusters (Weirdale, Snowden, and Fort à la Corne proper) with
a total of some 82 anomalies. The first age date for these kimberlites was obtained by American
Research Laboratories. An Rb/Sr age of 94 ±3 Ma was derived from four mica separates from the 122
kimberlite body. During 1989, reconnaissance ground magnetic surveys were completed at 29 anomaly
sites derived from the aeromagnetic survey. This work involved minimal profile coverage to
establish the location and approximate size of each magnetic target. The profiles indicated at
least seven kimberlites had surface areas >20 ha.
9.2.3 1990 Exploration and Sampling Program
Geophysical work (ground magnetic, gravity and resistivity) involved surveys at 42 sites,
bringing the total number of aeromagnetic anomalies investigated to 54 (out of 88 indicated by the
1989 Terraquest survey). Geophysical surveys consisted of 126.1 kilometres of ground magnetics,
19.15 line-kilometres of gravity, and 8.75 kilometres of resistivity profiles. Forty-seven of the
targets investigated during this period were interpreted to be kimberlites; the remaining seven
being either basement or cultural features.
Seven targets were tested by 171.45 millimetres RCA drillholes. A total of 15 drillholes
intersected a combined total of 3,684 metres of kimberlite. Five of the targets, including the
120, 169, 180, 216 and 426 bodies had not been drill tested previously, while the remaining two
(219 and 611) had been tested earlier during the 1989 reconnaissance program. The drillholes
produced a total of 97.088 tonnes of kimberlite of which 41.297 tonnes (material >1.7
millimetres) was retained for macrodiamond recoveries.
40
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Five macrodiamonds with a combined weight of 0.84 carats were recovered from Kimberlite 169. All
were brown industrial grade diamonds. Eleven macrodiamonds were also recovered from Kimberlite 120
having an aggregate weight of 1.19 carats with a mix of gem quality stones, and brown
industrial-grade stones.
In every case deep drilling passed through kimberlite into the underlying country rock, suggesting
that the kimberlites were tabular in shape. Feeder dykes were not identified among any of the
targets drilled. Rb/Sr age determinations of 96 Ma were obtained from micas separates in the 120
kimberlite. Radiometric ages determined in 1989 and 1990 were corroborated in part by
micropaleontology studies of country rocks proximal to Kimberlites 169 and 611, which gave ages
between 94 and 98 Ma in terms of the K/Ar radiometric time scale, and fall within the lower portion
of the Lower Colorado Group.
During 1990, detailed ground magnetic coverage was obtained over six of the larger kimberlite
bodies which revealed a greater degree of complexity in the outline and magnetic zonation of the
bodies than that represented by the earlier reconnaissance-style magnetic coverage. As a
consequence, many of the kimberlite bodies were thought to be more extensive in area than
originally believed.
9.2.4 1991 Exploration and Sampling Program
A geophysics program involving 106.8 line-kilometres of linecutting, 283.75 kilometres of
ground magnetic and 99.15 kilometres of gravity was completed which was intended to evaluate the
remaining aeromagnetic targets from the 1989 Terraquest survey and to upgrade coverage over a
number of potentially large targets (>20 ha in size). A detailed grid of handcut lines was
established over the main grouping of large targets in the Fort à la Corne Forest (120/147/148)
with a network of 17 GPS control points established to provide precise geographic control for the
grid network. Gravity coverage was significantly increased and was used to enhance the
interpretation of kimberlite body outlines and thicknesses.
A total of 26 drillholes (7,223.8 metres) were completed by a combination of drilling techniques:
(158.8 millimetres diameter RCA plus 279.4 millimetres diameter underreaming). In all, 253.758
tonnes of kimberlite was recovered with individual bulk samples ranging between 1.499 and 28.638
tonnes. The sample recovery cut-off in the field varied between 30 and 50 mesh, with 145.302
tonnes of kimberlite retained and processed for macrodiamond recoveries.
Total diamond recovery in 1991 was 146 stones, with an aggregate weight of 5.109 carats. Diamond
grades for individual drillholes ranged between 0 and 0.083 carats/tonne, with the best overall
average from one target being 0.082 carats/tonne for the 150/151 kimberlite.
9.2.5 1992 Exploration and Sampling Program
De Beers Canada Inc. (then Monopros Limited) joined the FalC-JV under a three-year earning-in
period, after which the three partners would each hold 33% equity in the project. The 1992
geophysical program included 5,475 line-kilometres of airborne magnetometer survey by Sander
Geophysics Limited in the Forest Gate area in order to obtain magnetic coverage in the area
immediately northwest of the FalC-JV’s claims. Delineation of a possible source of the rafted
kimberlite blocks in the Sturgeon Lake area was one of the major objectives of this program. A
follow-up program of 19.05 line-kilometres of ground magnetometer survey was conducted over 12
anomalies identified by the aeromagnetic survey. In the Fort à la Corne area, 102.05
line-kilometres of ground magnetic survey was completed over 14 anomalies. At ten of the sites,
the objective of the work was to improve the outlines of shallow magnetic bodies located by earlier
ground magnetic surveys. Four new targets derived from the 1969 GSC aeromagnetic coverage in the
Bittern Lake and Weirdale area were also investigated. Two test reflection seismic profiles were
obtained in the vicinity of Kimberlite 169 by the Department of Geological Sciences, University of
Saskatchewan. This work was funded primarily by the GSC.
41
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
The purpose of the seismic modeling was to delineate morphological features of the buried
kimberlite which may be pertinent to further exploration for non magnetic kimberlites in the area.
The GSC drilled a 242 metre vertical corehole near the centre of the 169 kimberlite that
intersected approximately 100 metres of kimberlite. Borehole geophysical measurements were
obtained in the drillhole with a near comprehensive suite of logs acquired including seismic
velocity and magnetic susceptibility which complement ground geophysical surveys in the area. The
wide range of geophysical parameters investigated assisted in characterization of the physical
properties of the kimberlites and in the interpretation of other, more remote geophysical
measurements. Magnetic susceptibility measurements were completed on 16 coreholes from 11
different kimberlites, resulting in the acquisition of over 7,500 data points. The data was used
to establish reasonable average magnetic susceptibility values for the kimberlites for comparison
with model-derived values from ground magnetic data and to assess the variability of magnetic
properties within each body.
Nineteen targets were tested by HQ corehole drilling (7,041.5 metres). Eight of the targets were
previously untested geophysical anomalies. Ten large diameter RCA drillholes (260 millimetres
diameter) were completed at several follow-up targets for a total of 2,177 metres. In all, 237.713
tonnes of material (27.825 tonnes core and 209.888 tonnes chip cuttings) were recovered with 161.7
tonnes of sample retained for diamond recovery. Unfortunately, kimberlite samples destined for
processing were hijacked en-route to the facility in South Africa, with 21 drillholes samples and
approximately 10.3 tonnes of kimberlite affected. A total of 187 macrodiamonds collectively
weighing 9.475 carats were separated from the samples including a large composite sample composed
of kimberlite recovered from the hijacked material. Grade forecasts based on diamond recoveries
ranged from 0 to 0.234 carats/tonne.
Microdiamond analyses were completed on 200 samples of approximately 20 kilograms size from
selected drillholes by caustic dissolution. An additional 93 samples were submitted for heavy
mineral separation (including microdiamonds) and indicator mineral chemistry. A total of 602
samples were collected for detailed petrographic examination.
9.2.6 1993 Exploration and Sampling Program
Geophysical investigations included ground magnetic and gravity surveys. A total of 252.775
line-kilometres of ground magnetometer survey was completed over 29 separate targets in order to
define better the outlines of several shallow magnetic anomalies. Gravity coverage at 11 sites
representing 14 kimberlite-type targets was also obtained with the objective of continuing the
reconnaissance scale assessment of various kimberlite gravity signatures. This work was meant to
demonstrate which kimberlites were most amenable to mapping by gravity among targets with little or
no magnetite and to enhance interpretation of kimberlite thicknesses among some of the larger
bodies. The acquisition of magnetic susceptibility data for a range of kimberlites was continued
this year with over 3,000 data points measured in 18 coreholes.
The 1993 drill program consisted of 35 reconnaissance and redrill coreholes (63.5 millimetres
diameter), RCA holes (311.2 millimetres diameter), and rotary testholes (101.6 millimetres
diameter). Thirty-three drillholes successfully intersected kimberlite. A total of 4,883.0 metres
of HQ coring was completed at 19 locations providing 13.212 tonnes of kimberlite for diamond
recovery processing. Ten RCA drillholes penetrated 2,414.2 metres of kimberlite resulting in
126.315 tonnes of retained kimberlite submitted for diamond recovery processing. Six testholes
yielded an additional 9.900 tonnes of material from 5 targets. A total of 61 macrodiamonds having
a cumulative weight of 2.291 carats were recovered from 15 of the drillholes. Grade estimates for
the tested intervals range from 0 to 0.300 carats/tonne
Microdiamond analysis was conducted on 148 samples from 16 drillholes. An additional 56 samples
from 15 drillholes were submitted for heavy mineral separation (including microdiamonds) and
analysis of indicator mineral chemistry. A total of 1,760 microdiamonds were recovered from 14
drillholes.
42
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Petrographic examination of 562 samples was completed along with separate consultant studies of the
stratigraphy, sedimentology, and volcanology of the Fort à la Corne area.
9.2.7 1994 Exploration and Sampling Program
The 1994 exploration program concentrated on the acquisition of bulk samples to assess
macrodiamond potential, hence, only minor geophysical surveys were conducted in three locations
requiring sufficient coverage to spot drillholes (9.45 line-kilometres).
Large diameter drilling (298.45 millimetres diameter) was completed in order to maximize the size
of minibulk samples. Drillhole selection was based on completion of the first-pass drill-testing
of anomalies which were about 20 ha in size, as well as the need for additional sample material
from inadequately tested kimberlites. Seven previously untested targets and five kimberlites which
had indications of positive potential based upon earlier corehole drilling were tested by 13
drillholes which provided 209.300 tonnes of kimberlite for macrodiamond processing in 29
petrographically defined sample intervals. A total of 147 macrodiamonds with a cumulative weight
of 10.080 carats were recovered from 11 drillholes. Grade estimates for the tested targets ranged
from 0 to 0.157 carats/tonne.
Microdiamond analysis was conducted on 29 samples from the 13 drillholes corresponding to the
intervals defined for the bulk samples. In addition, one sample was selected from each drillhole
for heavy mineral separation (including microdiamonds) and indicator mineral chemistry. A total of
227 microdiamonds were recovered from 11 drillholes.
9.2.8 1995 Exploration and Sampling Program
Kensington Resources Ltd. joined the FalC-JV under a three-year earning-in period, after which
the four partners would each hold a 25% interest in the project.
Eight large diameter drillholes (LDDH) with diameters of approximately 300 millimetres were
completed on eight different kimberlite bodies. A total of 247.721 tonnes of kimberlite were
recovered (168.669 t actually retained for analyses) from a cumulative kimberlite intersection of
1,355.6 metres. Four LDDH were targeted on untested magnetic anomalies (Kimberlites 116, 126, 133,
163). The remaining four drillholes tested kimberlites where earlier drilling warranted additional
work (Kimberlites 119, 122, 140, 147). A total of 28 microdiamond and 16 indicator mineral
chemistry samples were also submitted for analysis. Seven additional samples from DH 145-04
completed earlier were also analyzed for microdiamonds. Microdiamonds were recovered in 5 of 8
LDDH, with 242 microdiamonds recovered by both caustic dissolution and jigging methods. A total of
51 macrodiamonds cumulatively weighing 2.815 carats were recovered from 13 of the 35 minibulk
samples processed in 1995. The best recoveries were noted in drillholes 140-08 and 147-03,
yielding average grades of 0.0123 and 0.0751 carats/tonne, respectively. Individual samples were
found to range in grade from 0 to 0.11857 carats/tonne. The largest diamond recovered was 0.27
carats from LDDH 147-03. Valuations on macrodiamond parcels were performed by De Beers, with a
value as high as $US 104.20 assigned to a two stone parcel from DH 140-08 weighing 0.225 carats.
9.2.9 1996 Exploration and Sampling Program
Thirty rotary testholes (7,079.6 metres) tested 22 previously untested kimberlite-type
anomalies with the purpose of recovering samples for indicator mineral chemistry and microdiamond
analyses. The drillholes also yielded small tonnage samples for macrodiamond processing. Eight
additional drillholes were also completed on previously tested targets were existing results
warranted further investigation. In all of the drillholes, sampling was directed at testing
geologically distinct kimberlite intervals for microdiamonds (2,308 kilograms,
43
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
180 samples) as well as macrodiamonds (67.751 t kimberlite retained, 28.404 t processed). An
additional 84 intervals from 20 different drillholes drilled in previous years also were tested for
microdiamond content. A total of 24 representative samples from 24 different kimberlite bodies
drilled in 1996 were submitted for indicator mineral studies.
Prior to drilling, ground magnetic profiles were completed across 17 targets (90.125
line-kilometres) to complete the ground magnetic coverage of all known targets in the project area.
Airborne GEOTEM (400 line-kilometres) and time-domain TEM test surveys (4.5 line-kilometres) were
also undertaken to test the applicability of these geophysical methods in delineating kimberlites
in the Fort à la Corne environment.
A total of 66 macrodiamonds with an aggregate weight of 1.2 carats were recovered from the minibulk
samples processed during 1996. A consultant’s valuation of all the Fort à la Corne diamonds
recovered to date (689 stones submitted, 34.7 carats) indicates the average carat price for the
parcel is US$ 43/carat, with the potential for many kimberlites to yield stones in the range of
US$50-100/carat range.
9.2.10 1997 Exploration and Sampling Program
The primary objective of the 1997 Fort à la Corne drilling program was to collect minibulk
samples for macrodiamond recoveries and small representative samples for microdiamond and indicator
mineral recoveries. A total of two small diameter drillholes with 130.2 millimetres diameter
(SDDH) and three RCA under-reammed large diameter drillholes with 444.6 millimetres diameter
(LDDH-UR) were completed on five different kimberlite bodies. A total of 137.294 tonnes of
kimberlite (theoretical) were recovered giving an actual minibulk sample of 72.897 t from a
cumulative kimberlite intersection of 592.0 metres. Twenty-seven composite intervals of kimberlite
ranging from 18 to 51 metres thick were created from 135 individual sample bags and were then
submitted for macrodiamond recoveries. A downhole tracer program was initiated to test the
recovery efficiency of materials from the borehole environment during both reverse circulation
drilling and under-reaming.
A total of 31 macrodiamonds cumulatively weighing 2.520 carats was recovered from three of the five
drillholes processed in 1997. The best recoveries were from LDDH-UR 220-02, which yielded a
weighted average grade of 4.4 cpht. Individual sample grades ranged from 1 to 10.9 cpht. The
largest diamond recovered was 0.7 carats from drillhole 220-02. SDDH 605-01 and SDDH 612-01 were
barren of macrodiamonds. Fourteen intervals were tested for microdiamond contents from composite
representative grab samples. Microdiamonds were produced from four of five drillholes including
150-05, 176-02, 220-02, and 605-01. Diamond recoveries from Kimberlites 150, 176, and 220
confirmed the presence of macrodiamonds and that further testing of these kimberlites is warranted.
Kimberlite 150 was further tested in 2001 and 2003 and was de-prioritized in 2004. Kimberlite
220 occurs as a minor pocket within the prospective megacluster hosting kimberlites 147, 148, and
120 and will be further tested if these larger bodies remain prospective. Kimberlite 176 is out of
the geographic scope of the current AE&E investigation, but may be considered for additional work
in the future. Microdiamonds were not recovered from SDDH 612-01 and it is considered to be
barren. A total of 206 stones, collectively weighing 0.04421 carats, were recovered by the caustic
fusion process.
9.2.11 1998 Exploration and Sampling Program
The primary objective of the 1997 Fort à la Corne drilling program was to maintain the FalC-JV
assets and to promote interest in testing selected prospective kimberlites. No exploration
activities were conducted in the field during 1998, although a drilling program was planned for the
winter of 1999. Results for 1997 program initiatives received in 1998 were evaluated and reported.
44
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Other work included preparation of a summary of exploration activities from 1992 to 1997, which was
disseminated to the public by way of technical papers and slide presentations. In addition, much
of the petrographic and stratigraphic data available from downhole studies were integrated with
geophysical modeling in a new interpretation of the geometry and architecture of the Fort à la
Corne kimberlite bodies. At the end of 1998, De Beers Canada Inc. became operator of the project.
9.2.12 1999 Exploration and Sampling Program
A large diameter drill program was conducted by SDS Drilling with four holes placed in two
kimberlites (147 and 220), yielding a theoretical mass of 87 tonnes over a kimberlite interval of
475.1m. The weighted average recovery was in the order of 65%. Processing resulted in the recovery
of 130 macrodiamonds (4.045cts).
A total of 400 kilograms of kimberlite was sent for microdiamond analysis, and further grab samples
were extracted for moisture, density, magnetic susceptibility and granulometry tests. Results of
the kimberlite processing were somewhat disappointing in that neither the macrodiamond grade, nor
the extrapolated microdiamond grades (both by Terraconsult and MINRED, the research arm of De
Beers) were significantly upgraded by the 1999 work. In addition, low confidence average stone
valuations for these two bodies indicated low prospectivity and further evaluation work was
discontinued. The additional microdiamond work however improved confidence levels on grade
prediction figures.
9.2.13 2000 Exploration and Sampling Program
A full review of all diamond recovery including 1999 work was completed by MINRED in early
2000. This prioritization was based on body size, depth, grade, and diamond size frequency
distribution. Two kimberlites were chosen for further work (large diameter drilling). Three 609
millimetres holes were placed into body 122 and two were placed into 141. A total of 487
macrodiamonds weighing 38.37 carats were recovered from the entire exercise. Best-fit and
optimistic modeled ore value estimates at +1.5 millimetres ranged from $US 11-18 per tonne for
Kimberlite 122 and $US 28-32 per tonne for Kimberlite 141. These estimates provided the basis for
the 2001 field program.
9.2.13.1 2000 Grade Forecasts and Focus on Prioritized Kimberlites
Evaluation of the Fort à la Corne kimberlite bodies during 2000 and early 2001 utilized a
synthesis of diamond recoveries, previous diamond valuations, and estimated body size to prioritize
the bodies with the most potential for economic diamond deposits. Results of the desktop studies
conducted in 1999 and 2000 are summarized in Table 3. Despite incomplete testing and difficulties
in rationalizing diamond recoveries from a variety of drilling and processing methods, exploration
was focused on five high-priority bodies. Prioritization was greatly facilitated by development of
enhanced grade forecasts by De Beers that have a higher degree of confidence than previously
available for Fort à la Corne kimberlites.
Kimberlites with grade forecasts indicating robust, commercial-sized stone populations were given
the highest priority and it is significant that De Beers grade experts consider the bodies listed
in Table 4 to have very favourable potential. Grade forecasts and sample information for
Kimberlites 122 and 141 were updated to reflect macrodiamond recoveries from 2000.
9.2.13.2 2000 Large Diameter Drilling, Sampling, and Macrodiamond Recovery
The primary objective of the 2000 program was to obtain large minibulk samples from two high
priority bodies. The drilling program was structured to enable maximum recovery of macrodiamonds
in order to provide a first-order, average value ($US/carat) of the stones in each body. Five – 24
inch diameter reverse circulation mudflood with air-assist drillholes were completed in the 2000
program. Three holes were located over the
45
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
deeper-going part of the 122 kimberlite body and two over the central part of Kimberlite 141. The
holes were placed within 200 metres of known kimberlite intersections, so a small measure of
geological control was available. A 1.2 millimetres screen was utilized in the field to separate
fines from the minibulk samples. All minibulk sample material was processed at the De Beers-owned
dense media separation (DMS) plant located in Grande Prairie, Alberta. Heavy mineral concentrates
produced here were then air-freighted to Johannesburg, South Africa for final diamond recovery by
De Beers under high-security conditions in a process utilizing screening to specific size fractions
followed by hand sorting.
9.2.13.3 2000 Macrodiamond Recovery Results
A total of 487 macrodiamonds were recovered form this program and specific results are shown
in Table 5. Past stone valuations were considered rough estimates only due to very small parcel
sizes and a lack of larger stones. Due to these factors, average diamond values per body were
often understated, despite a large fraction of gem-quality stones. Concern for these problems by
Kensington and De Beers Canada Inc. have led to the use of two methods to understand the quality of
diamond at Fort à la Corne. De Beers formulates modeled values based on integration of average
sieve fractions for commercial-sized stones with the diamond size distributions and grade
forecasts. In concert with this approach, individual stone values and average body values were
assessed by an independent diamond consultant with specific expertise in this area. All forecast
grades and modeled values were evaluated during revenue modeling for the prioritized bodies.
Modeled values and revenues for kimberlite bodies 122 and 141 are shown in Table 6, although the
conservative figures are not included.
Total
Total
Microdiamond
Total
Sample
Average
Sample
Size of
Micro-
Sample wt
weight
Macro-
Total
weight
Stone size
Grade
Body
Body
diamonds
(kg)
(octacarats)*
diamonds
carats
(tonnes)
(carats)
(cpht)
101
15.8
1
210.0
6,450
Not sampled
116
27.3
0
17.0
0
0
0.000
27.8
0.0
118
76.0
81
410.4
2,692,565
2
0.020
8.8
0.010
0.2
119
23.7
7
267.6
71,750
0
0.000
34.9
0.0
120
134.1
655
884.0
9,895,830
149
5.746
205.7
0.039
2.8
121
34.8
357
776.5
9,196,102
63
2.340
60.6
0.037
3.9
122
108.0
211
622.0
6,436,950
77
5.820
87.4
0.076
6.7
123
24.4
153
300.3
29,207,503
7
0.132
18.3
0.019
0.7
126
21.6
0
73.0
0
1
0.130
38.5
0.130
0.3
133
17.0
42
152.0
87,400
1
0.045
42.7
0.045
0.1
134
17.0
11
84.9
74,345
1
0.010
3.2
0.010
0.3
135
41.0
1
52.8
18,597
Not sampled
140
143.6
391
1122.6
12,410,200
39
2.010
77.6
0.052
2.6
141
106.8
102
574.2
4,175,600
18
0.925
34.8
0.051
2.7
144
32.0
2
68.8
11,250
Not sampled
145
42.7
490
985.4
22,711,356
32
0.908
52.7
0.028
1.7
147
135.4
658
207.0
12,113,910
114
4.180
78.3
0.037
5.3
148
184.0
374
262.0
3,711,050
70
2.369
121.4
0.034
2.0
150
67.2
162
473.0
9,894,000
37
2.885
117.1
0.078
2.5
151
No data
4
0.460
5.5
0.115
8.3
152
24.8
47
166.0
697,500
0
0.000
0.4
0.0
154
32.0
4
100.0
95,345
Not sampled
155
18.0
12
105.6
1,093,587
7
0.080
4.3
0.011
1.9
46
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Total
Total
Microdiamond
Total
Sample
Average
Sample
Size of
Micro-
Sample wt
weight
Macro-
Total
weight
Stone size
Grade
Body
Body
diamonds
(kg)
(octacarats)*
diamonds
carats
(tonnes)
(carats)
(cpht)
156
6.9
11
140.8
209,621
0
0.000
5.8
0.0
157
2.7
3
58.7
19,185
Not sampled
159
10.0
2
52.8
4,233
Not sampled
162
55.5
33
234.0
262,950
3
0.120
17.9
0.040
0.7
166
15.0
19
88.0
177,821
3
0.042
3.0
0.014
1.4
167
69.5
30
252.0
50,000
8
0.315
15.4
0.039
2.0
168
31.9
1
20.0
1,450
5
0.215
30.6
0.043
0.7
169
78.5
128
626.4
4,581,540
47
4.075
74.0
0.087
5.5
170
25.0
36
93.6
573,415
7
0.099
5.1
0.014
1.9
174
37.8
112
296.8
9,632,700
2
0.035
11.7
0.018
0.3
175
36.8
47
251.6
343,500
5
0.290
10.1
0.058
2.9
176
26.0
172
258.7
15,993,385
17
0.966
49.3
0.057
2.0
181
13.0
2
339.6
17,750
0
0.000
30.7
0.0
218
22.0
5
143.0
8,400
2
0.180
17.8
0.090
1.0
219
42.4
47
192.2
1,927,950
4
0.185
39.9
0.046
0.5
220
23.7
409
199.4
13,195,244
69
3.133
69.7
0.045
4.5
221
7.2
73
264.4
7,658,734
21
0.341
5.5
0.016
6.2
223
4.7
10
60.5
227,442
2
0.123
2.2
0.062
5.6
269
8.3
3
8.3
9,884
Not sampled
326
43.4
0
18.0
0
2
0.060
20.2
0.030
0.3
601
86.2
24
100.1
108,158
1
0.008
4.8
0.008
0.2
602
68.3
4
234.0
36,200
0
0.000
3.0
0.0
603
19.3
1
18.0
4,850
1
0.270
36.2
0.270
0.7
606
43.8
21
213.0
229,550
0
0.000
3.9
0.0
611
1.8
1
57.3
1,000
0
0.000
2.9
0.0
614
24.0
1
139.0
900
17
1.425
26.7
0.084
5.3
615
12.2
3
68.6
4,632
Not sampled
*
1 octacarat is equivalent to 1x10-8 carat
Table 3: Kimberlite and Diamond Information Utilized in 2000 Prioritization Study
De Beers
Modeled
Average
Macro-
Forecast
Est.
Mass
# of
Minibulk
Micro-
diamond
Commercial
Kimberlite
Area
(millions
Drill
Mass
diamond
Grade
Grade
Body
(Ha)
of tonnes)
Holes
(tonnes)
(stones/tonne)
(cpht)
(cpht)
122
108
540
11
388
340
5.2
16
140
144
537
8
74
377
4.4
5-19
141
107
395
5
271
180
4.8
19
147
135
497
5
73
3,180
7.2
15
148
184
675
12
121
1,425
2.2
10
150/151
112
336
6
120
340
4.8
16
Table 4: Prioritized Kimberlite Bodies
47
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.13.4 2000 Microdiamond Recovery
Samples slated for microdiamond recovery were collected by hand from the oversize pieces of
kimberlite prior to DMS processing. This kimberlite was collected on a per sample basis and
represented 12 metre intervals of the full kimberlite intersection from selected drillholes.
Microdiamond recovery was primarily undertaken by Kimberley Acid Laboratory (KAL) in South Africa,
although one third of the samples were processed at Lakefield Laboratories in Ontario for a
comparative check on recovery at the De Beers facility.
Microdiamonds recovered from this program were integrated into the existing diamond database for
the 122 and 141 kimberlites and utilized for grade forecasts based on statistical diamond size
distribution methods.
9.2.14 2001 Exploration and Sampling Program
The 2001 kimberlite evaluation program was a combined drilling program of core and large
diameter, reverse circulation holes followed by macrodiamond recovery from the acquired kimberlite
bulk samples. Following the initial macrodiamond recoveries, and subsequent revenue modeling by
MINRED in 2000 and early 2001, it was noted that at the middle and upper end of ore value
estimates, the 141 kimberlite had the potential to be economic, when compared to the 1996 Fluor
Daniel Wright Scoping Study.
Average
Kimberlite
Minibulk
Number
Sample
Intersection
Mass
Of
Grade
Drillhole
(m)
(kilograms)
Stones
Carats
(cpht)
Large Stone Recovery
122-09
155.7
129.153
63
4.235
3.3
1 stone >0.5 carats
122-10
146.0
118.092
57
5.105
4.3
1 stone >0.5 carats
122-11
102.8
81.078
92
7.970
9.7
4 stones >0.5 carats
Subtotal
404.5
328.324
212
17.310
5.3
2 stones >0.5 carats;
141-04
168.1
138.590
169
12.840
9.3
2 stones >1.0 carat
141-05
144.5
113.260
106
8.220
47.2
4 stones >0.5 carats
Subtotal
312.6
251.850
275
21.060
8.4
2000 Total
717.1
580.175
487
38.370
Table 5: Macrodiamond Recoveries from 2000 Drillholes
Grade
Grade
Model
Model
Model
Model
Sample
Forecast
Forecast/
Value
Value
Revenue
evenue
Carats
/cpht(+1
cpht
US$/ct.
US$/ct.
US$/t
US$/t
Model
Body
(+1mm)
mm)
(+1.5mm)
(+1mm)
(+1.5mm)
(+1.0mm)
(+1.5mm)
Description
122
17.31
8
7.5
133
144
11
11
Best fit
122
13
12
136
147
18
18
Optimistic
141
21.06
19
18
148
153
28
28
Best fit
141
19
18
173
179
33
32
Optimistic
Table 6: Modeled Values and Revenue for Kimberlites 122 and 141
A program was designed to collect sufficient diamonds to reduce the uncertainty surrounding the
diamond value estimates for Kimberlite 141. MINRED suggested that 100 carats (total recovery)
should be sufficient to achieve this aim. Some discussion was held to determine the best method to
collect these stones as well as to test or investigate a larger part of the kimberlite.
48
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Added to this was the possibility that both Kimberlites 141 and 140 were in fact part of the same
body. Barbara Scott Smith first suggested this possibility in 1994 after viewing core and data from
both kimberlite areas. While diamond size frequency plots for the two bodies looked quite
different, it was felt that this difference may have been a reflection of sample bias. Removing
some questionable drill hole diamond size frequency data from plots of kimberlite 140 flattened the
curve to resemble the relatively coarse size frequency distribution of kimberlite 141.
MINRED stated they would require 100 carats from Kimberlite 141 to enable them to model diamond
value with a higher degree of confidence. Calculated from the 2000 kimberlite intersections and
results, eight large diameter drill holes would be necessary to recover the additional 80cts
required. Some work was proposed on Kimberlite 150 as this was the third prioritized target from
the MINRED 2000 review. Two large diameter drill holes were planned for 150. As the 2000 Large
Diameter Drillhole (LDDH) program produced high volumes, diamonds larger than one carat and minimal
breakage, the 24” reverse flood method was again chosen as the preferred drilling technique.
9.2.14.1 2001 Core Drilling Program
The high cost of large diameter drilling, along with the poorly understood but possibly
complex kimberlite geology of kimberlite 141, prompted a proposed program of core drilling to
ensure planned LDDH’s were correctly sited. Up to eight PQ sized holes were originally proposed but
upon receiving drill quotes from contractors, and discussing petrographic requirements with the De
Beers’ petrographic consultant, Barbara Scott Smith, it was decided that up to 16 NQ sized (47.6
millimetres) core holes could be installed for the same cost and benefit.
A core hole was therefore planned for each proposed large diameter site to gain some geological
control before the larger diameter work. This left a further 6 core holes available for
geology-only investigations. Large diameter drill holes were planned in the expectation that
reasonable intersections of kimberlite could be obtained around the 2000 sites. All drill holes
were sighted on a UTM grid established over the kimberlites and field staff were prepared to
relocate large diameter sites based on corehole intersections. The final program therefore called
for sixteen core holes (14 planned on Kimberlite 140/141 and 2 on Kimberlite 150) and ten 24” drill
holes (8 holes into Kimberlite 141, 2 holes into Kimberlite 150).
Drilling of sixteen NQ (1.875 inch diameter) cores, predominantly from the 141 body, permitted
geological evaluation of the kimberlites and was a means to spot the locations of the large
diameter drillholes. Sixteen NQ (47.6 millimetres) diameter drill holes were completed, comprising
13 holes on Kimberlite 141, one hole into Kimberlite 140 and two core holes into Kimberlite 150. A
summary of corehole statistics is summarized in Table 7.
In general, coreholes were constructed with the use of three bits of different size. Surface holes
were installed using a mud circulation system and an HW tricone milled tooth bit (130.2 millimetres
diameter). At around 30 metres, the HW tricone was replaced with a NW tricone bit (98.4
millimetres) and again mud was used for circulation. This was used until 93-96 metres when an NQ
core bit replaced the tricone and coring commenced. Core drilling was generally conducted with
either fresh water or at least low viscosity mud. Casing was generally installed to 80 metres
although on occasion this dropped so additional lengths had to be added.
Two exceptionally thick intersections of kimberlite were sampled. The first was in drillhole
141-09 (Table 7) where 257.8 metres of kimberlite was intersected. This hole was located on the
modeled margin of kimberlite 141. The second deep intersection occurred in hole 141-13. Kimberlite
was intersected between 111 metres and the bottom of the hole at 450 metres. The hole was
terminated in kimberlite. It is believed that both holes are located near or within the main feeder
vent of the 141 body.
49
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Top of
Bottom of
Kimberlite
Drillhole
Kimberlite (m)
Kimberlite (m)
Thickness (m)
141-06
103.5
246.0
142.5
141-07
109.5
238.5
129.0
141-08
109.5
273.5
164.0
141-09
105.0
362.8
257.8
141-10
101.5
254.9
153.4
141-11
102.5
192.0
89.5
141-12
112.5
266.5
154.0
141-13
111.16
450+
338.84
141-14
105.01
207.8
102.79
141-15
115.3
233.6
118.3
141-16
105.8
221.1
115.3
141-17
114
250.8
136.8
141-18
110.95
201
90.05
140-09
116
229.5
113.5
150-06
97.4
282.6
185.2
150-07
95.6
236.4
140.8
Total:
2,431.78
Table 7: 2001 Core Intersection Summary
Petrographic studies suggest that the core hole geology can be broadly separated into three main
types. These features were the “megagraded bed”, “multigraded beds” and fine grained dominated
texture. Descriptions by Dr. Barbara Scott-Smith of these beds are as follows:
Megagraded bed: (Holes dominated by a single mega-graded bed up to 130 metres thick)
The brief macroscopic examination of the chips from 141-04, the 2001 macrodiamond results, and the
1994 macrodiamond results for 141-03 all suggest that significant diamond contents found in
previous drilling were derived from the mega-graded bed.
Fine Grained Kimberlite: (Holes dominated by fine grained kimberlite (FK), although of variable
type and with other types of kimberlite present)
Based on the nature of the 141-04 and 141-02 drill chips, and the related microdiamond results, it
appears that at least some FK’s have low grade or is barren. Thus it is recommended that these
areas not be used for the 2001 RC drilling program, which is aimed at recovering carats. It is
suggested, however, that these holes should be extensively sampled for microdiamonds.
Multigraded beds: (Holes dominated by repetitive graded beds <10m thick)
50
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
The third group of cores reflect a mode of pyroclastic deposition not previously encountered in
141. It is not known, therefore, whether this type of kimberlite will yield the required relatively
high quantities of diamond. Thus taking bulk samples at these sites has an element of risk.
However, the kimberlitic constituents forming these kimberlites more closely resemble those of the
mega-graded bed. It seems, therefore, that drilling at these sites is a reasonable risk.
The dominant kimberlite phase intersected in each drillhole is as follows:
141-01 – mega-graded bed
141-06 – mega-graded bed
141-07 – mega-graded bed
141-08 – mega-graded bed plus additional complex kimberlite below
141-14 – mega-graded bed
140-09 – mega-graded bed
141-12 – multiple graded beds
141-15 – multiple graded beds
141-17 — multiple graded beds
141-02 – dominated by FK
141-09 – dominated by FK plus deeper different kimberlite
141-10 – dominated by FK plus deeper different kimberlite
141-11 – dominated by FK plus deeper different kimberlite
141-13 – dominated by FK plus deeper different kimberlite
The geology of 141-16, 141-17 and 141-18 were described as being somewhat nondescript and it was
not clear how they fit the present geological model. Each of these three holes is dominated by
pyroclastic kimberlite (PK) composed of constituents, which are similar to those forming the multi
and megagraded kimberlites. Drillcore 141-17 contains sufficient recognizable repeated graded beds
to suggest that it belongs to the multigraded group. The dominant kimberlite in holes 141-16 and
141-18 is similar to the mega-graded bed but the full sequence is not represented; for example, the
basal kimberlite breccia is missing. It is distinctly possible that these intersections may
represent distal lateral equivalents of the mega-graded bed. 141-16 and 141-18 also display some
internal fluctuations that could alternatively suggest that they belong to the multigraded group.
At Kimberlite 150, Scott Smith used her previous notes on drillhole 150-02 to help interpret the
geology of the core holes completed in 2001. Her on-site comments are as follows: “The total
drillcore can be subdivided into at least 5 different, and mostly distinctive, phases of
pyroclastic kimberlite (PK). The contrasting phases of kimberlite are very likely to have different
diamond grades showing that the internal geology of this pipe should have an important impact of
the evaluation of this body. Two of these kimberlites form extensive intersections and are
repeated in different holes”.
(1) A medium grey poorly sorted medium to coarse grained (M-CK) olivine lapilli tuff forms the
uppermost parts of all three holes and occurs in the following intersections:
(2) A pale green coloured better sorted bedded very very fine to medium grained olivine tuff forms
the following intersections:
150-02 254.1-265.3m
150-06 134-235.75m (probable, in disintegrated core).
51
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Based on these recommendations and the intersection thicknesses encountered, it was decided that
ten 2001 large diameter drill holes would be placed next to (within 5m) the following core holes:
141-06, 141-07, 141-08, 141-12, 141-14, 141-15, 141-16, 150-06, 150-07, and one additional site
located 100m east of 141-15 (actually between 141-15 and 141-03).
9.2.14.2 2001 Large Diameter Drilling and Minibulk Sampling Program
The main objective of the 2001 program was to obtain sufficient macrodiamonds to give 60
additional carats for valuation in order to increase the confidence level of reported modeled
values and revenue for the 141 kimberlite. Also, the shape, size, diamond distribution, and
internal architecture of the body will be estimated using the 3D capabilities of GEMCOM, a computer
program that plots drillhole and diamond recovery information. A combined kimberlite intersection
of 1,327.2 metres facilitated excavation of a total of 889.8 tonnes of kimberlite of which 471
tonnes of wet chips greater than 1.5 millimetres in size were retained for diamond recovery. Of
these totals, 120.96 tonnes were excavated from the kimberlite 150 body with 60.37 tonnes of wet,
coarser chips saved for processing. A total of 768.85 tonnes of wet chips were excavated from
kimberlite 141. Theoretical (excavated) kimberlite masses shown in Table 8 were calculated using
continual borehole diameter information from downhole caliper surveys. Some sample information
listed here was revised from previous news releases.
Theoretical Mass
Total Depth of
Kimberlite
Kimberlite
Hole
Drillhole Number
Intersection (m)
(tonnes)
(m)
141-20
145.5
95.586
255.2
141-21
142.2
93.399
245.0
141-22
119.0
84.129
231.0
141-23
160.8
104.589
267.0
141-24
115.7
76.940
231.0
141-25
101.3
66.681
206.6
141-26
126.1
82.472
236.2
141-27
115.6
76.463
219.5
141-28
135.2
88.589
244.7
150-08
165.9
120.958
262.0
Total:
1,327.2
889.8
2,398.2
Table 8: 2001 Summary of Minibulk Sampling
Initial processing of 117 samples (each representing approximately 12 metres of kimberlite
intersection) was conducted at the De Beers DMS facility at Grande Prairie between September 19,2001 and October 20, 2001. The total headfeed weight of drained kimberlite was 413.134 tonnes for
the bulk sample from kimberlite 141 and 57.988 tonnes for the kimberlite 150 minibulk sample.
Reduction of material for diamond recovery by concentration of heavy minerals (and diamonds)
resulted in a 99.2% decrease in mass. Consequently, only 3,773 kilograms of +1.5 millimetres
material were shipped to De Beers facilities in South Africa for final diamond recovery and sorting
(Table 9). Ten audit samples and 5 repeat samples were run during processing.
Dense Media
Heavy Mineral
Concentrate % of
Number of
Headfeed Mass
Concentrate Weight
Headfeed
Drillholes
Samples
(tonnes)
(kilograms)
Mass
141-20 to 28
103
413.134
2,852.08
0.7
150-08
14
57.988
920.90
1.6
Program Total:
117
471.122
3,772.98
0.8
Table 9: Summary of 2001 Initial Processing by Dense Media Separation
52
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.14.3 2001 Macrodiamond Recovery and Grade Estimates
A total of 769 tonnes of kimberlite was excavated in 2001 from kimberlite 141 utilizing large
diameter drillholes. Final diamond recovery from 3,773 kilograms of heavy mineral concentrate,
derived from the dense media separation process, gave recovery of a total of 466 stones with
cumulative mass of 45.59 carats. Of this total, 431 macrodiamonds (>1.5 millimetres in size)
weighing 42.455 carats were recovered and added to the existing kimberlite 141 inventory of 248
stones weighing 21.22 carats recovered from program samples acquired in 2000. Notably, a single
stone weighing 3.335 carats was recovered from the 141 samples. The average sample grade (total
program carats divided by total sample tonnes) was 5.5 carats per hundred tonne; this compares with
18 cpht from forecast grades, which are expected to better reflect the average grade over the
entire kimberlite rather than localized (areal and stratigraphic) deficiencies or abundances due to
extreme nugget effects known to be common to heterogeneous diamond deposits. Diamond recovery for
the samples from kimberlite 150 yielded 35 stones weighing 3.135 carats. Fewer carats than
initially anticipated were recovered from the 2001 program resulting in lower minibulk sample
grades and less stones in the greater than 0.5 carat range (particularly, in comparison to 2000
samples for kimberlite 141). Some reasons for this discrepancy include:
i)
Poor drilling completion in 3 of 10 holes resulting in the inability to sample the
bottom-most kimberlite strata that were expected to yield significant numbers of stones;
ii)
Change in lower treatment size cut-off from 1.0 millimetres to 1.5 millimetres in 2001,
which resulted in fewer stones and less carats recovered;
iii)
Re-calculation of kimberlite density from 2.5 to 2.21, based on several hundred sample
measurements; this re-calculation impacts on the sample grade calculation; and
iv)
Complexity in kimberlite lithotype encountered by drilling that may reflect variations
in diamond distribution.
Table 10 shows sample grades for the eleven 610 millimetres diameter boreholes drilled in 2000 and
2001 that range up to 41.5 carats per 100 tonnes (cpht) and cumulatively average 5.5 cpht.
Notably, the high-end sample grade includes the 3.335-carat stone recovered from a 2001 sample.
Individual minibulk sample grades are not considered representative of the average grade of the
kimberlite, rather the range of values likely brackets the actual grade of specific kimberlite
phases or units, of which there may be several within a given drillhole. Grade estimates derived
from statistical modeling of diamond size distributions for Kimberlite 141 ranged from 5 to 12
cpht. These estimates are extrapolations for stones greater than 1.5 millimetres in size and
pertain only to the central portion of Kimberlite 141 where testing was conducted during 2000 and
2001.
Preliminary Estimate
Year
Range of Minibulk
Average Borehole
of Number of
Drillhole
Drilled
Sample Grade (cpht)
Sample Grade (cpht)
Kimberlite Phases
141-20
2001
0 — 41.5
6.6
3
141-21
2001
0 — 16.1
6.4
4
141-22
2001
0 — 17.7
7.2
2
141-23
2001
0 — 11.4
5.5
2
141-24
2001
0 — 21.3
5.2
3
141-25
2001
0 — 9.7
2.7
2
141-26
2001
0 — 17.2
5.5
at least 2
141-27
2001
0 — 6.9
2.1
2
141-28
2001
0 — 13.9
4.2
3
53
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Preliminary Estimate
Year
Range of Minibulk
Average Borehole
of Number of
Drillhole
Drilled
Sample Grade (cpht)
Sample Grade (cpht)
Kimberlite Phases
141-04
2000
0 - 34.3
8.4
4
141-05
2000
0 - 19.7
7.1
4
Table 10: Minibulk Sample Grades for 2000 and 2001 Drillholes in Kimberlite 141
9.2.14.4 2001 Microdiamond Recovery
Representative core samples from drillholes 141-09 and 141-12 were selected for total diamond
recovery using caustic dissolution methods in De Beers facilities. A total of 424 microdiamonds
were recovered from this procedure with a cumulative weight of 0.143 carats. Data derived from
this exercise were incorporated in the forecast grade estimates for parts of Kimberlite 141.
9.2.14.5 2001 Interpretive Results for 2001 Drilling and Sampling Program
De Beers Canada Inc., the operator of the project, oversaw preparation of an evaluation report
authored by managers and geoscientists in Mineral Resource Services (MRS) a department of De Beers
located in Johannesburg, South Africa. The report, for which preliminary results were supplied
during July 2002, was finalized in November 2002 from currently available information and modeled
by De Beers using proprietary techniques. Macrodiamond recoveries for 2000 and 2001 were carried
out at De Beers’ facilities located in Canada and South Africa. The total microdiamond inventory
that was recovered in early 2002 and utilized in the current grade forecasts was recovered both
from Lakefield Laboratory in Canada and De Beers’ laboratories in Kimberley, South Africa.
