Low grade but if the diamond valautions are high, it can be a profitable mine........frank
STAR DIAMOND PROJECT: OVER 2,100 CARATS TO DATE - 19.7, 11.6 AND 8.1 CARAT DIAMONDS IN 309 CARAT PARCEL
Shore Gold Inc. has received the ninth set of diamond recoveries from the Star kimberlite. The diamond recoveries to date total 2,120.68 carats from 16,206.88 dry tonnes processed. These results are for seven kimberlite batches of a total of about 80 to 100 kimberlite batches that will be processed as part of the bulk sampling program on the Star diamond project, the aim of which is to recover a parcel of about 3,000 carats for valuation purposes. A total of 2,162 commercial-sized diamonds (greater than 1.18-millimetre square mesh screen), collectively weighing 304.52 carats, has been recovered from the treatment of 1,630.94 dry tonnes of kimberlite. Forty-two diamonds greater than one carat have been recovered and the four largest stones are: 19.68, 11.57, 8.07 and 5.31 carats, respectively. In addition, 292 diamonds (4.43 carats) were recovered down to a 0.85-millimetre square mesh. The colour of 73 per cent of these diamonds has been classified as white, with a further 11 percent classified as off-white.
These seven kimberlite batches (of a total of 50 processed) have been mined from the southeast drive (batches 35A, 35B, 36, 37, 38A and 38B) and the North drive (batch 40) developed from the 235-metre shaft station. All of these kimberlite batches have been recovered from within the early Joli Fou equivalent kimberlite. Results to date have shown that higher diamond grades are associated with the early Joli Fou equivalent kimberlite than with the late Joli Fou equivalent kimberlite. The relationships between these two kimberlites types are illustrated in cross sections available on the Shore Gold website: www.shoregold.com.
Batches 39, 41, 42A, 42B, 43, 44, 45A and 45B (all from 235-metre level) have been processed on-site and the concentrates dispatched to the sorting laboratory for final diamond recovery. Results from these batches are pending. A total of 18,600 dry tonnes has been processed through the on-site DMS plant. All batches processed to date are classified as crater facies volcaniclastic kimberlites.
Kimberlite processed and diamond results for seven sample batches are listed in the table below. Grades are expressed in carats per hundred tonnes (cpht).
Diamonds Largest
Dry No. of Total Grade stone
tonnes stones (carats) (cpht) (carats)
Location 235 metres below surface,
level: SE drive
Batch No. 35A
193.81 282 20.20 0.42 1.22
Batch No. 35B
205.07 319 45.02 21.96 11.57
Batch No. 36
239.21 353 56.50 23.62 5.31
Batch No. 37
254.85 568 53.35 20.94 3.87
Batch No. 38A
185.83 211 38.92 20.94 8.07
Batch No. 38B
264.56 383 48.69 18.40 4.77
Location 235 metres below surface,
level: N drive
Batch No. 40
287.61 338 46.27 16.09 19.68
------- ----- ------ ------
Total
1,630.94 2,454 308.95 18.94
The four largest stones are: 19.68 (batch 40, off-white), 11.57 (batch 35B, grey), 8.07 (batch 38A, off-white) and 5.31 (batch 36, brown) carats, respectively. Seventeen diamonds exceed two carats and 42 diamonds exceed one carat, of which 22 are white, 10 are off-white, nine are grey and one is brown. A total of 94 diamonds exceeds 0.5 carat. Seventy-three per cent of the total diamond parcel is classified white in colour, with a further 11 per cent classified as off-white. The diamond parcel includes 11 pink, 23 yellow and 14 amber stones. Ninety-nine per cent of the carat weight of this parcel occurs in diamonds greater than 1.18-millimetre square mesh.
Senior vice-president exploration, George Read, states: "To date, kimberlite bulk sample processing has produced a 2,120-carat diamond parcel. The diamond parcel contains a significant proportion of large stones and an abundance of white diamonds, which will contribute favourably to the average value ultimately determined for the bulk sample diamond parcel. Among the most recent batches processed we have recovered two stones of particularly high value: 1) the 19.68-carat off-white, fragment of a considerably larger stone, recovered from batch 40. The fresh breakage surface suggests that this stone was broken during underground mining activities; and 2) the 4.77-carat white, flawless octahedron recovered from batch 38B. These stones confirm the presence of large, high-value diamonds in the Star kimberlite. Photographs of these two diamonds will be available this week on the Shore Gold website: www.shoregold.com."
The diamond recovery procedure includes on-site processing of kimberlite through the modular dense media separator (DMS), after which DMS concentrates are batch fed through an X-ray flow-sort. In order to ensure the recovery of low-luminosity diamonds, the flow-sort tailings are processed over a grease table. Flow-sort and grease table concentrates are transported by a secure carrier to SGS Lakefield Research for final diamond recovery. The SGS Lakefield Research process includes drying, screening, magnetic separation, manual sorting, and diamond weighing and description. SGS Lakefield Research is accredited to the ISO/IEC 17025 standard by the Standards Council of Canada as a testing laboratory for specific tests.
Senior vice-president exploration, George Read, professional geoscientist in the provinces of Saskatchewan and British Columbia, is the qualified person responsible for the verification and quality assurance of analytical results.
The Star diamond project is designed to recover a parcel of at least 3,000 carats of diamonds to enable an accurate valuation of the stones. Up to 25,000 tonnes of kimberlite will be recovered from the shaft and drifts and processed on-site to produce this diamond parcel. |
