NEWSStar Diamond Project: Diamond results 7.1, 6.0 and 5.0 carat diamonds in 344 carat parcel
15:24 EST Wednesday, November 02, 2005
SASKATOON, Nov. 2 /CNW/ - George H. Read, P. Geo., Senior Vice President Exploration, is pleased to announce the second set of diamond results from the additional 15,000 tonne bulk sample collected from the Star Kimberlite as part of the prefeasibility study. The aim of this additional bulk sample is to increase the size of the diamond valuation parcel from 4,000 to 6,000 carats. The diamond recoveries total 343.96 carats from 1,895.50 dry tonnes processed. Included in this release are results for ten kimberlite batches of a total of some 50 kimberlite batches that will be processed as part of the additional bulk sampling program on the Star Diamond Project. A total of 2,289 commercial sized diamonds (greater than 1.18 millimetre square mesh screen), collectively weighing 342.78 carats, has been recovered from the ten batches. Forty-nine diamonds greater than one carat have been recovered and the four largest stones are: 7.06, 5.97, 4.99 and 4.90 carats, respectively. In addition, 66 diamonds (1.18 carats) were recovered down to 0.85 millimetre square mesh. The colour of 60 percent of these diamonds has been classified as white, with a further 12 percent classified as off-white.
All of these kimberlite batches have been mined on the 235 metre level from drifts developed south of the shaft. All kimberlite batches have been recovered from within the Early Joli Fou equivalent kimberlite. The contrasting grades of Batches 97 (9.75 cpht) and 98 (23.28) illustrate the spurious numbers that can result from small (less than 200 tonne) samples from kimberlites with significantly different textures. Batch 97 is a very coarse breccia and the 55.99 tonne is not representative, while Batch 98 is an olivine macrocrystic kimberlite and this 45.55 tonne sample is probably representative of grade. To date, some 15,000 tonnes of kimberlite have been skipped to surface and over 7,500 tonnes have been processed through the on- site plant. The X-ray Flow-sort and grease table concentrates of Batches 103 to 109 (inclusive) have been shipped to SGS Lakefield Research for final diamond recovery.
Kimberlite processed and diamond results for the ten sample batches are listed in the table below. Grades are expressed in carats per hundred tonnes (cpht).
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Batch Location Dry Diamonds Total Grade Largest
No. Tonnes Number of (carats) (cpht) Stone
Stones (carats)
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93 SOUTH 12 Raise 1 202.88 325 42.42 20.91 7.06
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94 SOUTH 13B 319.40 376 56.61 17.72 2.59
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95 SOUTH 12 Raise 2 79.29 133 14.93 18.82 2.78
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96 SOUTH 11B 321.81 341 58.34 18.13 4.90
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97 SOUTH 11C 55.99 26 5.46 9.75 4.14
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98 SOUTH 14 END SLASH 45.55 62 10.61 23.28 1.89
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99 SOUTH 4I 221.58 229 33.68 15.20 5.97
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100 SOUTH 8G 231.08 265 43.14 18.67 4.04
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101 SOUTH 7D 240.19 300 43.90 18.28 4.99
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102 SOUTH 15C 177.72 298 34.88 19.63 2.52
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Total 1,895.50 2,355 343.96 18.15
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The four largest stones are: 7.06 (Batch 93, Grey), 5.97 (Batch 99, Grey), 4.99 (Batch 101, Brown) and 4.90 (Batch 96, White) carats, respectively. Seventeen diamonds exceed two carats and 49 diamonds exceed one carat, of which 20 are white, 7 are off-white, 15 are grey and 5 are brown. A total of 132 diamonds exceed 0.5 carat. Sixty percent of this diamond parcel is classified white in colour, with a further 12 percent classified as off- white. The diamond parcel includes 4 yellow, 2 pink and 3 amber stones. Ninety-nine percent of the carat weight of this parcel occurs in diamonds greater than 1.18 millimetre square mesh.
Senior Vice President Exploration, George Read, states: "The recovery of the additional 15,000 tonnes of kimberlite from the Star underground workings is nearing completion. These results increase our total diamond recoveries to 4,923.82 carats and 41,309 stones from 33,652.87 dry tonnes. The Star prefeasibility study is proceeding on schedule and Shore geologists and contractors are compiling new data from drilling and underground bulk sampling. Preliminary results of the prefeasibility study are most encouraging, particularly the intersection of the Cantuar feeder vent, which significantly increases the Star kimberlite volume."