Services and interpretations rendered to the FalC-JV by De Beers are not independent or “at
arms-length” due to their involvement in the project as a partner.
2001 Modeled Diamond Values and Preliminary Assessment of Revenue
Actual average parcel diamond values for the 2001 stones were posted at $US 52.60/carat, reflecting
a substantial increase from $US 33.67/carat for the 2000 stones. De Beers notes that since the
valuation of the 2000 diamond parcel, the rough market has undergone a negative shift, a trend that
only recently is showing signs of a reversal. For the purpose of modeling diamond value, the 2000
and 2001 parcels were not valued as a single parcel; rather they were combined on paper only,
keeping the diamonds separate for later layout exercises that are used to determine if the
recovered diamonds differ in a gross sense across the 140/141 kimberlite body as drilled to date.
Modeled dollar per carat values in diamond exploration takes account of the expected diamond size
distribution from any potential, future production scenario. An average dollar/carat value is based
on diamond values extrapolated upwards to include recoveries modeled in the larger diamond sieve
sizes. A model for 141 was fitted around the actual dollar per carat per sieve class recoveries
leading to average values for all of the applicable diamond sieve categories. Combination of the
modeled revenue curve and diamond size distribution yielded updated dollar per carat value
estimates. This gave modeled values for macrodiamonds from 141 that range from $US 20 to $US
220/carat. In light of the difference between modeled parcel and actual values, De Beers suggests
that for small diamond samples, the actual parcel value is highly variable and the actual dollar
per carat value for a potential producer is usually understated.
Modeled values were combined with grade estimates and dollar per tonne values were calculated for
the modeled size distributions. Hence, as a preliminary assessment of revenue based on value and
grade estimates, De Beers indicates a range from $US 1 to 26/tonne. Confidence limits of 80% for
the modeled values and
54
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
preliminary assessment of revenue reflect variability in diamond size distribution and diamond
value, and not of grade. However, the Company considers all estimates, particularly those of
grade, with low confidence in respect of newly-defined geological complexity (at least 4 phases of
kimberlite) and variations in diamond size distribution in the 141 and 140 bodies, overall small
diamond parcel sizes, and low levels of sampling across the breadth of the body (nugget-effect).
Valuation of the 2000/2001 diamonds was conducted during November 2002 by WWW International
Diamond Consultants Ltd. (hereafter, WWW). WWW indicated an overall average value based on its
open market price book some 15-20% higher than that listed by De Beers for the same diamond
parcels. The De Beers valuations were made utilizing the DTC June 2002 price book. The single
large stone measuring 3.335 carats that was recovered from large diameter drillhole 141-20 was
given a value of $US 450/carat, compared to $US 390/carat attributed by De Beers. WWW also
pointed out the technical difficulties of putting a realistic market value on a relatively small
geological sample. The principals of WWW are associated with the Kensington Technical Committee
and also may have a financial interest in Kensington Resources Ltd..
9.2.14.6 2001 Macrodiamond Breakage Study
A total of 441 macrodiamonds from Kimberlites 141 and 150 were examined for fresh, unetched
surfaces that are considered the result of man-made breakage caused by drilling or diamond
recovery procedures. Of the 33 stones examined from kimberlite 150, thirteen were significantly
broken with estimated loss of diamond ranging from 50% to >75%. Two stones were “fragments”,
which are defined as diamonds that have no original faces intact, thus obscuring determination of
the size of the original stone, and three stones were “minor” to “very minor” fragments with
estimated diamond loss of greater than 50% of the stone that strongly suggests shattering of
larger diamonds. In total, 39.4% of the diamonds from Kimberlite 150 were broken to some degree.
All stones recovered from Kimberlite 150 were captured in round diamond sieves having openings
2.845 millimetres and smaller. The increased breakage is due to the relatively harder and higher
density rock in kimberlite 150 compared to softer, more altered kimberlites as seen in bodies 141
and 122.
Seventy-six macrodiamonds of a total of 407 examined from kimberlite 141 samples were damaged to
some degree. Of the total number from Kimberlite 141, approximately 3% (12 stones) were
“fragments” and 4% (17 stones) classed as “minor” to “very minor” pieces that strongly suggest
shattering of a larger diamond. The remaining 47 broken stones constitute 10.8% of the diamonds
making a cumulative macrodiamond breakage of 18.7%. This figure is marginally higher than the 17%
breakage observed in the investigation of samples from body 141 in 2000 and is considered an
acceptable low level of breakage by De Beers during a large diameter drill program. Of the 98
stones captured by a 2.464 millimetres round diamond sieve or larger, 11 stones had estimates of
greater than 25% loss due to breakage, although, most of the largest stones captured by 3.454
millimetres sieves and larger did not have significant breakage. However, loss of “fragments” and
“minor” pieces to the discarded, undersize fraction of the excavated kimberlite (<1.5
millimetres) cannot be adequately quantified and shattering of larger diamonds may still be an
issue beyond simple estimation of loss from recovered stones. Estimation of the actual amount of
diamond lost from broken pieces is not factored into the grade calculations or grade forecasts,
which are based on size distribution of the recovered stones.
9.2.15 2002 Exploration and Sampling Program
The budget for this program was estimated at $5.2 million. A two-stage drilling program
(coring and minibulk sampling) was focused on improving the understanding of geology, diamond
distribution, and diamond values within the combined 140/141 body with a goal of ultimately proving
up resource tonnage. Minibulk samples were acquired from three large diameter, reverse-circulation
drillholes (914.4 millimetres or 36 inch), which were targeted on the central part of the northwest
eruptive centre. These drillholes were targeted to provide additional stones in order to improve
confidence levels in diamond valuations for this part of the body. In addition, five favourable
locations were chosen from the sparsely-tested southeastern and central portions of the
55
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
140/141 body for minibulk sampling using large diameter (609 millimetres or 24 inch) reverse
circulation drilling.
The program gave emphasis to the following:
i)
A 2 Phase Drilling Program composed of 25 NQ coreholes (1.875
inch diameter), three —
36 inch diameter RC boreholes, and five — 24 inch diameter RC boreholes;
ii)
Geophysical Studies: Ground Magnetic and Gravity Surveys, and a Magneto-Telluric Survey;
iii)
De Beers Evaluation by MRS: Grade Forecasts, Valuation, and Revenue Calculations;
iv)
Geotechnical Studies – Test structural integrity of bedrock and kimberlite;
v)
GEMCOM Modeling of the Kimberlite and Economic Parameters; and
vi)
Conceptual Modeling Exercise: an in-house study conducted by AMEC engineering with
assistance from the JV partners, to define thresholds for continued economic evaluation of
the kimberlites. This is an internal report that is not specifically applicable to a
single body.
Large diameter, air-assist, mud-flood, reverse circulation drilling (LDDH) was conducted by
Layne-Christensen Drilling. Three cased 36-inch LDDH are targeted in a tight cluster around
corehole 141-29 and LDDH 141-04 which returned significant grades and larger stones in 2000. The
remainder of the LDDH program included five 24-inch boreholes strategically placed in locations of
favourable corehole intervals with indications of higher diamond prospectivity. The eight large
diameter drillholes will provide additional carats to increase the level of confidence in grade
forecasts, valuations and revenue modeling by De Beers.
9.2.15.1 2002 Geophysical Program
Ground geophysical surveys completed in summer of 2002 on the 140/141 body and surrounding
areas indicated the possibility of thicker kimberlite than originally expected in areas extending
from and close to the combined body (Figure 2). One such adjacent area was shown by coincident
gravity and magnetic anomalies as a large extension (approx. 600 x 600 metres) westwards from the
southern part of kimberlite body 140. In addition, an intense gravity anomaly coincident with a
weak magnetic dipole occurs off the western flank of 141. Another gravity anomaly of similar
magnitude and size (approx. 600 x 600 metres) exists approximately 800 metres to the southeast of
body 140. These anomalies fit in well with the linear northwest trend apparent in the main
kimberlite cluster. JV geophysicists are evaluating these anomalies to ascertain whether they are
prospective for new areas of kimberlite.
9.2.15.2 2002 Core Drilling Program
A total of 25 NQ coreholes (diameter of 1.875 inches or 47.6 millimetres) were completed on
kimberlite 141/140. Drillhole 141-36 intersected 171.0 metres of kimberlite, and corehole 140-21
produced 264.2 metres of kimberlite and was terminated while still in kimberlite due to poor
drilling conditions. The coarseness of kimberlite and thicker interval may indicate that this hole
is on or near the vent of kimberlite 141/140 and is considered highly prospective for diamonds due
to indicator mineral abundance, coarse grain size, and presence of mantle xenoliths. Preliminary
evaluation of core from the south-central portion of the 140/141 body indicated a new area of
stratigraphically distinct upper kimberlite which exhibits characteristics that are considered
prospective for diamond grade. Boreholes 141-18 and 141-37 were both terminated in kimberlite due
to lost steel downhole, and borehole 140-20 was shut down in kimberlite due to drilling
difficulties. Table 11 summarizes the core drilling program.
9.2.15.3 2002 Reverse Circulation Drilling and Sampling for Macrodiamond Recovery
Three large diameter drillholes (914.4 millimetres or 36 inch) were targeted on the central part of
the northwest eruptive centre in order to maximize recovery of diamonds to improve confidence
levels for diamond valuations
56
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
in this part of the body. Each of the three drillholes were spotted within 15 metres of a
centrally located NQ corehole (141-29) that was drilled in 2002 to permit better understanding of
the kimberlite intersection, which provided the best macrodiamond recoveries in 2000 (large
diameter drillhole 141-04).
Figure 2: 2002 Geophysical Surveys on Kimberlite 140/141
Ground gravity above and Ground magnetic below. Grid is 100 metre spacing; symbols
represent historical drillholes.
57
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Subsequent to core drilling, several of the most prospective kimberlite intersections were
identified for minibulk sampling by large diameter (609 millimetres or 24 inch) reverse
circulation, mud-flood with air-assist drilling methods, which were conducted from September
29th to November 22nd. A total of 1,271.9 tonnes of kimberlite was excavated
from the boreholes and then screened onsite for disposal of fines <1.5 millimetres in size.
Drilling and sampling information for all eight large diameter boreholes is shown in Table 12.
The initial stage of diamond recovery was conducted at a Dense Media Separation plant (DMS) with 5
tonnes/hour capacity that treated material in the size range of 1.5 millimetres to 12.5 millimetres
after preparations to remove clayey fines and crushing of >12.5 millimetres oversize material.
The plant is located in Grande Prairie and is operated by De Beers Canada Inc. Separation
procedures produced 1.5 tonnes of diamond-bearing heavy mineral concentrate from the eight large
diameter drillholes. Final diamond recovery occurred at high-security facilities operated by De
Beers in Johannesburg, South Africa.
Bottom of
Kimberlite
Total Drill
Drillhole
Top of
Kimberlite
Thickness
Depth
Number
Kimberlite (m)
(m)
(m)
(m)
140-10
110.0
242.0
132.0
250.8
140-11
102.0
167.0
65.0
201.0
140-12
102.0
242.9
140.9
247.5
140-13
110.0
236.6
126.6
243.0
140-14
109.0
244.3
135.3
249.0
140-15
102.0
336.5
234.5
342.0
140-16
99.7
237.3
137.6
243.0
140-17
104.1
258.2
154.1
261.0
140-18
99.8
120.0
20.2
120.0
140-19
104.1
218.1
114.0
231.0
140-20
99.5
221.0
121.5
221.0
140-21
105.3
369.5
264.2
369.5
140-22
107.8
185.0
77.2
198.0
140-23
125.0
180.9
55.9
192.0
140-24
110.7
214.8
104.1
225.0
140-25
108.2
189.6
81.4
195.0
140-26
110.7
218.5
107.8
225.0
140-27
118.7
207.4
88.7
219.0
141-29
105.8
273.0
167.2
279.0
141-34
101.4
238.1
136.7
246.0
141-35
109.0
215.0
106.0
222.0
141-36
102.5
273.5
171.0
280.0
141-37
104.8
124.0
19.2
124.0
141-37
104.8
255.1
150.3
261.0
141-38
106.2
218.5
112.3
231.0
Totals:
3,023.7
5,875.8
Table 11: Summary of 2002 Core Drilling Program
58
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
RCmud1
Hole
Proximal NQ
Kimberlite
Total Drill
Excavated
Sample
Drillhole
Diameter
Corehole2
Thickness
Number of
Depth
Mass
Mass
Number
(mm)
(Pilot hole)
(m)
Samples3
(m)
(tonnes)
(tonnes)
141-30
914.4
141-29
161.6
14
264.6
233.82
104.09
141-31
914.4
141-29
166.8
14
269.8
241.39
95.88
141-32
914.4
141-29
165.8
28
4
268.8
253.78
96.59
141-33
609
141-09
252.6
23
359.0
176.48
100.83
140-285
609
140-21
111.8
10
217.1
72.16
57.65
140-29
609
140-16
131.2
12
230.8
84.87
58.22
140-30
609
140-17
150.0
13
259.0
100.10
63.82
140-31
906
~80 m from 140-21
166.4
15
274.7
109.24
69.93
Totals:
1,306.3
129
2,143.8
1,271.87
647.01
1
= RCmud refers to Reverse Circulation, mud-flood with air-assist drilling methods
2
= Information for the core drilling program was reported in a news release by
Kensington Resources Ltd. dated Oct. 15, 2002
3
= Typically 12 metre sample interval
4
= 6 metre sample interval utilized to improve resolution
5
= Drillhole terminated prematurely at a depth of 217.1 metres due to downhole
problems
Table 12: Kimberlite Intersections and Sample Tonnages for 2002 Program
9.2.15.4 2002 Results of Macrodiamond Recovery
On March 28, 2003, the Company reported the initiation of final diamond recovery for minibulk
samples from the 2002 program. Approximately 1.5 tonnes of DMS heavy mineral concentrate samples
containing macrodiamonds were separated from 1,272 tonnes of kimberlite excavated by three 914
millimetres (36 inch) and five 610 millimetres (24 inch) diameter drillholes targeted on the
140/141 composite kimberlite body. The Company conducted on-site due-diligence auditing and
monitoring of the final diamond recovery procedures by Brent C. Jellicoe, P.Geo., the Company’s
Qualified Person, and Anthony Bloomer of Venmyn Rand (Pty) Ltd. of Johannesburg, South Africa, an
independent firm of mining and minerals management advisors. Final diamond recovery for the Fort à
la Corne drillholes was conducted at the newly renovated De Beers’ Group Exploration Macro-diamond
Laboratory (GEMDL), located in Johannesburg, South Africa. Laboratory renovations completed during
2003 focused on increasing the levels of efficiency and security in the facility, while in
compliance with ISO 17025 accreditation standards.
The final macrodiamond recovery values were reported to the FalC-JV partners in July of 2003. A
summary of all recoveries is shown in the Table 13 followed by a summary of large stone recovery
by drillhole in Table 14. Recovered macrodiamonds were subjected to characterization studies
including; luminescence, magnetic susceptibility, and photography. The stones were then cleaned,
re-weighed, and re-sized before valuation in Charter House, London England, a De Beers facility.
The stones were then sent back to Kimberley, South Africa for a Breakage Study
A total of 54 macrodiamonds larger than 0.25 carats were recovered from the samples. These stones
had a combined weight of 42.03 carats. Only 5 macrodiamonds weighing 0.645 carats were recovered
from
59
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
concentrate cage cleanups, DMS Audits, and composite granulometry samples. This is less than 1%
of the total stone recovery.
Range of
Average
RCmud1
Kimberlite
Sample
Minibulk
Borehole Sample
Drillhole
Thickness
Excavated Mass
Mass
Total
Total
Sample Grade
Grade
Number
(m)
(tonnes)
(tonnes)
Stones
Carats
(cpht)
(cpht)
141-30
161.6
233.82
104.09
155
14.77
0 – 15.6
6.317
141-31
166.8
241.39
95.88
153
16.62
0- 22.1
6.885
141-32
165.8
253.78
96.59
144
16.93
0 – 17.6
6.671
Subtotal 36” LDDH
494.2
729.99
296.56
452
48.32
141-33
252.6
176.48
100.83
45
16.795
0 – 114.4
9.516
140-282
111.8
72.16
57.65
15
1.22
0 – 8.2
1.691
140-29
131.2
84.87
58.22
72
14.45
1.6 – 58.1
17.026
140-30
150.0
100.10
63.82
55
9.49
0 – 46.7
9.490
140-31
166.4
109.24
69.93
29
3.125
0 – 16.6
2.861
Subtotal 24” LDDH
812.0
542.87
350.45
216
45.09
Other3
1
0.35
Totals:
1,306.3
1,271.87
647.01
669
93.760
1
= RCmud refers to Reverse Circulation, mud-flood with air-assist drilling methods
2
= Drillhole terminated prematurely at a depth of 217.1 metres due to downhole problems
3
= Recovery from composite granulometry samples and Gravel Purge after processing
Table 13: Summary of Final Macrodiamond Recovery Results and Grades for 2002 Program
9.2.15.5 2002 Results of Macrodiamond Breakage Study
Macrodiamond breakage studies indicate potential diamond loss due to adverse drilling methods
and recovery procedures. Recent breaks in a diamond caused by mechanical damage can often be
discriminated from those formed by natural causes. A total of 644 diamonds recovered from the
Fort à la Corne kimberlite bodies 140 and 141 during 2002 were examined for fresh breakage by the
Harry Oppenheimer House (HOH) Geology team. Only breakage with unetched (i.e. “fresh”) surfaces
were considered. “Chipped” stones, or those that have less than 5% of the original diamond having
been removed through fresh breakage, are considered “whole”. “Significantly broken” is defined as
more than 5% of the original diamond lost due to fresh (man-made) breakage. “Major“ particles
refer to the breakage of diamonds to the extent where more than 50%, but less than 95% of the
original diamond is remaining A “minor” fragment constitutes less than half of the original
diamond. The presence of minor fragments, especially very minor or “less than 25% remaining and
fragment”, strongly suggests the shattering of stones. A fragment is defined as a diamond that has
no original faces remaining, rendering it impossible to determine the original size of the stone.
Some 22% of the total 644 diamonds examined from kimberlite 140/141 samples were damaged to some
degree. Approximately 10.4% were chipped and are considered “whole”. Seventy diamonds or 10.87%
are major particles with greater than 50% of the stone remaining. Only three diamonds or 0.47%
are “minor” fragments that have less 50% remaining. This indicates that shattering of larger
stones was minimal in 2002, and much lower than the 3-4% seen in 2001. However, loss of
“fragments” and “minor” pieces to the
60
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
discarded, undersize fraction of the excavated kimberlite (<1.5 millimetres) cannot be
adequately quantified and shattering of larger diamonds may still be an issue beyond simple
estimation of loss from recovered stones. Total diamond breakage (not including “chipped” stones)
is 11.34%, which is significantly lower than total breakage seen in 2000 and 2001. In 2002,
Kimberlite 141 displayed a higher level of breakage (13.66%) than body 140 (4.35%). However, due
to the small number of stones recovered from each drillhole from 140, comparison on a percentage
basis should be made with considerable caution. Estimation of the actual amount of diamond lost
from broken pieces is not factored in to the grade calculations or grade forecasts, which are based
on size distribution of the recovered stones only.
>0.25 and <0.5 ct.
>05. and <0.75 ct.
>0.75 and <1.0 ct.
>1.0 carat
RCmud1
Drillhole
Number
Number
Number
Number
Number
Number
Number
Number
Number
of Stones
of Carats
of Stones
of Carats
of Stones
of Carats
of Stones
of Carats
141-30
8
2.910
0
0
0
0
0
0
141-31
8
2.985
1
0.695
1
0.860
0
0
141-32
7
2.320
4
2.230
0
0
1
1.045
141-33
4
1.340
1
0.630
1
0.855
1
10.230
140-282
0
0
0
0
0
0
0
0
140-29
5
1.490
0
0
0
0
4
8.145
140-30
3
0.825
0
0
1
0.895
1
3.610
140-31
1
0.325
1
0.515
0
0
0
0
Other3
1
0.35
0
0
0
0
0
0
Totals:
37
12.545
7
4.070
3
2.610
7
23.030
1
= RCmud refers to Reverse Circulation, mud-flood with air-assist drilling
methods
2
= Drillhole terminated prematurely at a depth of 217.1 metres due to downhole
problems
3
= Recovery from composite granulometry samples and Gravel Purge after processing
Table 14: Summary of Large Stone Recovery for 2002 Program
9.2.15.6 2002 Raw Valuations of Macrodiamonds
Macrodiamonds recovered from the 2002 drill program were valued in August 2003 using the De
Beers July 2003 price book. Macrodiamonds from the 2000 and 2001 programs were updated to this
price book at the same time. Table 15 summarizes the raw macrodiamond values. The full spread of
values per sieve size were utilized to calculate modeled values, which are reported in the De
Beers’ Mineral Resource Management (MRM) Report summarized later in this overview.
2000
2001
2002
Av/Pr
Av/Pr
Av/Pr
Carats
Value
($/ct)
Carats
Value
($/ct)
Carats
Value
($/ct)
21.6
806.62
37.34
42.08
2,733.38
64.96
90.96
3,371.12
37.06
Table 15: Raw Stone Values Based on the De Beers’ July 2003 Price Book
61
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.15.7 2002 Results of Microdiamond Recoveries
Representative core samples from drillholes 140-16 and 140-17 were selected for total diamond
recovery using caustic dissolution methods at Lakefield Research in Ontario. Residues from the
caustic procedures conducted at Lakefield were shipped to the De Beers’ Kimberley Acid laboratory
in South Africa for final picking and imaging. The coreholes intersected previously untested
kimberlite phases including thick intervals of xenolith-rich breccia, coarse olivine pyroclastic
kimberlite, and matrix-supported kimberlite located in the south and central part of the combined
140/141 kimberlite body. Recoveries of a total of 446 microdiamonds (206 stones from 140-016 and
240 stones from 140-17) were combined with the existing diamond dataset and incorporated into the
2002 grade modeling exercise conducted by De Beers.
Samples also were collected from corehole 140-12 for the dual purpose of increasing the
microdiamond inventory from two distinct kimberlite phases identified in the southern part of the
140/141 kimberlite, and to test diamond recovery procedures at the SRC. Thirty-one microdiamonds
were recovered from 41.54 kilograms sampled from the “speckled beds”; this calculates to 74.6
stones per 100 kilograms. Eighty microdiamonds were recovered from 40.92 kilograms sampled from
the “kimberlite breccia beds”; this calculates to 195.9 stones per 100 kilograms. Comparable stone
concentrations numbers are as follows,
Kimberlite Breccia in 140-16:
162.5 stones/100 kilograms
Kimberlite Breccia in 140-17:
120.3 stones/100 kilograms
Speckled beds in 140-16:
72 to 128 stones/100 kilograms
Speckled beds in 140-17:
88 to 102 stones/100 kilograms
Range for “Coarse” Megagraded bed:
5 to 194, but averaging about 75 stones/100 kilograms
Range for “Fine” Megagraded bed:
5 to 175, but averaging about 50 stones/100 kilograms
It is very important to keep in mind that it is the size distribution of the stones that is most
important, not the stone concentration. Five stones were large enough to be recovered on the +212
micron screen and one stone was recovered on a +1180 micron screen; this single large stone weighed
9.52 mg or 0.0476 carats and is considered a macrodiamond; the three axes of the stone measure 2.14
x 1.78 x 1.70 millimetres. Proper allocation of diamonds to specific kimberlite phases by De Beers
in the 140/141 body remains contentious until the geology of this complex body is better resolved.
A PQ corehole was drilled proximal to the three 36 inch diameter drillholes near the centre of the
141 deeper-going zone. This core was slabbed and then representatively sampled for diamond
recovery using caustic dissolution at Lakefield Research Laboratory. All diamonds and residues
from processing were forwarded to Kimberley Microdiamond Laboratory for routine weighing, shape
classification, and normal due diligence. A total of 396 stones were recovered from 636.9
kilograms of kimberlite sample. These stones were added to the diamond inventory for the
megagraded beds of 141 and form part of the diamond dataset utilized for grade forecasting by De
Beers.
9.2.15.8 2002 Grade Forecasts, Modeled Values, and Modeled Revenue Estimates
The MRM department of De Beers Consolidated Mines has carried out annual reviews of the Fort à
la Corne project since 1999 that included resource estimation work as well as recommendations for
prioritization of the kimberlite bodies. MRM prepared an update for kimberlite 140/141
incorporating all relevant historical microdiamond and macrodiamond diamond recovery data as well
as geological information current to Spring of 2003. This report was received in a final format
during September 2003.
In 2002, the 140/141 body was classified at the “deposit” level for all variables considered
including geology, grade, revenue, and sampling data. The 2002 Fort à la Corne MRM review utilized
data to differentiate the
62
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
kimberlite into coarse and fine zones based on diamond size frequency. Grade forecasts for
these zones ranged from 7 to 12 cpht and corresponding revenues, US$ 20-220/tonne.
Based on these findings, MRM recommended a program of large diameter drilling in the vicinity of
holes 141-04 and 141-05 aimed at increasing the macrodiamond parcel for revenue modeling. A
cluster of three 36” diameter holes were drilled within close proximity of 141-04 and a total of
48.24 carats were recovered. In addition, MRM recommended improving understanding of the
geological model for the kimberlite through core drilling that would also provide opportunities for
identification of coarser grained zones. Based on kimberlite intersections in these coreholes,
five 24” diameter drillholes were drilled in locations extending from the 141 central area to the
140 central area. Of these holes, one was targeted to investigate the “fine-grained vent”
intersected at corehole 141-33, and the others to test the assumed extension of the mega-graded
bed. A total of 45.09 carats were recovered from these drillholes.
9.2.15.9 2002 Geological Subdivisions of the 140/141 Kimberlite
A substantial amount of geological investigation continues on core drilled from the 140/141
body. In summary, five geological subdivisions were utilized for modeling evaluating diamond
results.
These units are very briefly described as follows:
o
Mega-graded Bed – overall fining-upwards kimberlite commencing with xenolith-rich
breccia units at the base and terminating in fine to very fine-grained material on top; the
mega-graded bed itself can be separated into “fine” and “coarse” size distributions, which
in terms of spatial location, are related to proximity to the interpreted eruptive centre
of the 141 mega-graded bed – i.e., coarser diamond distribution closer to the centre of
eruption.
o
Cyclic/repeated gradational Beds – similar to the mega-graded bed but consisting of
stacked, internally fining-upwards beds with subtle to very obvious subdivisions or
contacts in an overall fining-upwards sequence; these beds likely represent clear changes
in energy levels during eruption and asymmetry within the eruption column.
o
Fine-grained Kimberlite (Vent) – postulated younger central vent feature characterized
by relatively fine-grained kimberlite.
o
Kimberlite Breccia – a separate xenolith-rich unit distinguished from the breccias
located at the base of the mega-graded unit containing variably abundant mantle-derived
material.
o
Speckled Kimberlite – a distinctive matrix-supported kimberlite containing variably
abundant mantle-derived material (ilmenites and garnets, in particular); this phase
contains subordinate units of both kimberlite breccia and macrocrystic, coarse olivine
kimberlites.
9.2.15.10 2002 Grade Forecasts
The relatively sparse data, particularly when separated into the different geological units,
implies that global estimates per geological subdivision are the only meaningful calculations
possible. A grade-size plot was derived from the combination of micro- and macro-diamond data for
each of the five geological units. Size frequency distributions were plotted from these data
leading to calculation of grade estimates that were then both incorporated into revenue models. A
sixth unit was created by division of the mega-graded bed into fine and coarse size frequency
distributions.
63
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
The coarsest diamond size distributions were seen in the Mega-graded-coarse, Kimberlite
Breccia and Fine-grained Vent units, although the distribution of the latter unit appears
anomalously coarse due to the presence of a 10.23 carat stone. The Mega-graded bed-coarse shows
the most consistency across the micro- and macro-diamond size ranges reflecting the larger number
of recovered stones of all sizes, particularly with addition of the diamonds from the three 36 inch
diameter holes. The other kimberlite units show varying numbers of stone counts, but all are
substantially less than the coarse mega-graded bed and highlight the uncertainty associated with
grade results generated in this report. Stone counts utilized in the size frequency distributions
and grade forecast results are shown in Table 16.
9.2.15.11 2002 Revenue Models
Raw values of the macrodiamonds were determined by the DTC in London, England based on the
July 2003 price book. Valuation data was electronically compiled into six geological/size
distribution units as previously described. Actual and forecast grade data is shown in Table 17
with revenue per geological unit in dollars per carat.
Tonnes1
Stone Counts
of
Micro-
Macro-
Carats
Geological Unit
Kimberlite
diamond
diamond
Total
>1.5 mm
Mega-graded-coarse
1,048.9
311
888
95.8
88.6
Mega-graded-fine
371.1
226
86
10.9
10.0
Mega-graded-repeated
254.9
180
155
13.6
12.7
Fine Kimberlite (Vent)
176.5
171
43
16.5
16.5
Speckled kimberlite
93.9
126
45
4.6
4.3
Kimberlite Breccia
74.0
183
67
14.3
13.7
1 Some barren samples have been excluded for grade calculation purposes
Table 16:
Total Microdiamond and Macrodiamond Stone Counts and Weights
Grade in cpht (>1.5 mm)
Revenue in US$/carat (>1.5 mm)
Actual
2001
2002
2002
2001
2002
Geological Unit
Sample
Forecast
Forecast
Raw Values
Forecast
Forecast
Mega-graded-coarse
8.4
12
12
32.9
115
97
Mega-graded-fine
2.7
5
7
17.2
38
71
Mega-graded-repeated
5.0
—
8
22.2
—
75
Fine Kimberlite (Vent)
9.3
—
5
33.7
—
93
Speckled kimberlite
4.5
—
9
40.0
—
67
Kimberlite Breccia
18.6
—
15
53.6
—
97
Table 17:
2002 Evaluation Program – Actual and Modeled Grade and Revenue Data with Comparison to 2001 Program
Each of these sub-parcels were plotted in log-space showing average sieve size against dollar per
carat. Some 150 carats of macrodiamonds were available for revenue modeling, but the number per
sub-parcel was considerably smaller. As would be expected, the extremely small parcels showed no
consistent trends or obvious differentiation and the decision was made to combine electronically
the complete data and model a single dollar per carat per sieve class. A geologically-based
revenue split could be made in the future if sufficiently more stones are added to each dataset.
64
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Plotted in log-space, the combined data showed a degree of consistency from a revenue perspective
in the smaller sieve classes below +13 diamond sieve (4.521 millimetres). Very few carats exist in
the larger size classes (only 15% by weight of the total parcel) and considerable modeling of
assortment (model, quality, and colour) is required. Existing data from De Beers’ group
operations, combined with the assortment profile of the smaller diamonds was used to extrapolate
the revenue curve up to the +23 diamond sieve (10.312 millimetres). The resultant dollar per carat
per sieve class table has subsequently been applied to the six modeled size
frequency distributions. Variations in diamond coarseness of the units lead to six distinct
overall dollar per carat figures at a bottom cut-off of 1.5 millimetres and at SSV on the DTC July
2003 price book.
9.2.15.12 2002 Deposit Risk
Attempting to define confidence limits or upside and/or downside potential on deposit level
resource data is problematic. By definition deposit level resources imply considerable risk and
hence broad confidence limits. The estimation of the microdiamond-macrodiamond relationship and
hence grade estimation from limited data is, to some degree, a subjective process.
Furthermore, it is likely that the emplacement model of the Fort à la Corne deposits will have some
bearing on the microdiamond -macrodiamond relationship. The microdiamond content (and size
distribution) can vary as a function of emplacement, under-recovery of microdiamonds from wind
action during the sub-aerial pyroclastic event(s), and gravity sorting, which will result in
different ratios of macrocrysts, phenocrysts and interstitial material. These processes can cause
either dilution or concentration of micro diamond potential.
The impact of dilution or concentration of microdiamonds can affect the grade estimation process.
In addition, any physical “sorting” within the microdiamond size ranges will affect the size
frequency distribution and hence revenue estimation.
The deposit risk can be summarized into four main areas:
o
internal geology, the lateral and vertical extent (i.e. volume) of each geological identified unit,
o
the grade of each geological unit,
o
the size distribution of each geological unit, and
o
the assortment (US$/carat/per size) per geological unit.
The risk associated with grade and size frequency distribution has been previously mentioned. In
terms of the assortment profile, the revenue modeling process was forced to assume a similar
assortment for all the geological units. Despite this amalgamation the diamond parcel consists of
about 150 carats, which is well below the 2000 to 5000 carats considered necessary to make a
forecast with reasonable levels of confidence.
9.2.15.13 Conclusions and Recommendations from the 2002 MRM Report
The advances made in the geological model of 140/141 necessitated a complete rethinking of the
grade and revenue estimation processes. It is likely that as geological knowledge and deposit
delineation evolve so will the estimation methodologies. A natural consequence of refining a
geological model is that the available sampling data has to be separated into the relevant
geological subdivisions. This frequently results in creating a situation where there is
insufficient data per geological subdivision for evaluation purposes.
The 2002 Fort à la Corne update classified the project at the Deposit stage for all variables and
parameters. Subsequent to the report the geological model has been revised and further LDD drilling
has been conducted. The recognition of a more complex internal geology resulted in the necessity of
more detailed data per geological unit. Thus despite additional data from the 2002 program, the
project status has not changed significantly and remains at the Deposit stage for geology, volume,
grade, density and revenue.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Based on the current geological understanding of 140/141 the following recommendations can be made:
o
Petrographic studies from existing material (chemical fingerprint, XRF etc) should be done to assist in
geological unit identification, differentiation and the emplacement model.
o
Increase micro diamond database (from existing core) for the fine, speckled and breccia kimberlites.
o
Investigate the potential for diluting and or concentrating micro diamonds as a function of the host
kimberlite.
o
Improve the geological understanding and the extent of the kimberlite breccia unit by delineation drilling.
o
Should the volumetric extent of the kimberlite warrant further investigation this should be in the form of
single 36” diameter LDD holes on a systematic grid.
9.2.15.13.1 Discussion Points Concerning the 2002 MRM Report
In consideration of the MRM Report, the following discussion points are relevant:
1.
The 140/141 kimberlite is characterized by stratigraphic complexity and there appears to be a
high degree of variability in grade and diamond size distribution; it is very likely that the
140/141 kimberlite is the product of at least two eruptive centres or feeders that have
produced a coalescent kimberlite body; at present the geological model is complex and it is
very important to recognize different kimberlite phases and then to properly allocate diamond
recoveries to these units in preparation for modeling grade and revenue; it is the opinion of
the author that further work is required on the geological model and that allocation of
diamond results may change as the geological model evolves.
2.
Most data relates to the mega-graded bed; the mega-graded bed is more a local feature rather
than a pervasive kimberlite wide feature; 50% of the mega-graded samples are “Fine” and are
tested only in the central part of the 141 sector (about 20 ha); the grades and values are not
representative of the entire body; combining data from the mega-graded bed at 140 and from 141
is not advisable as they likely came from two different vents and eruptive events.
3.
Considerable additional sampling will be required to obtain a confident geological model for
the entire kimberlite; this model requires broad distribution of drillholes and representative
sampling both vertically and horizontally in order to model the spatial distribution of
diamonds in terms of size and number; however, delineation of the extent of higher grade zones
may permit early estimation of the volume and tonnage of that phase – this becomes a relevant
evaluation criterion that may discourage further work if the calculated tonnage falls below
that which is thought to be required for an economic deposit.
4.
In previous years, grade forecasts for Fort à la Corne Grade kimberlites typically have been
2-3 times higher than actual sample grades. Two forecasts this year are lower than the actual
sample grades. De Beers has explained that this is the other side of the nugget-effect
whereby a greater amount of diamond is recovered from a sample than that which would be
representative of a larger sample. Both the breccia and Fine Kimberlite (Vent) would fall
under this explanation if the kimberlite unit contacts and corresponding allocation of
diamonds were correctly determined.
5.
Recovery derived from total content models for the subdivisions was factorized in respect of
the smaller diamond to represent a probable production type diamond size distribution, thus
eliminating smaller diamonds that would normally be screened out to undersize or locked in
tailings during production.
6.
Small parcel sizes limit confidence in the modeled grades, values, and revenues; in
particular, all phases besides the mega-graded bed have very small diamond parcels.
7.
It is difficult to compare results from 2000, 2001, and 2002 due to different presentation
formats and different (evolving) ways of modeling the data.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.15.13.2 Disclaimers and Cautionary Points — 2002 MRM Report
1.
Grade was derived from the total diamond content model. This procedure assumes that the
observed diamond content distribution with size is reflected correctly by sampling and
provides a global grade estimate for the part of the kimberlite covered by sampling.
2.
Revenue figures supplied in this report are based on very small amounts of diamonds and could
vary substantially from actual average values determined from larger diamond parcels.
3.
Actual parcel value is calculated by dividing total dollar value by total carats in the
parcel. For small samples, this value is highly variable and simulations have shown that the
actual dollar per carat value for a producer is usually understated this way.
4.
Modeled dollar per carat value takes account of the expected diamond size distribution for
the producer and is based on average values extrapolated for larger diamond sieves.
5.
Under normal conditions, it is possible to draw a valid comparison only if the diamond parcel
contains more than 2000 carats. The absence of a sufficient number of large stones means that
there is still considerable uncertainty associated with the revenue model.
6.
If the presence of any part of the size distribution has been influenced by secondary events
in any part of the body, local grade derived from these methods would not be valid and serious
difference in diamond size distribution and grade may occur locally within the kimberlite.
7.
More confidence in the extrapolated values can only be achieved by having a larger diamond
parcel for valuation.
8.
Diamonds could be lost during sampling and treatment as a result of breakage or non-recovery
due to low luminescence; breakage is not accounted for in any of the modeling, despite the
preponderance of breakage in larger stones.
A joint Federal / Provincial Targeted Geoscience Initiative (TGI) was established between the
GSC and the Saskatchewan Energy and Mines (SEM, now Saskatchewan Industry and Resources or SIR, and
including the Saskatchewan Geological Survey or SGS) to further the study of the Fort à la Corne
kimberlite field. The project was initiated in 2001 and designed to encourage an interest and
understanding of the diamond potential of central Saskatchewan. The TGI group primarily is driven
by Gary Delaney (SGS), J.P Zonneveld (GSC), and Bruce Kjarsgaard (GSC).
The TGI is made up of two main components/phases. The first is an update of the Diamonds of
Saskatchewan SEM review. The second is to involve both a limited 3D seismic survey over the Star
Kimberlite (located on ground held by Shore Gold Inc.) and a more extensive 2D survey over
kimberlite 141 (now defined as the northwest part of the combined 140/141 complex) held by the
FalC-JV. The FalC-JV indicated an interest in participating in the second phase of the program as
it was seen as a way of increasing an understanding of what is thought to be a relatively complex
kimberlite without the need for further drilling. The FalC-JV agreed to donate $10,000 to the
exercise, and Cameco later agreed to complement an additional $5,000 to the program.
The TGI group suggested that it would be useful to run downhole logs in a number of core holes to
aid in the seismic profile. The FalC-JV therefore purchased and installed 2” PVC casing in four
drill holes. Casings were installed in drillholes 140-09, 141-11, 141-12, and 141-15 to depths of
183 metres, 171 metres, 240 metres, and 243 metres, respectively. Multi-parameter downhole
geophysics was conducted in these holes by the GSC/SGS group (and therefore independent to the JV)
between the 16th and 19th of August. The geophysical tools that were run
included natural gamma ray, magnetic susceptibility, density and sonic (porosity). The GSC and SIR
have been allowed full access to the core for geological logging. The need for additional sampling
will be assessed on a case by case basis. Samples collected from core to date will be used for
micropaleontological studies (examination of foraminifera for biostratigraphic age and
paleoenvironment), sedimentology (polished
67
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
slabs to be photographed and returned),
petrology/volcanology, whole rock geochemistry, and geochronology (perovskite/phlogopite/zircon
recovery – small samples).
Data from the multi-parameter downhole geophysics program on four FalC drillholes has been
integrated into the TGI results. Field work for a broad 2D survey over most of the 140/141
kimberlite was completed during the first quarter of 2003. Data from both of these surveys was
processed during the remainder of 2003.
Coreholes from 2002 and prior have at least a simple log showing major contacts; works continues on
constructing full petrographic and stratigraphic logs for each of the coreholes. These graphic
logs will be incorporated into fence diagrams that approximate the 2D seismic lines and several
other cross-sectional views. Coreholes drilled in 2003 from kimberlite 140/141 have been logged
and incorporated into cross-sections and 3D block diagrams. The geological model for this body is
undergoing review by the JV partners and a final report is in preparation. Approximately 128
samples have been collected from core to date, which will be used for micropaleontological studies,
sedimentology, petrology/volcanology and geochronology.
9.2.15.15 2002 Venmyn Rand Mini-Audit Report on Macrodiamond Recovery
Venmyn Rand (Pty) Ltd. was hired by the Company to evaluate efficiency and suitability of
final diamond recovery procedures and equipment at the newly renovated GEMDL facility. The
end-product of the evaluation was an independent Qualified Person’s report documenting the new
configuration of the laboratory and recommendations for future analytical work. This report
remains as an internal reference document for the company and is not considered material. In
addition to monitoring diamond recovery, Mr. Jellicoe (Kensington’s Qualified Person) visited
several highly successful De Beers-operated, small to large, open pit mines in Botswana and South
Africa. During these visits, he familiarized himself with scales of mining and ore processing that
may one day be applied to high priority FalC-JV kimberlite bodies.
9.2.16 2003 Exploration and Sampling Program
During the first eight months of 2003, no field programs were conducted at Fort à la Corne as
the bulk of the 2002 diamond recovery and interpretation program was underway. In August 2003, the
FalC-JV partners met to discuss a work program for 2003 and decided to implement a $3.0 million
program in part based on recommendations put forward by geoscientists of De Beers’ MRM following
evaluation of draft interpretations of results from the combined 2000, 2001, and 2002 programs.
This program focused on improving the understanding of geology, diamond distribution, and diamond
values of the southern part of the 140/141 body with a goal of ultimately proving up resource
tonnage for the “kimberlite breccia”. In addition, a significant drilling and sampling effort was
aimed at investigating the geology and diamond distribution in other high priority bodies including
Kimberlites 122, 148, and 150.
9.2.16.1 2003 Airborne Geophysical Survey
The 2003 work program commenced with a fixed-wing airborne tri-sensor magnetic gradiometer
survey over the entire FalC-JV project claim area that was run by Goldak Airborne Surveys. The
survey had some over-run beyond the claim boundaries and the affected claim holders were offered
hard copy results covering their land. Two blocks were flown for a total of 3,090 line kilometres
at a 150 metre line spacing. The airborne survey provides a much improved magnetic dataset
compared to previous airborne data acquired in 1989 and 1990. An example of the survey results is
shown in Figure 3.
Kensington received a final report documenting the program and including a full digital record of
the results. The project operator has produced full scale colour maps and interpreted the results.
Six new magnetic anomalies potentially representing un-tested kimberlite bodies were identified.
These targets required drill-testing to confirm the presence of kimberlite and to permit logging
for petrographic character.
68
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.16.2 2003 CSAMT Survey
Although CSAMT (a type of magneto-telluric survey) was unsuccessful in 2002, this type of
geophysical survey was attempted again using a different array of frequencies to produce a better
resistivity differentiation between kimberlite and country rock. The survey was run by Empulse
Geophysics in September 2003 over the 140/141 kimberlite. Results are held by the Operator, De
Beers, and are not considered relevant or material due to operational difficulties.
9.2.16.3 2003 Ground Gravity Surveys
Ground gravity surveys accompanied by differential GPS were conducted by an in-house De Beers’
crew over kimberlite 122, a large area embracing kimberlites 148, 150, and the area around
kimberlite 140/141, which was partially surveyed in 2002.
Figure 3: 2003 Airborne Tri-sensor Magnetic Gradiometer Survey
Colour contour map of gradiometer results; circular to ovoid purple masses are FalC
kimberlites held by the FalC JV.
The surveys used 100 metre line spacing and 100 metre stations; a total of 2,482 stations were
acquired over a 3 month period. A large gravity anomaly of significant amplitude was delineated
immediately east of, and contiguous to, the 150 kimberlite (shown as the central mass of red colour
contours in Figure 4). The anomaly
69
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
covers an area three times that of the known 150 kimberlite
body, or about 200 hectares. Both the gravity and magnetic data indicate that some kimberlites may
have greater extents than previously outlined. The outlined extent of kimberlite bodies to a 30
metre thickness cut-off by modeling geophysical data is in progress by the operator. Kensington
has received a final report documenting the program and including a full digital record of the
results. The project operator has produced full scale colour maps and interpreted the results.
