A 3.26-carat stone, described as a grey-coloured, translucent composite, was recently pulled from a 6-tonne mini-bulk sample of the Renard 9 kimberlite. In total, 5.56 carats of diamonds exceeding a 1.18-mm cutoff were recovered from the sample, the average grade being 0.92 carat per tonne. (If the 3.26-carat stone is excluded, the sample grade falls to 0.38 carat per tonne.) The second-biggest stone in the parcel is a clear, pale-brown irregular weighing 0.68 carat.
Renard 9, discovered early in 2003, had shown potential for large stones based on the initial microdiamond results from the discovery holes. A 212-kg sample of kimberlitic material from three drill holes had returned an impressive 178 microdiamonds. The largest stone was a pale brown composite crystal weighing 0.11 carat, caught in the 1.7-to-2.36-mm sieve size fraction. (Table 1 shows caustic fusion microdiamond results.)
Renard 9 is 50 metres south of Renard 4 and covered entirely by water. The 6-tonne sample was collected in the winter of 2004. Drilling suggests the Renard 9 body is 160 metres long by 25-55 metres wide.
Ashton believes Renard 9 could add significantly to the core area’s potential. In 2004, as part of a major campaign to recover at least 300 carats of diamonds for valuation purposes, the partners undertook a comprehensive bulk-sampling and drilling program on the Renard 2, 3, 4 and 65 bodies. The four pipes form a higher-grade core area at the southern end of a 2-km-long cluster of nine diamond-bearing bodies, in the south-central part of the 2,000-sq.-km Foxtrot property. A sixth body in the core area, known as Renard 8, was discovered in late 2002, 150 metres south of Renard 65. It showed weak results, returning only nine microdiamonds in a 112-kg sample of the discovery holes.
The partners exceeded their original 300-carat goal by recovering 457 carats of diamonds from the 664 tonnes of sampled kimberlite material. The samples were collected from the drilling of 50 core holes and 23 large-diameter reverse-circulation (RC) holes on Renard 2, 3, 4 and 65. Twenty-five of the recovered diamonds weigh more than 1 carat apiece, including eight that exceed 2 carats. The five largest diamonds weigh 4.3, 2.9, 2.7, 2.3 and 2.3 carats. The 4.3-carat and one of the 2.3-carat stones are described as clear, colourless octahedrons. (Bulk-sample results for each of the Renard 2, 3, 4, 65 and 9 bodies are provided in Table 2.)
The valuation of the diamond parcel is planned for early April. In the meantime, the joint-venture partners are trying to define Renard 2, 3 and 4, the three bodies thus far with the highest estimated grade. Additional drilling is planned for Renard 9.
Based on a model prepared on behalf of the joint venture by Wardrop Engineering, the Renard 2, 3, 4 and 65 bodies contain a potential 17.7 million tonnes of kimberlitic material. (Table 3 summarizes the tonnage estimates and drill data.) More than 90% of the modeled tonnage occurs within 200 metres of surface. Kimberlite has been encountered to depths of at least 280 metres in each of the four bodies.
Renard 9 had shown potential for large stones based on the initial microdiamond results from the discovery holes.
Renard 9 | Renard 8 | |
Sieve Size | #Diamonds | #Diamonds |
+1.70 mm | 1 | 0 |
+1.18 mm | 0 | 0 |
+0.850 mm | 1 | 0 |
+0.600 mm | 17 | 0 |
+0.425 mm | 9 | 1 |
+0.300 mm | 21 | 0 |
+0.212 mm | 38 | 3 |
+0.150 mm | 48 | 2 |
+0.100 mm | 43 | 3 |
Total Diamonds | 178 | 9 |
Sample Wt. (kg) | 212.4 | 111.8 |
Kimberlitic | Sample Wt. | Diamonds | Largest Diamonds | Estimated | |
Body | (tonnes) | Recovered | (carats) | Grade (carats) | (carats/tonne) |
Renard 2 | 173 | 160 | 2.27, 2.05,1.87 | 0.92 | |
Renard 3 | 155 | 191 | 4.3, 2.7, 2.29 | 1.23 | |
Renard 4 | 171 | 69.3 | 2.9, 0.94, 0.88 | 0.40 | |
Renard 65 | 165 | 36.6 | 0.88, 0.83, 0.82 | 0.22 | |
Total | 664 | 457 | |||
Renard 9 | 6.04 | 5.56 | 3.26, 0.68 | 0.92 |
Table 3: Estimated Tonnage
KimberliticSizeDimensionsTonnage#Drill
Body | (ha) | (metres) | (tonnes) | Holes |
Renard 2 | 0.6 | 120 by 65 | 2.3 million | 31 |
Renard 3 | 0.3 | 145 by 25 | 1.4 million | 34 |
Renard 4 | 1.0 | 180 by 70 | 6.0 million | 46 |
Renard 65 | 1.5 | 280 by 60 | 8.0 million | 36 |
Total | 17.7 million |
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