Snap Lake Tonnage Estimates by MRDI Canada
Winspear Resources Ltd. (WSP.V) is pleased to report on tonnage estimates made by MRDI Canada, a Division of H.A. Simons Ltd., on the NW dyke, Snap Lake area, Camsell Lake property. This property, situated approximately 140 miles northeast of Yellowknife, NWT, is operated by Winspear on behalf of the Camsell Lake joint venture.
MRDI Canada has reported interim tonnage estimates based on all available drilling that has been undertaken on the NW dyke. This includes all holes completed in the 1999 spring drilling program as well as those drilled into the dyke during 1997 and 1998 programs. These tonnage estimates have also been calculated and reported below for those areas within which the kimberlite dyke exceeds 1 and 2 metres in thickness.
NW Dyke – In Situ Global Tonnage Estimates
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Within Geological Model Limits
"Global Tonnage" Estimate
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Total >1 M >2 M
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Total Tonnes (000's) 23,400 23,200 19,200
Average vertical thickness (m) 2.44 2.76 3.00
Number of drill hole intersections 180 175 163
Macrocrystic Kimberlite, tonnes (000's) 20,600 20,400 16,800
Average vertical thickness (m) 2.15 2.41 2.61
Number of drill hole intersections 180 175 163
Kimberlite Breccia, tonnes (000's) 1,300 1,300 1,200
Average vertical thickness (m) 0.49 0.16 0.18
Number of drill hole intersections 22 22 19
Internal Waste tonnes (000's) 1,500 1,500 1,200
Average vertical thickness (m) 0.39 0.19 0.20
Number of drill hole intersections 41 41 34
Macrocrystic kimberlite + kimberlite breccia,
Total tonnes (000's) 21,900 21,600 18,000
Average vertical thickness 2.28 2.57 2.80
Number of drill hole intersections 180 175 163
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Several aspects of these estimates are as follows:
True thickness is estimated to be at least 90% of vertical thickness as reported above over large areas of the dyke. Substitution of true for apparent thickness will not have a significant impact on tonnage calculations.
The relatively uniform thickness of the dyke is emphasized by the large percentages of total tonnage that are contained within the 1 and 2 metre thickness contours.
Kimberlite has been subdivided into macrocrystic (hypabyssal) kimberlite and kimberlite breccia. The latter is defined as kimberlite containing > 15% fragments of country rock more than 4 mm in diameter. Although these fragments will serve to dilute the overall diamond grade relative to inclusion-free kimberlite, relative volumes as indicated above suggests the overall impact on grade of the NW dyke will be low.
MRDI Canada has also calculated that a portion of the global tonnage estimate occurs in contiguous blocks and with sufficient confidence that it can be used for feasibility study purposes to estimate the recoverable kimberlite tonnage on the NW dyke. Results of these calculations are reported below.
NW dyke – In Situ Tonnage estimates within 90% Confidence Interval +/- 15%
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Within 90% Confidence Interval +/- 15%
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Total >1 M >2 M
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Total Tonnes (000's) 9,600 9,600 8,800
Average vertical thickness (m) 2.81 2.81 3.00
Number or drill hole intersections 140 140 132
Macrocrystic Kimberlite, tonnes (000's) 7,700 7,700 7,000
Average vertical thickness (m) 2.27 2.41 2.48
Number of drill hole intersections 140 140 132
Kimberlite Breccia, tonnes (000's) 800 800 800
Average vertical thickness (m) 0.50 0.29 0.31
Number of drill hole intersections 18 18 18
Internal Waste tonnes (000's) 1,100 1,100 1,000
Average vertical thickness (m) 0.40 0.34 0.34
Number of drill hole intersections 34 34 33
Macrocrystic kimberlite + kimberlite breccia,
Total tonnes (000's) 8,500 8,500 7,800
Average vertical thickness (m) 2.51 2.69 2.79
Number of drill hole intersections 140 140 132
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Several aspects of these estimates are as follows:
The 8.7 million tonnes of macrocrystic kimberlite and kimberlite breccia reported in the above table has been defined with sufficient confidence that the actual tonnage achieved will not be expected to vary by more than 15%, 9 times out of ten.
While these tonnage estimates have been defined to levels acceptable for feasibility study purposes, it is important to note that they refer only to in situ kimberlite. The next step will be to superimpose grade estimates on these figures throughout the NW dyke. Grade estimates are presently being calculated from microdiamond results that have been obtained from drill hole intersections of kimberlite.
Mining methods are being investigated that would allow for effectively 100% extraction of kimberlite that meets feasibility standard criteria. These methods will likely involve filling mined out areas with cemented paste backfill to allow for extraction of intervening areas of kimberlite.
The relative predictability of thickness and continuity of the NW dyke suggests that with a limited amount of in-fill drilling, a significant portion of tonnage as calculated within the limits of the geological model can be converted to tonnage within the confidence interval used in the above table.
The accompanying map shows the extent of the area drilled and the drill density over the NW dyke to date. The drill holes used in this compilation include intersections obtained on the NW dyke during the 1997, 1998 and 1999 programs. The 1999 spring drill program is now finished with a total of 103 holes (20,083 metres) being completed. The table included with the map lists the number of intersections obtained in each of the 400 x 400 metre blocks that define the area tested together with the average thickness of the dyke in each of the blocks.
Most of the holes drilled during the 1999 spring program were completed on the NW dyke as depicted on the accompanying map. Of the 103 holes drilled during this program, 71 were drilled as exploration holes on the NW dyke, 21 holes were drilled to define the limits of Pits 3 and 4, four geotechnical holes were drilled on the NW peninsula, and 7 holes were drilled to test the down-dip extent of the three kimberlite dykes identified on the SE arm of Snap Lake during the 1998 spring drilling program. Some of the areas in the SE arm appear promising with intersections to 2.24 metres being encountered. Additional drilling is required in this area to further test its economic potential.
Some comments on results of the drilling program are as follows:
The NW dyke continues to demonstrate characteristics of a continuous sheet comprising a single mantle phase of kimberlite that is dominated by macrocrystic hypabyssal material. Local areas occur within the NW dyke where a relative abundance of country rock fragments define the material as kimberlite breccia. As indicated in the accompanying table, this variety of kimberlite is uncommon, is generally thin, and normally occurs with thicker sections of macrocrystic kimberlite.
Included locally within this kimberlite is material defined as internal waste. This refers to host rock material greater than 10 cm thick that occurs within the kimberlite intersection. This host rock material has been treated as internal waste in the tonnage calculations reported above. Re-evaluation of this definition may result in some of this material being re-classified as xenoliths.
The tonnage reported above includes approximately 667,000 tonnes of kimberlite on the NW peninsula that MRDI Canada has previously determined could be mined by open pit techniques.
Drilling to date indicates that the NW dyke remains open and thickens to the north and east but becomes thinner to the south and southeast.
All drill results obtained from the NW dyke are subject to on-going evaluation. Upon completion of the microdiamond analyses from drill intersections obtained during the 1999 program, grade estimates will be made over that portion of the NW dyke that is included within the present area covered by the geological model. This information will then be incorporated into a feasibility study of the NW dyke to establish its economic potential.
Winspear remains highly encouraged by results obtained to date from the 1999 program on the NW dyke. Work will continue on the property and will include a range of geotechnical, environmental, and engineering studies designed to advance the Snap Lake project to a detailed evaluation of its economic feasibility.
Winspear Resources Ltd.
Randy.C. Turner, P.Geo.
President and Director
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