Figure 4: Compilation of 2002 and 2003 Ground Gravity Survey and 2003 Magnetic Survey
Ground gravity data superimposed over a gray-tone image of airborne magnetic contours.
9.2.16.4 2003 Core Drilling Program
Boart-Longyear mobilized three LF-70 hydraulic core drilling rigs for this program. A total
of 49 core holes provide significant opportunities for understanding the geology of 4 separate,
prioritized kimberlite bodies and for diamond recovery geared to better understanding their diamond
content and distribution.
Drilling concluded during mid-November with a total of 48 HQ (63.5 millimetres or 2.5 inches)
coreholes and one NQ (47.6 millimetres or 1.875 inches) corehole. Diamond core bits are composed
of traceable synthetic cutting diamonds that can easily be distinguished from natural stones.
Significant intersections of prospective kimberlite were encountered in each of the kimberlite
bodies investigated and sufficient coverage of the bodies from this program and previous drilling
will permit construction of geological models. The table shown below
70
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
summarizes the drilling
program. The core was subsequently petrographically logged in detail and sampled for microdiamond
recovery and geochemistry according to priority and prospectivity. A summary of kimberlite core
intersections is shown in Table 18.
Base of
Thickness of
Thickness of
Kimberlite
Thickness
Top of Main
Main
Main
Total
End
Body /
of Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
of Hole
Drillhole
(m)
(m)
(m)
(m)
(m)
(m)
140-32
101.06
101.06
244.30
143.24
146.29
291.00
140-33
100.42
100.42
199.35
98.93
98.93
208.00
140-34
100.20
100.20
205.50
105.3
105.72
219.00
140-35
104.95
113.60
152.43
38.83
56.85
216.00
140-36
99.00
99.00
139.62
40.62
40.62
142.00
140-37
102.92
131.93
142.33
1
10.40
10.40
147.00
140-38
101.90
105.00
214.96
109.96
109.96
228.00
141-40
109.20
138.93
161.35
22.42
25.23
272.00
140-39
100.17
100.17
243.40
143.23
143.23
249.00
140-40
102.00
102.00
237.35
135.35
138.55
246.00
140/141 Total
1,021.82
837.88
875.78
2,218.00
03-150-01
106.32
106.32
198.85
92.53
92.53
207.00
03-150-02
112.78
112.78
214.13
101.35
101.35
225.00
03-150-03
110.42
123.96
169.17
45.21
45.21
180.00
03-150-04
106.80
111.23
169.70
58.47
60.59
192.00
03-150-05
99.90
104.53
154.90
50.37
50.42
174.00
03-150-06
96.28
96.28
216.16
119.88
119.88
222.00
03-150-07
104.15
121.49
157.56
36.07
36.07
165.00
03-150-08
113.73
117.67
205.96
88.29
88.29
213.00
03-150-09
99.00
101.16
183.05
81.89
81.89
192.00
03-150-10
103.47
109.63
135.00
2
31.60
31.60
135.00
03-150-11
113.47
120.90
158.00
3
35.33
35.33
158.00
03-150-12
102.90
102.90
192.50
89.60
89.60
201.00
150 Total
1,269.22
763.66
832.76
2,264.00
03-148-01
92.39
92.39
251.20
158.81
158.81
258.00
03-148-02
93.65
93.65
201.50
107.85
107.85
231.00
03-148-03
92.75
92.75
203.87
111.12
111.12
216.00
03-148-04
99.15
99.15
153.38
54.23
54.23
183.00
03-148-05
0.00
4
67.00
03-148-05a
92.18
92.18
181.00
88.82
91.77
204.00
03-148-06
91.80
91.80
200.09
108.29
108.29
207.00
03-148-07
100.88
100.88
147.24
46.36
46.36
153.00
03-148-08
99.31
99.31
147.12
47.81
47.81
156.00
03-148-09
109.90
109.90
124.93
15.03
16.95
156.00
03-148-10
112.54
112.54
152.31
39.77
39.77
159.00
03-148-11
102.49
102.49
134.80
32.31
36.64
150.00
03-148-12
92.20
92.20
272.85
180.65
180.65
282.00
03-148-13
96.00
96.00
193.33
97.33
97.33
210.00
03-148-14
93.02
93.02
222.85
129.83
129.83
234.00
03-148-15
92.56
92.56
198.31
105.75
105.75
207.00
148 Total
1,460.82
1,323.96
1,333.16
3,073.00
71
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Base of
Thickness of
Thickness of
Kimberlite
Thickness of
Top of Main
Main
Main
Total
End
Body /
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
of Hole
Drillhole
(m)
(m)
(m)
(m)
(m)
(m)
03-122-01
117.05
140.36
204.25
63.89
63.89
213.00
03-122-02
117.10
118.70
230.29
111.59
111.59
249.00
03-122-03
119.45
119.45
195.00
75.55
75.55
204.00
03-122-04
107.20
107.20
225.00
117.80
117.80
231.00
03-122-05
108.48
113.80
183.20
69.40
69.60
195.00
03-122-06
112.41
112.41
178.24
65.83
66.02
186.00
03-122-07
106.80
119.25
195.28
76.03
83.63
204.00
03-122-08
114.00
114.00
193.92
79.92
79.92
204.00
03-122-09
111.60
111.60
268.30
156.70
158.06
279.00
03-122-10
112.00
112.00
140.62
28.62
28.89
144.00
03-122-11
108.00
108.00
153.39
45.39
45.39
165.00
122 Total
1,234.09
90.72
900.34
2,274.00
Grand Total
4,985.95
3,816.22
3,942.04
9,829.00
% of Total
50.7
38.8
40.1
1
= drillhole 140-37 prematurely terminated in disturbed kimberlitic sediments
2
= drillhole 03-150-10 prematurely terminated in kimberlite due to drilling
difficulties
3
= drillhole 03-150-11 prematurely terminated in kimberlite due to drilling
difficulties
4
= drillhole 03-148-05 prematurely terminated in overburden due to drilling
difficulties
Table 18: Preliminary Summary of 2003 Core Drilling at Fort à la Corne
An initial allocation of 12 drillholes was targeted on Kimberlite 148 (drillhole 03-148-05 was
terminated prematurely due to downhole problems). This was later complimented by an additional 4
holes located on the north-central portion of the body where highly prospective, medium- to
coarse-grained, macrocrystic kimberlite was identified. Seven of the drillholes intersected
greater than 100 metres of kimberlite, with an additional two between 90-100 metres. Prospective
core intersections range up to 150 metres in thickness and occur over an area of at least 800x400
metres in size. Figure 5 shows the locations of coreholes drilled in 2003.
Drillholes were widely spread over a grid encompassing most of the deeper-going zone interpreted
from geophysical surveys in the 1990’s. The deepest intersections were encountered over the
north-centrally located gravity anomaly. Prospective core from 03-148-01, 02, 12,14, and 15 proved
to be susceptible to varying amounts and degrees of disintegration due to hydration and swelling.
The core was split and sampled for diamond recovery utilizing caustic dissolution methods at the
SRC, in Saskatoon. Diamonds recovered from these samples were added to the inventory for this
body.
A broad pattern of drilling across Kimberlite 150 produced an additional two 100+ metre
intersections. Kimberlite thicknesses show a significant deeper-going zone located in the west
central part of the body. Prospective medium-grained, macrocrystic kimberlite types were common in
this area. The core was split and sampled for diamond recovery utilizing caustic dissolution
methods at the SRC, in Saskatoon. Diamonds recovered from these samples were added to the
inventory for this body. See Figure 6 for location of the 150 drillholes.
72
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 5: Location of 2003 Coreholes on Body 148 Showing Main Kimberlite Thicknesses
Figure 6: Location of 2003 Coreholes on Body 150 Showing Main Kimberlite Thicknesses
73
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Drillhole placement on Kimberlite 140/141 was targeted to maximize intersection of kimberlite
phases including the “speckled beds” and the “breccia beds”. The objective of this drilling was to
delineate the vertical and areal extent of the breccia beds in particular. These prospective
kimberlite units appear to thin towards the southwest and the west into the interpreted extension
of the 140/141 body as delineated in the 2002 geophysical program. Geological interpretation and
modeling of deposit tonnages for this body are a priority for the operator.
Corehole 141-40 was targeted on a significant gravity anomaly located to the west of the 140/141
body; only 25.23 metres of kimberlite were intersected within mudstones of the Colorado Shale.
Hence the anomaly is not attributed to a substantial new kimberlite body. Similarly, corehole
141-37 intersected only 10.4 metres of main kimberlite, indicating significant kimberlite thickness
is not through-going to the southwest extension, or the gravity anomaly may not be entirely related
to the presence of kimberlite. Four of the 140/141 kimberlite cores were digitally imaged using a
test machine by De Beers. See Figure 7 for location of the 140/141 drillholes.
Figure 7: Location of 2003 Coreholes on Body 140/141 Showing Main Kimberlite Thicknesses
Drillholes targeted on Kimberlite 122 were placed over a broad grid to provide better
representivity over the body for both an understanding of the geology and for microdiamond
sampling. Three drillholes encountered intervals of greater than 100 metres of kimberlite and
prospective medium- to coarse-grained, macrocrystic kimberlite phases were intersected in 8 of the
drillholes. The core was split and sampled for diamond recovery
74
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
utilizing caustic dissolution
methods at the SRC, in Saskatoon. Diamonds recovered from these samples were added to the inventory
for this body. See Figure 8 for location of the 122 drillholes.
Figure 8: Location of 2003 Coreholes on Body 122 Showing Main Kimberlite Thicknesses and Areas Dominated by
Discrete Kimberlite Phases
Roads are shown in red and the dashed lines indicate estimated boundaries between
sectors based on lithological predominance. The light grey grid denotes UTM lines.
9.2.16.5 Geology of Kimberlite Bodies Drilled in 2003
9.2.16.5.1 Kimberlite 140/141
Geological modeling of Kimberlite 140/141 shows it is dominated by a thick interval of graded
fine to coarse-grained olivine pyroclastic kimberlite that have relatively thin intervals of
xenolith-rich, breccia beds in the northern part of the body. Diamond grades and revenue modeling
for these units were reported between 2000
75
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
and 2003. Investigation of the southern part of the
extensive body during 2002 and 2003 by core drilling and a limited numbers of 24-inch reverse
circulation drillholes showed the presence of several new kimberlite phases, although the dominant
kimberlite types are medium to very coarse grain xenolith-rich breccias and matrix-supported
kimberlites (“speckled” kimberlites) considered to be older than the overlying, relatively thin
veneer of graded olivine-rich pyroclastic beds.
Preliminary geological modeling of the southern part of the body, in part from the new core
intersections revealed four main phases of kimberlite including: 1.) repeated graded beds similar
to the graded fine to coarse-grained olivine pyroclastic kimberlite beds located to the north and
east; 2.) a moderately thick interval of older breccia beds having a closer textural affinity to
the speckled beds below; 3.) variably thick intervals of underlying “speckled”, matrix-supported
kimberlite containing thin, areally limited, interbedded coarse-olivine pyroclastic beds and
breccias; and 4.) several stratigraphically diverse “other” kimberlites that are currently grouped
together until better differentiation of the phases can be made.
The current GEMCOM 3D model for Kimberlite 140/141 has being updated by De Beers to include
information from the 2003 drillholes with due consideration given to work by the GSC under the TGI
Program in this area. Figure 9 shows an in progress cross-sectional geological model through the
central part of the 140/141 body constructed by the GSC and SGS. Several discrete kimberlite units
are shown in different colours. A 3D block diagram constructed by the GSC and SGS is shown in
Figure 10. These two figures give an approximation of the size, geometry, and complex architecture
of a large, multi-vent Fort à la Corne kimberlite.
Figure 9: Geological Cross-section oriented NW-SE across the 140/141 Kimberlite Body
(Courtesy of the Geological Survey of Canada and Saskatchewan Geological Survey)
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 10: 3D Diagram of Geological Model for Kimberlite 140/141. Drillholes in the 141 portion of
the kimberlite are shown in yellow while those in the 140 portion are shown in red (view towards
north).
9.2.16.5.2 Kimberlite 148
Preliminary geological modeling of Kimberlite 148 shows the body is dominated by a relatively
uniform and extensive, medium to coarse-grained olivine pyroclastic kimberlite (MPK) that contains
thin intervals of xenolith-rich, breccia beds (MPK-B). Three other subordinate kimberlite types
have been identified from core drilled in 2003, although geological interpretation of the body
continues. The additional kimberlite phases include: finely bedded volcaniclastic kimberlite
(FBVK), other pyroclastic kimberlite units (OPK), and well sorted – fines enriched pyroclastic
kimberlite (WS-FE).
9.2.16.5.3 Kimberlite 122
Initial geological modeling of distinct kimberlite phases by De Beers based on drill core from
Kimberlite 122 shows the body is divisible into two main craters, with a subordinate third area
based on relatively sparse drill control. Figure 8 shows the estimated areal extent of the craters
in Kimberlite 122. Also shown are kimberlite intersection thicknesses for the 2003 drillholes
(normal text) and for historical drillholes (in italicized text). The northern half of the body is
dominated by massive to graded beds of olivine/lapilli pyroclastic kimberlite (MPK-N) with common
indicator minerals. This is overlain by up to 43 metres of interbedded sediments, resedimented
kimberlite, and kimberlite (UCSK-N).
Similarly, the south crater is dominated by variably massive to bedded, fine- to coarse-grained,
olivine/lapilli pyroclastic kimberlite (MPK-S) to a thickness of some 103 metres in the 2003
drillholes. The thicker, more massive intersections occur proximal to drillhole 03-122-09 with
more obvious bedding intervals increasing in abundance and thickness towards the north and west,
and being more pronounced in the upper part of the MPK
77
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
intersections of the proximal drillholes.
The northern fringe of the southern crater has a partial cap of interbedded sediments and
resedimented kimberlite ranging from 0 to 12 metres thick (UCSK-S). In general, the pyroclastic
kimberlite within the north crater is finer grained than the pyroclastic kimberlite within the
south.
Towards the southeast and southern-most part of the body, at least three distinct intervals of
other pyroclastic kimberlite (OPK) were noted. OPK dominates the kimberlite intersection at
drillhole 03-122-10, but the overall kimberlite intersection here has attenuated to 28.9 metres
from a thicker interval of 53.4 metres in drillhole 03-122-09. The distribution of OPK beds are
not shown in detail in Figure 8 with the exception of OPK-S1 which
forms a small pod near the centre of the southern crater. The OPK (and limited occurrence of other
volcaniclastic kimberlite (OVK)) phases will be better understood as more drillholes provide data
that allows the geological model to be further refined. As such, results for the OPK beds in
03-122-10 were added to the MPK-S unit. Drillhole 03-122-07 is the only intersection that has a
basal unit of interbedded sediments and kimberlite (SAK).
In general, average grain size of the kimberlites and thickness of kimberlite intersection
decreases towards the margins of the body. The order of emplacement for the individual kimberlites
and their contact relationships within, and between, the two main parts of body 122 are not fully
understood at this time.
9.2.16.5.4 Kimberlite 150
Due to geological complexity in the 150 kimberlite body, the results from the 2003 drillholes
were divided into three groups corresponding to the three areal lobes of the kimberlite outline
(see Figure 6) that may correspond to three separate eruptive vents.
9.2.16.6 2003 Sampling and Micro-diamond Recovery
A selection of representative intervals were sampled from each of the kimberlite bodies
drilled in 2003. Core from each of the bodies drilled in 2003 were macroscopically logged, slabbed
longitudinally by saw, and then selectively sampled. The main sampling effort was two-fold: to
collect representative samples for petrographic examination and archiving, and for complete diamond
recovery down to a lower cut-off of 75 microns using caustic dissolution methods. Samples of
slabbed core measuring up to 40 centimetres long were collected for archiving and future
petrographic studies. Representative samples for diamond recovery were collected over variable
intervals within attention to sampling discrete phase of kimberlite.
Diamond recovery was completed in two stages. The SRC recovered diamonds using caustic dissolution
and concentrate beneficiation methods. Stones were hand-picked from the resulting residue, and
then described and weighed. Recently, the SRC was certified under ISO 17025 for Diamonds (see
CAN-P-1579 in the Guide to the Accreditation of Mineral Analysis Lab). The second stage involved
shipping the recovered diamonds and selected caustic residue to the De Beers’ Kimberley
Microdiamond Lab (KMDL), in South Africa for further auditing and verification of individual stone
size, shape, and sieve category using proprietary techniques. Both sets of data were released to
the FalC-JV partners, however, the KMDL weighs were utilized in grade forecasting based on
statistical evaluation of diamond size distributions.
For results following in this section, the reader is cautioned that viewed in isolation,
microdiamond stone counts can be misleading and the estimation of macrodiamond grade from
microdiamond results require an interpretation of the diamond size frequency distributions.
78
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.16.6.1 Diamond Recovery from Kimberlite 140/141 in 2003
Average microdiamond recoveries from three of the 2002 coreholes targeted on the central and
southern parts of the body ranged from 12.7 to 13.5 stones per 10 kilograms, but these averages
reflect sampling of at least three different kimberlite phases. These drillhole averages are at
least twice that seen for similar recoveries from other parts of the body. Allocation of diamonds
to appropriate kimberlite phases by De Beers’ experts facilitated an early grade forecast of 18.6
cpht for the breccia beds and 4.5 cpht for the speckled beds. Given the relatively small numbers
of microdiamonds in the dataset for discrete kimberlite types or phases, and the need to better
delineate the extent of the new kimberlite phases, nine HQ coreholes (2.5 inch or 63.5 millimetres
diameter) were drilled.
A total of 1,159 microdiamonds were recovered utilizing caustic dissolution methods from 595.15
kilograms of core submitted to the SRC from Kimberlite 140/141. Samples for microdiamond recovery
were extracted from six of the corehole intersections. The SRC reported 97% recovery of internal
tracers during diamond recovery and stone picking was routinely audited by a supervisor. The
microdiamond results from these drillholes were integrated with the 140/141 dataset including
results from similar kimberlite types intersected in earlier drillholes (140-12, 140-16, 140-17,
and 141-09), followed by modeling of grade forecasts for the southern part of the 140/141 body. A
summary of diamond recovery results for the drillholes and these phases are reported in Tables 19
and 20 illustrating how the best stone abundances were recovered from the repeated graded beds and
the breccias immediately underlying them. Table 21 shows diamond recovery results by sieve size
range for the same kimberlite types. Locations for the 2003 coreholes are shown in Figure 7.
Stones
Sample
Average
larger than
Drillhole
Mass
(kg)
# of Stones
Stones/10 kg
0.5 mm
140-32
99.90
173
17.3
1
140-33
92.65
219
23.6
1
140-38
100.80
173
17.2
1
140-34
91.85
166
18.1
0
140-39
110.60
199
18.0
1
140-40
99.35
229
23.0
0
Total:
595.15
1159
19.5
4
Table 19: Summary of 140/141 Microdiamond Results by Drillhole
Sample
Stones
Mass
# of
Average
larger than
Kimberlite Type
(kg)
Stones
Stones/10 kg
0.5 mm
Repeated Graded Beds
142.55
323
22.7
2
Breccia Beds
274.90
593
21.6
2
Other
Kimberlite Units
68.00
109
16.0
0
Speckled Beds
109.70
134
12.2
0
Total:
595.15
1159
19.5
4
Table 20: Summary of 140/141 Microdiamond Results by Kimberlite Type
79
+0.075mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+0.600mm
+0.850mm
Kimberlite Type
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Repeated Graded Beds
176
94
30
17
3
1
0
2
Breccia Beds
309
159
87
26
9
1
2
0
Other Kimb.
Units
58
34
10
5
2
0
0
0
Speckled Beds
66
40
20
6
2
0
0
0
Total:
609
327
147
54
16
2
2
2
Table 21: 140/141 Microdiamond Recoveries by Sieve Category and Kimberlite Type
The “repeated graded beds” and the “breccia beds” immediately underlying them yielded the best
stone abundances. The average microdiamond abundance for all 140/141 samples is 19.5 stones per 10
kilograms while the repeated graded beds and breccia beds yielded average microdiamond abundances
of 22.5 and 21.6 stones per 10 kilograms, respectively. This is much higher than previous results
for Kimberlite 140/141. A total of four stones larger than 0.5 millimetres were recovered from the
repeated graded beds and the breccia beds, two of which was recovered from the 0.850 sieve screen.
Simple evaluation of microdiamond stone counts in isolation are insufficient to estimate
macrodiamond contents, but can be utilized in diamond size frequency distributions to give grade
forecasts.
In addition to the results from caustic dissolution, a high quality diamond weighing 0.77 carats
was encountered during sample preparation of kimberlite core in the FalC-JV warehouse. The diamond
was liberated while HQ core, from a depth of 117.86 metres in drillhole 140-34, was being slabbed
by a rock saw utilizing a non-diamond masonry blade. The diamond was not damaged by the blade,
although the stone halted the cutting process and scored the blade. Both halves of the slabbed
core retained a clear impression of the stone within kimberlite of the repeated graded beds. The
diamond was weighed and measured by the SRC in Saskatoon. According to the SRC, the stone measures
5.50 x 4.40 x 4.20 millimetres in three dimensions and was described as a colourless, clear
octahedroid with etched trigons and hillocks (Figure 11).
Figure 11: Photograph of the 0.77 carat stone recovered from 140-34 core (117.86 m depth)
In addition to testing new core, ten kimberlite core samples collectively weighing 82.46 kilograms
were collected from a 55 metre interval of hole 140-12 (drilled in 2002) located on the southern
part of Kimberlite 140/141 during the 4th Quarter of 2003 for a due diligence audit of
the SRC diamond recovery process. A total
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
of 127 diamonds were recovered, of which 6 stones were larger than a 0.212 square sieve. The
larger stones ranged in size from 0.36 x 0.34 x 0.3 millimetres up to 2.14 x 1.78 x 1.7
millimetres. These diamond recoveries were added to the 140/141 diamond dataset for grade
forecasting.
9.2.16.6.2 Diamond Recovery from Kimberlite 148 in 2003
A total of 2,059 microdiamonds were recovered from 739.8 kilograms of core sampled from
Kimberlite 148. The average diamond grade for all samples was 27.8 stones per 10 kilograms, which
compares favourably to previous results from corehole 148-09 (drilled and tested in 1993) showing
14.3 stones per 10 kilograms from a total of 262 kilograms of sample. The highest stone abundance
figures for previous Fort à la Corne samples range up to 18.3 stones per 10 kilograms.
The best stone abundances were seen in the FBVK and the MPK units, although the three largest
stones were recovered from OPK. A total of 14 macrodiamonds with at least one dimension larger
than 0.5 millimetres were recovered from the samples. Diamond results by kimberlite type are shown
in Table 22. Diamond results by kimberlite type and sieve category are shown in Table 23.
Sample
Microdiamond
Kimberlite
Mass
Number of
Carat Weight
Abundance
Stones larger
Type
(kilograms)
Stones
(milligrams)
(stones/10 kilograms)
than 0.5 mm
FBVK
194.75
708
10.033
36.4
4
MPK
316.95
983
10.809
31.0
4
WS-FE
40.70
79
3.705
19.4
0
OPK
146.55
226
5.785
15.4
4
MPK-B
40.85
63
1.008
15.4
2
Total
739.80
2,059
31.340
Average of 27.8
Table 22: 148 Microdiamond Results by Kimberlite Type
Kimberlite
+0.075mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+0.600mm
+0.850mm
Type
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
FBVK
310
195
121
60
15
5
2
0
MPK
422
336
135
63
21
4
2
0
WS-FE
29
22
12
10
3
2
0
1
OPK
116
53
30
18
5
1
2
1
MPK-B
26
20
9
7
0
1
0
0
Total
903
626
307
158
44
13
6
2
Table 23: 148 Microdiamond Results by Sieve Category and Kimberlite Type
The SRC reported 97% recovery of internal tracers during diamond recovery and stone picking was
routinely audited by a supervisor. Microdiamond results from these drillholes were integrated with
the 148 dataset including results from similar kimberlite types intersected in earlier drillholes.
Modeling of grade forecasts for the different major kimberlite units currently is in progress.
81
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.16.6.3 Diamond Recovery from Kimberlite 122 in 2003
A total of 327 microdiamonds were recovered from 412.65 kilograms of core sampled from
Kimberlite 122. Representative slabbed core samples were collected from 11 HQ coreholes widely
spaced across the 122 body. Six of these stones have at least one dimension exceeding 0.5
millimetres in length and are considered to be macrodiamonds.
Samples from the north crater of Kimberlite 122 gave total recovery of 133 stones, of which 2
macrodiamonds had at least one dimension greater than 0.5 millimetres. Most of the stones were
recovered from the MPK-N kimberlite phase producing the best average stone abundance of 9.8
stones/10 kilograms. In addition, the overlying UCSK-N gave an average abundance of 7.5 stones/10
kilograms based on recovery of 18 stones from a much smaller sample mass. Table 24 shows the
recovery of stones by kimberlite type and area.
Range of Sampled
Stones
Phase Thickness
Sample
# of
Average
larger than
Kimberlite Type
(m)
Mass (kg)
Stones
Stones/10 kg
0.5 mm
North Main
Pyroclastic
Kimberlite (MPK-N)
56 - 74
117.55
115
9.8
1
North Upper Complex
sediments and
Kimberlite (UCSK-N)
11 – 43
23.95
18
7.5
1
Total 122 North
Crater:
141.50
133
9.4
2
South Main
Pyroclastic
Kimberlite (MPK-S)
36 – 103
222.55
163
7.3
4
South Upper Complex
sediments and
Kimberlite (UCSK-S)
3 – 12
7.75
3
3.9
0
South Other
Pyroclastic
Kimberlite (OPK-S1)
23 – 53
32.40
26
8.0
0
Total 122 South
Crater:
262.70
192
7.3
4
Basal Sediments and
Kimberlite (SAK),
south periphery of
body
7
8.45
2
2.4
0
Total 122:
412.65
327
7.9
6
Table 24: Summary of 122 Microdiamond Results by Kimberlite Type
By comparison, samples from the south crater returned lesser stone abundances of 7.3 and 3.9
stones/10 kilograms for the MPK-S and UCSK-S phases, respectively. The MPK-S unit had four
macrodiamonds with at least one dimension greater than 0.5 millimetres. OPK-S1 in the southeastern
part of the body returned an average value of 8.0 stones/10 kilograms based on the recovery of 26
stones from 32.40 kilograms of sample.
In terms of size fractions, approximately 38% of the stones were recovered on the 0.075 millimetres
sieve and 83% of the stones retained in sieves less than 0.212 millimetres (Table 25). Overall,
percentage recoveries by sieve class were very similar for the north and south sectors.
Stone recoveries from 122 cannot easily be compared to those from bodies 148 and 140/141 as these
kimberlites were formed from separate volcanic eruptions that most likely have a distinct
population of micro- and macrodiamonds. Simple evaluation of microdiamond stone counts in
isolation are insufficient to estimate
82
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
macrodiamond contents, however, they can be utilized in diamond size frequency distributions to
give grade forecasts.
Kimberlite
+0.075mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+0.600mm
+0.850mm
Type
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
MPK-N
50
30
19
8
4
3
0
1
UCSK-N
4
7
4
2
0
1
0
0
North Crater:
54
37
23
10
4
4
0
1
% of North:
40.6
27.8
17.3
7.6
3.0
3.0
0
0.7
MPK-S
61
48
26
16
5
3
4
0
UCSK-S
0
3
0
0
0
0
0
0
OPK-S1
8
4
6
7
1
0
0
0
South Crater:
69
55
32
23
6
3
4
0
% of South:
35.9
28.6
16.7
12.0
3.1
1.6
2.1
0
SAK
1
0
1
0
0
0
0
0
Total 122:
124
92
56
33
10
7
4
1
% of 122:
37.9
28.1
17.1
10.2
3.1
2.1
1.2
0.3
Table 25: 122 Microdiamond Recoveries by Sieve Category and Kimberlite Type
A comparison of recent stone recoveries from caustic dissolution to similar types of historical
results can be made on a limited basis. For the 122 north crater, combined MPK-N/UCSK-N diamond
abundances are 3 times that seen in rotary hole 122-01, which was drilled in 1989. This drillhole
produced kimberlite samples in the form of chips. Diamond recovery was achieved by combined
crushing, jigging, heavy liquid separation, and caustic fusion. A total of 77 kilograms of
kimberlite chips were analyzed for diamond content and produced 22 stones, of which five were
macrodiamonds having at least one dimension greater than 0.5 millimetres and two of the stones had
their largest dimension close to 1 millimetres. It is not known what the bottom cutoff for
recovery was for this procedure, although the smallest stone size recovered from these samples was
0.10 millimetres, a relatively coarse bottom cut-off may explain the comparatively low stone
abundances for 122-01, despite recovery of a significant proportion of larger diamonds. Table 26
shows a comparison of diamond abundances for historical and recent results.
Several drillholes located on the south part of 122 were tested for diamond content from 1993 to
1996. Diamond abundances for these drillholes ranged from 2.5 to 4.5 stones/10 kilograms compared
to an average of 7.3 stones/10 kilograms for the 2003 coreholes located in the 122 south crater
(MPK-S and OPK areas). Kimberlite core samples totaling over 400 kilograms from coreholes 122-05
and 122-06, and an additional 252 kilograms of chip samples from large diameter reverse circulation
drillholes 122-07 and 122-08 averaged between 2.5 to 4.5 stones/10 kilograms based on recovery of
218 diamonds. All four of these drillholes are located within the south and southeastern part of
body 122 (Figure 8). Stone abundances for 2003 coreholes in the 122 south crater (MPK-S and OPK-S1
areas) were about twice these recoveries with an average of 7.3 stones/10 kilograms.
The SRC reported 95.3% recovery of internal tracers during diamond recovery and stone picking was
routinely audited by a supervisor. Microdiamond results from these drillholes were integrated with
the 122 dataset including results from similar kimberlite types intersected in earlier drillholes
(122-01, 122-05, 122-06, 122-07, 122-08).
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.16.6.4 Diamond Recovery from Kimberlite 150
Kimberlite 150 was selected for delineation drilling and microdiamond sampling due to
favourable historical diamond recoveries and its size. The new results were combined with
historical data in order to make grade forecasts based on stone size distributions.
Diamond
Recovery
Year of
Diamond
Bottom
Sample
Drillhole/Area
Diamond
Recovery
Cut-off
Mass
# of
Average
Comparison
Recovery
Facility1
(mm)
(kg)
Stones
Stones/10 kg
122 North Crater
122-01
1989
C.F. Minerals
?
77
22
2.9
MPK-N, UCSK-N
2003
SRC
0.075
141.5
133
9.4
122 South Crater
122-05
1992
KAL
0.074
169
42
2.8
122-06
1993
KAL
0.074
239
99
4.5
122-07
1994
KAL
0.074
181
51
2.5
122-08
1995
KAL
0.074
71
26
4.1
122-09
2001
KAL
0.074
264
22
0.8
122-10
2001
KAL, Lakefield
0.074
417
38
0.9
122-11
2001
KAL
0.074
167
20
1.2
MPK-S, UCSK-S,
OPK-S1
2003
SRC
0.075
262.70
192
7.3
1
= Abbreviated forms are as follows: Saskatchewan Research Council, Saskatoon
(SRC), De Beers’ Kimberley Acid Laboratory, South Africa (KAL), Lakefield Research Labs,
Ontario (Lakefield)
Table 26: Comparison of Recent and Historical 122 Microdiamond Results by Area
Representative slabbed core samples were collected from 12 HQ coreholes widely spaced across the
150 body. A total of 392 microdiamonds were recovered from 51 samples utilizing caustic
dissolution methods on 422 kilograms of core submitted to the SRC. The SRC recovered and reported
diamonds down to a lower cutoff of 0.075 mm in size; diamonds passing through a 0.075 mm screen
were not included in the stone tallies. The SRC reported 98.6% recovery of internal tracers during
diamond recovery and stone picking was routinely audited by a supervisor.
Recovered diamonds and selected caustic residues were sent to the De Beers’ Kimberley Microdiamond
Laboratory (KMDL) for further auditing and verification of individual stone size, shape, and sieve
category using proprietary techniques. KMDL reported 238 stones with dimensions equivalent to a
+74 micron sieve cut-off and having a combined weight of 0.248 carats including one macrodiamond
weighing 0.226 carats recovered in the 2 millimetres sieve category. The average diamond grade for
all samples was 5.7 stones per 10 kilograms utilizing only stones greater than 74 microns.
Due to geological complexity in the 150 kimberlite body, the results from the 2003 drillholes were
divided into three groups corresponding to the three areal lobes of the kimberlite outline (Table
27). Diamond results by kimberlite type and sieve category are shown in Table 28.
In terms of stone size fractions, approximately 49.4% of the stones were recovered on the 0.074
millimetres sieve and 94.1% of the stones were retained in sieves less than 0.212 millimetres
(Table 28). However, 91% of
84
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
the total carat weight of diamond from these samples was recovered in a single stone from the west
lobe. Viewed in isolation, microdiamond stone counts can be misleading and the estimation of
macrodiamond grade from microdiamond results will require an interpretation of the diamond
grade-size plots.
The 2003 microdiamond dataset was made available for modeling grade estimates by MRM. From the
combined dataset of historical and new results, 352 microdiamonds from the west lobe were available
for modeling, of which 46 were re-categorized as less than 74 microns in size, and therefore not
used. Due to the prevalence of stones in only four size classes, historical macrodiamond data for
56 stones was utilized to stabilize the grade-size curve. The grade forecast for this lobe is 3
cpht and encompasses an estimated mass of 68 million tonnes of kimberlite based on integration of
drillhole information and geophysical data. Currently, confidence limits for the modeled data are
not available.
Microdiamond
150
Total Carat
Stones
Abundance
Kimberlite
Sample Mass
Weight
> 74
> 74 microns
Stones larger
Area
(kg)
Total Stones
(octacarats)
microns
(stones/10 kg)
than 0.5 mm
North Lobe
82.7
80
394,500
47
5.7
West Lobe
239.5
258
24,332,850
161
6.7
1;
0.226 cts.
South Lobe
99.5
54
183,400
31
3.1
Total
421.7
392
24,910,750
239
Average of 5.7
One octacarat is equivalent to 1x10-8 carats
Table 27: 150 Microdiamond Results by Kimberlite Type
+0.600 to
Kimberlite
+0.074mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+0.850 mm
+2 mm
Type
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieves
Sieve
North Lobe
22
18
3
4
0
0
0
0
West Lobe
78
49
25
6
2
0
0
1
South Lobe
18
9
3
1
0
0
0
0
Total
118
76
31
11
2
0
0
1
Table 28: KMDL 150 Microdiamond Results (>74 microns) by Sieve Category and Kimberlite Type
Modeling of the south lobe of the body utilized 129 microdiamonds (23 unused stones were
categorized as less than 74 microns in size) grouped into four size categories. Only 15
macrodiamonds were recovered from this lobe in the past and this number of stones was insufficient
to include in the modeling. The south lobe was assigned a forecast grade of 3 cpht encompassing a
mass of 50.5 million tonnes based on integration of drillhole information and geophysical data. The
north lobe was not modeled due to the availability of only 67 microdiamonds and no historical
macrodiamonds. The estimated mass for this lobe is 32.1 tonnes.
The reader is cautioned that the grade estimates are conceptual in nature. The grade of kimberlite
above a 1.5 millimetres bottom cutoff is estimated from a combination of micro- and macrodiamond
data. Confidence levels for these figures are low and additional testing of macrodiamond content
may be required to increase confidence levels in the grade forecasts. The reader should also be
aware that insufficient geological control and quantity of sampling has been obtained to permit
rigorous application of economic considerations and that there is no certainty that these
preliminary assessments will be realized. In short, the figures presented herein are utilized as
an exploration tool and their primary value is for comparison of diamondiferous kimberlite targets
within the focus of the ongoing evaluation program.
85
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Both the new data and the grade forecasts by MRM of De Beers do not support further drilling and
sampling work on this kimberlite but efforts on the other prospective bodies will continue under
the current, accelerated program.
9.2.17 2004 Exploration and Sampling Program
During the first eight months of 2004, no field programs were conducted at Fort à la Corne.
In July 2004, the FalC-JV partners implemented a $7.62 million program in part based on
recommendations put forward by geoscientists of De Beers’ MRM and in recognition of large,
relatively sparsely tested kimberlite bodies located proximally to the centre of the large cluster
in the southern part of the main kimberlite trend.
The 2004 exploration program had three main objectives. One was to determine geological models for
four high-interest kimberlite bodies and to adequately sample individual kimberlite units in each
body for diamond content. The four bodies include kimberlites 120, 147, 121, and 221. None of
these four bodies have been drilled in at least the past 5 years. The second objective was to test
for the presence of kimberlite in five geophysical anomalies located around the central cluster
using HQ core holes. The third objective was to improve the understanding of geology, diamond
distribution, and diamond values of the southern parts of both the 140/141 body and 122 body with a
goal of ultimately proving up resource tonnage for the higher grade zones. A combination of
coreholes (as pilot holes) and large diameter reverse circulation drillholes were used in these two
bodies. The 2004 program included ten large diameter minibulk drillholes positioned on the
higher-grade zones in Kimberlites 140/141 and 122. The 140/141 kimberlite had been the subject of
drilling in 2000, 2001, 2002, and 2003, however the 2004 work focused on the south west portion of
the kimberlite where little information was available. Kimberlite 122 was last drilled in 2000
when three large diameter (610 millimetres) reverse circulation drillholes (LDDH) were completed on
the south-central part of the body. The rationale for mini-bulk sampling in 2004 was to increase
the confidence in the grade forecast models and the average diamond values in the kimberlite units
of higher grade interest in bodies 140/141, 122 and 148. During 2004, mini-bulk sampling was
carried out on the oscillating breccia unit of body 140/141 and the MPK unit within the southern
crater of body 122.
9.2.17.1 Recent Geological Modeling, Grade Forecasts, and Prioritization
During 1999 and the early part of 2000, an in-depth evaluation and synthesis of all available
information for each kimberlite body was conducted separately by De Beers Canada Inc. and
Kensington staff. Based on these studies, De Beers identified 17 kimberlites having sufficient
information on which to prioritize their diamond resource potential. From this list, five targets
were selected for continued evaluation of diamond content and value. These targets included
kimberlites 122, 140/141, 147, 148, and 150. Drilling and sampling programs have been conducted on
Kimberlites 140/141, 122, and 150 since the 2000 prioritization study.
Preliminary results determined by the De Beers’ Mineral Resource Management Department (“MRM”) on
geological modeling and grade forecasts for kimberlite bodies 140/141, 148 and 122 were reported in
June 2004. Table 29 shows relevant data supplied by MRM and utilized by the FalC-JV partners in
planning the work program for 2004/2005. Currently, confidence limits for the data supplied in
Table 29 are not available.
The reader is cautioned that the grade and value estimates are conceptual in nature and were
determined by MRM using statistical diamond size distributions combining both microdiamonds and
macrodiamonds, and application of resulting grade forecasts to valuations of small parcels of
macrodiamonds to determine modeled (average) values should be viewed with caution. Confidence
levels for these figures are low and additional testing of macrodiamond content is required to
increase confidence levels in the grade forecasts, especially for kimberlite bodies 122 and 148 as
their grade forecasts were based primarily on extrapolation of microdiamond size distributions
only. The reader should also be aware that insufficient geological control and quantity of
sampling has been obtained to permit rigorous application of economic considerations and that there
is no certainty that these preliminary assessments will be realized. In short, the figures
presented in Table 29 are
86
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
utilized as an exploration tool and their primary value is for comparison of diamondiferous
kimberlite targets within the focus of the ongoing evaluation program.
Estimated
Estimated
Tonnage
Average Grade
Area of Body
(Million
>1.5 mm
Body
(Hectares)
Unit of Interest
tonnes)
(cpht)
140/141
250
Coarse Mega-graded Beds
105
9
Breccia Beds
29
16
148
239
Main Pyroclastic Unit
156
7
122
126
Main South Pyroclastic Unit - upper
45
14
Main South Pyroclastic Unit - lower
34
12
Totals
369
10
Table 29: Fort à la Corne Kimberlite Units of Economic Interest
Volumes for each of the high interest zones are early estimates derived from computer-generated
3-dimensional models of kimberlite units within areas defined by drillhole intersections. Volume
to tonnage estimates were calculated using a specific gravity 2.4 g/cm3 for all
kimberlite units. The tonnage estimates require further delineation drilling to better ascertain
lateral and vertical extents of the geological units. The surface area of the kimberlites of
interest were based on estimated 30 metre thickness cut-offs applied to integrated and modeled
geophysical data for the body.
The combined kimberlite units of economic interest within body 140/141 total 134 million tonnes
grading an average of 11 carats per hundred tonnes with an estimated average value of US$115 per
carat. Grade forecasts for this kimberlite unit and four others were based on a statistical
treatment of 3,683 microdiamonds and 1,361 macrodiamonds weighing 155.695 carats; this number of
macrodiamonds was used in the determination of average values shown for the specific units,
although 105 carats (1071 macrodiamonds) were utilized in the modeling of grade and value for the
“Coarse Mega-graded Beds”, and 14.3 carats (69 macrodiamonds) were utilized for the breccia beds.
Average grade and value estimates, rather than ranges of value, were provided by MRM for Kimberlite
140/141 due to the nature of the statistical grade forecasting and modeling of average diamond
value. The tonnage estimate was based on kimberlite core descriptions and determinations of unit
contacts from fifty NQ, HQ, and PQ coreholes within an area measuring 1400 by 1200 metres.
Drillhole spacing is primarily on mixed 100 and 200 metre intervals with total depth of holes
ranging from 150 to 450 metres.
Within body 148 the main pyroclastic unit is of economic interest and contains 156 million tonnes
of kimberlite at a grade of 7 carats per hundred tonnes. Grade forecasts for this unit and two
others were based on the statistical treatment of 2,448 microdiamonds and 70 macrodiamonds weighing
2.369 carats. All macrodiamonds and 1,618 microdiamonds were utilized in modeling the “Main
pyroclastic unit” of body 148. Average diamond value is not currently available for this unit due
to insufficient quantities of macrodiamonds. The tonnage estimate for this unit was based on
kimberlite core descriptions and determinations of unit contacts from eleven HQ coreholes within an
area measuring 1000 by 600 metres. Drillhole spacing is primarily on mixed 200 and 400 metre
intervals with total depth of holes ranging from 150 to 282 metres.
The combined units of economic interest in body 122 contain 79 million tonnes at a grade of 13
carats per hundred tonnes. Grade forecasts were based on the statistical treatment of 693
microdiamonds and 289 macrodiamonds weighing 23.13 carats. Grade and value modeling for the “Main
South Pyroclastic Unit – upper” and “Main South Pyroclastic Unit – lower” units was based on 513
microdiamonds and 269
87
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
macrodiamonds (19.885 carats). In 2000, the Mineral Resource Evaluation Department (now MRM) of De
Beers indicated a grade forecast for commercial-size stones (>1.5 millimetres) ranging from 7.5
to 12 cpht and a value ranging from US$144 to US$146 per carat for the 122 kimberlite. Estimates
of diamond value for Kimberlite 122 were based on modeling of both Best Fit and Optimistic grade
forecasts. The tonnage estimate for this unit was based on kimberlite core descriptions and
determinations of unit contacts from eight HQ coreholes and three large diameter drillholes within
an area measuring 600 by 500 metres. Drillhole spacing is primarily on mixed 200 and 300 metre
intervals with total depth of holes ranging from 144 to 279 metres.
Exploration work in 2004 was conducted on additional higher priority kimberlite bodies located
within the central cluster of the main kimberlite trend including 120, 147, and the combined
121/221 bodies.
9.2.17.2 Planning, Permits, Environmental Health and Safety
At the project level, De Beers submitted a detailed exploration/evaluation program plan to
Saskatchewan Environment (SE) prior to the start of the field program which included all
anticipated impacts caused by the drilling activities in the Fort à la Corne Forest area (road
construction, drill pad preparation, water sources and rehabilitation). Approval for drillsite
access and drill pad construction was granted through a Timber Permit issued separately by
Saskatchewan Environment. Authority to withdraw surface water for drilling was covered by a
Temporary Water Rights Licence issued by the Saskatchewan Watershed Authority. The Department of
Fisheries and Oceans (DFO) was advised by letter of the programme and responded with several
guidelines.
Prior to mobilization, a field visit was conducted by an SE conservation officer who inspected each
of the proposed drillsites. Photographs were taken at each site so that rehabilitation could be
checked against the original features of the land surface after drilling was completed.
9.2.17.3 2004 Core Drilling Program
Boart-Longyear mobilized two LF-70 hydraulic core drilling rigs for this program. A total of
39 HQ core (2.5 inches or 63.5 millimetres diameter) core holes provided significant opportunities
for understanding the geology of 6 separate, prioritized kimberlite bodies and for diamond recovery
geared to better understanding their diamond content and distribution. Ten of the coreholes were
used as pilot holes for large diameter, reverse circulation drilling in kimberlites 122 and
140/141. As well, five of the coreholes were targeted on geophysical anomalies to test for the
presence of kimberlite.
Drilling concluded during mid-November with a total of 38 HQ or HQ/NQ (63.5 millimetres or 2.5
inches) coreholes and one NQ (47.6 millimetres or 1.875 inches) corehole. Diamond core bits are
composed of traceable synthetic cutting diamonds that can easily be distinguished from natural
stones. Significant intersections of prospective kimberlite were encountered in each of the
prioritized kimberlite bodies investigated and sufficient coverage of the bodies from this program
and previous drilling will permit construction of geological models. Kimberlite was intersected in
two of the five geophysical anomalies, but will not be further discussed in this report. A summary
of kimberlite core intersections, not including drilling on geophysical anomalies is shown in Table
30.
Drillpad construction and site access was contracted to T&P Enterprises of Choiceland,
Saskatchewan. In most cases, a short trail was constructed to link up to pre-existing trails. At
each of the drillpads, an area of approximately 40 x 40 metres was cleared. Temporary in-ground
tailings sumps were also constructed in order to receive, store, and re-circulate mud and effluent
produced during the corehole drilling. HQ corehole drilling was completed using three different
sized bits. Initial surface holes were drilled using a mud and water circulation system and a PW
milled tooth tricone bit (139 millimetres diameter). At around 12-18 metres, the tricone bit was
replaced by a HW tricone bit (130.2 millimetres diameter) with bentonite mud and water used as a
circulant in the hole. Casing was generally installed to a depth of approximately 100 metres,
although on
88
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
occasion this was extended downwards to find a suitable seat. Once casing was installed, the HW
tricone was replaced by an HQ tungsten carbide bit and coring commenced. In a few tight holes,
coring could only proceed at depth after down-sizing the diameter of the hole to produce NQ core
(1.875 inches or 47.6 millimetres diameter). Most core drilling was conducted with either fresh
water or low viscosity mud.
Top of
Base of
Total
End of
Kimberlite
Kimberlite
Kimberlite
Hole
Drill hole #
Core Size1
(m)
(m)
Intersection2
(m)
04-140-041
HQ core
97.40
246.00
128.28
252.00
04-140-042
HQ core
97.56
241.22
140.76
243.00
04-140-043
HQ core
100.57
232.35
124.89
236.00
04-140-048
NQ core
104.90
137.66
58.65
180.00
04-140-050
HQ core
100.19
236.62
131.59
243.00
Subtotal
584.17
1,154.00
04-122-0123
HQ core
n/a
n/a
n/a
102.00
04-122-012A
HQ core
108.00
313.15
202.88
357.00
04-122-013
HQ core
114.00
200.37
86.37
213.00
04-122-014
HQ core
110.45
299.00
176.80
299.00
04-122-019
HQ core
107.24
314.65
207.41
345.00
Subtotal
673.46
1,316.00
1 = HQ core has a diameter of 2.5 inches or 63.5 mm; NQ core has a diameter of
1.875 inches or 47.6 mm.
2 = These values may not be equal to Base of Kimberlite minus Top of Kimberlite due to
intervening layers of country rock
3 = Drillhole 04-122-012 was lost due to drilling difficulties at a depth of 102
metres.
Top of
Base of
Total
End of
Kimberlite
Kimberlite
Kimberlite
Hole
Drill hole #
Core Size1
(m)
(m)
Intersection2
(m)
04-120-021
HQ core
104.00
236.97
132.97
242.00
04-120-022
HQ core
108.00
293.80
185.80
306.00
04-120-023
HQ core
111.00
234.88
123.88
246.00
04-120-024
HQ core
115.88
125.50
9.62
192.00
04-120-025
HQ core
111.00
240.55
130.55
244.00
04-120-026
HQ/NQ core
105.00
243.60
131.96
255.00
04-120-027
HQ core
102.00
234.50
126.00
246.00
04-120-028
HQ core
119.52
218.80
99.28
237.00
Subtotal
940.06
1,968.00
04-121-009
HQ/NQ core
112.03
289.53
177.50
291.00
04-121-010
HQ core
112.67
204.50
91.83
222.00
04-121-011
HQ core
109.84
200.78
90.94
207.00
04-121-012
HQ core
116.33
154.61
36.63
168.00
04-121-013
HQ core
131.24
168.33
32.27
179.00
Subtotal
429.17
1,067.00
04-221-002
HQ core
112.05
170.80
51.16
180.00
04-221-003
HQ core
121.35
196.73
75.38
303.00
04-221-004
HQ core
109.55
183.49
68.59
195.00
Subtotal
195.13
678.00
04-147-006
HQ core
106.28
181.22
74.94
192.00
04-147-007
HQ core
101.35
184.56
83.21
195.00
04-147-008
HQ core
101.12
218.19
117.07
228.00
04-147-009
HQ core
103.40
221.82
118.42
231.00
04-147-010
HQ core
96.00
221.68
125.68
231.00
89
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Top of
Base of
Total
End of
Kimberlite
Kimberlite
Kimberlite
Hole
Drill hole #
Core Size1
(m)
(m)
Intersection2
(m)
04-147-011
HQ core
99.78
218.03
118.25
228.00
04-147-012
HQ core
101.42
202.96
101.54
213.00
04-147-013
HQ core
95.16
211.31
116.15
222.00
Subtotal
855.26
1,740.00
Total 2004
Core Drilling
3,709.07
8,797.00
1
= HQ core has a diameter of 2.5 inches or 63.5 mm; NQ core has a diameter of
1.875 inches or 47.6 mm; drillholes listed with both core sizes started with HQ diameter, but were
forced to decrease to NQ size due to drilling difficulties.
2
= These values may not be equal to Base of Kimberlite minus Top of Kimberlite due to
intervening layers of country rock
Table 30: Summary Tables of 2004 Evaluation Core Drilling at Fort à la Corne
Evaluation of the core included: measurements of rock density, magnetic susceptibility, rock
hardness (point load tests), core quality, baseline geotechnical parameters such as: strength of
the rock (point load tests), fracture counts, measurement of core angles, description of joints,
identification of natural and mechanical breaks, total core recovery, and solid core recovery. Only
selected geotechnical information and the main characteristics of the kimberlite such as density,
magnetic susceptibility, and petrography are included in this report. Digital photos were taken of
all kimberlite core intervals.
Density measurements on the core were determined using the water displacement method with sampling
undertaken at approximately 10 metre intervals or at lithological changes in drillholes. The
density obtained from these measurements is classified as an “in-situ” bulk density. Measurements
for “dry” density were completed after drying samples in an oven for forty-eight hours. The in-situ
and dry density values were obtained by dividing the wet and dry masses by the volume.
Magnetic susceptibility data for each of the coreholes was collected at one-metre intervals along
the entire length of the drillcore using a hand held Exploranium Kappameter KT-9. The data were
used to establish average magnetic susceptibility values for the kimberlites for comparison with
model-derived values from ground magnetic data and to assess the variability of magnetic properties
within each body. The results show the magnetic susceptibility response to be variable and often
related to lithology. The overburden, kimberlite and country rocks were all seen to have different
responses. The overburden composed of till was found to have a low magnetic response. Although
magnetic susceptibility values for the kimberlite were seen to vary within the body (at the contact
zones and within kimberlite), they were generally higher than those of the enclosing country rocks.
All holes were surveyed by a single shot Reflex instrument (EZ Shot) supplied by the drill
contractor to determine the deviation of drillholes from the vertical. Measurements were made at
the bottom of each of the drillholes, with azimuth and dip data entered into a database for later
3D modeling of the kimberlite in GEMCOM. The Reflex survey results show that the drillholes
generally remained within 3o of vertical.
9.2.17.4 2004 Sampling of Core and Microdiamond Recovery
A selection of representative intervals were sampled from each of the kimberlite bodies
drilled in 2004. Core from each of the bodies drilled in 2004 were macroscopically logged, slabbed
longitudinally by saw, and then selectively sampled. The main sampling effort was two-fold: to
collect representative samples for petrographic examination and archiving, and for complete diamond
recovery down to a lower cut-off of 75 microns using caustic dissolution methods.
90
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
At present, the sampling strategy for diamond recovery utilizing caustic dissolution methods is
based on collection of representative material from within boundaries marking lithological
contacts. Representative samples for diamond recovery were collected over variable intervals, but
from within discrete phase of kimberlite. Samples are made up to a maximum of 8 kilograms each and
closed with numbered seals that cannot be tampered with. In addition, during 2004, samples of
slabbed core measuring up to 40 centimetres
long were collected for archiving and future petrographic studies. The number of samples collected
per drillhole is a function of several factors including:
-budgetary considerations for the diamond recovery program
-number of discrete phases present in the drillhole and in the kimberlite as a whole (complexity of geology)
-thickness of intersection and discrete kimberlite phases
-estimate of diamonds required for further evaluation
Diamond recovery was completed in two stages. The SRC recovered diamonds using caustic dissolution
and concentrate beneficiation methods. Stones were hand-picked from the resulting residue, and
then described and weighed. The second stage involved shipping the recovered diamonds and selected
caustic residue to the De Beers’ Kimberley Microdiamond Lab (KMDL), in South Africa for further
auditing and verification of individual stone size, shape, and sieve category using proprietary
techniques. Both sets of data are to be released to the FalC-JV partners, however, the KMDL
weights which were utilized in grade forecasting based on statistical evaluation of diamond size
distributions is to be compiled and finalized before release.
Diamond recovery information and results for each drillhole and kimberlite are recorded in tabular
form. De Beers (Mineral Resource Management Department or MRM) and independent consultants/experts
use this data for grade calculation exercises and prediction of stone sizes. For some bodies,
microdiamond data are relatively sparse, sometimes being derived from a single drillhole, and
represent the only diamond data (macro or micro) available for a given body.
For results following in later sections, the reader is cautioned that viewed in isolation,
microdiamond stone counts can be misleading and the estimation of macrodiamond grade from
microdiamond results will require an interpretation of the diamond size frequency distributions.
9.2.17.5 2004 Large Diameter Drilling Program
Drill operations were conducted by Encore Drilling, who subcontracted Central Caissons of
Saskatoon, to complete initial pilot holes. Central Caissons used an HR150 Mait auger rig to drill
the overburden and seat the casing. Drilling of 910 millimetres diameter (36”) reverse flood holes
was conducted over two twelve-hour shifts using a TH150 top drive drill rig. Up to nine technical
staff were utilised for data monitoring and sample collection.
Site preparation was contracted to T&P Enterprises, which is based in Choiceland, Saskatchewan. T&P
have provided heavy machinery field services to the FalC-JV on a regular basis since 1990, and have
extensive experience in drill-pad preparation and restoration, sump construction, and trail
building and maintenance.
Site access to Kimberlite Bodies 141/140 and 122 was through use of existing roads and trails and
all road and pad preparation was cleared with Saskatchewan Environment prior to construction. All
drilling pads were roughly circular or square and centred on previously constructed pads of ~ 40
metres diameter hosting staked targets for pilot hole/core drilling. Once the decision was made to
drill a large diameter hole at a core site, the drill pad was expanded to approximately 80m in
diameter. Actual sizes varied as topography allowed. In each case though, the duff or organic layer
was scraped to one side and retained to allow acceptable rehabilitation to occur later. No
marketable wood product needed clearing during pad construction. T&P also constructed in-
91
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
ground
tailing sumps, which were designed to receive, store and allow the re-circulation of mud effluent
and fines from the drilling process. Large sump pit areas were constructed to act as central
repositories for used drilling mud and for freshwater holding pits.
Drilling in 2004 at Fort à la Corne used the same basic methodology as was used in 2002. Drilling
however was conducted on a greater scale with only 910 millimetres diameter holes attempted.
Production drilling was conducted using the reverse flood, air lift assist method. This technique
introduces air into the hole two-thirds of the way to the bottom of the drill string via 1-1/4” PVC
pipe. This pipe runs down the centre of single wall drill pipe and allows a pressure equilibrium
point to be reached within the hole relatively easily. Small pressure increases ensure chip removal
from the hole at relatively low exit velocities. The drill product is removed in a mud / water /
product slurry that cushions the material from heavy impact. The drilling method is therefore
relatively kind to the drill product (and therefore diamonds) and requires only a fraction of the
air pressure (and therefore fuel to the compressor) to recover the drill product.
Surface holes and initial 30” or 42” casings were constructed by subcontractor Central Caissons,
using a 1992 HR150 Mait auger rig. This rig weighed 46,500 kilograms and generated up to 206
kilowatts of power. It had a 100 kilonewtons pull-up force. Pilot holes were drilled with 42” auger
bits. These bits were tipped with steel teeth. Tungsten carbide tips were available but were not
required. Casing was installed through the surficial sand cover and was seated in thick overburden
clay at around 35m. The clay provided a quality seal that allowed a circulation system to be
created when reverse flood drilling commenced. A water/drilling mud (Quick Gel) slurry was used in
all subsequent drilling and this was sufficient to hold the remaining (approximately) 70 metres of
overburden in place.
Encore utilized a heavily fortified TH-100 (referred to as a TH150) top drive drill rig, which
contained a winch rated to 110,000 lb. The rig mast was rated to 120,000 lbs. and the top drive had
an estimated torque of 25,000 ft.lbs. Encore had “tuboscoped” all drill rods and joiners prior to
mobilisation to ensure quality fittings on the drill string. The drill string and collars are 50%
owned by De Beers Canada. Drill rods were consistently 6 metres in size. The drill rig mast had
been lengthened to 60 feet in length so drill rods could be added in two’s. The rig equipment also
included five collars, designed to apply weight on the bit during the early stages of drilling. The
rods and collars permitted drilling to occur as deep as 400 metres. A kelly linked the drill rods
with the swivel and outlet hose. The kelly sat above the top drive motor and was a constant source
of repair time during drilling. The rig design allowed too much weight to be applied to the Kelly
and swivel, hence the breakdowns. Reverse flood drilling was conducted with 36-inch milled tooth
tricone and drag bits. During reverse flood drilling, kimberlite was brought to the surface in a
slurry of water and bentonite mud. Mud was generally mixed directly into the recirculation pit. A
mud viscosity of between 45 and 50 seconds (viscup measure) was considered optimum for hole
integrity, although this figure was increased for some of the moredifficult 24-inch holes.
During drilling, the drill product would leave the rods / kelly through a feeder pipe linking the
rig kelly with a De Beers designed dropout box. This box was constructed to slow the flow of
kimberlite / water / mud in a controlled manner, thereby limiting potentially harmful impacts. The
box was coated with linatex to reduce wear, but because of the design, this linatex continually
required repair. The kimberlite was then split and dropped onto one of two Brandt King Cobra
vibrating shaker tables, which was lined with silicon sealed 1.58 millimetre screens. The
kimberlite was dewatered and washed via Bex FP5025 high impact flat spray nozzles, before falling
into Endurapak 38-inch x 38-inch x 42-inch double walled minibulk bags. Given the speed of
discharge and the angle of the 1.58 millimetre screens, kimberlite was deemed to have been screened
to 1.5 millimetre. A common hopper into which the washed sample dropped linked both shaker tables.
As high clay contents were observed and viscous muds used during drilling, the clay content of the
retained sample was relatively high. A high pressure water pump was installed part of the way
through the programme to supply more water to the spray bars to reduce this problem.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
The fines were discharged through the 1.58 millimetres screens into a split sump at the bottom of
the screen. This sump was divided so that the discharge from the spray nozzles did not enter the
mud circulation system and water down the mud and thereby reduce the effectiveness of overburden
hold-back (and increase hose and equipment wear). The majority of the mud and a reasonable
percentage of the kimberlite fines were gravity fed from the
shaker sump to a “U” shaped sump pit. This discharge was dropped into one end of the pit and
re-circulated back down the hole from the other end of the pit via a 12” plastic pipe inserted into
the conductor casing of the hole.
During overburden drilling, material extracted from the hole was allowed to fall into the bucket of
the T&P backhoe and stockpiled for later hole backfilling.
Data was recorded at the drill site by a Drill Parameter Recorder (DPR). This unit uses sensors
mounted on the drill rig to provide real-time parameter recording on a computer screen in the
geologists shack, on a touch screen next to the driller and to a secure internet site via direct
uplink to satellite. The data recorded included bit RPM, weight on bit, depth of bit, air pressure
and most importantly, rate of penetration (ROP). This data is displayed both numerically and
graphically. Drill holes were calipered on site using downhole tools that measured the change in
diameter on a centimetre-basis.
9.2.17.6 2004 Minibulk Sampling and Macrodiamond Recovery
The core drilling was designed to aid LDDH placement and to improve geological understanding
of the thicker parts of the kimberlite. Large diameter drilling was designed to both recover
sufficient diamonds to improve diamond value data, and to test the southern part of the kimberlite
from macrodiamonds. Various sample parameters were therefore geared to achieve this aim. Minibulk
samples were collected at the end of a shaker screen with 1.58 millimetre screens. The samples were
deemed to have been screened to +1.5millimetres through this flow sheet. Samples were divided into
(approximately) 12 metre intervals, corresponding to two drill rods. Each sample was assigned a
specific sample number with a “DGF” prefix. This number was allocated to each sample (6 metre or 12
metre) intersection and minibulk bags were labelled with this number and a letter (e.g. DGF220A),
representing each bag in the sample. The DGF number is easily transferred to the De Beers African
laboratories and is a security measure to prevent kimberlite number, sample number and depth data
to become common knowledge.
When bulk sample bags were full, they were sealed with Envopak Posigrip plastic security seals.
These seals were single piece 475 millimetre plastic strips with 5 digit security numbers. When
conditions cooled, steel security seals were used for added security. Bags were weighed on site and
loaded on trailers provided by Ridsdale Transport. The bags were securely covered, affixed with
security seals, and transported immediately to the De Beers Processing Facility in Grande Prairie.
Small archive samples were collected on a per-metre basis at the end of the shaker table hopper.
The samples included standard drill chips and usually one slightly larger fragment to aid in
petrographic identification. These were visually inspected on site by the shift geologist, but
most geological interpretation was made on core material. These samples were collected in 400
millilitre plastic containers and stored in 20 litre plastic pails. Granulometry samples were
collected over each minibulk sample interval (either 6m or 12m interval) at the bottom of the
shaker table and assigned the same DGF number. Samples were collected consistently throughout the
12 metre intersections at the end of the shaker table. Therefore some of the –1.5 millimetre
material had been removed prior to sample collection, except for particularly clay rich intervals.
Granulometry samples were sealed in plastic bags and were analyzed on site. The samples were
generally 2-3 kilogram in size and had been pre-washed over the 1.58 millimetre screen. The
configuration of the shaker table made alternative sampling arrangements difficult. Samples were
collected in plastic bags and sealed in the same way as the minibulk bags. Granulometry samples
were analyzed on site. Samples were dried and split into –1.4 millimetre, -4.0+1.4 millimetre,
-8.0+4.0 millimetre, 12.5+8.0 millimetre, -16.0+12.5 millmetre and +16.0 millimetre fractions
using a Rotap vibrator.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Minibulk samples were shipped to the De Beers’ dense media separation plant located in Grande
Prairie, Alberta for the first stage of diamond recovery procedures. This process included rinsing
and sizing (combined screening and crushing circuits) of the kimberlite chips to produce a uniform
feed within a size range of 1.5 – 12 millimetre
to ensure efficient and complete separation of heavy minerals (including diamond). Separation of
heavy minerals in the dense media process typically produced a concentrate of only a few percent of
the original mass of sample. Concentrates were then air-freighted to an ultra-high security
facility in Johannesburg, RSA for final diamond recovery and stone characterization procedures.
The diamonds were then studied for the presence of drilling or process-induced breakage, then
cleaned in an acid bath, and valued in parcels based on sieve class size.
9.2.17.7 2004 Drilling and Sampling Results
9.2.17.7.1 Kimberlite 120
The 120 kimberlite occurs in the main cluster of the Fort à la Corne Kimberlite Province and
is located on western end of the irregular shaped 148/147/120/220 volcanic complex with the 148
kimberlite directly to the southeast and the 220 kimberlite immediately to the east. Eight
coreholes on Kimberlite 120 (Figure 12) provided 940.05 metres of kimberlitic material from a total
meterage of 1,968.0 metres. The top of the first kimberlite intersection ranged between 102.0 to
115.88 metres and the bottom of the last kimberlite unit situated between 234.5 and 243.6 metres.
Kimberlite thicknesses varied between 9.62 and 185.8 metres. The average total core recovery for
the 2004 drillholes was 93.7%.
9.2.17.7.1.1 Previous Drilling on Kimberlite 120
As summarized in Table 31, twenty drillholes were completed on the 120 kimberlite body between
1990 and 1993. Various thicknesses of kimberlite ranging between 0.0 and 170.0 metres were
encountered by the drilling. The top of the kimberlite in the drillholes was noted to be between
97.0 and 115.0 metres depth.
The initial drilling programme testing the 120 body in 1990 consisted of four reverse circulation
drillholes (120-01 to 120-04). Follow-up holes (DH’s120-02 to 120-17) were completed in 1991 and
1992. These consisted of reverse circulation mini-bulk sample and coreholes (76 millimetres). One
of the reconnaissance holes drilled in 1992 (DH 120-18) did not recover any kimberlite. One other
hole, DH 120-05X, had to be abandoned while drilling overburden when problems were encountered in
the hole. A second hole, DH 120-05 was completed at the same location. The following year 120-14
was abandoned and was replaced by 120-15. The reconnaissance drillhole 120-18 did not intersect any
kimberlite in 1992. Drillhole 120-20 was a redrill of holes 120-12 and 120-13 in order to confirm
macrodiamond recoveries in the earlier drillhole.
9.2.17.7.1.2 Geology of the 120 Kimberlite
Eight coreholes were completed in the 120 kimberlite body in 2004. The body forms part of the
so-called 148 complex which includes the 120, 147, and 220 kimberlites. Petrographic logging of the
120 drillholes and subsequent macroscopic and microscopic investigation of the core samples has led
to the identification of four main phases of kimberlite and a zone of mixing between two of the
phases.
The four main phases are: the Main Pyroclastic Kimberlite (MPK); the Carbonate Lath-Rich
Volcaniclastic Kimberlite (CLR-VK); the Brown Mantle Rich Pyroclastic Kimberlite (BMR-PK); and the
Olivine Phenocryst-Rich Pyroclastic Kimberlite (OPR-PK). The MPK and CLR-VK phases have been
variably mixed to produce intermediate zones within the pipe, termed MPK+CLR-VK where the relative
proportion of MPK-derived components is greatest, or CLR-VK+MPK where the reverse is true. In a
preliminary geological model, these variably mixed intervals have been modeled as a single pipe. An
interval of volcaniclastic kimberlite intersected
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
in a hole collared near the previously modeled
contact between the 120 and 148 pipes is broadly comparable to the TBVK phase in the 148 kimberlite
body and has been modeled as part of that pipe, although further work is required to improve
confidence in this preliminary model.
Note: This table does not include microdiamonds and macrodiamonds that may have been recovered
from caustic dissolution or jigging recovery methods.
Table 31: Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 120
The main petrographic units encountered in the drillholes are described below:
Main Pyroclastic Kimberlite
The MPK intersected in five of the eight drillholes completed in the 120 body represents the
dominate rock type in terms of total metres logged. The MPK consists mainly of units classified
during logging as PK, as well as minor units classified as VK. The PK intervals are massive to
diffusely bedded lapilli tuffs, whereas the VK intersections are either massive or well-bedded
olivine ash/lapilli tuffs. The dominant grain sizes in the PK units are medium and coarse grained,
while the VK units include a greater proportion of very fine and fine grained material. The MPK is
characterized by a high proportion of mantle-derived indicator minerals (garnet, ilmenite and
chrome diopside). The country rock xenolith content of the PK intersections is low (<3%) and
includes altered basement gneiss/schist, limestone and lesser mudstone. The VK units are
characterized by higher country rock xenolith contents (5-80%) and include localized breccias
typically dominated by mudstone xenoliths.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Carbonate Lath Rich Volcaniclastic Kimberlite
The CLR-VK was intersected in only two of the 2004 coreholes and its volume is therefore poorly
constrained in the current model. The CLR-VK is a diffusely to more distinctly bedded lapilli/ash
tuff. The average olivine macrocryst grain size varies from very fine to medium grained. Phlogopite
macrocrysts are common and are a
distinctive feature of this phase. The proportion of mantle-derived indicator minerals (garnet,
ilmenite and chrome diopside) is moderate to high. The country rock xenolith content is low
(<2%) and includes limestone and altered basement gneiss/schist xenoliths.
Figure 12: Location of 2004 Coreholes on Body 120 Showing Kimberlite Thickness
Mixed Zone
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
The MPK and CLR-VK phases have been variably mixed to produce intermediate zones within the pipe.
These variably mixed intervals were intersected in four of the eight 2004 drillholes and have been
modeled as a single pipe-like body in the preliminary geological model. These lapilli/ash tuffs
display a range of structures that include massive, to diffuse, to well bedded intervals. The
average olivine macrocryst grain size of the mixed units is highly variable between drillholes and
depends on the relative location of the holes and the presence and nature of bedding structures
within the intervals. The defining feature of these mixed units is the presence of juvenile
lapilli/ash derived from both the MPK and CLR-VK phases. The presence and nature of the two types
of lapilli can only be discerned microscopically. The proportion of mantle-derived garnet, ilmenite
and chrome diopside is moderate to high or high throughout the mixed zone. The country rock
xenolith content is typically low (<2%) and includes limestone and altered basement
gneiss/schist. Green-black mudstone occurs in variable proportions.
Brown Mantle Rich Pyroclastic Kimberlite
The BMR-PK is a distinct phase that occurs in a 32.5 metres thick intersection in only one of 2004
coreholes. The same unit was identified in only one of the previous drillholes. The BMR-PK is a
massive to diffusely bedded olivine lapilli tuff, characterized by a high proportion of
mantle-derived constituents, particularly in the very coarse grained intervals. The country rock
xenolith content is low (<2%) and includes limestone and altered basement gneiss/schist.
Olivine Phenocryst-Rich Pyroclastic Kimberlite
The OPR-PK is a distinct phase that occurs in a 40.4 metres thick intersection in one of 2004
drill holes. The unit consists of a diffuse and thickly bedded olivine lapilli/ash tuff. The
dominant average olivine macrocryst grain sizes are very fine to fine and fine to medium grained.
The proportion of mantle-derived indicator minerals (garnet, ilmenite, chrome diopside) and
xenoliths is low compared to the other main phases. The country rock xenolith content is variable.
It is very low (<1%) through most of the intersection, but below approximately 146.5 metres
depth, a number of the very fine to fine grained intervals contain common mudstone xenoliths
forming localized breccias.”
9.2.17.7.1.3 Density Measurements
The calculation of 98 in-situ density values on kimberlite samples in 2004 was found to have a
mean value of 2.53 g/cm3, a median value of 2.53 g/cm3 and a standard
deviation of ± 0.1 g/cm3. The frequency distribution of density values shown in Figure
13 appears tightly constrained, with a limited range of values between 2.48 and 2.78
g/cm3. In drillholes 04-120-022, -023 and -028 density values were noted to decrease at
the bottom of the hole where larger quantities of country rock were noted. At the bottom of hole
04-120-027, coarse to medium grained kimberlite was noted which likely explains the slight increase
in density at depth in this drillhole. A plot of in-situ density versus depth is shown ion Figure
14.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 13: Frequency Histogram of 2004 Density Measurements for the 120 Kimberlite
Figure 14:
Chart of 2004 In-Situ Density Measurements for the 120 Drillholes
(Kimberlite, Overburden and Country Rock Samples)
9.2.17.7.1.4 Magnetic Susceptibility
Magnetic susceptibility for each of the holes completed is shown graphically in Figure 15. Of
all the drillholes completed during the reporting period, DH 04-120-026 was found to have the
highest magnetic response (max. value: 159 x10-3 SI units) due to the presence of
magnetite in various sections of the kimberlite. Overall higher magnetic responses were also noted
among drillholes in the western portion of the body (DH’s 120-22, 23, 26, 27, 28).
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.17.7.1.5 Archeological and Flora/Fauna Surveys
Golder Associates Ltd. of Saskatoon, Saskatchewan was contracted to undertake a flora and
fauna survey of the 120 kimberlite body as well a heritage resource review of proposed drillsite
areas in accordance with the provincial Heritage Property Act. Once reports of the findings of the
various surveys were submitted and reviewed by the Cultural and Heritage Branch (Heritage Resource
Review) and Saskatchewan Environment (Flora and Fauna Survey) approval was granted by the various
regulatory bodies for drilling activity. Nine drillpads were surveyed by the archaeological crew
encompassing approximately 9 hectares. No major archeological artifacts were found in the
Kimberlite 120 area.
Figure 15: Chart of 2004 Magnetic Susceptibility Measurements for
the 120 Kimberlite Drillholes
9.2.17.7.1.6 120 Sampling and Microdiamond Recoveries
A total of 962 microdiamonds were recovered from 643.4 kilograms of kimberlite core in 79
samples utilizing caustic dissolution methods at the SRC. Microdiamond recoveries were audited and
individual stone sizes calculated by experts at the De Beers Kimberley Microdiamond Laboratory
(KMDL) in South Africa. Since the FalC-JV partners have not received the full suite of modeled size
data from KMDL, only microdiamond data from the SRC are reported here. Summaries of diamond
recovery by kimberlite drillhole and by sieve category are shown in Tables 32 and 33.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Microdiamond recoveries in 2004 compare favourably with historical recoveries which are shown at
the bottom of Table 32. The average stone density of the 2004 recoveries is significantly higher
at 15 stones/10 kilograms and there are similar recoveries of stones larger than 0.5 millimetres
(per kilograms). Microdiamonds recovered from the 2004 program will be combined with all suitable
historical diamond results and submitted to MRM of De Beers for grade forecasts of commercial-sized
diamonds based on statistical and graphical treatment of the data.
Carat
Number of
Sample
Weight
# of
Average
Stones larger
Drillhole
Samples1
Mass (kg)
(carats)
Stones
Stones/10 kg
than 0.5 mm2
04-120-021
12
97.75
0.0073550
127
13.0
0
04-120-022
16
129.62
0.0104550
155
12.0
1
04-120-023
10
82.05
0.0095050
102
12.4
1
04-120-024
1
8.05
0.0004100
9
11.2
0
04-120-025
12
98.40
0.0355650
196
19.9
1
04-120-026
10
81.65
0.0072700
137
16.8
0
04-120-027
11
89.16
0.0061850
99
11.1
0
04-120-028
7
56.72
0.0075550
137
24.2
0
Total:
79
643.40
0.0843000
962
15.0
3
120 Historical3
13 DH; 59 samples
1104.68
0.1664583
734
5.36
6
1 = For the 2004 samples, representative sample intervals ranged from 6.5 to 18 metres
of kimberlite intersection; sample weights ranged from 8.05 to 8.35 kilograms
2 = Stones with at least one axis greater than 0.5 millimetres in length
3= Due to the wide variance in sample mass per historical drillhole, the
average stones/10 kilograms for the historical results was weighted by the mass of individual
samples (a simple average of drillhole values was calculated at 4.77 stones/10 kilograms).
Table 32: Summary of 2004 and Historical Kimberlite 120 Microdiamond Results
+0.075mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+0.600mm
+1.400mm
Drillhole
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
04-120-021
39
54
19
10
5
0
0
0
04-120-022
58
54
31
9
2
1
0
0
04-120-023
37
35
14
10
5
0
1
0
04-120-024
3
4
1
1
0
0
0
0
04-120-025
79
74
32
10
0
0
0
1
04-120-026
56
40
21
17
2
1
0
0
04-120-027
25
49
13
7
5
0
0
0
04-120-028
59
44
22
10
1
1
0
0
Total:
356
354
153
74
20
3
1
1
Table 33: Kimberlite 120 Microdiamond Recoveries by Drillhole and Sieve Category
9.2.17.7.2 Kimberlite 147
The 147 kimberlite occurs in the main cluster of the Fort à la Corne Kimberlite Province and
is located at the eastern section of the irregular shaped 148/147/120/220 volcanic complex with the
148 kimberlite directly to the south-west and the 220 kimberlite immediately to the west. Eight HQ
coreholes (1,740.0 metres) were completed during October and November 2004 in order to provide
geological information on the 147 kimberlite and to provide additional information on the diamond
potential of the body through microdiamond sampling. The location of the drillholes is shown in
Figure 16.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
The coreholes provided 855.38 metres of kimberlitic material from a total meterage of 1,740.0
metres. The top of the first kimberlite intersection ranged between 96 to 106.28 metres and the
bottom of the last kimberlite unit situated between 181.22 and 221.82 metres. Kimberlite
thicknesses varied between 74.94 and 125.68 metres. Three main kimberlite units were recognized
within body 147. The average total core recovery for the 2004 drillholes was 97.4%.
9.2.17.7.2.1 Previous Drilling
Five reverse circulation drillholes were completed in the 147 kimberlite prior to 2004.
Drillhole information for these holes is summarized in Table 34.
Figure 16: Location of 2004 Coreholes on Body 147 Showing Kimberlite Thickness
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
The initial drillhole testing in 1991 consisted of a single reverse circulation drillhole.
Follow-up holes (DH’s147-002 and 147-003) were completed in 1992 and 1995. Between1995 and 1999,
larger RCA holes were completed within the kimberlite. Each of drillholes encountered technical
problems. While completing DH 147-03 in 1995, the casing seal was lost and subsidence around the
rig caused it to tilt. Ground collapse around the casing once again in 1999 (DH147-04) was
corrected with the drillhole completed without further incident. In drillhole 147-05, a hard ledge
at the bottom of the kimberlite body could not be penetrated and the hole was ended in kimberlite.
Subsequent drilling in the 147 kimberlite area was aimed towards determining if 120, 147 and 148
bodies constituted a single kimberlite. The 148 body was tested by four holes in 2003. Kimberlite
thicknesses in this body ranging in thickness from 15.03 to 180.65 metres were found to be more
variable than holes drilled in the 147 kimberlite body.
This table does not include microdiamonds and macrodiamonds that may have been recovered
from caustic dissolution or jigging recovery methods.
Table 34: Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 147
There is limited geological information available on previous work completed on the 147 kimberlite
in reports produced by Uranerz (UEM Annual Report 1991, 1992, 1995, 1999). Although drill chips
were logged, drill logs provided minimal useable information on the geology of the body. Slabs or
thin sections were not produced from any drillholes, nor were any detailed macroscopic or
petrographic investigations completed on the cuttings.
9.2.17.7.2.2 Preliminary Geology of the 147 Kimberlite
The purpose of the macroscopic and microscopic investigations was to establish petrographic
descriptions for the kimberlite phases composing the body and to highlight any rock types
characterized by a high diamond carrying capacity. The 147 kimberlite pipe occurs in the main
cluster of the Fort à la Corne Kimberlite Province, Saskatchewan, Canada. The 147 kimberlite is
located at the eastern section of the irregular shaped 148/147/120/220 volcanic complex (148
complex) with the 148 kimberlite directly to the south-west and the 220 kimberlite immediately to
the north-west.
Three main petrographic units were recognized in the 147 body: TBVK (Thinly Bedded Volcaniclastic
Kimberlite, DGBPK (Dark Grey Bedded Pyroclastic Kimberlite) and MGU (Mega Graded Unit). A fourth
minor unit, FLVK (Fine Laminated Volcaniclastic Kimberlite), was also identified in several
drillholes. The thinly bedded volcaniclastic kimberlite unit appears to be the main kimberlite type
infilling the 147 body based on its extent in the 2004 drillholes. This unit occurs predominantly
within the centre portion of the 147 body outline. The TBVK unit is similar in character to the
TBVK unit in the adjacent 148 kimberlite.
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9.2.17.7.2.3 Density Measurements
Density values for 117 kimberlite samples from the adjacent Kimberlite 148 in 2003 were found
to have a mean value of 2.41 g/cm3 for in-situ density. A slightly lower range in values
was noted for 88 kimberlite samples obtained from the 2004 drilling on Kimberlite 147. This suite
of data indicated a mean value of 2.38 g/cm3, a median of 2.37 g/cm3 and a
standard deviation of ± 0.08 g/cm3. The frequency distribution of in-situ density values
for the 147 kimberlite is shown graphically in Figure 17.
Fine grained kimberlite at the bottom of drillholes 04-147-007 and 012 was noted to have lower
density values compared to holes 04-147-008 and 010 which had higher values associated with medium
grained kimberlite. The results of the 2004 density measurements versus depth are shown graphically
in Figure 18. At a depth of approximately 200m the density values seem to slightly increase in
drillholes 04-147-008, -009 and -013 where mainly medium grained kimberlite was logged.
Figure 17: Frequency Histogram of the 2004 Density Measurements for the 147 Kimberlite
Figure 18:
Chart of 2004 In-Situ Density Measurements for the 147 Drillholes
(Kimberlite, Overburden and Country Rock Samples)
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 19: Chart of Magnetic Susceptibility Measurements for the 147 Drillholes
9.2.17.7.2.4 Magnetic Susceptibility
The susceptibility data is summarized for each drillhole in Figure 19. Of the drillholes
completed, holes 04-147-007 (max value: 181 SI 10-3) and 04-147-006 (max. value: 109
SI 10-3 units) were found to have higher magnetic susceptibility responses due to
the presence of magnetite in various sections of the kimberlite.
9.2.17.7.2.5 Archeological and Flora/Fauna Surveys
Golder Associates Ltd. of Saskatoon, Saskatchewan was contracted to undertake a flora and
fauna survey of the 147 kimberlite body as well a heritage resource review of drillsite areas in
accordance with the provincial Heritage Property Act. Once reports of the findings of the various
surveys were submitted and reviewed by the Cultural and Heritage Branch (Heritage Resource Review)
and Saskatchewan Environment (Flora and Fauna Survey) approval was granted by the various
regulatory bodies for drilling activity. The collar location for drillhole 04-147-012 was moved
after tool construction rock chip artefacts were discovered at the originally proposed drillsite
location. At total surface of about 9 hectares was surveyed by the archeologists in order to cover
8 drillpads and the drillpad area of 04-147-012 that was avoided.
9.2.17.7.2.6 Sampling and Microdiamond Recoveries for 147
A total of 2,432 microdiamonds were recovered from 515.20 of kimberlite core in 63 samples
utilizing caustic dissolution methods at the SRC. Microdiamond recoveries were audited and
individual stone sizes calculated by experts at the De Beers Kimberley Microdiamond Laboratory
(KMDL) in South Africa. Since the FalC-JV partners have not received the full suite of modeled
size data from KMDL, only microdiamond data from the
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
SRC are reported here. Summaries of diamond
recovery by kimberlite drillhole and by sieve category are shown in Tables 35 and 36.
Carat
Number of
Sample
Weight
# of
Average
Stones larger
Drillhole
Samples1
Mass (kg)
(carats)
Stones
Stones/10 kg
than 0.5 mm2
04-147-006
13
106.40
0.025255
378
35.53
0
04-147-007
4
32.65
0.004075
67
20.52
0
04-147-008
7
57.35
0.052650
650
113.34
2
04-147-009
7
57.20
0.036245
155
27.10
1
04-147-010
7
57.40
0.030035
311
54.18
0
04-147-011
7
57.25
0.017215
238
41.57
1
04-147-012
6
48.90
0.014190
201
41.10
1
04-147-013
12
98.05
0.025415
432
44.06
1
Total:
63
515.20
0.205080
2432
47.21
6
147 Historical3
3 DH; 10 samples
292
0.1042626
559
21.1
7
1
= For the 2004 samples, representative sample intervals ranged from 3.2 to 24.2
metres of kimberlite intersection; sample weights ranged from 8.05 to 8.25 kilograms
2
= Stones with at least one axis greater than 0.5 millimetres in length
3
= Due to the wide variance in sample mass per historical drillhole, the average
stones/10 kilograms for the historical results was weighted by the mass of individual samples (a
simple average of drillhole values was calculated at 21.4 stones/10 kilograms)
Table 35: Summary of 2004 and Historical Kimberlite 147 Microdiamond Results
Microdiamond recoveries in 2004 were significantly higher than historical recoveries which are
shown at the bottom of Table 35. At 47 stones/10 kilograms, the average stone density of the 2004
recoveries is more than double that of the historical recoveries and is actually much higher if the
128 microdiamonds measuring less than 0.075 millimetres are not included in the historical tally.
In comparison, less than half of the stones larger than 0.5 millimetres were recovered.
Microdiamonds recovered from the 2004 program will be combined with all suitable historical diamond
results and submitted to MRM of De Beers for grade forecasts of commercial-sized diamonds based on
statistical and graphical treatment of the data.
9.2.17.7.3 Kimberlites 121 and 221
The 121 and 221 kimberlites occur in the main cluster of the Fort à la Corne Kimberlite
Province and are located east of the 148/147/120/220 volcanic complex. Eight HQ coreholes (120-09
to 13, 221-02 to 04) were completed during October and November 2004 in order to improve the
geological understanding of the 121 and 221 kimberlite bodies (Figure 20). The eight holes
provided a total metreage of 1,745 metres of core with a total of 624.3 metres of kimberlitic
material cored. Kimberlite thicknesses varied between 32.27 metres and 177.5 metres for kimberlite
body 121 and between 51.16 metres and 75.38 metres for kimberlite body 221. Drillholes 04-121-011
and 04-221-002 were reduced to NQ size core at a depth of 165 metres due to technical problems
encountered while drilling. From the core logging of the eight drill cores examined from
kimberlite bodies 121/221, it has been determined that the medium to coarse-grained pyroclastic
units intersected in the centre of the 121 and 221 bodies represent the material of highest
interest. The average total core recovery for the 2004 121/221 drillholes was 97.1%.
9.2.17.7.3.1 Previous Drilling
Eight previous drillholes of various types (rotary, NQ core and reverse circulation mini-bulk
sample holes) have tested the 121 kimberlite during the period 1989 through 1996. As shown in
Table 37, the majority of past drillholes in the target area are clustered towards the centre of
the circular to ovoid shaped 121 kimberlite body which ground magnetic modelling has forecasted to
be 28 ha in size.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
+0.075mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+0.850mm
+1.000mm
Drillhole
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
04-147- 006
130
118
67
48
15
0
0
0
04-147-007
26
17
14
9
1
0
0
0
04-147-008
195
229
123
64
34
5
0
0
04-147-009
51
58
22
12
8
3
0
1
04-147-010
93
112
58
28
11
9
0
0
04-147-011
92
74
34
27
8
2
1
0
04-147-012
80
66
28
20
5
1
1
0
04-147-013
168
156
64
29
11
4
0
0
Total:
835
830
410
237
93
24
2
1
Table 36: Kimberlite 147 Microdiamond Recoveries by Drillhole and Sieve Category
Note: This table does not include microdiamonds and macrodiamonds that may have been recovered
from caustic dissolution or jigging recovery methods.
Table 37: Summary of Historic Drillholes and Minibulk Macrodiamond on 121 and 221
Variable thicknesses of kimberlite were also encountered by previous drillholes testing the 121
body ranging from 47.6 metres (incomplete, rotary test hole) to 172.0 metres depth. The average
thickness of kimberlite encountered by the seven complete historic holes testing the body is 126.4
metres. Taking local variations in elevation into consideration, the top of the kimberlite in the
121 body is approximately at 111-116 metres depth.
The magnetic indicated outline of the 221 body indicates a circular 15 ha body appended to the
northwest margin of the 121 kimberlite. A single 43/4” rotary drillhole (DH 221-01) collared at the
centre of the body tested the target in 1996. A 168.6 metres intersection of kimberlite was
recovered in the hole.
9.2.17.7.3.2 Geology of the 121 and 221 Kimberlites
The results of logging eight drillholes from the 121/221 kimberlite bodies indicate that the
121 kimberlite is asymmetric and steep walled. The 221 kimberlite is smaller in size, slightly more
symmetric, but even more steep walled. A GEMCOM model for the combined bodies (Figure 21) prepared
by De Beers shows that each kimberlite consists of two main petrographic units.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 20: Location of 2004 Coreholes on Body 121/221 Showing Kimberlite Thickness
The occurrence of distinctively pyroclastic kimberlite units is limited almost entirely to the
centre of each body i.e. drill holes 04-121-09 and 04-221-03. Both of these holes are dominated by
pyroclastic material with only minor occurrences of resedimented volcaniclastic kimberlite at the
tops of the either hole. Another drillhole (04-121-11) collared between the centres of the 121 and
221 kimberlites, also contains a dominant pyroclastic phase. The pyroclastic kimberlite in this
area may represent a more distal, finer-grained equivalent (fine-medium grained kimberlite) of the
proximal material intersected in drillhole 04-121-09 (medium-coarse grained kimberlite) near the
121 vent, whereas the fine to medium pyroclastic kimberlite in DH 04-221-03 is thought to represent
proximal material from a separate, smaller vent at 221. Petrographically, the highest interest
packages are the medium to coarse grained pyroclastic kimberlite units intersected in drillhole
04-121-09, followed by the fine to medium grained pyroclastic kimberlite units noted in holes
04-121-11 and 04-221-03 respectively.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Overall the pyroclastic units in the 121/221 kimberlites contain both single olivines, often with
very thin possible magmatic rims (these could also be alteration rims), and pyroclasts. The
pyroclasts are variable in their composition, size and shape. Pyroclasts can comprise single
olivines (macrocrysts or phenocrysts) with a thin magmatic rim, to single olivines with much
thicker rims often containing groundmass spinel, phlogopite and olivine phenocrysts or even other
macrocrysts. In some cases, the pyroclast rims comprise only light-green serpentine and can be
difficult to distinguish from the matrix. Shapes vary from round to curvilinear. The size of the
juvenile grains varies from fine to coarse grained. The juvenile component of the pyroclastic
kimberlite (olivine grains and pyroclasts) varies between 55-85% depending on the size and packing
of the juvenile grains. Overall the units are fairly massive in character, but the size of
juveniles often varies on a centimetre-scale and often resembles a coarsely defined bedding or
layering. These variations can also occur on a scale of metres or even several metres. The packing
of these juveniles can also vary from well packed to poorly-packed.
Overall the pyroclastic kimberlite units contain a full range of mantle indicators known from Fort
à la Corne i.e. garnet, clinopyroxene, ilmenite, mica. The garnets present are mainly orange and
red in colour. Garnet is usually the most abundant indicator mineral. The clinopyroxenes are
difficult to recognize and are altered to a whitish/pink colour. Ilmenite can also be difficult to
recognize in places, mainly due to the presence of secondary magnetite. Mica is not usually a
common mineral. Spinel was not identified. Coarser units tend to contain mantle xenoliths which
include both peridotites and eclogites (clinopyroxene and garnet), which often have magmatic rims.
Country rock xenoliths are generally not abundant and most of the pyroclastic kimberlite units
contain between 2-5% country rock, but this can be higher in places. The country rock xenoliths
comprise rounded to angular black, beige and grey mudstones, limestones and basement gneisses. The
mudstones usually appear to have been competent fragments included in the pyroclastic kimberlite,
but rarely appear to have been soft by their deformed and even ‘interstitial’ nature (they appear
to form a matrix component in places). Many of these dark mudstones also show olivines penetrating
into their margins. The limestones can be difficult to recognize in places as they are often
totally altered to the light-green matrix serpentine. Likewise, the basement xenoliths are also
often highly altered and are often difficult to recognize.
The dominant intra-clast matrix type in the pyroclastic kimberlites is serpentine, which is
predominantly light-green in colour but can be very dark-green in places. The light-green
serpentine often forms veins and even pools in places. Magnetite is also a common matrix mineral
and often forms patches in the matrix and also replaces olivine in places. Carbonate is not
generally common in the matrix, but can be locally abundant.
The resedimented volcaniclastic kimberlite units are not volumetrically significant and are
represented in the 121/221 bodies by units from 2.7 metres up to 15.4 metres. These units are
located within the central portions of the bodies as well as along the margins of the bodies and
are always located at the top contact of the kimberlite with the overburden.
Overall the resedimented volcaniclastic kimberlite units varies from ‘kimberlitic shale’ to finely
bedded, fine grained kimberlitic material containing olivine and spinel. The kimberlitic shales
comprise extremely fine-grained, very clay-rich and horizontally laminated material with only
traces of mica and garnet. The ‘bedded’ resedimented volcaniclastic kimberlites are generally very
well packed, fine-grained units containing mainly juvenile material with minor country rock as
black mudstone, and mantle indicator minerals (garnet, clinopyroxene, ilmenite, and mica). The
juvenile material usually comprises single olivines but in one case comprised altered spinel
grains. This spinel-rich unit also contained a vermiform secondary mineral (antigorite) which
appears to replace much of the original mineralogy and texture in the redsedimented units. These
spinel-rich units have been noted in other bodies in the cluster. The intra-clast matrix of the
‘bedded’ resedimented volcaniclastic kimberlite units comprises serpentine and carbonate. Bedding
in these resedimented volcaniclastic kimberlite units is normally well defined and upward fining on
a centimetre scale, often with a coarser basal lag. The bedding normally has a very shallow dip and is usually
horizontally laminated with very
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
little internal structure, although trough crossbedding is observed in places. The well sorted and
bedded nature of these deposits implies reworking, possibly in a sub-aqueous environment. The
resedimented volcaniclastic kimberlite units are still poorly understood and further work is
required in order to determine their process of deposition.
Volcaniclastic kimberlites in the 121/221 drillholes display characteristics of both pyroclastic
kimberlite and resedimented volcaniclastic kimberlite. These units are thought to represent distal
pyroclastic fall deposits or fine-grained, reworked tephra ring deposits (possibly a combination of
both). All of the drillholes completed during the reporting period (except 04-121-12) contain a
volcaniclastic kimberlite unit and these can be divided into two main types:
Coarse-grained basal contact volcaniclastic kimberlite units are generally thin (~1 metre but up to
~4 metres) and are located at the basal contact of the kimberlite and the country rock. These units
probably represent the first phase of crater infill and are rich in coarse-grained juveniles,
mainly single olivines with minor pyroclasts, and large sub-rounded to sub-angular country rock
xenoliths (mudstones, basement and limestone) and rounded mantle xenoliths and indicator minerals.
The intra-clast matrix is serpentine but closer to the contact this can be replaced by carbonate.
It is unclear whether these units are coarse-grained pyroclastic fall deposits from the initial
crater forming explosion, or whether they are avalanche or debris-flow deposits formed by slumping
of the outer tephra ring. They may in fact form by a combination of both processes. Fine grained
upper volcaniclastic units are usually located on the margins of the bodies and range from 1 to 50
metres thick. They are either found as units between overlying resedimented volcaniclastic
kimberlite and underlying pyroclastic kimberlites or as generally thicker units below a
resedimented volcaniclastic kimberlite, usually comprising the rest of the hole. These deposits are
generally fine-grained, juvenile rich (single olivines and pyroclasts), crustal xenolith and mantle
xenocryst poor. Variations in sorting, packing and structure (bedding, grading) of these components
are observed. Alteration is also highly variable in these units, from fresh to highly carbonate
veined and totally carbonatized in places.
From the logging of the eight drillholes in 2004, it has been determined that the medium to coarse
grained pyroclastic units intersected in the centres of the 121 and 221 bodies represent the
highest interest material. If it becomes necessary to further define the extent of individual
units, then further drilling will be required and must be completed at a closer spacing.
9.2.17.7.3.3 Density Measurements
The 2004 density data for the 121 kimberlite body (43 kimberlite samples) indicates a mean value of
2.42 g/cm3 for in-situ density, a median of 2.41 g/cm3, and a standard
deviation of ± 0.15 g/cm3. The density data for the 221 kimberlite (29 kimberlite
samples) was found to be somewhat lower with a mean value of 2.25 g/cm3, a median of
2.26 g/cm3, and a standard deviation of ± 0.21 g/cm3.
The difference in density values between the two bodies suggests they may constitute two separate
bodies. The slightly higher average density for the 121 body may be explained by the fact that this
kimberlite consists of fine-medium grained kimberlite whereas the 221 body contains mostly very
fine-fine grained kimberlite. The 121 kimberlite also contains a higher, more consistent content of
limestone and mudstone xenoliths which may also contribute to the higher density for the body. The
increase in density at a depth of 180 metres at drillhole 04-121-009 might be explained by the
increase of the size of limestone xenoliths. The results of the 2004 density measurements are
shown graphically in Figures 22 and 23.
109
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 21: Views of the GEMCOM Model for the 121 and 221 Kimberlites
110
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Frequency distribution Kimberlite Body 121
Frequency distribution Kimberlite Body 221
Figure 22: Frequency Histograms of 2004 Density Measurements for the 121 and 221 Kimberlites
111
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
In Situ Density vs. Depth for body 121
In Situ Density vs. Depth for body 221
Figure 23:
Charts of 2004 In-Situ Density Measurements for the 121 and 221 Kimberlite Drillholes
(Kimberlite and Country Rock Samples)
112
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.17.7.3.4 Magnetic Susceptibility
The results show the magnetic susceptibility response to be variable and often
lithology-related. The overburden, kimberlite and country rock were all seen to have different
responses. The overburden composed of till was also seen to have a low magnetic susceptibility.
Although magnetic susceptibility values for the kimberlite were seen to vary within the body (at
the contact zones and within kimberlite), they were generally higher than those of the enclosing
country rocks (Figure 24).
Rather high magnetic values of up to 276 10-3 SI units in drillhole 04-121-013 are due
to the presence of magnetite veins and blebs within the kimberlite. Hole 04-221-003 drilled in the
centre of the 221 body was also seen to contain abundant magnetite with magnetic susceptibility
values of 242 10-3 SI units.
Magnetic Susceptibility vs. Depth for Body 121
Magnetic Susceptibility vs. Depth for Body 221
Figure 24:
Charts of Magnetic Susceptibility Measurements for the 121 and 221 Kimberlite Drillholes
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.17.7.3.5 Archeological and Flora/Fauna Surveys
Golder Associates Ltd. of Saskatoon, Saskatchewan was contracted to undertake a flora and
fauna survey of the 121 and 221 kimberlite bodies as well a heritage resource review of proposed
drillsite areas in accordance with the provincial Heritage Property Act. Once reports of the
findings of the various surveys were submitted and reviewed by the Cultural and Heritage Branch
(Heritage Resource Review) and Saskatchewan Environment (Flora and Fauna Survey) approval was
granted by the various regulatory bodies for drilling activity. Ten planned drillpads were surveyed
by the archaeological crew in the 121/221 kimberlite area encompassing approximately 10 hectares.
While conducting ground checks on an existing access road connecting the 221 and 147 target areas,
a stone tool was found by the archaeologists. As the ground had been bladed and no in-situ findings
were made, a recommendation to proceed with work was received from Cultural and Heritage Branch.
9.2.17.7.3.6 121 and 221 Sampling and Microdiamond Recoveries
Kimberlite 121
A total of 326 microdiamonds were recovered from 295.25 kilograms of kimberlite core in 36 samples
utilizing caustic dissolution methods at the SRC. Microdiamond recoveries were audited and
individual stone sizes calculated by experts at the De Beers Kimberley Microdiamond Laboratory
(KMDL) in South Africa. Since the FalC-JV partners have not received the full suite of modeled
size data from KMDL, only microdiamond data from the SRC are reported here. Summaries of diamond
recovery by kimberlite drillhole and by sieve category are shown in Tables 38 and 39.
Stones
larger
Number of
Sample
Carat Weight
# of
Average
than 0.5
Drillhole
Samples1
Mass (kg)
(carats)
Stones
Stones/10 kg
mm2
04-121-009
19
155.95
0.430420
248
15.90
1
04-121-010
4
32.95
0.000715
13
3.95
0
04-121-011
5
41.00
0.000710
25
6.10
0
04-121-012
4
32.65
0.005110
25
7.66
1
04-121-013
4
32.70
0.000530
15
4.59
0
Total:
36
295.25
0.437485
326
11.04
2
121 Historical3
7 DH; 43 samples
875.75
0.1049610
378
5.18
17
1
= For the 2004 samples, representative sample intervals ranged from 4.2 to 33.6 metres
of kimberlite intersection; sample weights ranged from 8.05 to 8.35 kilograms
2
= Stones with at least one axis greater than 0.5 millimetres in length
3
= Due to the wide variance in sample mass per historical drillhole, the average
stones/10 kilograms for the historical results was weighted by the mass of individual samples (a
simple average of drillhole values was calculated at 4.32 stones/10 kilograms)
Table 38: Summary of 2004 and Historical Kimberlite 121 Microdiamond Results
At first look, microdiamond recoveries in 2004 appear considerably higher than historical
recoveries, which are shown at the bottom of Table 38. At 11 stones/10 kilograms, the average
stone density of the 2004 recoveries is more than double that of the historical recoveries and is
actually much higher if the 94 microdiamonds measuring less than 0.075 millimetres are not included
in the historical tally. However, the average is affected significantly by very high stone
recoveries in 04-121-009, which was located near the centre of the body (see Figure 20) and
proximal to three historical holes with drillhole averages of greater than 6 stones/10 kilograms.
While stone densities for the four drillholes located some 200 to 250 metres away from the
postulated central eruptive vent are
114
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
comparable to the historical results, there is some indication that the centre of the pipe is more
microdiamond-rich than the margins.
Two stones larger than 0.5 millimetres were recovered from Kimberlite 121 in 2004 including one
diamond recovered on the 2.8 millimetres sieve screen and weighing 0.41667 carats from corehole
04-121-009. Most of the larger stones recovered in the historical programs were from the same
central area of the body as this drillhole.
Microdiamonds recovered from the 2004 program will be combined with all suitable historical diamond
results and submitted to MRM of De Beers for grade forecasts of commercial-sized diamonds based on
statistical and graphical treatment of the data.
+0.075mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+2.800mm
Drillhole
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
04-121-009
96
85
39
19
7
1
1
04-121-010
6
2
3
2
0
0
0
04-121-011
11
10
4
0
0
0
0
04-121-012
4
7
4
4
3
3
0
04-121-013
7
4
3
0
1
0
0
Total:
124
108
53
25
11
4
1
Table 39: Kimberlite 121 Microdiamond Recoveries by Drillhole and Sieve Category
Kimberlite 221
A total of 168 microdiamonds were recovered from 203.33 kilograms of kimberlite core in 25 samples
utilizing caustic dissolution methods at the SRC. Microdiamond recoveries were audited and
individual stone sizes calculated by experts at the De Beers Kimberley Microdiamond Laboratory
(KMDL) in South Africa. Since the FalC-JV partners have not received the full suite of modeled
size data from KMDL, only microdiamond data from the SRC are reported here. Summaries of diamond
recovery by kimberlite drillhole and by sieve category are shown in Tables 40 and 41.
Carat
Stones
Number of
Sample
Weight
# of
Average
larger
Drillhole
Samples1
Mass (kg)
(carats)
Stones
Stones/10 kg
than 0.5 mm
04-221-002
3
24.65
0.001030
16
6.49
0
04-221-003
19
154.44
0.034955
137
8.87
2
04-221-004
3
24.24
0.001370
15
6.19
0
Total:
25
203.33
0.037355
168
8.26
2
121 Historical
1 DH; 8 samples
264.35
0.0781664
74
2.78
3
1
= For the 2004 samples, representative sample intervals ranged from 5.15 to 25.8
metres of kimberlite intersection; sample weights ranged from 8.08 to 8.25 kilograms
Table 40: Summary of 2004 and Historical Kimberlite 221 Microdiamond Results
Microdiamond recoveries in 2004 were considerably higher than historical recoveries which are shown
at the bottom of Table 40. At 8.26 stones/10 kilograms, the average stone density of the 2004
recoveries is close to three times that of the historical recoveries and is slightly higher if the
12 microdiamonds measuring less than 0.075 millimetres are not included in the historical tally.
Most of the stones were recovered from a large amount of sample taken from the centrally located
corehole 04-221-003 that was targeted on the eruptive vent and near to historic drillhole 221-001
drilled in 1996 using a conventional circulation rotary drilling method.
115
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Two stones larger than 0.5 millimetres were recovered from Kimberlite 221 in 2004 including one
stone from corehole 04-221-003 caught on a 1.18 millimetres sieve screen and weighing just over
0.025 carats
Microdiamonds recovered from the 2004 program will be combined with all suitable historical diamond
results and submitted to MRM of De Beers for grade forecasts of commercial-sized diamonds based on
statistical and graphical treatment of the data.
+0.075mm
+0.106mm
+0.150mm
+0.212mm
+0.300mm
+0.425mm
+1.180mm
Drillhole
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
04-221-002
8
6
0
1
1
0
0
04-221-003
55
33
27
15
5
1
1
04-221-004
6
5
2
1
1
0
0
Total:
69
44
29
17
7
1
1
Table 41: Kimberlite 221 Microdiamond Recoveries by Drillhole and Sieve Category
9.2.17.7.4 Kimberlite 140/141
Four HQ coreholes (04-140-41, 42, 43, 50) were completed during September and October 2004 in
order to provide geological control for five large diameter drillholes completed in the south
central portion of the 140/141 kimberlite body testing the diamond potential of an oscillating
kimberlite breccia unit. The holes provided material for petrographic logging and microdiamond
sampling. A total of 974.0 metres of core was drilled with a total kimberlite intersection of
525.52 metres. The top of the first kimberlite intersection was encountered at a depth of 97.4 to
100.57 metres; the bottom of the last kimberlite unit was drilled at a depth of 232.35 to 241.22
metres. In three of the four drillholes three different kimberlite intersections were cored. A
fifth corehole, 04-140-048 was completed on the southern-most part of the 140/141 magnetic anomaly.
It was drilled to a depth of 180.0 metres and intersected three separate kimberlite units totaling
158.65 metres. New geological information from these coreholes together with the existing
geological model was used to determine the location of several large diameter drillholes.
Intersections of the Oscillating Breccia unit were shorter than that predicted by the model, with a
maximum thickness of 81 metres found for the unit. At greater depth, all the holes intersected the
“speckled kimberlite” (SPK). The average total core recovery for the 140 drillholes completed in
2004 was 98.6%.
9.2.17.7.4.1 Previous Drilling
Between 1992 and 2003, seventy-seven drillholes were completed on the composite 140/141
kimberlite involving 18,738.2 metres of drilling. This total includes 9,044.3 metres of kimberlite.
Past drilling of the composite 140/141 body indicates that a relatively deep intersection of
kimberlite exists near DH 140-21 which may correspond to the location of a second vent in the
140/141 body, the first being identified in DH 141-02 in 1992 and the second identified in DH
141-13 in 2001. As summarized in Tables 42 and 43 and shown in Figure 25, past drilling along the
eastern margin of the 140/141 body intersected relatively thin intersections of kimberlite. Several
holes drilled along the western margin of the body resulted in deeper than expected intersections.
It would also appear from these results that kimberlite with some thickness also extends beyond the
currently modelled western margin of the 140/141 body.
Ground magnetic and gravity surveys completed during 2002 more clearly defined internal
complexities of the 140/141 body. It is most likely that variations in magnetic susceptibility and
density measurements noted in drillholes testing the body are attributable to secondary alteration
and therefore may not accurately reflect distinct phases or petrographic units within the
kimberlite. The integrated magnetic and gravity datasets do
116
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
suggest however that the body is larger laterally than initially estimated, and may in fact
incorporate parts of the adjacent 133 and 145 kimberlite bodies.
This table does not include microdiamonds and macrodiamonds that may have been recovered
from caustic dissolution or jigging recovery methods.
Table 42: Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 140
9.2.17.7.4.2 140/141 Corehole Drilling
The purpose of the 2004 drill program in the central portion of the 140/141 kimberlite was to
generate additional geological information about the kimberlite and to enhance the geological model
of the kimberlite body. Three of the four coreholes were used primarily as pilot holes for
subsequent large diameter drillholes which tested the areal extent of the oscillating kimberlite breccia unit and provided sufficient
diamonds to
117
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
obtain a preliminary diamond revenue estimate for the unit. The location of the drillholes is shown
in Figure 25 and in a more detailed map in Figure 26.
This table does not include microdiamonds and macrodiamonds that may have been recovered
from caustic dissolution or jigging recovery methods.
Table 43: Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 141
118
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
One hydraulic LF-70 corehole rig was mobilized into the Fort à la Corne Forest by Boart Longyear
Ltd. on September 2, 2004. As summarized in Table 30, four coreholes were completed in the area.
Drill pad construction and site access was contracted to T&P Enterprises of Choiceland,
Saskatchewan with access to the 141/140 kimberlite gained via previously constructed trails. At
each of the drill pads an area approximately 40 x 40 metres was cleared. Temporary in-ground
tailings sumps were also constructed in order to receive, store, and re-circulate mud and effluent
produced during the corehole drilling.
HQ corehole drilling during the reporting period was generally completed using three different
sized bits. Initial surface holes were drilled using a mud and water circulation system and a PW
milled tooth tricone bit (139 millimetres diameter). At between 12 and 35 metres depth, the tricone
bit was replaced by a HW tricone bit (130.2 millimetres diameter) with bentonite mud and water used
as a circulant in the hole. At a depth of around 90-96 metres, the HW tricone was replaced by an HQ
tungsten carbide bit and coring commenced. The core drilling was conducted with either fresh water
or low viscosity mud. Casing was generally installed to around 95 metres in the hole, although on
occasion the casing string slipped downhole, so that additional lengths of casing had to be added.
A total of 168 metres of HWT schedule casing and 37.5 metres of PWT casing were lost in three of
the four holes completed during the drillhole program.
9.2.17.7.4.3 Geology of the 140/141 Kimberlite
Geological modeling of Kimberlite 140/141 shows it is dominated by a thick interval of graded
fine to coarse-grained olivine pyroclastic kimberlite that have relatively thin intervals of
xenolith-rich, breccia beds in the northern part of the body. Diamond grades and revenue modeling
for these units were reported during 2000 to 2003. A substantial amount of geological
investigation continues on core drilled from the 140/141 body.
In summary, five geological subdivisions were developed in previous programs for evaluation and
modeling of diamond results. These units were described very briefly as follows:
o
Mega-graded Bed – overall fining-upwards kimberlite commencing
with xenolith-rich breccia units at the base and terminating in
fine to very fine-grained material on top; the mega-graded bed
itself can be separated into “fine” and “coarse” size
distributions, which in terms of spatial location, are related to
proximity to the interpreted eruptive centre of the 141 mega-graded
bed – i.e., coarser diamond distribution closer to the centre of
eruption.
o
Cyclic/repeated gradational Beds – similar to the mega-graded bed
but consisting of stacked, internally fining-upwards beds with
subtle to very obvious subdivisions or contacts in an overall
fining-upwards sequence; these beds likely represent clear changes
in energy levels during eruption and asymmetry within the eruption
column.
o
Fine-grained Kimberlite – postulated younger central vent feature
characterized by relatively fine-grained kimberlite.
o
Kimberlite Breccia – a separate xenolith-rich unit distinguished
from the breccias located at the base of the mega-graded unit
containing variably abundant mantle-derived material.
o
Speckled Kimberlite – a distinctive matrix-supported kimberlite
containing variably abundant mantle-derived material (ilmenites and
garnets, in particular); this phase contains subordinate units of
both kimberlite breccia and macrocrystic, coarse olivine
kimberlites.
119
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 25: Location of 2004 Coreholes on Body 140/141
Investigation of the southern part of the extensive body during 2002 and 2003 by core drilling and
limited numbers of 24-inch reverse circulation drillholes showed the presence of several new
kimberlite phases, although the dominant kimberlite types are medium to very coarse grain
xenolith-rich breccias and matrix-supported kimberlites (“speckled” kimberlites) considered to be
older than the overlying, relatively thin veneer of graded olivine-rich pyroclastic beds.
Preliminary geological modeling of the southern part of the body, in part from the new core
intersections, revealed four main phases of kimberlite including: repeated graded beds similar to
the graded fine to coarse-grained olivine pyroclastic kimberlite beds located to the north and
east, a moderately thick interval of older breccia beds having a closer textural affinity to the
speckled beds below, variably thick intervals of underlying “speckled”, matrix-supported kimberlite
containing thin areally limited, interbedded coarse-olivine pyroclastic beds and breccias (speckled
beds), and several stratigraphically diverse “other” kimberlites that currently are grouped
together until better differentiation of the phases can be made.
120
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 26: Detailed View of 2004 Drillhole Locations for Kimberlite 140/141
Review of Geological Model in 2004/2005
The results of the four drillholes completed in 2004 were used in conjunction with the geological
model to determine the locations of large diameter drillholes. Intersections of the high interest
oscillating breccias group were thinner than expected in the drillholes as compared with the
existing model. As indicated by previous drilling, the intersections of the Breccias Group are
complex.
The three dimensional geological model (GEMCOM) for the 140/141 kimberlite was subsequently
modified to reflect the new information for the body. The outline of the Breccias Group was
decreased at depth but remains relatively unchanged near surface. Intersections termed Repeated
Graded Beds and OPK have been included within Breccias Group, as before. All the intersections of
the Oscillating Breccias were shorter than that predicted by the model, with maximum thicknesses of
about 81 metres, 74 metres, 62 metres and 68 metres in holes 04-140-041, 042, 043 and 050
respectively. At greater depth, all the coreholes intersected the so-called “Speckled” Kimberlite
(SPK) which is forecast as having a low macrodiamond grade.
In two of the holes completed in 2004 (140-041 and 050), the uppermost intersections in the
drillhole (about 46 metres) consist of repeated graded beds of olivine tuffs containing minor
breccias. Based on criteria developed for GEMCOM volumes in previous holes, these intersections are
termed Repeated Graded Beds Group (RGBPK). A similar breccia-poor, 25 metres intersection at the
top of drillhole 140-043 displays only ill-defined grain size variations and is thus included in
the Breccias group and not the Repeated Graded Beds group. All intersections previously termed
Repeated Graded Beds Group have been included in the appropriate nearby major kimberlite type
(either the Mega graded bed or the Breccias). Examining the present distribution of Repeated Graded
Beds indicates a coherent, elongate volume of material distributed along the western part of
121
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
the 140 body which may indicate this rock type may represent a single phase of kimberlite that
might possibly be separated from already modeled volumes.
9.2.17.7.4.4 Density Measurements
In 2001, nearly 400 density readings were calculated from corehole material to obtain an average
value of 2.21 g/cm3 for the 141 kimberlite. In 2002, additional density readings were
collected in order to determine whether density values remained reasonably consistent in the
southern portion of the 140/141 body where drilling was concentrated. The 2002 density data (139
samples) was found to have a mean value of 2.24 g/cm3, a median of 2.20
g/cm3, and a standard deviation of ± 0.2 g/cm3. The median value of 2.21
g/cm3 obtained in 2001 was confirmed by the 2002 testing and was used in theoretical
mass calculations for the body. In 2003, seventy kimberlite samples were measured for density with
a mean value of 2. 29 g/cm3 obtained for an in-situ density.
The 2004 density data (60 samples) was found to have a mean value of 2.25 g/cm3, a
median of 2.22 g/cm3, and a standard deviation of ± 0.13 g/cm3 which is in
close agreement with density values from previous years for the 140/141 body. The results of the
2004 density measurements are shown graphically in Figures 27 and 28. The 2004 data for drillholes
140-04-41 and 140-04-050 indicate relatively high densities at the end of either hole (about 230
metres in kimberlite) which appear to correlate with the presence of mudstone/mudstone xenoliths.
9.2.17.7.4.5 Magnetic Susceptibility
Magnetic susceptibility for each of the 140/141 coreholes completed in the 2004 program is
shown graphically in Figure 29. Drillholes 140-04-041 (max. value: 85x10-3 SI units)
and 140-04-050 were seen to display higher magnetic susceptibility responses which are due to the
presence of magnetite in various sections of the kimberlite.
Frequency
Figure 27:
Frequency Histogram of 2004 Density Measurements for the 140/141 Kimberlite
(Kimberlite Samples Only)
122
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
In Situ Density vs. Depth for Body 140
Figure 28:
2004 In-situ Density Measurements for the 140/141 Kimberlite Drillholes
(Kimberlite, Overburden and Countryrock Samples)
Magnetic Susceptibility vs. Depth for Body 140
Figure 29:
Magnetic Susceptibility Chart for the 140/141 Kimberlite Drillholes
123
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.17.7.4.6 Archeological and Flora/Fauna Surveys
Golder Associates Ltd. of Saskatoon, Saskatchewan was contracted to undertake a flora and
fauna survey of the 140/141 kimberlite body as well a heritage resource review of drill site areas
in accordance with the provincial Heritage Property Act. Once reports of the findings of the
various surveys were submitted and reviewed by the Cultural and Heritage Branch (Heritage Resource
Review) and Saskatchewan Environment (Flora and Fauna Survey) approval was granted by the various
regulatory bodies for drilling activity. Drill pads for three coreholes were surveyed by the
archaeological crew covering a surface of 3 hectares; the fourth drillhole was placed adjacent to
a previously surveyed cluster of core and large diameter drillholes holes and required therefore
no investigation.
9.2.17.7.4.7 140/141 Sampling and Diamond Recovery
Samples were obtained from three different HQ (2.5 inches or 63.5 millimetres diameter)
drillholes that intersected the “breccia beds” and underlying “speckled beds” located in the
southern part of the 140/141 kimberlite body. Similar to 2003 results, the “breccia beds” yielded the better stone abundances,
although both kimberlite units yielded a single macrodiamond larger than 0.5 millimetres. The
average microdiamond abundance for all 140/141 samples from 2004 is 13.3 stones per 10 kilograms
while the breccia beds give average microdiamond abundances of 17 stones per 10 kilograms. While
the average 2004 stone abundance for the breccia beds is slightly lower than the 21.6 stones per 10
kilograms recorded in 2003, the latter were taken from a much broader area and variation in local
diamond distribution is thought to account for the lower values seen in these three closely spaced
drillholes.
A total of 658 microdiamonds were recovered from 496 kilograms of kimberlite core utilizing caustic
dissolution methods at the SRC. Microdiamond recoveries were audited and individual stone sizes
calculated by experts at the De Beers Kimberley Microdiamond Laboratory (KMDL) in South Africa.
All recoveries reported here include stones with modeled sizes less than 74 microns in size in
order to be directly comparable to 2003 results from the SRC that were reported for this zone.
Summaries of diamond recovery by kimberlite phase, drillhole, and by sieve category are shown in
Tables 44, 45, and 46.
Kimberlite
Type By
Sample
# of
Average
Stones larger
Year
Tested
Mass (kg)
Stones
Stones/10 kg
than 0.5 mm
2003 Breccia Beds
274.9
593
21.6
4
2004 Breccia Beds
312.0
531
17.0
1
2003 Speckled Beds
109.7
134
12.2
0
2004 Speckled Beds
184.0
127
6.9
1
2004 Total:
595.15
1159
19.5
2
Table 44: 140/141 Microdiamond Results by Kimberlite Type and Year Tested
Sample
Average
Stones larger
Drillhole
Mass (kg)
# of Stones
Stones/10 kg
than 0.5 mm
140-41
160
245
15.3
1
140-42
176
266
15.1
2
140-43
160
147
9.2
0
Total:
496
658
13.3
3
Table 45: Summary of 140/141 Microdiamond Results by Drillhole
124
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Kimberlite
-0.074mm
+0.074mm
+0.104mm
+0.150mm
+0.212mm
+0.300mm
+0.500mm
+1.00mm
Type
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Breccia Beds
130
221
111
46
15
6
1
1
Speckled Beds
25
52
36
12
1
0
0
1
Total:
155
273
147
58
16
6
1
2
Table 46: 140/141 Microdiamond Recoveries by Sieve Category and Kimberlite Type
9.2.15.7.4.8 Large Diameter Drilling on Kimberlite 140/141
Five large diameter minibulk sampling holes were targeted on the oscillating breccia beds unit
located in the south part of Kimberlite 140/141 in order to expand the parcel of diamonds from this
body so that confidence levels in grade and revenue estimates could be increased.
9.2.17.7.4.9 Minibulk Sampling and Macrodiamond Recovery from 140/141
The total estimated mass of kimberlite excavated from body 140/141 in 2004 was 792.216 tonnes
of which 494.066 tonnes of material greater than 1.5 millimetres in size was retained for
macrodiamond recoveries. All five drillholes primarily sampled the oscillating pyroclastic breccia
group (OPKBGP). Minibulk samples were shipped to the De Beers’ dense media separation plant
located in Grande Prairie, Alberta for the first stage of diamond recovery procedures, followed by
final diamond recovery in an ultra-high security facility in Johannesburg, RSA.
Total macrodiamond recovery from the five LDDH on 140/141 was 553 stones with a combined weight of
83.200 carats. Individual sample grades range from 1.68 cpht to 69.15 cpht, the latter grade being
markedly influenced by recovery of the 10.23 carat stone. Drillhole grades range from 7.05 to 12.20
cpht. Two large macrodiamonds weighing 10.53 carats and a 4.09 carats and 58 other stones larger
than 0.25 carats were added to the inventory of large macrodiamonds recovered from the 140/141
breccia beds during the 2004 program. These recent larger stones and historical recoveries
including diamonds weighing: 1.0, 1.16, 1.18, 1.26, 1.32, 1.39, 1.48, 1.5, 1.8, 2.57, 2.59, and
3.61 carats contribute significantly to the evidence supporting a large stone distribution in the
oscillating breccia unit.
LDDH 04-140-044
The total estimated mass of kimberlite excavated from Large Diameter drillhole (LDDH) 04-140-044
was 198.903 tonnes of which 94.362 tonnes of material greater than 1.5 millimetres in size were
retained for macrodiamond recoveries. The pilot hole for this LDDH is corehole 04-140-041. A
summary of sampling information and diamond recovery results for this drillhole is shown in Table
47.
Theoretical
Est. # of Diamonds
Sample
Excavated
Drillhole
Drillhole
> 0.25 cts.
Kimberlite
Interval
Mass
Total
Grade
Total
stones/
(largest
Drillhole
Unit
(m)
(tonnes)1
Carats
(cpht)
Stones
tonne
stone)2
04-140-044
140 Breccia Beds
128.36
186.29
21.06
11.30
160
0.86
14 stones (4.09 cts.)
1
The calculation of theoretical mass was based on the volume of a vertical cylinder
and a kimberlite rock density of 2.21.
2
Diamond weights were provided in terms of total carats per sieve class. The reader
is cautioned that for interval samples (12 m) with multiple stone recoveries, the number of
stones >0.25 carats was estimated by dividing carat weight by the number of stones in the
+9 sieve class for selected samples and all of the +11 and larger sieve classes.
Table 47: Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-044
125
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
A total of 160 macrodiamonds weighing 21.06 carats, including a 4.09 carat stone, were recovered
from large diameter drillhole 04-140-044. Large stone recoveries in drillhole 04-140-044 included
an estimated 14 diamonds greater than 0.25 carat in size with a combined weight of 9.58 carats.
These 14 diamonds, or some 8.8% of the total number of stones, account for 45.5% of the carat
weight of the parcel. The 4.09 carat stone was recovered from the 118 to 130 metre interval within
the upper part of the kimberlite body. The size distribution of the recovered diamonds from this
drillhole is shown in Table 48.
+1
+2
+3
+5
+6
+7
+9
+11
+13
+15
+21
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
>1.09
>1.32
>1.48
>1.83
>2.16
>2.46
>2.85
>3.45
>4.52
>5.41
>7.93
Drillhole
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
04-140-044 Carats
0.01
0.145
1.025
3.035
1.96
3.37
2.77
3.13
0.65
0.86
4.09
04-140-044 Stones
1
3
29
54
22
26
12
8
1
1
1
*
An additional 2 stones weighing a cumulative 0.015 carats were recovered in the -1 sieve category (<1.09 millimetres).
Table 48: Summary of Macrodiamond Recovery by Sieve Size Category for Drillhole 04-140-044
LDDH 04-140-045
The total estimated mass of kimberlite excavated from Large Diameter drillhole (LDDH) 04-140-045
was 143.128 tonnes of which 102.877 tonnes of material greater than 1.5 millimetres in size were
retained for macrodiamond recoveries. A total of 135 macrodiamonds weighing 15.445 carats were
recovered from LDDH 04-140-045. The pilot hole for this LDDH is corehole 04-140-050. A summary of
sampling information and diamond recovery results for this drillhole is shown in Table 49.
Est. # of
Theoretical
Diamonds
Sample
Excavated
Drillhole
Drillhole
> 0.25 cts.
Kimberlite
Interval
Mass
Total
Grade
Total
stones/
(largest
Drillhole
Unit
(m)
(tonnes)1
Carats
(cpht)
Stones
tonne
stone)2
04-140-045
140 Breccia Beds
96.7
140.34
15.455
11.1
135
1
16 stones (0.46)
1
The calculation of theoretical mass was based on the volume of a vertical cylinder
and a kimberlite rock density of 2.21.
2
Diamond weights were provided in terms of total carats per sieve class. The reader
is cautioned that for interval samples (12 metres) with multiple stone recoveries, the number
of stones >0.25 carats was estimated by dividing total carat weight by the number of stones
in the +11 and larger sieve classes.
Table 49: Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-045
Large stone recoveries in drillhole 04-140-045 included an estimated sixteen diamonds greater than
0.25 carat in size with a combined weight of 6.845 carats. These 16 stones, or some 11% of the
total number, account for 44% of the carat weight of the parcel. The size distribution of the
recovered diamonds from this drillhole is shown in Table 50.
126
Technical
Report For the Fort à la Corne Diamond Project — November 09, 2005
-1
+2
+3
+5
+6
+7
+9
+11
+12
+13
Sieve
+1
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
<1.09
Sieve
>1.32
>1.48
>1.83
>2.16
>2.46
>2.85
>3.45
>4.089
>4.52
Drillhole
mm
>1.09 mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
04-140-045 Carats
0.020
0.040
0
0.740
2.090
1.560
2.585
1.575
4.320
2.065
0.460
04-140-045 Stones
6
4
0
22
39
17
21
10
11
4
1
Table 50: Summary of Macrodiamond Recovery by Sieve Size Category
LDDH 04-140-049
The total estimated mass of kimberlite excavated from Large Diameter drillhole (LDDH) 04-140-049
was 150.591 tonnes of which 74.545 tonnes of material greater than 1.5 millimetres in size were
retained for recovery of commercial-sized diamonds. A total of 100 macrodiamonds weighing 10.615
carats were recovered from LDDH 04-140-049. The pilot hole for this LDDH is corehole 04-140-051.
A summary of sampling information and diamond recovery results for this drillhole is shown in Table
51.
Large stone recoveries in drillhole 04-140-049 included 6 diamonds greater than 0.25 carat in size
with a combined weight of 2.78 carats. These 6 stones, or some 6% of the total number, account for
39% of the carat weight of the parcel. The size distribution of the recovered diamonds from this
drillhole is shown in Table 52.
Est. # of
Theoretical
Diamonds
Sample
Excavated
Drillhole
Drillhole
> 0.25 cts.
Kimberlite
Interval
Mass
Total
Grade
Total
stones/
(largest
Drillhole
Unit
(m)
(tonnes)1
Carats
(cpht)
Stones
tonne
stone)
04-140-049
140 Breccia Beds
102.56
148.84
10.615
7.132
100
0.7
6 stones (1.005 cts)
1
The calculation of theoretical mass was based on the volume of a vertical cylinder
and a kimberlite rock density of 2.21.
Table 51: Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-049
+3
+5
+6
+7
+9
+11
+12
+13
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
>1.48
>1.83
>2.16
>2.46
>2.85
>3.45
>4.089
>4.52
Drillhole
mm
mm
mm
mm
mm
mm
mm
mm
04-140-049 Carats
0.765
2.105
1.705
1.115
1.715
1.595
0.24
1.375
04-140-049 Stones
19
37
19
8
9
5
1
2
Table 52: Summary of Macrodiamond Recovery by Sieve Size Category
LDDH 04-140-051
The total estimated mass of kimberlite excavated from LDDH 04-140-051 was 156.026 tonnes of which
117.045 tonnes of material greater than 1.5 millimetres in size were retained for recovery of
commercial-sized diamonds. A total of 68 macrodiamonds weighing 18.560 carats including a 10.53
carat stone were recovered from large diameter drillhole 04-140-051. The large, clear, yellow,
macrodiamond measures approximately 1.4
127
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
x 1.0 x 0.75 centimetres was recovered during diamond recovery procedures at the De Beers Group
Exploration Diamond Laboratory in Johannesburg, RSA and is classed as a higher-value Fancy stone.
The pilot hole for this LDDH is corehole 04-140-032. A summary of sampling information and diamond
recovery results for this drillhole is shown in Table 53.
Est. # of
Theoretical
Diamonds
Sample
Excavated
Drillhole
Drillhole
> 0.25 cts.
Kimberlite
Interval
Mass
Total
Grade
Total
stones/
(largest
Drillhole
Unit
(m)
(tonnes)1
Carats
(cpht)
Stones
tonne
stone)2
04-140-051
140 Breccia Beds
101.93
147.93
18.56
12.545
68
0.46
7 stones (1.32 cts. and 10.53 cts)
1
The calculation of theoretical mass was based on the volume of a vertical cylinder
and a kimberlite rock density of 2.21.
2
Diamond weights were provided in terms of total carats per sieve class. The reader
is cautioned that for interval samples (12 metres) with multiple stone recoveries, the number
of stones >0.25 carats was estimated by dividing carat weight by the number of stones in
the +9 sieve class for selected samples and all of the +11 and larger sieve classes.
Table 53: Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-051
Large stone recoveries in drillhole 04-140-051 included an estimated 7 diamonds greater than 0.25
carat in size with a combined weight of 13.665 carats. These larger diamonds account for 73.6% of
the total carat weight, but represent only 10.3% of the total stones in the parcel. Four of the
seven larger diamonds, including the 10.53 carat stone, were recovered from samples taken from the
upper 30 metres of the kimberlite body within the oscillating breccia beds. The size distribution
of the recovered diamonds from this drillhole is shown in Table 54.
+2
+3
+5
+6
+7
+9
+11
+12
+15
+23
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
>1.32
>1.48
>1.83
>2.16
>2.46
>2.85
>3.45
>4.09
>5.41
>10.312
Drillhole
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
04-140-051 Carats
0.075
0.455
1.045
0.815
0.700
1.84
0.885
0.895
1.32
10.53
04-140-051 Stones
4
13
18
10
6
10
3
2
1
1
*No stones were recovered in the -1 (<1.09 millimetres) and +1 (>1.09 millimetres) sieve
categories.
Table 54: Summary of Macrodiamond Recovery from LDDH 04-140-051 by Sieve Size Category
LDDH 04-140-052
The total estimated mass of kimberlite excavated from LDDH 04-140-052 was 143.567 tonnes of which
105.567 tonnes of material greater than 1.5 millimetres in size were retained for recovery of
commercial-sized diamonds. A total of 90 macrodiamonds weighing 17.51 carats, including a 1.39
carat stone, were recovered from LDDH 04-140-052. The nearest corehole to this LDDH is 04-140-032.
A summary of sampling information and diamond recovery results for this drillhole is shown in
Table 55.
128
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Est. # of
Theoretical
Diamonds
Sample
Excavated
Drillhole
Drillhole
> 0.25 cts.
Kimberlite
Interval
Mass
Total
Grade
Total
stones/
(largest
Drillhole
Unit
(m)
(tonnes)1
Carats
(cpht)
Stones
tonne
stone)2
04-140-052
140 Breccia Beds
91.05
132.14
17.51
13.25
90
0.68
17 stones (1.39 cts.)
1
The calculation of theoretical mass was based on the volume of a vertical cylinder
and a kimberlite rock density of 2.21.
2
Diamond weights were provided in terms of total carats per sieve class. The reader
is cautioned that for interval samples (12 metres) with multiple stone recoveries, the number
of stones >0.25 carats was estimated by dividing carat weight by the number of stones in
the +9 sieve class for selected samples and all of the +11 and larger sieve classes.
Table 55: Summary of Macrodiamond Recovery for Minibulk Samples from Drillhole 04-140-052
Large stone recoveries in drillhole 04-140-052 included an estimated 17 diamonds greater than 0.25
carat in size with a combined weight of 11.13 carats. These larger diamonds account for 63.6% of
the total carat weight, but represent only 18.9% of the total stones in the parcel. Eleven of the
17 larger diamonds were recovered from samples taken from the upper 50 metres of the kimberlite
body. The size distribution of the recovered diamonds from this drillhole is shown in Table 56.
+2
+3
+5
+6
+7
+9
+11
+12
+13
+17
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
Sieve
+15 Sieve
Sieve
>1.32
>1.48
>1.83
>2.16
>2.46
>2.85
>3.45
>4.09
>4.52
>5.41
>5.74
Drillhole
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
mm
04-140-052 Carats
0.07
0.3
1.23
1.325
1.6
2.29
2.29
0.435
4.14
2.57
1.26
04-140-052 Stones
3
8
23
14
16
10
7
1
5
2
1
*No stones were recovered in the -1 (<1.09 millimetres) and +1 (>1.09 millimetres) sieve categories.
Table 56: Summary of Macrodiamond Recovery by Sieve Size Category
9.2.17.7.5 Kimberlite 122
Five HQ coreholes (04-122-012, 012A, 013, 014, 019) were completed during September and
October 2004 in order to provide geological control for five large diameter drillholes completed in
the south central portion of the 122 kimberlite body. The purpose of the drilling was to generate
additional information in the southern portion of the 122 kimberlite and enhance geological
modeling for the body. Drillhole 04-122-012 had to be abandoned due to technical problems. The
primary object of the LDDH drilling was to obtain sufficient diamonds in order to obtain a
preliminary revenue estimate of the MPK unit. A total metreage of 1,316 metres of core was
obtained having a combined kimberlite intersection of 673.46 metres. The kimberlite thicknesses
varied between 86.37 and 207.41 metres. The average total core recovery for the 122 drillholes was
95.8%.
9.2.17.7.5.1 Previous Drilling
As seen in Table 57, twenty-two drillholes totalling 4,855 metres of drilling were completed
between 1989 and 2003 on the 122 kimberlite body. Of this total, 2,139.2 metres of kimberlite
material was cored. The first reconnaissance drillholes testing the body were completed in 1989
with one rotary drillhole collared in the centre of the body. An airborne magnetic survey over the
entire Fort à la Corne claims in 2003 followed by ground gravity surveys more clearly defined the
shape and internal complexities of the 122 body. The results of
129
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
the survey showed intense positive gravity anomalies that extended beyond the boundaries of the magnetic anomaly for the target.
Note: This table does not include microdiamonds and macrodiamonds that may have been recovered
from caustic dissolution or jigging recovery methods.
Table 57: Summary of Historic Drillholes and Minibulk Macrodiamond Recovery for 122
Prior to 2003, drilling consisted primarily of reverse circulation drillholes of various sizes. In
2003, eleven HQ coreholes were drilled in various parts of the body in order to provide a better
understanding of the geology of the kimberlite. Past drilling of the body had indicated a
relatively deep intersection of kimberlite exists in the vicinity of holes 122-06, 07, 09 which may
correspond to the location of a vent in the 122 body.
9.2.17.7.5.2 Preliminary Geology of the 122 Kimberlite
Initial geological modeling of distinct kimberlite phases in 122 was conducted by De Beers in
2003. The model was based on drill core from Kimberlite 122 and shows the body is divisible into
two main craters, and a subordinate third area based on relatively sparse information. Figure 30
shows the estimated areal extent of the craters in Kimberlite 122 and Figure 31 shows a more
detailed view of the distribution of holes in the south-central part of the body. Also shown are
kimberlite intersection thicknesses for the all drillholes (blue italicized text). The northern
half of the body is dominated by massive to graded beds of olivine/lapilli pyroclastic kimberlite
(MPK-N) with common indicator minerals to a thickness of some 74 metres in recent drillholes. This
is overlain by up to 43 metres of interbedded sediments, resedimented kimberlite, and kimberlite
(UCSK-N).
Similarly, the south crater is dominated by variably massive to bedded, fine-grained to
coarse-grained, olivine/lapilli pyroclastic kimberlite (MPK-S) to a thickness of some 103 metres in
the 2003 drillholes. The thicker, more massive intersections occur proximal to drillhole 03-122-09
with more obvious bedding intervals
130
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
increasing in abundance and thickness towards the north and
west, and being more pronounced in the upper part of the MPK intersections of the closer
drillholes. The northern fringe of the southern crater has a partial cap of interbedded sediments
and resedimented kimberlite ranging from 0 to 12 metres thick (UCSK-S). In general,
the pyroclastic kimberlite within the north crater is finer grained than the pyroclastic kimberlite
within the south.
Figure 30: Preliminary Geology and Kimberlite Thicknesses in Plan View for Body 122 (pre-2004)
131
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 31: Detailed View of the 2004 Drillhole Locations for Kimberlite 122
Towards the southeast and southern-most part of the body, at least three distinct intervals of
other pyroclastic kimberlite (OPK) were noted. OPK dominates the kimberlite intersection at
drillhole 03-122-10, but the overall kimberlite intersection here has attenuated to 28.9 metres
from a thicker interval of 53.4 metres in drillhole 03-122-09. The distribution of OPK beds are
not shown in detail in Figure 30 with the exception of OPK-S1 which forms a small pod near the
centre of the southern crater. The OPK (and limited occurrence of other volcaniclastic kimberlite
(OVK) phases will be better understood as more drillholes provide data that allows the geological
model to be further refined.
In general, average grain size of the kimberlites and thickness of kimberlite intersection
decreases towards the margins of the body. The order of emplacement for the individual kimberlites
and their contact relationships within, and between, the two main parts of body 122 are not fully
understood at this time. Revisions to the geological model are underway and may require additional
drilling in future programs to finalize a preliminary model. The results of the four drillholes
completed in 2004 were used in conjunction with the geological model to determine the locations of
large diameter drillholes.
9.2.17.7.5.3 Density Measurements
In-situ density data from 103 kimberlite samples recovered from the 122 kimberlite body in 2003 was
found to have a mean value of 2.47 g/cm3. The 2004 density determinations were found to
have a very similar mean value of 2.50 g/cm3, a median of 2.49 g/cm3, and a
standard deviation of ± 0.11 g/cm3. The slightly higher density values in 2004 might be
due to the higher proportion of limestone and carbonate xenoliths in the southern part of the 122
kimberlite body tested by drilling.
132
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
As summarized in Figures 32 and 33, density values in the 122 kimberlites are seen to increase
slightly at depth. The grain size of the kimberlite does not vary, although field logs indicate an
increase in the maximum size of xenoliths (limestone and mudstone) at depth in the kimberlite.
Figure 32: Frequency Histogram of 2004 Density Measurements for the 2004 Coreholes
Figure 33:
2004 In-situ Density Measurements for 2004 Coreholes from Kimberlite 122 (Kimberlite, Overburden and Country Rocks)
9.2.17.7.5.4 Magnetic Susceptibility
Magnetic susceptibility for each of the holes completed is shown graphically in Figure 34.
Drillholes 04-122-019 (max. value: 224x10-3 SI units) and 04-122-012A (max. value:
202x10-3 SI units) were seen to have the highest magnetic responses which were due to
the presence of magnetite in various sections of the kimberlite in
133
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
either drillhole. As seen in
Figure 33, magnetic susceptibility values in the core demonstrated a variety of magnetic responses.
Intervals of limestone at the bottom of some holes were seen to have consistently low
susceptibility values.
9.2.17.7.5.5 Archeological and Flora/Fauna Surveys
Golder Associates Ltd. of Saskatoon, Saskatchewan was contracted to undertake a flora and
fauna survey of the 122 kimberlite as well a heritage resource review of drillsite areas in
accordance with the provincial Heritage Property Act. Once reports of the findings of the various
surveys were submitted and reviewed by the Cultural and Heritage Branch (Heritage Resource Review)
and Saskatchewan Environment (Flora and Fauna Survey) approval was granted by the various
regulatory bodies for drilling activity. As large diameter and core holes were located in the same
area, no specific sites had to be surveyed by the archaeological team specifically for core
drilling. A total of approximately 3 hectares was surveyed.
Figure 34: Chart of 2004 Magnetic Susceptibility Measurements for the 122 Kimberlite Drillholes
9.2.17.7.5.6 Re-sampling Core and Microdiamond Recovery for Kimberlite 122
Selected 2003 coreholes were re-sampled to provide additional material for diamond recoveries
utilizing caustic dissolution methods. Additional kimberlite samples totaling 464 kilograms from
eight 2003 coreholes located across the body were submitted for diamond recovery utilizing caustic
dissolution methods at the SRC in Saskatoon. The SRC recovered and reported diamonds down to a
lower cutoff of 0.075 millimetres in size. A total of 269 additional microdiamonds were recovered
for use in grade forecasting of specific kimberlite zones. Microdiamond recoveries were audited and
individual stone sizes calculated by experts at the De Beers Kimberley Microdiamond Laboratory
(KMDL) in South Africa. All recoveries reported here include stones
134
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
with modeled sizes less than 74 microns in size in order to be directly comparable to 2003 results from the SRC that were
reported for several kimberlite units (Table 58).
Initial geological modeling of distinct kimberlite phases by De Beers, based on drill core from
Kimberlite 122 shows the body is divisible into two main craters, and a subordinate third area
based on relatively sparse information. Both craters are dominated by massive to graded beds of
olivine/lapilli pyroclastic kimberlite (MPK-N and MPK-S) overlain by interbedded sediments,
resedimented kimberlite, and kimberlite (UCSK-N and UCSK-S). The order of emplacement for the
individual kimberlites and their contact relationships within, and between, the two main parts of
body 122 are not fully understood at this time.
The average microdiamond abundance for all 122 samples from 2004 is 5.8 stones per 10 kilograms
while the upper 122 North beds (UCSK-N) gave the best results with average microdiamond abundances
of 8.3 stones per 10 kilograms. In general, the results for the North crater are comparable
between 2003 and 2004, but a significant decrease in recovery was noted for both units in the South
crater (Table 59). There is no obvious reason for the difference in results between years for the
same core, except that which is expected from the “nugget-effect”, whereby there is irregular
recovery of diamonds within small sample masses. Both 2003 and 2004 results will be combined by
kimberlite unit to produce higher confidence grade forecasts. A summary of diamond recovery by
kimberlite phase is shown in Table 60.
The SRC reported 97% recovery of internal tracers during diamond recovery and stone picking was
routinely audited by a supervisor. Recovered diamonds and selected caustic residues will be sent
to the De Beers’ Kimberley Microdiamond Laboratory (KMDL) for further auditing and verification of
individual stone size, shape, and sieve category using proprietary techniques. The microdiamond
results from these drillholes will be integrated with the 122 dataset including results from
similar kimberlite types intersected in earlier drillholes (122-01, 122-05, 122-06, 122-07, 122-08)
followed by modeling of grade forecasts for the southern and northern parts of the body, as well as
by major kimberlite unit.
Audited and modeled microdiamond results from the 2004 coreholes have not yet been received in
their entirety from KMDL. These results will be disclosed to the public as soon as they are added
to the database and properly interpreted.
Sample Mass
Average
Stones larger
Drillhole
(kg)
# of Stones
Stones/10 kg
than 0.500 mm
122-01
72
39
5.4
0
122-02
96
110
11.5
0
122-03
56
20
3.6
1
122-04
32
11
3.4
1
122-05
64
24
3.8
0
122-06
24
3
1.3
1
122-07
80
41
5.1
0
122-08
40
21
5.3
0
Total:
464
269
5.8
3
Table 58: Summary of 122 Microdiamond Results by Drillhole
135
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Range of Sampled
Phase Thickness
Sample
Average
Stones larger
Kimberlite Type
(m)
Mass (kg)
#of Stones
Stones/10 kg
than 0.5 mm
2003 MPK-N
56 - 74
117.55
115
9.8
1
2003 UCSK-N
11 – 43
23.95
18
7.5
1
2004 MPK-N
56 - 74
240.0
153
6.4
1
2004 UCSK-N
11 – 43
48.0
40
8.3
0
Total
122 North Crater:
429.5
326
7.6
3
2003 MPK-S
36 – 103
222.55
163
7.3
4
2003 UCSK-S
3 – 12
7.75
3
3.9
0
2004 MPK-S
20 – 68
168.0
74
4.4
2
2004 UCSK-S
6.2
8.0
2
4.3
0
Total
122 South Crater:
406.3
242
6.0
6
Total 122:
835.8
568
6.8
9
Table 59: Summary of 2004 Microdiamond Results for 122 by Type and Year Sampled
+0.075m
+0.212m
+0.300m
+0.500m
-0.075mm
m
+0.106m
+0.150m
m
m
m
+2.000m
Kimberlite Type
Sieve
Sieve
m Sieve
m Sieve
Sieve
Sieve
Sieve
m Sieve
MPK-N
11
68
39
24
6
4
1
0
UCSK-N
8
13
10
8
1
0
0
0
North Crater:
19
81
49
32
7
4
1
0
% from North:
63
68
72
89
100
80
50
0
MPK-SB
10
39
18
4
0
1
1
1
UCSK-S
1
0
1
0
0
0
0
0
South Crater:
11
39
19
4
23
1
1
1
% from South:
37
32
28
11
0
20
50
100
Total 122:
30
120
68
36
7
5
2
1
% of 122:
11
45
25
13
3
2
1
0.3
Table 60: 2003-2004 Microdiamond Recoveries by Sieve Class and Kimberlite Type for 122
9.2.17.7.5.7 Microdiamond Recovery for 2004 Pilot holes on Kimberlite 122
Four coreholes designated as pilot holes for large diameter drilling were sampled during the
2004-2005 program to provide additional material for diamond recoveries utilizing caustic
dissolution methods. A total of 212 microdiamonds were recovered for use in grade forecasting of
specific kimberlite zones. These results include the recovery of seven stones with at least one
dimension greater than 0.5 millimetres.
Representative samples totaling 309.44 kilograms from four HQ coreholes (2.5 inches or 63.5
millimetres diameter) located in the central part of the South Crater of Kimberlite 122 were
submitted for diamond recovery utilizing caustic dissolution methods.
Geological modeling of distinct kimberlite phases to date by De Beers shows the body is divisible
into two main craters. Both craters are dominated by massive to graded beds of olivine/lapilli
pyroclastic kimberlite (MPK-S and MPK-N) overlain by units of interbedded sediments, resedimented
kimberlite, and kimberlite (UCSK-S and UCSK-N). The South Crater also has other pyroclastic
kimberlite (OPK) units of limited areal extent including OPK-13, a different kimberlite type
identified only in corehole 04-122-013. A total of 195.62 kilograms of
136
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
MPK-S kimberlite was tested
from core intervals in drillholes 04-122-012A, 04-122-014, and 04-122-019 as well as 113.82
kilograms of OPK-13 from drillhole 04-122-013 (Table 61).
LDDH
Kimberlite
Calculated
Stones > 0.5
Pilot Hole
Equivalent
Unit
Mass (kg)
#of Stones
stones/10 kg
mm*
04-122-015
04-122-012A
04-122-016
MPK-S
122.18
62
5.1
2
04-122-013
n/a
OPK-13
113.82
135
11.9
5
04-122-014
04-122-018
MPK-S
32.62
6
1.8
0
04-122-019
04-122-021
MPK-S
40.82
9
2.2
0
Total
309.44
212
6.9
7
* recovered stones with at least one dimension greater than 0.5 millimetres
Table 61: Summary of 122 Microdiamond Results from 2004 Pilot Hole Samples
The average microdiamond abundance for all pilot hole samples is 6.9 stones per 10 kilograms. The
average microdiamond abundance for MPK-S in the pilot holes is 3.9 stones per 10 kilograms compared
to 6.1 stones per 10 kilograms from previous results in this kimberlite unit. One explanation may
be that sampling of some 73.4 kilograms of the total mass occurred below a depth of 275 metres in
coreholes 04-122-014 and 019. These deep intervals range from very fine-to medium-grained
kimberlite and may represent a different kimberlite unit from the rest of the MPK-S above.
Notably, the 11.9 stones per 10 kilograms for OPK-13 may indicate the presence of a more
prospective sub-unit within the main kimberlite phase of the south crater, of which the size and
extent must be further investigated. Table 62 shows diamond recovery by sieve category for the
2004 pilot holes alone. Results from 2004 will be combined with historic diamond recoveries to
produce higher confidence grade forecasts for individual kimberlite units.
Drill Hole
+0.075mm
+0.106mm
+0.15mm
+0.212mm
+0.300mm
+0.425mm
+0.500mm
+0.600mm
+0.850mm
04-122-12
25
19
9
3
4
0
0
2
0
04-122-13
38
42
28
13
9
2
0
3
0
04-122-14
4
1
1
0
0
0
0
0
0
04-122-19
6
2
1
0
0
0
0
0
0
TOTAL
73
64
39
16
13
2
0
5
0
Table 62: Diamond Recovery by Sieve Category for the 2004 Pilot Holes
9.2.17.7.5.8 Large Diameter Drilling on Kimberlite 122
Four large diameter minibulk sampling holes were targeted on the south part of Kimberlite 122
(MPK — South Kimberlite Unit) in order to expand the parcel of diamonds from this body so that
confidence levels in grade and revenue estimates could be increased. The total estimated mass of
kimberlite excavated from body 122 in 2004 was 739.2 tonnes of which 318.1 tonnes of material
greater than 1.5 millimetres in size was retained for macrodiamond recoveries. All four drillholes
primarily sampled the main, massive to bedded pyroclastic kimberlite unit (MPK). One of the four
drillholes was lost within the top 2 metres of kimberlite due to drilling problems, but is listed
in the results. An additional two drillholes did not reach the top of kimberlite due to downhole
difficulties and there are no results to report. Minibulk samples were shipped to the De Beers’
dense media separation plant located in Grande Prairie, Alberta for the first stage of diamond
recovery procedures, followed by final diamond recovery in an ultra-high security facility in
Johannesburg, RSA.
137
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
9.2.17.7.5.9 Minibulk Sampling and Macrodiamond Recovery for Kimberlite 122
A total of 248 macrodiamonds weighing 28.81 carats, including 23 stones larger than 0.25
carats, were recovered from three 36-inch (914 millimetres) diameter drillholes located on
Kimberlite 122 during the 2004 minibulk sampling program (Table 63).
The recovery of many stones larger than 0.25 carats and two larger than one carat supports the
model of a larger stone population in Kimberlite 122. Diamond recoveries and actual sample grades
for stones in the +5 and higher sieve categories from 2004 are comparable to those seen in 2000,
although the total carats recovered last year fell short of program expectations.
Est. # of
Actual
Diamonds
Main
Sample
Excavated
Drillhole
Drillhole
> 0.25 cts.
Kimberlite
Interval
Mass
Total
Grade
Total
stones/
(largest
Drillhole
Unit
(m)
(tonnes)1
Carats
(cpht)
Stones
tonne
stone)2
04-122-016
122 South MPK
98.57
166.82
5.565
3.34
43
0.26
4 stones (1.01 cts.)
04-122-018
122 South MPK
178.56
312.68
11.990
3.84
90
0.29
12 stones (1.11 cts.)
04-122-021
122 South MPK
151.45
257.89
11.255
4.36
115
0.45
7 stones (0.73 cts.)
04-122-015
122 South MPK
1.20
1.81
0
n/a
0
n/a
0
Total/Avg.
429.78
739.20
28.810
3.90
248
0.33
23 stones
1
The calculation of actual mass was based on interval borehole volume measured by a
3-arm caliper tool and a kimberlite rock density of 2.5.
2
Diamond weights were provided in terms of total carats per sieve class. The reader is
cautioned that for interval samples (12 metres) with multiple stone recoveries, the number of
stones >0.25 carats was estimated by dividing carat weight by the number of stones in the
sieve class.
Table 63: Actual 2004 Macrodiamond Recoveries from Kimberlite 122
Macrodiamond recoveries for the three main drillhole intersections are reported by sieve size
category in Table 64. Drillhole 04-122-015 was lost at a depth of 106.6 metres after cutting only
1.2 metres of kimberlite due to loss of steel downhole.
+5 Sieve
+6 Sieve
+7 Sieve
+9 Sieve
+11 Sieve
+12 Sieve
+13 Sieve
+15 Sieve
+17 Sieve
Drillhole
stones carats
stones
carats
stones
carats
stones
carats
stones
carats
stones
carats
stones
carats
stones
carats
stones
carats
04-122-016
8
0.440
12
1.065
4
0.440
3
0.765
4
1.035
1
0.550
0
0
1
1.015
0
0
04-122-018
22
1.110
17
1.340
15
1.945
16
3.405
6
2.165
0
0
1
0.630
0
0
1
1.110
04-122-021
33
1.570
19
1.505
13
1.805
13
2.230
4
1.375
1
0.560
2
1.395
0
0
0
0
Total:
63
3.120
48
3.910
32
4.190
32
6.400
14
4.575
2
1.110
3
2.025
1
1.015
1
1.110
Table 64: Summary of 2004 Macrodiamond Recovery from Kimberlite 122 by Sieve Size Category
138
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
The pilot holes for these LDDH are as follows: LDDH 04-122-015 with corehole 04-122-012A, LDDH
04-122-016 with corehole 04-122-012A, LDDH 04-122-018 with corehole 04-122-014, and LDDH 04-122-021
with corehole 04-122-019.
Minibulk sampling programs in 2000 and 2004 differed in the bottom cut-off size for macrodiamonds
utilizing a 1.0 millimetres screen in 2000 versus a 1.5 millimetres screen in 2004. In order to
compare macrodiamond results from these two programs, all diamonds passing through a +5 round
diamond sieve screen (equivalent to 1.47 millimetres square sieve size) were subtracted from the
program totals. These results are shown in Table 65. While normalizing the data reduces the total
stone counts and to a lesser extent grades, a more accurate comparison of diamond recoveries can be
made for the two programs.
Est. # of
Actual
Diamonds
Main
Sample
Excavated
Drillhole
Drillhole
> 0.25 cts.
Kimberlite
Interval
Mass
Total
Grade
Total
stones/
(largest
Drillhole
Unit
(m)
(tonnes)1
Carats
(cpht)
Stones
tonne
stone)2
122-0093 (2000)
122 South MPK
155.70
129.15
3.270
2.53
20
0.15
5 stones (0.61 cts.)
122-0103 (2000)
122 South MPK
146.04
118.09
4.565
3.87
33
0.28
5 stones (0.72 cts.)
122-0113 (2000)
122 South MPK
102.82
81.08
6.875
8.48
42
0.52
6 stones (0.76 cts.)
Total/Avg. (2000 only)
404.56
328.32
14.710
4.48
95
0.29
16 stones
04-122-016 (2004)
122 South MPK
98.57
166.82
5.310
3.18
33
0.20
4 stones (1.01 cts.)
04-122-018 (2004)
122 South MPK
178.56
312.68
11.705
3.74
78
0.25
12 stones (1.11 cts.)
04-122-021 (2004)
122 South MPK
151.45
257.89
10.440
4.05
85
0.33
7 stones (0.73 cts.)
04-122-015 (2004)
122 South MPK
1.20
1.81
0
n/a
0
n/a
0
Total/Avg. (2004 only)
429.78
739.20
27.455
3.71
196
0.27
23 stones
1
The calculation of actual mass was based on interval borehole volume measured by a
3-arm caliper tool and a kimberlite rock density of 2.5.
2
Diamond weights were provided in terms of total carats per sieve class. The reader is
cautioned that for interval samples (12 metres) with multiple stone recoveries, the number of
stones >0.25 carats was estimated by dividing carat weight by the number of stones in the
sieve class.
3
Results for the 2000 and the 2004 drillholes were adjusted to make them comparable to
2004 values; the lower cutoff for minibulk samples was 1.0 millimetres in 2000 compared to 1.5
millimetres in 2004, therefore all diamond recoveries in the sieve categories less than +5
were excluded in order to simulate a 1.5 millimetres cutoff.
Table 65: Comparison of Adjusted 2000 and 2004 Macrodiamond Recoveries from Kimberlite 122
Comparison of diamond recovery between the two programs shows that the overall grade was higher in
2000 with a significant contribution from the higher sample grade in drillhole 122-011 as well as
recovery of more stones larger than 0.25 carats in size per tonne, but with occurrence of larger
stones in the 2004 samples. Macrodiamond recoveries in 2004 will be added to the existing stone
inventory in order to determine the change
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
in grade forecast for Kimberlite 122. As macrodiamonds
from the 2004 program are added to the 122 diamond inventory, confidence levels in both the forecast grade and estimated average value are expected to
increase. An updated grade forecast for Kimberlite 122 is in preparation by the MRM of De Beers.
The combined units of economic interest in body 122 contain 79 million tonnes at an average grade
of 13 carats per hundred tonnes. Grade forecasts were based on the statistical treatment of 693
microdiamonds and 289 macrodiamonds weighing 23.13 carats. Grade and value modeling for the “Main
South Pyroclastic Unit – upper” and “Main South Pyroclastic Unit – lower” units was based on 513
microdiamonds and 269 macrodiamonds (19.885 carats). The tonnage estimate for this unit was based
on kimberlite core descriptions and determinations of unit contacts from eight HQ coreholes and
three large diameter drillholes within an area measuring 600 by 500 metres. Drillhole spacing is
primarily on mixed 200 and 300 metre intervals with total depth of holes ranging from 144 to 279
metres.
The reader is cautioned that the grade estimates are conceptual in nature. The grade of kimberlite
above a 1.5 millimetres bottom cutoff is estimated from a combination of microdiamond and
macrodiamond data. Confidence levels for these figures are low and additional testing of
macrodiamond content is required to increase confidence levels in the grade forecasts. The reader
also should be aware that insufficient geological control and quantity of sampling has been
obtained to permit rigorous application of economic considerations and that there is no certainty
that these preliminary assessments will be realized.
Volumes for each of the high interest zones are early estimates derived from computer-generated
3-dimensional models of kimberlite units within areas defined by a limited number of drillhole
intersections. Volume to tonnage estimates were calculated using a specific gravity 2.4 g/cm3
for all kimberlite units. The tonnage estimates require further delineation drilling to
better ascertain lateral and vertical extents of the geological units. The surface area of the
kimberlites of interest were based on estimated 30 metre thickness cut-offs applied to integrated
and modeled geophysical data for the body.
9.2.17.7.6 Drilling of Geophysical Anomalies
Five HQ coreholes were completed during September and November 2004 in order to test for the
presence of kimberlite in five different geophysical anomalies and to determine whether subtle
magnetic features and resistivity anomalies represented buried kimberlites not having an obvious
magnetic character.
Coreholes were targeted on two magnetic anomalies (284 and 285), one gravity anomaly (150 east
extension), and two GeoTEM resistivity anomalies (292 and 300). Figure 35 shows the locations of
the anomalies.
Kimberlite was intersected in only two of the coreholes and these provided material for
petrographic logging and microdiamond sampling. The large gravity anomaly located east of the
known 150 body was targeted with an HQ corehole during the last week of September, 2004. No
substantial kimberlite interval was intersected, although a three metre thick kimberlitic ash bed
was encountered within mudstone of the Lower Colorado Group at a depth of 142.6 metres. The
corehole was terminated at a depth of 195 metres. The source of the gravity anomaly remains
unknown.
Those coreholes without kimberlite intersections provided uninterrupted intervals of host rock that
could be incorporated into regional stratigraphic studies. A total of 874.0 metres was drilled
with a combined kimberlite intersection of 31.82 metres. A sixth test corehole was completed on the
southern-most part of the 140/141 magnetic anomy and is briefly described in the previous section
on Kimberlite 140/141. This corehole is listed in Table 66 separately for comparison to the other
targets.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 35: Location of 2004 Coreholes on Geophysical Anomalies around the Central Cluster
Top of
Base of
Core
Kimberlite
Kimberlite
Total Kimberlite
End of Hole
Drill hole #
Anomaly Type
Size1
(m)
(m)
Intersection2
(m)
04-150-013
Gravity
HQ
142.6
147.0
4.4
195.0
04-284-001
subtle Magnetic
HQ
162.0
04-285-001
subtle Magnetic
HQ
141.3
183.8
27.4
195.0
04-291-001
GeoTEM
HQ
160.0
04-300-001
GeoTEM
HQ
162.0
Total
31.82
874.0
04-140-048
Magnetic
HQ
104.9
173.2
58.7
180.0
1
= HQ core has a diameter of 2.5 inches or 63.5 millimetres
2
= These values may not be equal to Base of Kimberlite minus Top of Kimberlite due to intervening layers of country rock
Table 66: Summary of Core Drilling on Geophysical Anomalies
9.2.17.7.6.1 Archeological and Flora/Fauna Surveys
Golder Associates Ltd. of Saskatoon, Saskatchewan was contracted to undertake a flora and
fauna survey of the area around each anomaly as well a heritage resource review of drill site
areas in accordance with the provincial Heritage Property Act. Once reports of the findings of
the various surveys were submitted and reviewed by the Cultural and Heritage Branch (Heritage
Resource Review) and Saskatchewan Environment (Flora and Fauna Survey) approval was granted by the
various regulatory bodies for drilling activity. Drill pads for four coreholes were surveyed by
the archaeological crew covering a surface of 3 hectares.
9.2.17.7.6.2 2004 Venmyn Rand Audit of Macrodiamond Recovery
Venmyn Rand (Pty) Ltd. was hired by the Company to evaluate efficiency and suitability of
final diamond recovery procedures and equipment at the newly renovated GEMDL facility. The
end-product of the evaluation was an independent Qualified Person’s report documenting the new
configuration of the laboratory and
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
recommendations for future analytical work. This report
remains as an internal reference document for the
company and is not considered material. The audit was successful in that only two very minor
potential security issues were identified. Overall, the independent Qualified Person was satisfied
with the configuration, procedures, and efficiency of the plant.
In addition to monitoring diamond recovery, Mr. Jellicoe (Kensington’s Qualified Person) visited a
highly successful small, low grade, and high average value open pit mine in Lesotho and a
large-scale diamond recovery operation from historic mine tailings operated by de beers in
Kimberley, South Africa. During these visits, he familiarized himself with scales of mining and
ore processing that may one day be applied to high priority FalC-JV kimberlite bodies.
9.2.17.7.6.3 2004 Development of the Advanced Exploration and Evaluation Plan
Consideration of the longer term view for the Fort à la Corne Project has provided the FalC-JV
Partners with a clear perspective on the way forward. Predicted supply, demand, and price trends
for rough diamonds into the next decade provide a rationale for accelerating the present rate of
work on the project in order to be well positioned with respect to the favourable forecasts.
Results from the historical programs have shown that the Fort à la Corne kimberlites contain
higher-grade zones. As such, it is possible that higher-grade units from a number of kimberlites,
when considered collectively, may form a resource which can be profitably mined. At present, some
35 million carats distributed over 369 tonnes and 3 different kimberlites have been identified at a
deposit level of confidence. The project strategy has now been revised to focus on the
higher-grade units within proximally-located priority kimberlite bodies and to consider them in
combination. This approach has the advantage of considerably increasing the size of the potential
resource and may permit significant economy of scale to be achieved for a large scale mining
operation.
Exploration activity in the 1990’s had not resulted in a clear indication of which kimberlites
warranted additional work, if any. In 2000, after becoming the project operator in late 1998, De
Beers and Kensington completed a review of the available microdiamond and macrodiamond data with a
view to prioritizing the kimberlites. At that time, little information was available regarding the
internal geology of the kimberlites as in most cases only one or two core holes had been drilled.
Hence, this review relied entirely upon the diamond data.
From this work, four kimberlites were selected as the targets that represented the highest
opportunity; these were kimberlites 140/141 (originally two anomalies, now considered as a single
kimberlite), 122, 148 and somewhat later, body 150. From 2000 to 2002 some work was undertaken,
including geological drilling and macrodiamond sampling, particularly on kimberlites 140/141 and
122.
Results from several annual programs considerably improved the knowledge of the kimberlites
examined and suggested clearly that the way forward was to first establish a basic geological
framework followed by extensive use of microdiamond sampling in order that the most prospective
sub-units within each kimberlite could be identified prior to LDD sampling. Furthermore, the
practice of drilling a pilot core hole prior to each LDD hole provided valuable geological and
metallurgical control data. This in turn increased the value of each hole drilled in terms of
information supplied.
In early 2004, additional consideration was given to the need to be able to provide a resource of
sufficient size to meet the high mining rates concluded from the Conceptual Study. This was
required in order to exceed the financial hurdle rate. It was therefore concluded that a number of
such higher-grade sub-units would need to be identified. In combination, these could provide a
resource of sufficient size and value.
The decision was made to undertake an exploration program in 2004 with two primary objectives:
first, to obtain a preliminary average diamond value ($/ct) figure for the 140/141 Oscillating
Breccia and the 122 MPK-
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SB/SM; second, to continue to investigate other kimberlites for similar
higher-grade units. Inherent in this revised Fort a la Corne strategy, was the idea that the
additional higher interest units sought must come from
areas relatively close by. This is in order to take advantage of a centralized treatment facility
and consequent economy of scale should mining operations take place there at some time in the
future. In prioritizing the kimberlites, the distance from the “centre” of the southern cluster of
kimberlites, with the exception of kimberlites 101 and 158, was set at a maximum of 5 kilometres.
Each kimberlite would be greater than 25 ha in area; if two kimberlites were very close, in
aggregate they would be greater than 25 ha. The two criteria yielded a total of 16 kimberlites from
which to choose. These kimberlites were then further prioritized on the basis of the available
geological and diamond data. This resulted in the selection of kimberlites 120, 121/221 and 147 for
investigation in 2004.
Clearly, a new approach was required to evaluate a large number of large kimberlite bodies in a
timely fashion to obtain sufficient information and analysis to decide whether to undertake a Fort
à la Corne pre-feasibility study. Management and technical staff from each of the FalC-JV partners
met for strategic planning sessions held in Saskatoon and Vancouver in 2004. The meetings used a
facilitated process (run by AMEC) known as Enhanced Systematic Planning (ESP). An overview
perspective of the Fort à la Corne Project, from present day to an assumed eventual mining
operation was examined and a time-line developed (Figure 36). The current phase of the project
was denoted as the Advanced Exploration and Evaluation Study (AE&E) and was estimated to require 3
years in order to complete. The overall time-line for the Fort à la Corne Project is considered to
be aggressive, being driven by the need to favourably position the commencement of mining
operations in terms of long term rough diamond supply and demand predictions.
The objective of the ESP session, as developed by the FalC-JV partners was: “ to develop an
aggressive Action Plan for the AE&E leading to a go/no-go decision for the Pre-feasibility Study by
mid 2008, with a conscious forward looking perspective to be time- and cost-efficient over the
global project development period”. Furthermore, the project objective was defined as the intent:
“to develop and operate the Fort à la Corne Project in a financially, environmentally and socially
responsible manner”. The purpose of the AE&E Project is to provide theFalC-JV partners with
sufficient information and analyses to decide whether to undertake a Fort à la Corne
pre-feasibility study.
The Plan seeks to delineate at least 70 million carats in the ground from the higher grade units
within the larger (greater than 20 hectares) kimberlites in the south-central cluster. Twenty
primary kimberlite targets have been identified to date, most within a radius of five kilometres in
the southern cluster of kimberlites. Four of the twenty targets were investigated by evaluation
and delineation drilling programs during 2000, 2001, 2002 and 2003, namely kimberlites 122,
140/141, 148 and 150. One of the four, kimberlite 150, was determined to be of no further interest.
Two kimberlites, 122 and 140/141, were determined to be of significant interest, and mini-bulk
sampling was conducted on them as part of the 2004 Exploration Program. Kimberlite 148 remains to
be minibulk tested and first stage results will be compared to those obtained from other
kimberlites investigated in 2005. Three more bodies including 120, 147 and 121/221 were drilled in
the 2004 work program. The remaining bodies of interest will be tested with up to 10 coreholes each
to determine the existence of higher-grade units. The Plan assumes nine of these will produce
strong results for further corehole sampling of the higher-grade units. Of these, it is believed
six bodies will graduate to mini-bulk sampling.
The program is considered to be aggressive and will require careful management of project
activities in order to achieve the objectives within the allotted time. Only funding for the 2005
program is presently approved and funding for the 2006 program and beyond will depend on a
responsible and step-wise approach based on results from components tackled in each program.
Should remarkable results be encountered as better potential kimberlites are investigated
initially, then these targets may be preferentially accelerated through each aspect of evaluation.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Components of the AE&E Study
The AE&E Study’s key planning parameter is that there are five distinct exploration drilling
components, with strategic objectives for each. During the ESP Session, the basis for each
component of the global AE&E drilling program was established by a number of consensus-based
assumptions. Advancement of any kimberlite target or high-grade zone from one type of drilling to
the next is results driven. For this reason a large number of bodies is tested at the start with
the expectation of winnowing-out of less attractive targets as the mini-bulk phase is approached.
In general, there is the expectation that each component must be completed for the group of
kimberlite targets as a whole before advancing to the next level of drilling. However, kimberlite
targets with very positive or exceptional results may be accelerated through to greater levels of
sampling. In addition, kimberlite targets already at a more advanced stage of evaluation also may
proceed ahead of the 2005 targets.
The main components of the AE&E study are as follows:
2004 Geological Drilling and Mini-bulk Sampling
Essentially, this was the first component of the geological drilling. Following the 2000 to 2003
exploration programs that focused on kimberlites 140/141, 150, 122, and 150, the three bodies
considered to represent the next highest level of opportunity of the original twenty became the
targets for the 2004 Exploration Program — namely kimberlites 120, 121/221, and 147. Core drilling
on these three bodies was completed in November 2004. Follow-up activities such as logging,
analysis, and interpretation are expected to be completed by the end of September 2005. The 2004
Exploration Program results are anticipated during the initial months of the AE&E Study and may
impact the direction of the new work. For that reason, it is included in the overall action plan
for the AE&E Study.
Geological Drilling
This component of drilling consists of appropriately spacing core drill holes into a kimberlite so
that sufficient data can be extracted to construct a basic internal geological model. Petrographic
investigation and microdiamond sampling of the drill cores will be used to estimate the grade of
the units. Data from core logging and microdiamond sampling will provide information on the basic
geological internal model of each kimberlite, and identification of higher interest sub-zones,
including grade estimates, if any, within each kimberlite. This work continues the geological
drilling program commenced in 2004. This component will be undertaken to establish a basic
internal geological model on up to 17 of the kimberlites in the southern cluster. A process of
prioritization was undertaken by the FalC-JV partners to determine the actual scope of the
geological drilling program. This component shall include the following activities:
• A total of 34,000 metres of core drilling has been allocated to this phase.
• Geological, geotechnical and down-hole geophysical logging will be performed.
• Microdiamond sampling and analysis will be undertaken on 9,750 kilograms of drill core generated
by the drilling.
• Whole rock geochemical analyses will be performed on up to 1,300 samples.
• Geological models, including where relevant – geochemical, geophysical and geotechnical domains –
will be constructed for each kimberlite.
• Microdiamond analyses will be modelled to provide estimates of the macrodiamond grade potential
for the sub-units within each kimberlite.
• Kimberlite core will be stored for future use in a warehouse facility off-site.
• Environmental and heritage studies will be undertaken within and around the study area as
required by regulation.
• Site clearing and rehabilitation
• Accommodation on-site and logistical support.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Delineation Drilling
Delineation drilling will target high interest units identified in the Geological Drilling phase.
This drilling and sampling component will define, through additional core drilling and microdiamond
sampling, the volume, areal extent, and a higher level of confidence estimate of grade of higher
interest sub-zones to the extent that the next component of work can be undertaken, results
permitting. The three kimberlites investigated during the 2004 drilling program together with the
remaining 13 kimberlites to be considered for the Geological drilling program, provide up to 16
targets from which to select targets for the delineation drilling program. It was assumed for the
ESP plan and cost estimates that a maximum of nine kimberlites would be selected for this component
of work. Up to nine kimberlites (selected from the three drilled in the 2004 program and the 17
drilled in Geological Drilling) will be investigated, targeting the highest interest sub-units
within the selected kimberlites. This component shall include the following activities:
• A total of 15,000 metres of core drilling has been allocated to this phase.
• Geological, geotechnical and down-hole geophysical logging will be performed.
• Microdiamond sampling and analysis will be undertaken on 6,750 kilograms of drill core generated
by the drilling.
• Whole rock geochemical analyses will be performed on up to 900 samples.
• Geological models, including where relevant – geochemical, geophysical and geotechnical domains –
will be constructed for each kimberlite.
• Microdiamond analyses will be modelled to provide estimates of the macrodiamond grade potential
for the sub-units within each kimberlite.
• Kimberlite core will be stored for future use in a warehouse facility.
• Environmental and heritage studies will be undertaken within and around the study area as
required by regulation.
• Site clearing and rehabilitation
• Accommodation on-site and logistical support.
Mini-Bulk Sampling
This component of drilling and sampling will consist of taking a sufficient number of macrodiamond
samples to provide a global grade estimate, albeit, one with relatively large confidence limits.
Large diameter drilling (LDD) and mini-bulk sampling will be sufficient to confirm the abundance of
macrodiamonds and to provide an improved grade estimate. From the maximum of nine bodies, which
might be investigated during the delineation drilling component, together with those bodies
investigated during the 2000-2003 programs, it is expected that up to six kimberlites representing
the highest opportunity will be selected for mini-bulk sampling. A small parcel of diamonds would
be obtained which might be sufficient to obtain an initial low confidence revenue estimate. This
component shall include the following activities:
• Initial pilot hole core drilling to provide metallurgical and operational data prior to drilling
an LDD will be performed; a total of 9,900 metres of core drilling has been allocated to this
component.
• Geological, geotechnical and down-hole geophysical logging will be performed; microdiamond
sampling and analysis will be undertaken on 4,500 kilograms of drill core generated by the drilling
of pilot holes; whole rock geochemical analyses will be performed on up to 600 samples.
• Geological models, including where relevant – geochemical, geophysical and geotechnical domains –
will be constructed for each kimberlite.
• Microdiamond analyses will be modeled to provide confirmation of the macrodiamond grade potential
for the targeted sub-unit within each kimberlite.
• Kimberlite core will be stored for future use in a warehouse facility.
• Environmental and heritage studies will be undertaken within and around the study area as
required by regulation.
• Site clearing and rehabilitation
• Accommodation on-site and logistical support
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
• Large diameter drilling (915 millimetre diameter) at four sites per body. Allowance has been made
for an extra hole per body.
• A total of 6,600 metres of drilling to sample approximately 5,450 tonnes of kimberlite. The
sample is to be screened on-site, discarding the -1.5 millimetre fraction.
• Macrodiamond recovery of approximately 3,500 tonnes of kimberlite to produce an estimated 6,500
kilograms of heavy mineral concentrate
• Closure of the drill holes as directed by Saskatchewan Environment.
• A grade and, if possible, revenue estimate, are to be determined from the LDD sampling.
Supplemental Mini-bulk Sampling
This drilling and sampling component necessitates a sufficient number of samples be gathered to
provide a local macrodiamond grade estimate of the targeted high interest sub-unit. Additional LDD
and mini-bulk sampling will be completed to recover sufficient diamonds to provide local grade
estimates for the targeted unit and to generate revenue estimations. It is assumed that all six of
the bodies investigated during the mini-bulk sample program will be included in the supplemental
bulk sample. With this sampling and other geological information gathered during exploration, it
may be possible to declare an NI 43-101 compliant Inferred Resource based on the available data.
This component shall include the following activities:
• Initial pilot hole core drilling to provide metallurgical and operational data prior to drilling
a large diameter drillhole (LDDH) will be performed.
• A total of 13,500 metres of core drilling has been allocated to this component.
• Geological, geotechnical and down-hole geophysical logging will be performed.
• Microdiamond sampling and analysis will be undertaken on 4,500 kilograms of drill core generated
by the drilling of pilot holes.
• Whole rock geochemical analyses will be performed on up to 600 samples.
• Geological models, including where relevant – geochemical, geophysical and geotechnical domains –
will be constructed for each kimberlite.
• Microdiamond analyses will be modelled to provide estimates of the macrodiamond grade potential
for the sub-units within each kimberlite.
• Kimberlite core will be stored for future use in a warehouse facility.
• Environmental and heritage studies will be undertaken within and around the study area as
required by regulation.
• Site clearing and rehabilitation
• Accommodation on-site and logistical support
• Large diameter drilling (915 millimetre diameter) at 6 additional sites per body. Allowance has
been made for an extra hole per body.
• A total of 9,240 metres of drilling to sample approximately 7,600 tonnes of kimberlite. The
sample to be screened on site discarding the -1.5 millimetre fraction
• Closure of the drill holes as directed by Saskatchewan Environment.
• Macrodiamond recovery of approximately 4,900 tonnes of kimberlite to produce an estimated 9,150
kilogram of heavy mineral concentrate
• A local grade estimate and an improved confidence global revenue estimate are to be determined
from the macrodiamond LDD sampling.
In general, the geological drilling program will be complete in 2005 and delineation drilling will
begin late in 2005. To support this, the bulk of geotechnical and geohydrology work will be done in
2005. Delineation drilling, mini-bulk and supplemental bulk sampling will follow in years 2006
through early 2008. Geological and delineation drilling will provide geological models and
microdiamond data for the targeted kimberlites. These results will be compared against the criteria
established in the revised conceptual study, following which a decision to proceed to the next
round of drilling and sampling will be taken. In the mini-bulk and supplemental LDD programs,
samples will be treated and diamonds recovered and valued. The geological
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
model will be updated at the end of each round of drilling. An MRM report will first be prepared
based on the geological drilling results, then updated as new data become available throughout the
rest of the drill program.
AE&E Budget Estimates
De Beers’ budget estimates for the AE&E program are shown below by year:
2005
2006
2007
2008
All Years
Total Program
25,622,686
21,734,990
40,899,774
3,089,985
91,347,436
Kensington Share (46.94%)
13,125,073
11,026,505
21,520,532
1,120,647
46,792,758
“Best-Bodies First” Assumption
During the ESP Session, there was consistent intent within the planning team to pursue the most
promising bodies on a prioritized basis throughout the AE&E program as a means of consciously
attempting to develop an early measure of the opportunity presented by the global program.
Scope of Additional Work
In addition to the primary focus on resource exploration and evaluation work over the three year
period, it was recognized that in order to achieve the time objective of the AE&E study, additional
studies are required to run in parallel with the resource exploration and evaluation. It was also
considered essential that an updated conceptual study, incorporating the current options available,
would be required in order to provide a basis for go/no-go decisions on the project phases. These
additional studies, together with the resource work and project administration constitute ten work
areas:
1) Geotechnical/Geohydrological
Geotechnical domain and physical properties models will be developed and mine geotechnical
criteria prepared. Work is planned to construct both geohydrology and water chemistry models, as
well as perform geohydrology pumps tests to finalize geohydrology criteria and prepare
preliminary dewatering criteria. The majority of this work is planned to be undertaken once the
initial geological and delineation drilling programs have identified the priority targets to
advance through to the next stages of the AE&E. Provision has been made for specific
geotechnical and hydrogeological test holes to be undertaken concurrently with the Minibulk and
Supplemental-bulk sampling. A geotechnical domain model and pit-water management strategy will
be developed for use in the mining work stream.
2) Mining
An investigation of potential alternative and innovative mining strategies will be undertaken.
This will be a desktop-based study, supplemented by data obtained from the geological drilling.
Estimates of the capital and operational costs will be provided for inclusion into the AE&E
financial model and final study report.
3) Metallurgy and Mineral Processing
Metallurgical process concepts will be investigated and a metallurgical strategy developed.
Ore dressing requirements will be assessed and studied. A Bulk Sample Plant operational strategy
will be formulated, the BSP plan updated, and ODS and BSP data analyzed. Design criteria will be
produced, and flowsheets developed. Associated waste management concepts will be formulated and
the waste geochemistry assessed before a final waste concept is adopted. . Laboratory
testing and sample treatment plant data will provide the bulk of the ODS data. This information
will be used to provide and updated treatment strategy for the FalC kimberlites. Estimates of
the capital and operational costs will be provided for inclusion into the AE&E financial model
and study report.
4) Infrastructure, Support and Logistics
Short-term infrastructure opportunities will be assessed (mainly with regard to the site
access road), while longer-term concepts will be updated. Ore dressing data will be
obtained via drill samples,
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
both core and LDD. On-site infrastructure is required in order to
provide accommodation and to handle
kimberlite material. Off-site infrastructure will consist of a warehouse facility in Saskatoon
with sufficient capacity to store the kimberlite core and to allow for additional handling of
the core. Maintenance and necessary improvements to general site access roads are the
responsibility of the mineral licence holder.
5) Waste and Water Management
A strategy will be developed to manage both mine, and treatment plant waste, and to manage
excess and waste water. This work will be a desktop-based study, utilizing information provide
by other relevant work streams.
6) Socio-Economic
Socio-economic, environmental & permitting and government liaison all have an early start in
2005. It is recognized that these areas can be sensitive and may require significant lead-time
to successfully conclude. A global environmental strategy will be prepared and the baseline
collection and environmental program scoped and executed. Regulators will be consulted and
stakeholders will be informed and/or consulted as the work progresses. Government liaison and
fiscal regime strategies will be developed. Consultation with interested and affected
stakeholders, particularly the First Nations and established communities in the area, will be
undertaken. As appropriate to the project’s advancement, letters of understanding may be
negotiated in accordance with De Beers First Nations policy. Regular meetings to provide project
updates and to provide a forum for consultation and communication will be held.
7) Environmental and Permitting
Opinions will be gathered from environmental consultants on the potential environmental impacts
and cumulative effects requiring study during this phase of the FalC project. A review of the
global project area will be performed to establish realistic local and regional study areas for
all elements of the Environmental Baseline Plan. Government departments that may influence
project permitting at both the Federal and Provincial level will be identified and a strategy
will be developed to communicate with them on proposed baseline data collection. A list of key
areas for a Baseline Collection Program will be developed, taking into account the current plans
for the future project size, location, study areas and facilities. A plan will be prepared for
the collection of relevant data on key environmental areas. The Environmental Baseline Plan will
be initiated throughout the AE&E phase of the project and will be continued in future phases to
ensure that all required baseline data is available prior to request for environmental permits.
The objective of the environmental plan will be to satisfy an environmental assessment and other
Federal and Provincial permitting requirements within appropriate timelines. The components of
an environmental management plan will be identified, including baseline studies, monitoring,
reporting, permitting, operation, and closure. Finally, an estimate will be made of the costs of
environmental baseline studies, and of ongoing environmental management activities for all
project phases including permitting, construction, operation, and closure.
8) Governmental Liaison
The project taxation and royalty regime will be discussed with governmental with a view to
obtaining concessions favourable to the project and enhancing the project’s economic viability.
A high level plan was then developed for each of these eight work packages consisting of a series
of high level task or work packages.
Safety, Health and Environment (SHE) is an important focus, both on-site and off-site. It affects
all aspects of the work at hand and every effort will be made to supply and maintain safe working
environments as well as ensure that all personnel are properly trained in this regard. The site
will operate in accordance with De Beers Safety, Health and Environmental policies. In addition to
environmental and archaeological inspections required
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
by law, preliminary environmental,
groundwater quality and archaeological/traditional knowledge baseline surveys will be undertaken.
9.2.18 2005 Advanced Exploration and Evaluation Program
The present FalC-JV work program for 2005 encompasses the completion of the first phase of the
AE&E Action Plan, which consists primarily of geological drilling to establish the presence of
potential higher grade units within the kimberlites located in the southern part of the JV claims.
However, in order to take advantage of the results from the 2004 program (which, in part,
retroactively formed the initial thrust of the first drilling and sampling component through
investigation of four additional high-interest bodies within the central cluster), a provision has
been made in the 2005 budget for some delineation work should the results of the 2004 program be
sufficiently encouraging.
A 2005 budget of Cdn$25.6M applies to the period from 22 February 2005 to 15 December 2005. The
2005 budget will be applied to the first stage geological drilling of up to thirteen kimberlites in
the southern cluster of the FalC-JV claims. Funding for the 2006 program will be sought during the
4th quarter of 2005, provided sufficient positive results are available.
The AE&E budget for 2005 makes specific provision for the following work:
•
Update conceptual study to include mining of multiple pits.
•
Core drilling of up to 17 kimberlites, assuming on average 10 holes will be required per body.
•
Delineation drilling of up to three kimberlites
•
Microdiamond sampling involving treatment of up to 10000 kilograms of core
•
Minibulk sampling of one kimberlite, to obtain approximately 580 tonnes of kimberlite
for treatment.
•
Geotechnical and hydrogeological testing of up to 3 selected drill holes, including cone
tests and hydraulic pump tests.
•
Develop a preliminary geotechnical mine design model
•
Develop preliminary groundwater chemistry model and preliminary hydrological mine design
criteria
•
Geophysical borehole logging
•
Whole rock geochemical analyses
•
Commence investigation and develop possible alternative mining strategies
•
Investigate waste management concepts
•
Commence development of future infrastructure requirements
•
Investigate short term infrastructure needs.
•
Develop metallurgical process concepts, develop BSP operational strategy and upgrade BSP
•
Develop future Ore Dressing Study Requirements
•
Continue consultation with First Nations and government. Develop agreements with FN and
government on relevant issues.
•
Develop environmental baseline plan
•
Vegetation, wildlife and heritage surveys to support exploration permit applications.
In conjunction with the resource exploration and evaluation work, there are potential opportunities
to foreshorten the overall project time-line with minimal cost by undertaking studies of potential
mining, processing, waste management and infrastructure strategies. In addition to basic
environmental permitting requirements, limited baseline data will be obtained which will be
valuable in reducing project permitting time lines in the future. Consultations with key
stakeholders, including the local First Nations bands, will continue.
149
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Figure 36: Overview Timeline and Definitions of Possible Future Project
9.2.18.1 Update on the 2005 Drilling Program Currently in Progress
The current budgeted project activity represents work toward the first component of the
Advanced Exploration and Evaluation (AE&E) Plan. This component will consist mainly of geological
drilling and microdiamond analysis to determine the internal geology and grades of the targeted
kimberlites. These results will be used by De Beers to develop a model to help predict the grades
that could be seen in a commercial production scenario and to assist in modeling average diamond
values once a sufficient parcel of macrodiamonds is obtained. A budget of CDN $25.6 million was
planned for a minimum of 130 HQ coreholes during the 2005 program that will be distributed over
seventeen prioritized kimberlite bodies on individual grids of approximately 150-200 metres. A map
showing the central cluster of kimberlites and the seventeen 2005 prioritized bodies of interest is
presented in Figure 37, however, the following kimberlite bodies are grouped together on this map;
123 and 223, 134 and Star, and 116 and 216. Field activities will include downhole geophysical
surveys on most or all of the drillholes. This type of survey provides information on the physical
characteristics of the kimberlites as well as providing supplemental data to refine the placement
of boundaries between significant kimberlite units. First pass logging was completed on suitable
holes remaining from the 2004 program while all 2005 holes have had full downhole surveys where
possible.
Other areas of investigation traditionally viewed as being pre-feasibility levels of work, but are
embodied within the current AE&E Plan, are progressing under joint management of De Beers Canada
Inc. and their alliance partner, AMEC under the 2005 budget. Several of these investigations
include: environmental baseline studies and heritage resource impact assessments, metallurgical
studies based on geotechnical data, updating of conceptual studies and mining plans, ongoing
development of waste management and infrastructure concepts, development of government liaison
strategies and fiscal regimes. Kensington staff members lead several of these efforts and
contribute substantially to the latter three points of this list.
A total of 103 HQ coreholes (diameter of 2.5 inches or 63.5 millimetres) with kimberlite
intersections totaling 9,179.01 metres have been completed on thirteen high interest, prioritized
kimberlite bodies including the western part of the Star Kimberlite. Additionally, two coreholes
intersected 151.63 metres of kimberlite drilled for hydrogeological testing on Kimberlites 140/141
and 150. A total of 134 HQ coreholes are planned as part of
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
the 2005 program, which is budgeted at
CDN $25.6 million. Table 67 summarizes drilling results to August 31, 2005. The expected final
meterage for the current phase of drilling will be reached near the end of September.
Figure 37: Fort à la Corne South Cluster with 2005 Prioritized Kimberlite Bodies of Interest
151
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Number of
Number of
Number of
Total
Total
Thickest
Kimberlite
Coreholes
Coreholes
Coreholes
Drilled
Kimberlite
Kimberlite
Body
Planned
Completed
In Progress
Interval (m)
Thickness (m)
Interval (m)
Star
13
10
1
2,609.0
1,117.86
612.00
101
5
0
0
0.0
0.00
0.00
1161
5
5
0
1,167.0
475.87
218.30
118
11
11
0
2,526.0
1,044.24
192.95
119
6
6
0
1,324.0
414.80
202.34
123
6
2
2
405.0
149.05
88.50
133
6
6
0
1,362.0
309.66
90.36
134
5
5
0
1,134.0
474.35
145.10
135
6
5
1
1,260.4
473.82
141.90
145
11
11
0
2,503.0
1,027.47
176.50
152
6
0
0
0.0
0.00
0.00
158
11
11
0
2,642.5
950.32
190.25
163
9
0
0
0.0
0.00
0.00
2162
13
13
0
2,910.0
1,054.82
186.00
218
6
6
0
1,605.0
643.22
142.4
219
12
12
0
2,723.6
1,043.53
199.13
223
3
0
0
0.0
0.00
0.00
Total Priority
Drilling
134
103
4
24,171.5
9,179.01
1403
1
1
1
249.0
148.50
148.50
1503
1
1
1
249.0
3.13
2.81
Geotechnical
Drilling
2
2
2
498.0
151.63
Grand Total:
136
105
4
24,669.5
9,330.64
1
= orehole 116-05-006C was inclined at -60 degrees to investigate the wet, eastern
part of Kimberlite 116
2
= Coreholes 216-05-014C and 04-216-010C were inclined at -60 degrees to investigate
the wet, eastern part of Kimberlite 216; lithological contacts and thicknesses have not yet been
corrected for the dip of the hole; Corehole 216-05-009C was lost at a depth of 105 metres above
kimberlite due to drilling difficulties
3
= Geohydrological holes to test ground water flows.
Table 67: Fort à la Corne Joint Venture Core Drilling Summary to August 31, 2005
Drilling continues with three Boart-Longyear LF-70 core rigs operating on 24 hour schedules.
Two of the LF-70 rigs have been converted to helicopter-portable configurations in order to drill
on wet surface areas within Kimberlites 123, 223, 152, and the west extension of the Star. The
drill program remains on schedule and is 80% complete.
Corehole STR-05-003C, located 70 metres west of the Star shaft, intersected 612.0 metres of
kimberlite in a hole that was terminated at a total depth of 699 metres while still in kimberlite.
The corehole was centered on a deep-going part of the body that is interpreted to be a major feeder
vent for the volcanic complex. Two main phases of kimberlite were encountered with a thicker unit
extending from 108.15 metres to a depth of at least 395 metres, the base of core examined to date.
Preliminary description of the core indicates the unit is generally medium-grained with common
indicator minerals. It appears that this hole is quite different from other coreholes drilled by
the FalC-JV on the Star Kimberlite and the dominant rock unit appears to have characteristics
represented in both the Early Joli Fou and Late Joli Fou kimberlite phases. Further geological
logging of this core and comparison to other drillholes will be conducted by the operator once all
of the holes targeted on the Star Kimberlite are completed.
Methodical geotechnical measurements are conducted on each core including magnetic susceptibility,
rock competence, core quality, and density of natural fractures. Detailed core logging is in
progress by De Beers experts and slabbing of the core and sampling for diamond recovery continue in
the FalC-JV warehouse located in Saskatoon. The objective of this approach is to identify
sufficient higher-grade kimberlite to move forward with delineation drilling and minibulk sampling
in the subsequent phases of the AE&E Plan.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.18.1.1 Star Kimberlite
The Star Kimberlite is located at the south-eastern terminus of the south cluster. The body
has an estimated size of ~250 ha and ~240 million tonnes of kimberlite on the Shore Gold side of
the claim boundary. The area and mass of kimberlite on the FalC-JV side of the boundary has not
been estimated at this point due to a lack of relevant data. The FalC-JV side of the Star
Kimberlite was drilled first in the 2005 Program despite being second priority because of wet
conditions on Kimberlite 123, which had the highest priority. Fifteen coreholes were planned to
investigate the westward extent of prospective high-grade kimberlite that was recently the subject
of a successful 25,000-tonne bulk sampling program by Shore Gold Inc. Ten coreholes have been
completed with a combined intersection of 1,117.86 metres of kimberlite from 2,609.0 metres of
drilling. Individual intersections of kimberlite range from 8.8 to 612.0 metres. Table 68 shows a
summary of drilling results to August 31, 2005 and Figure 38 shows the location of completed and
proposed drillholes on this body.
Thicker intervals of the prospective Early Joli Fou (EJF) kimberlite unit were identified in three
of the drillholes. These were identified based on comparison of core to detailed kimberlite
descriptions available in public domain assessment reports (Saskatchewan Industry and Resources)
and to data from Shore Gold Inc.’s technical reports on SEDAR. The greatest interval of this unit
recovered thus far is some 77 metres thick.
Corehole STR-05-003C, located some 70 metres west of Shore Gold’s shaft into the Star Kimberlite,
intersected 612.0 metres of kimberlite in a hole that was terminated at a total depth of 699 metres
while still in kimberlite. The corehole was centered on a deep-going part of the body that is
interpreted to be a major feeder vent for the volcanic complex. There are two phases of kimberlite
recognized in the drill hole. The first is a thin, shallow kimberlite phase which is present from
90.3 to 108.15 metres. This unit is very fine grained, matrix supported, shale-clast rich and
likely associated with the Late Joli Fou kimberlite (LJF) as identified by Shore Gold Inc. on their
side of the property boundary. A second, deeper phase was intersected from 108.15 to 395 metres
(base of examined core). This unit is generally medium grained with common to very common indicator
minerals including garnet and ilmenite as well as trace to 10% shale xenoliths, varying from the
millimetres size up to 20 centimetres. It is apparent that this hole is quite different from other
coreholes drilled by the FalC-JV on the Star Kimberlite and that no kimberlite directly comparable
to the EJF was intersected nor were there any breccia units noted within the 395 metres of core
examined. A preliminary evaluation of the lower unit is that it is either a coarser-grained,
proximal version of the LJF kimberlite, or a new unit that has aspects of both the EJF and the LJF.
This unit may correspond to an intermediate kimberlite layer situated between the EJF and the LJF.
This kimberlite phase is considered to have moderate prospectivity by the Kensington geologist in
charge of core logging. Encouraging points include the relatively high abundance of mantle
indicator minerals including garnets, ilmenite, and clinopyroxene and, although not highly
abundant, the presence of mantle xenoliths. In addition, the presence of medium- to coarse-grained
olivine macocrysts is positive. Discouraging points include the high groundmass and shale xenolith
content, both of which tend to indicate potential dilution, and abundance of olivine phenocrysts,
which may reduce the relative proportion of olivine macrocrysts and reliability of this component
as an indicator of diamond content.
In comparison with work completed during the underground bulk sample program by Shore Gold Inc.,
this unit may be similar to MK (macrocrystic kimberlite) Type 5, which has been described as a
distinct grey green matrix rich MK that is probably the youngest unit of the EJF or is a transition
phase to basal LJF (ACA Howe Report dated March 16, 2005). This unit has been intersected in the
west-southwestern portion of the lateral drifts (see Map 15 in the ACA Howe report on the Star
kimberlite dated March 16, 2005 for details). The unit was sampled by Batch 62 and 72, both of
which are located about 50 metres southeast of STAR-05-003. The grades in batches 62 and 72 were
14.9 and 5.5 cpht respectively.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Map Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off; Blue Numbers =
Total kimberlite thickness (metres) in that drillhole; Red Dots = Drillhole locations drilled in
the 2005 Program; Black Squares = Planned coreholes remaining to be drilled; Yellow Dots =
Historical drillholes on FalC-JV kimberlites; Dotted Red Line =
Approximate claim boundary between the FalC-JV on the left and top and Shore Gold on the right;
Blue Squares = Drillholes by Shore Gold on the Star Kimberlite
Figure 38: Drillhole Map for the Star Kimberlite
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
STR-05-001C
not cored
104.35
235.90
85.75
3
118.95
258.0
STR-05-002C
not cored
99.36
218.65
104.05
2
108.94
231.0
STR-05-003C
not cored
87.00
699.00
612.00
1
612.00
699.0
STR-05-005C
90.69
133.90
181.60
47.70
1
47.7
210.0
STR-05-008C
not cored
107.70
230.90
74.85
3
76.41
252.0
154
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
STR-05-009C
105.85
150.10
213.14
38.70
4
61.59
237.0
STR-05-0010C
111.0
139.10
190.20
42.91
2
49.11
201.0
STR-05-0011C
88.20
114.80
156.00
17.50
3
19.10
180.0
STR-05-0012C
92.80
138.00
146.80
8.80
1
8.80
174.0
STR-05-0013C
not cored
129.23
142.45
13.22
2
15.26
167.0
Star Total:
1,117.86
2,609.0
Table 68: Preliminary Core Drilling Summary on for the Star Kimberlite (drilling in progress)
9.2.18.1.2 Kimberlite 134
Kimberlite 134 is located on the south-eastern limb of the south cluster and is adjacent to
the west side of the Star Kimberlite. The body has an estimated size of 31 ha and 53 million
tonnes of kimberlite. Five coreholes were completed on Kimberlite 134 as part of the westward
extending pattern of holes to map the relationship of the Star Kimberlite to the geology and
diamond content of Kimberlite 134. A total of 474.35 metres of kimberlite was intersected in
1,134.0 metres of drilling with individual kimberlite intervals ranging from 40.7 to 145.1 metres.
Finer grained kimberlite was encountered in four of the boreholes while a coarser, more prospective
unit was logged in the northern vent-proximal hole. Table 69 shows a summary of drilling results
to July 21, 2005 and Figure 38 shows the location of completed drillholes on Kimberlite 134.
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
134-05-002C
102.50
102.80
145.10
145.10
1
145.10
264.0
134-05-003C
105.00
114.80
75.95
75.95
1
75.95
198.0
134-05-004C
103.10
106.40
100.00
100.00
1
100.00
240.0
134-05-005C
not cored
102.00
112.60
112.60
1
112.60
243.0
134-05-006C
not cored
119.70
40.70
40.70
1
40.70
189.0
134 Total:
474.35
1,134.0
Table 69: Preliminary Core Drilling Summary for Kimberlite Body 134
9.2.18.1.3 Kimberlites 145 and 219
Kimberlites 145 and 219 are located between Kimberlites 140/141 to the south and Kimberlite
148 to the north, all very close to the centre of the south cluster. The body has an estimated
size of 103 ha and 178 million tonnes of kimberlite. Drilling on adjoined high-priority
kimberlites targets 219 and 145 is complete. Eleven coreholes were completed on Kimberlite 145
with a combined kimberlite intersection of 1,027.47 metres from 2,503.0 metres drilled. Twelve
coreholes were completed on Kimberlite 219 with a combined kimberlite intersection of 1,043.53
metres from 2,723.6 metres drilled. Kimberlite intersections ranged from 22.85 to 208.09 metres in
thickness although the 22.85 metre interval of kimberlite was encountered in a drillhole targeted
between the two bodies, but east of a narrow ridge of kimberlite that bridges the kimberlites with
155
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
thicknesses ranging from ~70 to 140 metres. Both bodies show oblong areas of thickness oriented to
the northwest and mimicking the primary linear trends throughout the main kimberlite field. These
oblong areas tend to have thicker kimberlite units that are coarser grained and generally more
prospective from a core logging point of view. All discrete kimberlite units in these two bodies
will be tested as well as the thicker bridge of kimberlite joining then on the western side. Much
of the bridge of kimberlite appears more similar to units in 145. Tables 70 and 71 show summaries
of drilling results to July 21, 2005 for Kimberlites 145 and 219, respectively. Figure 39 shows
the location of completed drillholes on both of these bodies.
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
145-05-007C
105.00
134.90
140.50
140.50
1
140.50
279.0
145-05-008C
105.60
105.60
214.80
74.50
2
105.70
249.0
145-05-009C
103.30
103.30
279.00
147.50
3
149.40
279.0
145-05-010C
103.57
103.57
197.26
35.48
4
80.50
216.0
145-05-011C
106.30
106.30
232.00
111.75
3
117.95
237.0
145-05-012C
110.50
110.50
153.30
42.80
1
42.80
159.0
145-05-013C
106.64
106.64
150.00
43.36
1
43.36
180.0
145-05-014C
111.50
111.50
176.50
176.50
1
176.50
312.0
145-05-015C
102.75
102.75
53.58
53.58
1
53.58
189.0
145-05-016C
99.00
99.00
159.30
33.25
2
41.68
183.0
145-05-017C
105.00
105.00
193.75
72.65
2
75.50
220.0
145 Total:
1,027.47
2,503.0
Table 70: Preliminary Core Drilling Summary for Kimberlite Body 145
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
219-05-005C
104.00
104.00
285.35
128.40
3
146.35
291.0
219-05-006C
108.23
108.23
195.88
33.25
4
91.50
222.0
219-05-007C
120.85
120.85
152.30
17.15
2
22.85
180.0
219-05-008C
109.10
109.10
167.10
51.30
2
56.20
198.0
219-05-009C
106.90
106.90
223.80
116.90
1
116.90
249.0
219-05-010C
105.40
105.40
192.69
77.38
3
80.96
231.0
219-05-011C
not cored
102.87
135.00
32.13
1
32.13
165.0
219-05-012C
103.67
105.32
189.24
36.08
3
51.73
201.0
219-05-013C
102.90
102.90
188.94
71.00
2
72.77
205.6
219-05-014C
105.33
105.33
316.31
199.13
2
208.09
324.0
219-05-015C
96.30
120.80
221.65
71.00
3
79.75
244.0
219-05-016C
105.70
110.40
194.70
84.30
1
84.30
213.0
219 Total:
1,043.53
2,723.6
Table 71: Preliminary Core Drilling Summary for Kimberlite Body 219
156
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Map Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off based on integrated geophysics and
kimberlite intervals in drillhole
Red Dots = Drillhole locations drilled or planned for the 2005 Program
Yellow Dots = Historical drillholes on FalC-JV kimberlites
Blue Numbers = Total kimberlite thickness (metres) in that drillhole.
Figure 39: Drillhole Map for Kimberlite Bodies 145 and 219
157
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.18.1.4 Kimberlite 119
Kimberlite 119 is located on the eastern side of the south cluster. The body has an estimated
size of 34 ha and 59 million tonnes of kimberlite. The 2005 drillholes intersected 2 main
kimberlite units. The older and deeper unit is typically medium-grained and weakly bedded to
massive. This unit thickens towards the south of the body. A shallower and younger unit is
generally massive and fine- to medium-grained, but becomes medium- to coarse-grained near to the
postulated vent around corehole 119-05-008C. The two units are separated by a thin shaly mudstone
horizon and/or a mudstone rich kimberlite breccia. Neither of the main kimberlite units are
thought to be highly prospective at this time. Table 72 shows a summary of drilling results to
July 21, 2005 for Kimberlite 119. Figure 40 shows the location of completed drillholes on this
body.
Thickness of
Total
Base of
Top of First
Base of Last
Main
Number of
Thickness of
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
Intervals (m)
(m)
119-05-004C
107.04
107.04
186.29
52.25
2
52.79
195.0
119-05-005C
not cored
111.00
158.60
39.00
2
43.20
189.0
119-05-006C
119.70
119.93
162.50
42.57
1
42.57
192.0
119-05-007C
119.30
126.40
192.80
17.60
3
29.30
219.0
119-05-008C
not cored
111.0
313.34
202.34
1
202.34
316.0
119-05-009C
not cored
111.0
185.20
34.50
4
44.60
213.0
119 Total:
414.80
1,324.0
Table 72: Preliminary Core Drilling Summary for Kimberlite 119
Map
Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off based on integrated geophysics and
kimberlite intervals in drillhole
Red Dots = Drillhole locations drilled or planned for the 2005 Program
Yellow Dots = Historical drillholes on FalC-JV kimberlites
Blue Numbers = Total kimberlite thickness (metres) in that
drillhole.
Figure 40: Drillhole Map for Kimberlite Body 119
158
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.18.1.5 Kimberlite 133
Kimberlite 133 is located near the eastern end of the south cluster and is adjacent to the
east side of Kimberlite 140/141. The body has an estimated size of 25 ha and 43 million tonnes of
kimberlite. Kimberlite 133 consists of at least three discrete kimberlite units. An older medium-
to coarse-grained unit up to seven metres thick, and located at depth, is separated from the main,
younger kimberlite by a substantial thickness of in-situ mudstone. The main kimberlite is
dominantly fine-grained, but has some medium- to coarse-grained beds below a depth of 155 metres.
The upper part of two drillholes in the north part of the body, close to the eastern edge of
Kimberlite 140/141, show a more prospective medium- to coarse-grained unit with thin breccia
horizons that appear similar to the potentially economic Joli Fou beds of 140/141. Table 73 shows a
summary of drilling results to July 21, 2005 for Kimberlite 133. Figure 41 shows the location of
completed drillholes on this body.
Map Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off based on
integrated geophysics and kimberlite intervals in drillhole
Red Dots = Drillhole locations drilled or planned for the 2005 Program
Yellow Dots = Historical drillholes on FalC-JV kimberlites
Blue Numbers = Total kimberlite thickness (metres) in that drillhole.
Figure 41: Drillhole Map for Kimberlite Body 133
159
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
133-05-002C
115.98
115.98
194.45
45.02
2
51.43
219.0
133-05-003C
not cored
113.28
231.80
90.36
4
100.74
261.0
133-05-004C
115.45
143.70
200.17
11.60
3
23.44
228.0
133-05-005C
125.51
125.51
195.16
34.81
2
46.25
213.0
133-05-006C
not cored
136
199.70
31.90
2
36.90
228.0
133-05-007C
not cored
117
194.70
33.40
4
50.90
213.0
133 Total:
309.66
1,362.0
Table 73: Preliminary Core Drilling Summary for Kimberlite 133
9.2.18.1.6 Kimberlite 158
Kimberlite 158 is located approximately 13 kilometres north of the centre of the south
cluster. The body has an estimated size of 58 ha and 100 million tonnes of kimberlite. Eleven
coreholes were completed in 2005 in a rough 200 metre grid. Two historical holes were drilled,
neither of them core holes. Two of the central 2005 coreholes intersected over 190 metres of
coarser grained, more prospective kimberlite with common indicator minerals such as ilmenite and
garnet, and the occurrence of rare mantle xenoliths. Kimberlite intersections in surrounding holes
thin outwards and become finer grained towards the margins of the body. The eastern flank remains
moderately coarser grained over a broader distance to an approximate thickness of 60 metres
compared to rapid thinning to <40 metres in all other directions. Table 74 shows a summary of
drilling results to July 21, 2005 for Kimberlite 158. Figure 42 shows the location of completed
and planned drillholes on this body.
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
158-05-003C
113.41
113.41
213.92
31.07
4
68.47
234.0
158-05-004C
114.68
114.68
197.40
36.22
3
68.82
222.0
158-05-005C
120.17
120.17
203.46
32.75
4
65.04
240.0
158-05-006C
114.50
114.50
210.70
41.50
3
70.10
246.0
158-05-007C
113.85
114.15
304.40
190.25
1
190.25
312.0
158-05-008C
113.50
113.50
303.60
190.10
1
190.10
313.0
158-05-009C
115.62
115.62
217.88
63.98
2
89.06
249.0
158-05-010C
118.73
118.73
145.26
26.53
1
26.53
186.0
158-05-011C
116.60
116.50
209.60
93.10
1
93.10
232.5
158-05-012C
not cored
120.00
206.90
60.45
2
64.55
222.0
158-05-013C
124.87
124.87
154.50
23.50
2
24.30
186.0
158 Total:
950.32
2,642.5
Table 74: Preliminary Core Drilling Summary for Kimberlite 158
160
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Map Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off based on
integrated geophysics and kimberlite intervals in drillhole
Red Dots = Drillhole locations drilled or planned for the 2005 Program
Yellow Dots = Historical drillholes on FalC-JV kimberlites
Blue Numbers = Total kimberlite thickness (metres) in that drillhole.
Figure 42: Drillhole Map for Kimberlite Body 158
9.2.18.1.7 Kimberlite 216
Kimberlite 216 is located in the eastern limb of the south cluster and adjacent to the
southwest margin of Kimberlite 140/141. Together 216 and the contiguous Kimberlite 116 have an
estimated size of 99 ha and 171 million tonnes of kimberlite. Twelve drillholes were completed
plus a thirteenth which was terminated above kimberlite due to drilling difficulties. Two
coreholes were inclined at -60 degrees and oriented at azimuth 090 degrees in order to test the
eastern margin of the 216 kimberlite, which resides beneath wet surficial conditions. Corehole
216-05-013C intersected 138.7 metres of dominantly very fine- to fine-grained kimberlite and minor
abundance of indicator minerals, garnet and ilmenite. Other kimberlite intervals to the west,
south, and east of this are considerably thinner and also show common very fine- to fine-grained
kimberlite. Table 75 shows a summary of drilling results to August 31, 2005 for Kimberlite 216.
Figure 43 shows the location of completed drillholes on this body and Kimberlite 116.
161
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Total
Thickness
Base of
Thickness of
of
Base of
Top of First
Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
216-05-004C
not cored
114.00
187.10
42.10
3
51.90
204.0
216-05-005C
not cored
108.00
294.00
186.00
1
186.00
309.0
216-05-006C
not cored
118.10
180.90
57.60
2
61.10
210.0
216-05-007C
120.10
120.10
162.45
42.35
1
42.35
201.0
216-05-008C
not cored
123.00
209.13
181.93
3
54.57
225.0
216-05-009C2
not cored
n/a
n/a
n/a
n/a
n/a
105.0
216-05-010C1
not cored
126.00
237.85
111.85
1
111.85
243.0
216-05-011C
114.50
142.20
184.95
42.75
1
42.75
219.0
216-05-012C
118.80
118.80
158.30
39.50
1
39.50
192.0
216-05-013C
111.00
112.44
251.13
138.69
1
138.69
264.0
216-05-014C1
120.60
120.60
228.00
96.58
2
103.31
228.0
216-05-015C
not cored
120.00
162.80
42.80
1
42.80
198.0
216-05-016C3
not cored
120.00
312.00
177.00
2
180.00
312.0
216 Total:
1,054.82
2,910.0
1
= Coreholes 216-05-014C and 04-216-010C were inclined at -60 degrees to investigate
the wet, eastern part of Kimberlite 216; lithological contacts and thicknesses have not yet been
corrected for the dip of the hole;
2
= Corehole 216-05-009C was lost at a depth of 105 metres above kimberlite due to
drilling difficulties;
3
= Corehole 216-05-016C was terminated at a depth of 312 metres in kimberlite due to
drilling difficulties.
Table 75: Preliminary Core Drilling Summary for Kimberlite 216
9.2.18.1.8 Kimberlite 116
Kimberlite 116 is located in the eastern limb of the south cluster and adjacent to the
southwest margin of Kimberlite 140/141. Five drillholes were completed. One corehole was
inclined at -60 degrees and oriented at azimuth 090 degrees in order to test the eastern margin of
the 116 kimberlite, which resides beneath wet surficial conditions. Table 76 shows a summary of
drilling results to August 31, 2005 for Kimberlite 116. Figure 43 shows the location of completed
drillholes on Kimberlite 116.
162
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Map Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off; Blue Numbers =
Total kimberlite thickness (metres) in that drillhole; Red Dots = Drillhole locations drilled in
the 2005 Program; Yellow Dots = Historical drillholes on FalC-JV kimberlites
Figure 43: Drillhole Map for Kimberlite Bodies 216 and 116
163
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
116-05-003C
not cored
108.00
181.60
73.60
1
73.60
213.0
116-05-004C
not cored
125.85
163.90
38.05
1
38.05
192.0
116-05-005C
not cored
105.00
323.30
218.30
1
218.30
330.0
116-05-006C1
not cored
114.00
239.40
125.40
1
125.40
246.0
116-05-007C
not cored
136.40
159.50
17.98
2
20.52
186.0
116 Total:
not cored
475.87
1,167.0
1
= Coreholes 116-05-006C was inclined at -60 degrees to investigate the wet, eastern
part of Kimberlite 116, depths and thicknesses are apparent and have not been converted to true at
this time.
Table 76: Preliminary Core Drilling Summary for Kimberlite 116
9.2.18.1.9 Kimberlite 118
Kimberlite 118 is located near the centre of the south cluster. The body has an estimated
size of 77 ha and 133 million tonnes of kimberlite. Eleven coreholes have been completed in a
rough 200 – 300 metre grid. Four historical drillholes were drilled, two of them coreholes, one a
reverse circulation hole, and one prematurely terminated in overburden. Five of the holes (three
in 2005, and 2 historical) intersected >100 metres of kimberlite that together form an elongate
deeper-going trend oriented to the northwest. While many of the kimberlite intersections show
medium-grained character, the central four holes have significant intervals of medium- to
coarse-grained kimberlite and appear to be more prospective. Table 77 shows a summary of drilling
results to August 31, 2005 for Kimberlite 118. Figure 44 shows the location of completed
drillholes on this body.
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
not cored,
118-05-005C
not cored
< 105
194.96
89.96
1
89.96
225.0
118-05-006C
not cored
114.00
211.19
65.95
4
85.49
237.0
118-05-007C
not cored
102.00
294.95
192.95
1
192.95
300.0
118-05-008C
122.20
127.80
280.17
152.37
1
152.37
291.0
118-05-009C
not cored
108.20
185.10
76.90
1
76.90
201.0
118-05-010C
not cored
114.53
161.95
47.42
1
47.42
189.0
118-05-011C
106.10
106.10
181.80
75.70
1
75.70
210.0
118-05-012C
not cored
102.0
229.70
127.70
1
127.70
240.0
118-05-013C
not cored
114.00
162.60
48.60
1
48.60
192.0
118-05-014C
not cored
120.00
184.10
64.10
1
64.10
213.0
118-05-015C
108.80
108.80
191.85
83.05
1
83.05
222.0
118 Total:
1,044.24
2,526.0
Table 77: Preliminary Core Drilling Summary for Kimberlite 118
164
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Map Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off based on
integrated geophysics and kimberlite intervals in drillhole
Red Dots = Drillhole locations drilled or planned for the 2005 Program
Yellow Dots = Historical drillholes on FalC-JV kimberlites
Blue Numbers = Total kimberlite thickness (metres) in that drillhole.
Figure 44: Drillhole Map for Kimberlite Body 118 and Kimberlite Body 150
165
Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
9.2.18.1.10 Kimberlite 218
Kimberlite 218 is located in the western limb of the south cluster 3 kilometres southeast of
Kimberlite 122. The body has an estimated size of 26 ha and 45 million tonnes of kimberlite. Six
coreholes have been completed. There is only one historical drillhole; this was a reverse
circulation hole drilled in 1994. Corehole 218-05-002C intersected predominantly fine- to
medium-grained kimberlite units of low interest. Corehole 218-05-003C intersected 236.25 metres of
kimberlite with two minor intervals of possibly slumped, kimberlite-infused host rock blocks. The
upper 48 metres of this interval is very very fine- to fine-grained and of low prospectivity.
Kimberlite units below this are typically fine- to medium-grained and are considered more
prospective. Given the very thick interval of kimberlite, this drillhole is possibly located
within the margin of a feeder vent for the body. Interestingly, a relatively thin, 56 metre
interval of kimberlite in corehole 218-05-04C located in the centre of the body separates two
kimberlite core intersections of >100m to the northwest and to the southwest and may indicate
the presence of two separate eruptive vents.
Table 78 shows a summary of drilling results to August 31, 2005 for Kimberlite 218. Figure 45
shows the location of completed and planned drillholes on this body and for Kimberlite 152. Core
drilling will begin on Kimberlite 152 in the near future.
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
218-05-002C
133.30
133.30
175.96
42.66
1
42.66
207.0
218-05-003C
not cored
144.00
395.95
142.40
3
236.25
423.0
218-05-004C
123.30
123.80
180.00
56.20
1
56.20
216.0
218-05-005C
126.80
141.00
210.00
69.00
1
69.00
237.0
218-05-006C
123.35
130.55
248.70
101.77
2
112.01
264.0
218-05-007C
127.40
127.40
254.50
127.10
1
127.10
258.0
218 Total:
643.22
1,605.0
Table 78: Preliminary Core Drilling Summary for Kimberlite 218
166
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
Map Key:
Green Shapes = Interpreted kimberlite body outline to a ~30 metre thickness cut-off based on integrated geophysics and kimberlite intervals in
drillhole
Red Dots = Drillhole locations drilled or planned for the 2005 Program
Yellow Dots = Historical drillholes on FalC-JV kimberlites
Blue Numbers = Total kimberlite thickness (metres) in that drillhole.
Figure 45: Drillhole Map for Kimberlite Body 218 and 152
9.2.18.1.11 Kimberlite 123
Kimberlite 123 is located 3.5 kilometres northwest of the drilling camp. The body has an estimated size of 45 ha and 53 million tonnes of kimberlite.
Two of six planned coreholes have been completed to date. Three historical holes were drilled including one corehole, one rotary, and one large
diameter reverse circulation drillhole. All three drillholes intersected between 84 and 90 metres of kimberlite with total recovery of 7
macrodiamonds weighing cumulative 0.132 carats and 15 microdiamonds. The two 2005 coreholes completed
167
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
to date intersected 60 and 89 metres of prospective medium to coarse-grained kimberlite. Table 79 shows a summary of drilling results to August 31,2005 for Kimberlite 123. Figure 46 shows the location of planned drillholes on this body and for Kimberlites 123 and 223.
Figure 46: Drillhole Map for Kimberlite Body 123 and 223
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
123-05-006C
not cored
105.00
193.50
88.50
1
88.50
222.0
123-05-009C
103.30
103.30
163.85
60.55
1
60.55
183.0
123 Total:
149.05
405.0
Table 79: Preliminary Core Drilling Summary for Kimberlite 123 (drilling in progress)
168
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
9.2.18.1.12 Kimberlite 135
Kimberlite 135 is located 5 kilometres southeast of the drilling camp. The body has an estimated size of 35 ha and 60 million tonnes of kimberlite.
Five of six planned coreholes have been completed to date. Only one historical rotary drillhole was completed 1996. Eleven samples were tested for
diamond content with only one microdiamond recovered from 52.8 kilograms of kimberlite. The 2005 drillholes intersected between 29 and 142 metres of
kimberlite. Core logging for this body is underway and will be reported once all drillholes are completed. Table 80 shows a summary of drilling
results to August 31, 2005 for Kimberlite 135. Figure 47 shows the location of completed and planned drillholes on this body.
Figure 47: Drillhole Map for Kimberlite Body 135
Total
Thickness
Thickness of
of
Base of
Top of First
Base of Last
Main
Number of
Kimberlite
End of
Till
Kimberlite
Kimberlite
Kimberlite
Kimberlite
Intervals
Hole
Drillhole Name
(m)
(m)
(m)
(m)
Units
(m)
(m)
135-05-002C
not cored
137.10
279.00
141.90
1
141.90
279.00
135-05-003C
120.40
139.53
169.40
29.87
1
29.87
198.35
135-05-004C
not cored
141.00
242.80
54.10
2
91.20
258.00
135-05-006C
not cored
128.72
198.23
69.51
1
69.51
213.00
135-05-007C
not cored
120.00
289.17
134.40
3
141.34
312.00
135 Total:
473.82
1,260.35
Table 80: Preliminary Core Drilling Summary for Kimberlite 135 (drilling in progress)
169
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
10.0 Drilling
Drilling has been conducted at Fort à la Corne since 1989 and has totaled some 349 holes up to 2004 into 69 proven kimberlite bodies using a wide
range of drilling techniques. Early drilling utilized conventional rotary or small diameter reverse circulation methods. Core drilling was done
extensively in 1993 and 1994, and larger diameter reverse circulation drilling has been used since 1994. Underreaming was used to enlarge drillholes
in 1993 and 1997. Reverse flood drilling at 610 millimetres diameter has been conducted since 2000 and a 914 millimetres version in 2002 and 2004.
Methodologies for conducting reverse circulation drilling have evolved significantly since the early 1990’s primarily in attempts to optimize
drilling chip product and to minimize potential for diamond damage.
Drill product has been used for all geochemical, mineralogical, and diamond recovery. Extensive indicator mineral chemistry data are available for
many kimberlites, and microdiamond samples have been analyzed for most kimberlites. Macrodiamond sampling has been done on roughly half of the
kimberlites in the field, particularly those with microdiamond contents.
Due to the changing nature of drilling programs over a long period of time (1989-2004), a description of drilling and sampling programs for each year
is included in the Exploration section. The reader specifically is directed to the section concerning prioritization of kimberlites and an evaluation
of all data and information from 1989 to 1999 investigated during a desktop study in 2000. All drilling conducted up to the investigation of
Kimberlite 116 and 216 during 2005 has been fully vertical – no inclined holes have been utilized in the past and all intersections of kimberlite are
considered true thicknesses. The orientation of the mineralized bodies is still under investigation and the full extent of the prospective zones are
not known. True kimberlite thicknessess for inclined drillholes into kimberlites 116 and 216 will be disclosed in the 2005 Drilling Report from the
project operator, De Beers Canada Inc. As the drilling into kimberlites 116 and 216 was conducted in 2005 and no diamond results have been received
for this low priority kimberlite yet (as determined by petrographic examination), the calculation of true thicknesses is irrelevant to this report.
It is the opinion of the Qualified Person that present-day core drilling and reverse circulation drilling methods, particularly from 2000 onwards,
have been optimized to minimize damage and loss of diamonds and are suitable for the current objectives of this project. It is recognized that the
density of drilling on any kimberlite body is too low to determine a geological model with sufficient levels of confidence for an Inferred Resource.
11.0 Sampling Method and Approach
Diamond recovery information and results for each drillhole and kimberlite are recorded in tabular form. De Beers (Mineral Resource Management) and
independent consultants/experts use this data for grade calculation exercises and prediction of stone sizes. For some bodies, microdiamond data are
relatively sparse, sometimes being derived from a single drillhole, and represent the only diamond data (macro or micro) available for a given body.
Due to the changing nature of drilling programs over a long period of time (1989-2002), a description of drilling and sampling programs for each year
is included in the Exploration section. In general, De Beers relies on detailed protocols and instruction for proper and consistent, representative
sampling of kimberlites. As such, and by observation, it is the opinion of the author that sample quality is high and all efforts have been made to
minimize the potential for subjective and natural bias.
The most important factor affecting potential bias in the sampling process, whether for coreholes or large diametre mini-bulk sampling, is that
diamonds are inherently rare in kimberlites, even for relatively “rich” deposits. Typically, diamonds occur in abundances measured in parts per
billion (ppb) and therefore are not reliably included in a given drillhole intersection or sample. This factor is termed the “nugget-effect” and this
is most pronounced in lower grade, high tonnage deposits such as Fort à la Corne. Kimberlites are the result of variable mixing processes inherent
within volcanic eruptions that result in an inhomogeneous distribution of
170
Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
diamonds. Hence, grades are rarely determined from just a few samples or drillholes. Rather, diamond recoveries from many drillholes and samples
spread across the body must be averaged in order to give some approximation of the whole rock grade. Determination of average value of the diamonds
presents even greater difficulties in that much larger tonnages of sample must be processed to give sufficiently large parcels of recovered diamond
in order to get reasonably accurate and reliable revenue estimations. The reason for this is that each diamond is unique and has a monetary value
determined by the combination of its characteristics including size, shape, colour, clarity.
In terms of sampling procedures, care must be taken to sample kimberlite from the same phase (type or volcano-stratigraphic layer) and that it is
representative of the unit. Typically, many samples are taken to give a continuous test throughout the kimberlite intersection.
11.1 Grab Samples for Recovery of Microdiamonds and Indicator Minerals
More than 18,000 kilograms of kimberlite comprising over 1,200 samples have been analyzed for microdiamonds on a project-wide basis, and some 9,000
stones have been recovered. Samples have been treated in four main facilities: Kimberley Microdiamond Lab (KMDL), Anglo American Research Lab
(AARL), SRC, and Lakefield Research. In general, all labs except AARL utilized similar bottom screen cut-points (74 or 75 microns) and results were
reported and compiled in standard sieve size ranges. Typically, microdiamonds were recovered utilizing caustic fusion/caustic dissolution methods,
although, rarely microdiamonds (to 150 microns bottom cut-off) were recovered along with indicator minerals using jigging methods.
Kimberlite samples derived from chip material were methodically collected as representative grab samples from the stream of kimberlite over the
shaker table. Samples collected from core material were assembled by collecting representative whole core pieces over set intervals. Only one
corehole was first slabbed and then sampled; this was PQ corehole 141-39 which was drilled and sampled during 2002-2003. Choice of sample interval
for the microdiamond and indicator mineral recovery changed over the course of the project. During the first three years of the project, sample
intervals ranged from a few metres to covering the entire thickness of kimberlite intersected in the drillhole. From 1993 to 1999, sample intervals
were variable and primarily based on lithological contacts. After 1999, samples for microdiamond recovery were selected from representative
intervals of core only.
In 2003, the FalC-JV partners constructed a core slabbing facility in Saskatoon to accommodate the larger number of core drilled. Samples were first
logged, then the selected or entire kimberlite intervals slabbed longitudinally. In this way, a permanent record of the kimberlite interval is
maintained for future comparison, thin-sectioning, and geochemical sampling.
Diamond recovery information and results for each drillhole and kimberlite are recorded in tabular form. De Beers (Mineral Resource Management
Department or MRM) and independent consultants/experts use this data for grade calculation exercises and prediction of stone sizes. For some bodies,
microdiamond data are relatively sparse, sometimes being derived from a single drillhole, and represent the only diamond data (macro or micro)
available for a given body.
It is the opinion of the Qualified Person that all present-day sampling methods are conducted with care, diligence, and sufficient precautions to
ensure that bias is minimized or removed from sampling both for assay (diamond recovery) and analytical purposes.
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11.2 Samples for Recovery of Macrodiamond
Macrodiamond samples have been collected within the project area since 1989. Bottom screen processing cutoffs have generally varied between 0.85
millimetres and 1.5 millimetres. Samples have been taken from a range of drill products including core, rotary drill chips, and reverse circulation
drill chips.
Kimberlite samples derived from chip material were methodically collected in plastic mesh bags after sizing on shaker tables to remove undersize
material. Samples collected from core material were crushed prior to diamond recovery. Choice of sample interval for the microdiamond and indicator
mineral recovery changed over the course of the project. During 1993 and 1994, several variably thick samples were taken from each drillhole
intersection of interest with some samples covering over 100 metres of kimberlite. From 1995 – 1999, sample intervals were tied to interpreted
lithofacies boundaries, and then from 2000 onwards to more consistent, 6 or 12 metre intervals that were either keyed to drill rod use or a uniform
datum within the kimberlite.
11.3 Representative Samples from Core
Prior to 2003, core was only selectively slabbed for collection of archive or petrographic samples. Most samples for diamond recoveries were
collected as broken or whole sections of core. Also, sample intervals were defined by depth (keyed to a datum) and may have crossed lithological
contacts. Some samples were taken as grabs from intervals covering 10’s of metres.
In 2003, core was methodically slabbed longitudinally prior to sampling. At present, the sampling strategy for diamond recovery utilizing caustic
dissolution methods is based on collection of representative material from within boundaries marking lithological contacts. Samples are made up to a
maximum of 8 kilograms each and closed with numbered seals that cannot be tampered with. In addition, during 2003, samples of slabbed core measuring
up to 40 centimetres long were collected for archiving and future petrographic studies. The number of samples collected per drillhole is a function
of several factors including:
-
budgetary considerations for the diamond recovery program
-
number of discrete phases present in the drillhole and in the kimberlite as a whole (complexity of geology)
-
thickness of intersection and discrete kimberlite phases
-
estimate of diamonds required for further evaluation
12.0 Sample Preparation, Analyses and Security
The author has repeatedly visited and inspected all of the preparation centres and labs employed, or operated, by the FalC-JV operator during the
past 10 years. It is my opinion that sampling, sample preparation, analyses, and security protocols utilized at these facilities are sufficient to
safeguard the integrity of the results reported herein. No part or aspect of sample preparation was conducted by an employee, officer, director, or
associate of the Kensington Resources or Shore Gold Inc.
Sample preparation in advance of the lab was minimal and typically consisted only of drying the material. Samples were collected and prepared by
contract and permanent employees of the project field management or operators.
Detailed descriptions of analytical work for a wide range of chemical analyses and indicator mineral recovery procedures are not included in this
document, but are available upon request or in a much summarized form in Lehnert-Thiel et. al. (1992) and Jellicoe et. al. (1998). A brief
description of sampling procedures and core slabbing also is given in Section 11 of this report.
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
The greatest focus of sample preparation and analytical work is on recovery of macrodiamonds and microdiamonds. These assays are completely different
and are conducted in different labs and under different conditions. The following descriptions are typical for the FalC diamond recoveries.
Sample Treatment at Grande Prairie DMS Plant
Once sufficient sample bags from the large diameter drill program were stockpiled (usually around 30 bags) they were loaded onto flat deck trailers
which could accommodate approximately 14 to 16 bags (~ 20,000 kilograms). The loaded trailers were then picked up, covered and secured in tarps, and
transported directly to the De Beers Processing Facility in Grande Prairie, Alberta. At the De Beers Grande Prairie facility, mini-bulk samples were
processed by means of Dense Media Separation (DMS).
Samples which were initially weighed in the field using a 5000 kilograms rated electronic load cell, were reweighed in Grande Prairie using a
electronic floor scale calibrated to measure in 1 kilograms increments. When the weights of the samples in the field (643.7 t) were compared to those
weights following thawing and draining of the samples in Grande Prairie (613.4 t), an average loss of 4.7% was noted. A total of 31.0 tonnes of audit
sample material was also run through the plant, bringing the total head feed tonnage processed in Grande Prairie to 644.4 tonnes. The final
concentrate yield excluding audit concentrates for the 2002 LDDH was 1,294.2 kilograms or 0.1% of the theoretical weight of the eight large diameter
holes drilled.
The sample prep module at the Grande Prairie plant consisted of a 0.8 metres x 1.2 metres long scrubber equipped with a 14 millimetres trammel screen
fitted onto the discharge end of the scrubber. The scrubber was revolved at 25 rpm, this being the optimum speed to allow for disaggregation of the
cuttings while avoiding diamond breakage. A 4 x 6 Osborne jaw crusher with a closed gap setting of 10 millimetres received all the +12.5 millimetres
material from the scrubber. The crushed oversize fraction was gravity fed into a 3/2 Warman pump and returned to the scrubber. The jaw crusher could
not be choke fed during sample treatment in 2002 due to the limited amount of +14 millimetres material present in the samples. Excessive clay in a
number of other samples required a 6 millimetres screen to be fitted over the outlet of the scrubber in an attempt to ensure all the clay in the
samples was broken down in the scrubber before being fed into the DMS.
During DMS processing, fines (-1.5 millimetres material) were removed on a preparation screen. The tailings were collected in bulk sample bags and
stored on a per-sample basis. The screened +1.5 millimetres size fraction was mixed with a dense medium (270D Ferrosilicon, FeSi) and fed at a
pressure of 92 Kpa into a 200 millimetres DMS cyclone. Lights (sample tailings) from the cyclone were drained, washed across a split screen deck to
recover the FeSi and then discharged to a bulk sample bag for storage. The DMS concentrate was washed across a separate deck of the product screen
and gravity fed into 20 litre concentrate pails located in a secure cage. Concentrate pails were then weighed, sealed and stored in locked transport
containers prior to shipment.
Various measures were put in place to prevent sample contamination at the Grande Prairie facility. A thorough plant clean out was undertaken after
every sample was run through the plant. This involved cleaning of the scrubber, feed bin, pumps and screens. Between holes, an even more thorough
cleaning and inspection of the plant was completed with a decontamination document completed by the plant supervisor.
Quality control measures to monitor the quality and integrity of the sample were carried out on a per shift basis at the Grand Prairie plant as well.
These measures included tracer tests, crusher gap tests and Marcy scale calibrations. Each shift, tracer tests involving eight different density
size fractions (2.8-3.54 g/cm3) were introduced into the plant feed stream and were collected after having passed through the DMS cyclone. The
density of the DMS plant medium was also controlled within limits set at ± 0.005 g/cm3. The accuracy of the dense media was monitored with a Marcy
density scale every 20 minutes and recorded. The set point of the
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
DMS plant was determined every shift by means of a tracer test at the inlet density valve where the cut-point was set to 3.15 g/cm3. A standard flow
sheet is shown in Figure 48 for the DMS treatment at Grande Prairie.
For each drillhole processed, an audit sample consisting of re-processed DMS tailings was run through the plant. In all, eight audit samples were
processed in 2002. Each audit sample was assigned a separate sample number and was consigned to the De Beers Group Exploration Macro Diamond
Laboratory in South Africa (GEMDL) who finalized the audit process by analyzing the concentrate for macrodiamond recoveries.
Upon completion of each drillhole, the concentrate cage in the DMS plant was vacuumed out resulting in another audit sample which was also consigned
to GEMDL for diamond recoveries. Prior to export, concentrate pails were weighed, palletized, and strapped with tamper-proof cable seals to prevent
unauthorized opening of the crates. The shipments were collected in Grande Prairie by armed guard and air freighted from Edmonton to Johannesburg for
consignment to GEMDL.
Figure 48: Schematic Flow Sheet for the Grande Prairie Dense Media Treatment Plant
Diamond Recovery at Group Exploration Macro Diamond Laboratory
DMS concentrates consigned to the De Beers Group Exploration Macro Diamond Laboratory (GEMDL) in Johannesburg, South Africa were treated for final
macrodiamond recoveries.
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
Upon arrival at the GEMDL, monitors were placed at random in the sealed concentrate containers as an internal audit on the recovery process. During
processing, the containers were opened in sealed cages and dumped into a stand-alone unit which washes, dries and sizes the material into three size
fractions: -2 millimetres/+1 millimetres, +2 millimetres/-4 millimetres and +4 millimetres. Once the samples had been split, all samples less than 10
kilograms in size were visually sorted and examined. All -4 millimetres sized material with a mass greater than 10 kilograms was concentrated further
using a 32 channel x-ray unit designed by De Beers DEBEX. The recovery performance of the x-ray unit is regularly checked by a series of luminescent
tracers.
Tailings from the x-ray machine were passed over a Permroll magnetic separator belt which separates the material into magnetic and non-magnetic
fractions, thereby separating possible low luminescent diamonds into an easily examinable non-magnetic fraction. Samples of magnetic tails were also
routinely hand sorted as part of a self-audit to determine the presence of any additional diamonds. The +4 millimetres concentrate fraction, x-ray
concentrate, and Permroll concentrates were kept in separate containers and hand sorted twice by trained personnel to ensure maximum diamond recovery
efficiency. Diamonds recovered from the hand sorting process were then transferred to a final recovery room via a sealed conveyor. Once signoff of
the final diamond recoveries had been approved, the diamonds were transferred to the Diamond Trading Council (DTC) in London for valuation purposes.
De Beers’ lab facilities are now in compliance with ISO 17025 accreditation standards, but are not themselves certified. Neither the DMS plant at
Grande Prairie or the GEMDL recovery facility is accredited or certified by any other standards association. However, De Beers is recognized as
building and operating world-class diamond recovery facilities based on over 100 years of experience, testing, and synthesis. They employ rigorous
internal standards and auditing to maintain a high level of accuracy and precision in diamond recovery.
A number of verification routines for assessing drilling damage and processing integrity have been utilized during macrodiamond recovery procedures.
The main types of audits and quality control measures are listed below including the program years in which they apply:
Downhole tracer studies to monitor recovery and diamond damage; 1997 and 1999 reverse circulation drilling programs
Density tests during DMS
concentration; all macrodiamond recoveries by De Beers
Re-run of DMS tailings; all macrodiamond recoveries by De Beers
Re-run of x-ray sortex
tailings; 1990 and 1991, 1997 onwards for all macrodiamond recoveries by De Beers
Jigging tracers; macrodiamond recovery by the SRC in 1996
Grease
table diamond tracers; De Beers recovery from 1992-1997
X-ray sorter tracers; 1990 and 1991, 1997 onwards for all macrodiamond recoveries by De Beers
Hand-picking of tails from x-ray sorting; primarily 1999 onwards by De Beers facilities
Hand-picking of separated magnetic fraction; primarily 1999
onwards by De Beers facilities
Full independent audit of diamond recovery facilities and procedures utilized in South Africa and Alberta, Canada
during 2001 by MPH, an engineering firm located in South Africa
Inspection and monitoring of DMS and final diamond recovery facilities in South
Africa and Alberta, Canada by personnel of Kensington Resources Ltd. during processing of 2001, 2002, and 2004 samples. Independent audits of the De
Beers’ macrodiamond recovery facilities in Johannesburg, South Africa were completed during processing of samples from the 2002 and 2004 programs.
Microdiamond Recovery
A wide variety of microdiamond recovery facilities have been used over the course of the project since 1989. The primary verification for
microdiamond recovery is to monitor the stones for loss due to dissolution in the caustic medium and by running additional aliquots from the sample
interval. These measures were employed throughout the project.
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
The primary lab utilized for diamond recovery is the Saskatchewan Research Council located in Saskatoon, Saskatchewan (SRC). The SRC is fully
(ISO/IEC 17025) accredited by the Standards Council of Canada as a testing laboratory for diamonds and indicator minerals. They utilize caustic
fusion to produce a concentrate that is then subjected to several stages of beneficiation by different acids. The remaining concentrate is then
washed, sieved to standard size categories and submitted for hand-picking under a binocular microscope. A flow sheet showing this process is in
Figure 49.
Figure 49: Caustic Fusion Method for Recovery of Diamonds — Saskatchewan Research Council
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
Security
Security on-site during collection of samples was minimal during 1998 to 1999. Security protocols were implemented during 2000 and have been
expanded since to minimize any probability of diamond theft or salting. These measures typically involve restricting or minimizing access to the
shaker table during sample collection. In addition, security tags and visual inspections of bag security were standardized and documented in chain of
custody documents.
All diamond recovery was conducted in secure facilities with varying degrees of anti-theft or anti-contamination measures. Facilities located in
Canada that were utilized for the 1989, 1990, 1991, and 1996 programs had minimal to moderate levels of security. Diamond recoveries conducted by De
Beers invariably involved moderate to very high levels of security designed to minimize human contact with diamond-bearing concentrates and diamonds.
13.0 Data Verification
In the opinion of the Qualified Person, best efforts have been maintained to ensure the integrity and proper representation of the datasets and in
verification of the data. I have verified microdiamond and macrodiamond recovery data, although the scope and extent of this project has precluded
verification of all data from every year. Data from all areas was directly verified by the author to 2000.
Quality assessment and quality control of the diamond recovery procedures for microdiamond and macrodiamond recoveries were the responsibility of the
individual labs utilized, as described in Section 12. Monitoring of the QA and QC programs by the operator (De Beers Canada Inc., in particular),
field program management teams, and project managers was inherent in the news release process and vetting procedures developed within the FalC-JV. De
Beers utilizes standard protocols for data management and quality control. I have reviewed these protocols and cross-checked a broad selection of the
datasets to original data. There has not been any significant lapses in management of sampling, drilling, geochemical and assay data to date.
14.0 Adjacent Properties
No information is reported from work conducted on adjacent properties.
15.0 Mineral Processing and Metallurgical Testing
A preliminary Ore Dressing Study recently was completed, but due to the general nature of the study and lack of depth, is not considered material at
this time. A suite of pre-feasibility style engineering, geotechnical, and early metallurgical work has begun since the inception of the AE&E
program. These lines of investigation are described in the AE&E sections of the 2004 and 2005 descriptions of activities. Any work conducted in these
investigations is currently in progress and is not considered material at this time.
16.0 Mineral Resource and Mineral Reserve Estimates
Most of the kimberlite bodies identified on the FalC-JV property are considered as early to advanced exploration stage targets. Only kimberlite
140/141 is in the advanced exploration/evaluation stage and as such, it remains a diamond deposit until sufficient grid drilling and minibulk
sampling allows determination of a reasonable, low to medium confidence estimate of grade and average diamond value. Furthermore, grid drilling must
be completed on the body with sufficient coverage and density so that continuity of geology and diamond
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distribution patterns can be resolved with a reasonable amount of assurance. Additional drilling and sampling is required on 140/141 to acquire
sufficient geological representivity of the body and statistically significant quantities of diamond.
17.0 Other Relevant Data and Information
No other data and information is considered necessary at this time.
18.0 Interpretations and Conclusions
The following points represent the major conclusions from exploration and evaluation work conducted since 1989. The author considers the facts and
information contained herein to be accurate,, representative, and complete. In light of the status of this project – that there is no properly
defined Inferred Resource or better — most of the conclusions given below are factual in nature and there is a minimum of purely interpretative or
speculative opinions. Rather, the opinions of the author are embodied within the project and program recommendations that follow this section.
o
49 of the 69 tested (71%) bodies are diamondiferous (microdiamonds or macrodiamonds).
o
34 of the 69 (49%) kimberlites tested contain macrodiamonds. This frequency is exceptional compared to other kimberlite fields.
o
A total of 2,774 macrodiamonds (minimum size of 0.85 millimetres in one dimension) with a cumulative weight of 347.45 carats were recovered
during exploration programs conducted from 1989 to 2004; over 10,000 microdiamonds have been recovered from all kimberlites to mid 2005.
o
Kimberlite body grades based on macrodiamond recovery alone range up to 7.7 cpht; these values are considered to be significantly understated
due to the limited amount of minibulk sample from each body.
o
Grade estimates for individual bulk samples range up to 114.44 cpht; sample intervals range from 12 to 194 metres.
o
Grades forecasts for commercial size stones modeled by De Beers range up to 16 cpht based on size distributions of combined microdiamonds and
macrodiamonds. A total of 17 kimberlite bodies with sufficient diamond recoveries were prioritized in 2000. The best five of these bodies have
been the target of various stages of advanced exploration efforts during the last 5 years, and 17 bodies within the south central cluster are
currently under investigation in the first component of the AE&E program.
o
Ongoing acquisition of large minibulk samples from prioritized bodies permits preliminary revenue modeling and evaluation of the economic
potential of select Fort à la Corne diamondiferous kimberlites.
o
Modeled average macrodiamond values determined by De Beers for kimberlite ore from Kimberlite 122 range from $US 133 to 147 per carat; best fit
to optimistic modeled revenue values range from $US 11 to
18 per tonne. These grades, values, and revenue figures are based on recovery of approximately 23.3 carats from the 122 body to date.
o
Based on 2000 data only, modeled average macrodiamond values determined by De Beers for kimberlite ore from body 141 ranged from $US 148 to 179
per carat; best fit to optimistic modeled revenue values
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
range from $US 28 to 33 per tonne. Modeled stone values and projected revenue ranges for Kimberlites 122 and 141 have low confidence levels
because of low numbers of diamonds included in the evaluation.
o
The largest stone recovered to date is a high value, yellow, stone weighing 10.53 carats; another high value diamond weighs 3.34 carats and has
a value of $US 580/carat as determined by De Beers and
WWW International Diamond Consultants; other largest stones include stones weighing 10.23, 4.09, and 3.61 carats in size.
o
Interpretation of 2001 to 2002 data indicates that grades for specific parts of the 141 body are variable depending on diamond distribution and
continuity of lithological facies, and that a greater degree of testing is required to substantiate grade forecasts over the entire body, and to
permit higher levels of confidence in calculation of average of diamond value; evaluation of small parcels of commercial-size stones shows
preliminary indications (considered low confidence until larger parcels are evaluated) that the average value of diamonds from Kimberlite 140/141
range from $US 67 to 97 per carat and Modeled
Revenue figures range up to $US 14.65 per tonne depending on the phase (or type) of kimberlite. Further work is ongoing to delineate all
discrete kimberlite phases in this body and to model estimated stone distributions and revenue per tonne.
o
Kimberlite body areas range from 2.7 to 250 hectares, typically based on a 30 metre thickness cut-off.
o
The estimated mass of individual kimberlite bodies, based on geophysical modeling, ranges from 3 million to 675 million tonnes. The integration
of 140 and 141 indicates a combined mass of 500+ million tones as derived from GEMCOM modeling, based on core drilling in 2001 and 2002 with a
minimum thickness threshold of 50 metres.
o
Age of emplacement of the various kimberlites occurred within the interval from approximately 90-112 Ma, during Cretaceous time. The kimberlites
range from simple mono-eruptive bodies to multi-eruptive, multi-vent bodies characterized by complex stacking and interlayering of multi-temporal
kimberlite units.
Ongoing studies of larger bodies indicate discernible vertical and areal zonation of kimberlite units and diamond distribution.
o
Two of four high priority, potentially economic kimberlites (bodies 140/141, and 148,) are located within a two mile radius in the central
portion of the Fort à la Corne trend; the total macro-diamondiferous kimberlite mass in this same radius (12 bodies), is some 3.6 billion tonnes.
The other prioritized kimberlite, body 122, is located approximately 5 kilometres to the west.
o
The Fort à la Corne Kimberlite Field has the largest concentration of diamondiferous kimberlite in the world; the total modeled mass for the
entire field is estimated at upwards of 9 billion tonnes. Kimberlite
140/141, with an estimated mass of >500 million tonnes, is the largest macrodiamond-bearing kimberlite in the world. The main objective for
Kensington in this project is to delineate an economic diamond resource at Fort à la Corne using a methodical stepwise approach.
o
Fort à la Corne kimberlites are best categorized as very large tonnage, lower grade diamond deposits overall, but with zones of higher grade
potential.
o
Overall, the kimberlites remain insufficiently tested in consideration of their large size. Only three bodies have minibulk testing for
macrodiamonds to a level greater than 100 tonnes. Considerable effort and money was expended simply in order to reconnoiter the majority of
kimberlite bodies in this field. Since most of the minibulk sampling efforts in the past were directed to testing to some degree, each of the 69
targets, many of the larger bodies have very limited coverage in an areal sense. Furthermore, vertical zonation has not been adequately tested in
most of the existing drillholes due to large sampling intervals.
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
Due to the prevalence of the “nugget effect” in kimberlites, average macrodiamond grades are expected to closely approach forecasted grade
levels as sample tonnage increases.
o
Evaluation work continues on Kimberlites 140/141, 122, and other high interest bodies in order to better understand the location, extent and,
continuity of high grade zones, to determine an understanding of diamond distribution and diamond grade for mineable resources, to upgrade
confidence in determination of the average value of diamonds (in $/carat) and, to determine the economic value of the body as represented by
potential revenue calculations for a diamond deposit given as an in-situ diamond value in $ per tonne (as per Canadian Institute of Mining CIM
recommendations) compared to best initial estimates of capital and operating expenses.
o
The current components of drilling and sampling within the AE&E Plan involves core drilling programs on the main part of the bodies to increase
the understanding of the geology (geometry and architecture) of the body and to identify higher potential zones. Higher grade zones are then
delineated in order to calculate a potentially mineable tonnage. This is then followed by identifying a subset of coreholes that are suitable
targets for minibulk sampling in order to test diamond distribution and to provide a representative sample of kimberlites from all prospective
phases and across the vertical and areal extent of the kimberlite bodies. A final inventory of some 100 to 300 carats will enable determination of
a high confidence grade forecast and a moderate level of confidence in the average value of commercial sized stones. The bulk sample information
coupled with the grid drilling and sampling information should be adequate for at least a determination of inferred resource over a significant
part of the bodies. All lines of investigation from the AE&E will then be integrated and evaluated in order to prioritize the potentially economic
targets and to reach a decision as to whether or not to proceed with a full pre-feasibility study as the next phase of work.
o
Additional work is required to satisfy two main goals for each of the priority kimberlite bodies. The AE&E encompasses a planned 43 months
schedule of work to advance the project to a major decision on pre-feasibility stage work. The plan is results driven and incorporates a
methodical, step-wise, 4-component approach in the evaluation of 17 candidate kimberlite bodies for higher-grade units that have potential to be
economically mined. The overall goal of the plan is to identify at least 70 million carats of commercial-sized stones in-ground in order to reach
a critical decision based on delineation of Inferred Resources on several kimberlite bodies by 2008. The AE&E plan identified firm objectives and
schedules to reach this goal.
o
The main objective for Kensington in this project is to delineate an economic diamond resource at Fort à la Corne using a methodical stepwise
approach.
19.0 Recommendations
On the basis of the information herein and the experience and expertise of the author, the following recommendations for the Fort à la Corne Diamond
Project are made to the owners and management of Kensington Resources Ltd.:
o
The Fort à la Corne Diamond Field has shown strong, incontrovertible evidence supporting the presence of kimberlite bodies hosting potentially
economic diamond mineralization. Furthermore, prospective kimberlites are characterized by high average diamond values, very large tonnages, and
the presence of coarse diamond populations. The information to date definitely indicates the need for substantial exploration and evaluation work
to delineate the extent, magnitude of tonnage, grade, value, and mining potential of prospective kimberlite bodies and zones in the south-central
part of the main kimberlite trend.
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Technical Report For the Fort à la Corne Diamond Project – November 09, 2005
o
The FalC Diamond Project should proceed according to the AE&E Plan as outlined in this report (and other more specific documents detailing the
plan), but with the following modifications:
o
The time line for the plan should be accelerated wherever possible, while maintaining the integrity of the data and information
collection, to define an Inferred Resource on the property and to reach a decision point for pre-feasibility stage activities.
Acceleration of the program could come about by increasing the magnitude of field operations and work force engaged in core
description, sampling, assay, and data management. Acceleration also could come about by significantly overlapping the four
components of field activities (core drilling and mini-bulk sampling) and not relying on an inflexible step-wise approach that
relies on completion of each component before starting the next. The current situation at FalC is amenable to this because several
high-priority kimberlite bodies are at more advanced stages of evaluation and that the plan is operated on a “best bodies first”
basis.
o
Bulk Sampling should be added to the AE&E Plan as part of the continuum of evaluation required take prospective bodies or high
grade zones to a Feasibility-stage decision. Similarly to the point made above, suitably propective bodies could be advanced to
bulk sampling while core drilling and mini-bulk sampling are underway on neighbouring bodies.
o
The postulated total FalC-JV budget of CND $91,347,436 for the AE&E program activities as defined by De Beers, the project operator, for the
time period from February 2005 through the second quarter of 2008 should be accepted as a reasonable expenditure dedicated to defining a NI 43-101
compliant Inferred Resource at Fort à la Corne. Kensington’s share of this expenditure would be CND $46,792,758 (46.94% funding interest).
Dated and Sealed at Saskatoon, Saskatchewan this 9th day of November, 2005.
PROFESSIONAL SEAL
/s/
Brent C. Jellicoe
Brent C. Jellicoe, B.Sc. P.Geo.
Qualified Person
Kensington Resources Ltd.,
A wholly-owned subsidiary of Shore Gold Inc.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Ashton, K.E., Hartlaub, R.P. and Lewry J.F., 1997: The Case for a Flin-Flon-Glennie
Protocontinent; in LITHOPROBE Trans-Hudson Orogen Transect, Report No. 62, University of
Saskatchewan, p. 1-5.
Avery, R., 1995: Fort à la Corne Project 71-47, 1995 Annual Assessment Report, submitted to
Saskatchewan Energy and Mines, 47 pp.
Banerjee, I., Ghosh, S.K., Abercrombie, H.J. and Davies, E.H., 1994: An integrated subsurface
study of the Mannville-Colorado group boundary in the Cessford Field, Alberta; Canadian Journal of
Earth Science. 31, 1994, p. 489-504.
Bank, C.-G., Ellis, R.M., Bostock, M.G., Hajnal, Z. and VanDecar, J.C., 1997: Lithospheric Mantle
Structure Beneath the Trans-Hudson Orogen from Teleseismic Travel-Time Inversion; in LITHOPROBE
Trans-Hudson Orogen Transect, Report No. 62, University of Saskatchewan, p. 6-9.
Berryman, A.K., 2000: Fort à la Corne Project Seasonal Exploration Report, Summer 2000;
confidential report prepared by De Beers Canada Inc. for the Fort à la Corne Diamond Project Joint
Venture Partners.
Berryman, A.K., Ellemers, K., Rihkotso, C., Muir, A. and Boyce, S., 2001: Fort à la Corne Project
Seasonal Exploration Report, Summer 2001; confidential report prepared by De Beers Canada Inc. for
the Fort à la Corne Diamond Project Joint Venture Partners.
Bloch, J., Schroder-Adams, C., Leckie, D.A., McIntyre, J., Craig, J. and Staniland, M., 1993:
Revised stratigraphy of the lower Colorado Group (Albian to Turonian), Western Canada; Bulletin of
Canadian Petroleum Geology, Vol. 41, No. 3 (September 1993), p. 325-348.
Chiarenzelli, J.R., Aspler, L.B. and Villeneuve, M., 1996: Characterization, Origin, and
Paleaproterozoic History of the Saskatchewan Craton and Possible Implications for Trans-Hudson
Orogen; in LITHOPROBE Trans-Hudson Orogen Transect, Report of Sixth Transect Meeting, Report No.
55, University of Saskatchewan, p. 26-38.
Christiansen, E.A. and Sauer, E.K., 1993: Red Deer Hill: a drumlinized, glaciotectonic feature
near Prince Albert, Saskatchewan, Canada; Canadian Journal of Earth Sciences, vol. 30, p.
1224-1235.
Collerson, K.D., Lewry, J.F., Van Schmus, R.W. and Bickford, M.E., 1989: Sm-Nd constraints on the
age of the basement in central and southern Saskatchewan: Implications for diamond exploration; in
Summary of Investigations 1989, Saskatchewan Geological Survey, Miscellaneous Report 89-4, p.
168-171.
Dufresne, M.B., Olson, R.A., Schmitt, D.R., McKinstry, B., Eccles, D.R., Fenton, M.M., Pawlowicz,
J.G., Edwards, W.A.D. and Richardson R.J.H., 1994a: The diamond potential of Alberta: A regional
synthesis of the structural and stratigraphic setting, and other preliminary indications of diamond
potential, Alberta Research Council Open File Report, 1994-10, 349 pp.
Gendzwill, D.J., and Matieshin, S.D., 1996: Seismic Reflection Survey of a kimberlite intrusion in
the Fort à la Corne District, Saskatchewan; in Searching for Diamonds in Canada, Geological Survey
of Canada Open File 3228, p. 251-254.
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Gerryts, E., 1970: Diamond prospecting by geophysical methods — a review of current practice; in
Mining and Groundwater Geophysics, Geological Survey of Canada, pp 439-446.
Green, A.J., Weber, W. and Hajnal, Z., 1985: Evolution of Proterozoic terrains beneath the
Williston Basin; Geology, vol. 13, p. 624-628.
Griffin, W.L., and Ryan, C.G., 1994: Trace Elements in Indicator Minerals: Area Selection and
Target Evaluation in Diamond Exploration; in: Diamond Exploration: Into the 21st
Century, Special Vol. Journal of Geochemical Exploration, 25 pages, 17 figures.
Gurney, J.J., Helmstaedt, H. and Moore, R.O., 1993: A review of the use and application of mantle
mineral geochemistry in diamond exploration; Pure and Applied Chemistry, vol. 65, no. 12, p.
2423-2442.
Jellicoe, B.C.., 1998: Fort à la Corne Project 71-47, 1998 Annual Exploration Report, confidential
report prepared for Monopros Limited, 23 pp.
Jellicoe, B.C. and Berryman, A.K., 1999: Fort à la Corne Project 71-47, 1999 Annual Exploration
Report, confidential report prepared for Monopros Limited, 23 pp.
Jellicoe, B.C., Kyser, T.K. and Caldwell, W.G.E., 1991: Environmental Reconstruction of the
Niobrara Marine Cyclothem in southeastern Saskatchewan; Joint Annual Meeting of the Geol. Assoc.
Canada/ Mineral. Assoc. Canada, May 27-29, 1991, Toronto, Ontario. [Abstr.]
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submitted to Saskatchewan Energy and Mines, 69 pp.
Jellicoe, B.C. and Bell, G., 1997b: Fort à la Corne Project 71-47, 1997 Annual Assessment Report,
submitted to Saskatchewan Energy and Mines, 39 pp.
Jellicoe, B.C., Robertshaw, P., Williamson, P. and Murphy, J., 1998: Summary of Exploration
Activities and Results for the Fort à la Corne Diamond Project, Saskatchewan; in Summary of
Investigations 1998, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 98-4, p.
144-157.
Kauffman, E.G., and Caldwell, W.G.E., 1993: The Western Interior Basin in space and time; in
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Association of Canada, Special Paper 39, p. 1-30.
Kjarsgaard, B.A., 1995: Research on Kimberlites and Applications of Diamond Exploration Techniques
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Geological Survey of Canada under the Geoscience Program of the Canada-Saskatchewan Partnership
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Open File 3119/Saskatchewan Geological Survey Open File 95-3, p. 213-226.
Leckie, D.A., Kjarsgaard, B.A., Bloch, J., McIntyre, D., McNeil, D., Stasiuk, L. and Heaman, L.,
1997: Emplacement and reworking of Cretaceous, diamond-bearing, crater facies kimberlite of
central Saskatchewan, Canada; GSA Bulletin, vol. 109, no.8, p.1000-1020.
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Mineral Development (1990-1995), (ed.) D.G. Richardson, Geological Survey of Canada Open File 3119
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Statement of Certification by Qualified Person
I, Brent C. Jellicoe of the city of Saskatoon, in the province of Saskatchewan do certify the
following:
o
At present, I am employed by Kensington Resources Ltd., a wholly-owned
subsidiary of Shore Gold Inc., as a Project Manager and Geologist.
This employment started on September 19, 2004.
o
I am a consulting geologist and principal of Jellicoe Resource
Associates with an office located in Suite 220 – 728 Spadina Crescent
East, Saskatoon, Saskatchewan, Canada S7K 4H7 Currently this company
is inactive while I am employed by Kensington Resources Ltd.,
o
I am a member in good standing of the Association of Professional
Engineers and Geoscientists of Saskatchewan registered as
“Professional Geoscientist” number 10319.
o
I have practiced my profession since 1992.
o
I practiced as a Geological Consultant primarily for diamond
exploration projects from December 1998 until September 2004.
o
I am a graduate of the Faculty of Arts and Science at the University
of Saskatchewan and earned a Bachelor of Science (Honours) Degree in
Geology in 1987. This was followed by five years of post-graduate
work in the College of Graduate Studies concerned with a variety of
geological and geochemical investigations of strata deposited within
the Cretaceous Western Canada Sedimentary Basin located within
Manitoba, Saskatchewan, and Alberta.
o
I am a member of the Saskatoon Section of the Canadian Institute of
Mining (CIM), a constituent society of the Canadian Institute of
Mining, Metallurgy, and Petroleum.
o
I have been involved with all aspects of diamond exploration and
drilling/sampling project management in the Fort à la Corne area of
Saskatchewan, since 1992. This experience is summarized in the
following:
o
I worked as a contract geologist for North Rim Exploration Ltd. from
December 1992 to October 1993 and was tasked with logging and interpretation of
Cretaceous bedrock and kimberlite drillcore from a 15-hole program in, and proximal
to, the Fort à la Corne kimberlite Field.
o
I was employed as a long-term, contract geologist by Rhonda Mining
Corporation as a drillsite geologist (1993-1994) and then Kensington Resources Ltd.
(1994 to 1997) as a senior geologist and field program manager for reverse
circulation, reverse circulation — underream, and rotary drillhole programs
conducted by the Fort à la Corne Joint Venture in Saskatchewan. I also logged all
kimberlite chip samples, prepared sampling strategies, evaluated results for heavy
mineral abundance/indicator mineral chemistry studies and diamond results, and
wrote all reports for the exploration programs conducted during 1995 and 1996. In
addition, I investigated bedrock stratigraphic relationships in conjunction with
intra-body correlation of Fort à la Corne kimberlites towards delineation of
zonation and continuity of petrographic character and diamond content. Also,
during employment with
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
Kensington, I was a team member involved in summarizing the known and potential
diamond and copper-gold resources of selected areas of Shandong Province, China.
o
I was employed as a Project Geologist by Uranerz Exploration and Mining
Limited from 1997 to November 1998 (including a three month extension of employment
during acquisition of Uranerz by Cameco) and continued managing drilling/sampling
programs and with reporting responsibilities for the Fort à la Corne Joint Venture
diamond project.
o
From December 1998 to October 1999, I was Project Geologist under
contract with De Beers Canada Inc. and acting in a similar capacity as at Uranerz,
again for the Fort à la Corne Joint Venture. Along with reporting
responsibilities, an internal study outlining new models for the geometry,
architecture, and emplacement of Fort à la Corne kimberlites was completed. During
this time period, I spent a two-week term as shift supervisor for geologists at the
Kennady Lake Diamond Project in the NWT. In addition, I was contracted as a
drilling specialist responsible for drilling optimization and data acquisition for
a large diameter ODEX (hammer) and reverse circulation (RC) waterflood drillhole
program at the Lomonosov Diamond Project in Russia. In this program, I supervised
drilling and sampling procedures as well as continued database management and
processing of data from: digital drilling parameter recorder, volume and mass
calculations from caliper logs, and drilling chip geology. This contract
culminated in a suite of detailed drillhole resumes and an extensive final Drilling
and Sampling report.
o
From December 1999 to Sept 2004, I acted as the Project Manager and
Chief Geologist for Kensington Resources Ltd. as a consultant. From September 2004
until October 28, 2005, I was employed as the Exploration Manager for Kensington
Resources Ltd. My primary responsibilities included:
o
review of all technical information and results from the operator
of the Fort à la Corne Joint Venture (De Beers Canada Inc.)
o
petrographic description and interpretation of all core and
drillhole intersections
o
composing all technical news releases for Kensington; including
reporting of Joint Venture project results
o
observation of field program activities for Kensington
o
observation and informal audit of diamond recovery procedures
o
creation and composition of all technical presentations, public
talks, and internal summaries for Kensington
o
oral and graphic presentation of all public, scientific, and
investor talks
o
I have acted as the onsite Drilling Manager for the Fort à la Corne
Joint Venture field programs during 2000, 2001, 2002, and 2004 reporting primarily
to the operator (De Beers Canada Inc.). Duties for this position includes day to
day oversight of the drilling operations with optimization of product quality (core
and reverse-circulation chips), compliance with sampling procedures, liaison with
the drilling supervisors, and supervision of other onsite contractors.
o
During 2000, 2001, 2002, 2003, 2004, and 2005 I completed extended
monitoring visits to dense media separation and final diamond recovery facilities
operated by De Beers both in Canada and South Africa.. I visited the Lakefield
diamond recovery facility in 2001 and
2002 to conduct due diligence on their procedures and security measures. In 2003 and
2004,
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
I visited the SRC diamond recovery facility in Saskatoon to conduct due
diligence on their procedures and security measures. In all cases, lab and site
visit were conducted while samples from Forte à la Corne were in some stage of
diamond recovery.
o
I have consulted for drilling projects mounted by Skeena Resources and
Shore Gold Inc. as Project Manager/Geologist in the Fort à la Corne area during
2000, 2001, and 2002. Responsibilities have included assessment report writing,
core-logging, and project management.
o
I have authored diamond exploration program reports for Uranerz
Exploration and Mining (now UEM Inc. a subsidiary of Cameco Corp.), De Beers Canada
Inc. and Kensington Resources Ltd. I have also authored numerous in-house studies
on the status of exploration as well as detailed kimberlite studies for the
companies listed above. Also, I have prepared detailed kimberlite petrography and
logging reports for the companies listed. The sum objective of these studies and
programs was to elucidate the character of kimberlites in Saskatchewan and to
determine the resource potential of the diamondiferous kimberlites. I continue to
undertake independent and contracted studies on kimberlites in Saskatchewan for
Saskatchewan Industry and Resources (Diamonds in Saskatchewan 2002) and for several
of the companies listed above.
o
I have been lead author in diamond exploration-related scientific
papers for the Saskatchewan Geological Survey (1998 Summary of Investigations) and
a CIM volume on Industrial Minerals In Canada (2002).
o
I was third author for a peer-reviewed scientific paper published in
the Proceedings of the Eighth International Kimberlite Conference (2004). The
paper was written on the geology and diamond recovery of the 140/141 Kimberlite
Body of the Forte à la Corne Diamond Field.
o
I have provided numerous free information sessions to the general
public in the form of digital slide presentations that summarize current diamond
exploration and historical results in the province of Saskatchewan. These
presentations contained a very subordinate element of promotion for the diamond
exploration efforts of Kensington Resources Ltd..
o
As a result of my experience and qualifications, I am a Qualified Person as defined in National Instrument 43-101.
o
As a matter of record, I do hold shares and option for warrants, as well as stock options in Kensington Resources Ltd.
o
Opinions and geological interpretations expressed herein are based on the information provided and on my general experience
and expertise. These opinions are offered up as further information for the consideration of the general public and are subject to
change as new data is acquired and digested.
o
I am not aware of any material fact or material change with respect to the subject matter of this technical report, which is
not reflected in this report, the omission to disclose that would make this report misleading in any way.
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Technical Report For the Fort à la Corne Diamond Project — November 09, 2005
o
I have read National Instrument 43-101 and Form 43-101 F1. In addition, I have completed a two-day seminar focused on
reviewing and discussing these regulations that was prepared by The National Conference Board of Canada during December of 2002. I
have also attended two single day seminars sponsored by B.C. Securities during 2003 and 2004. This report has been prepared in
compliance with these documents to the best of the author’s understanding.
Dated and Sealed at Saskatoon, Saskatchewan this 9th day of November, 2005.
PROFESSIONAL SEAL
/s/
Brent C. Jellicoe
Brent C. Jellicoe, B.Sc. P.Geo.
188
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has
duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.