Aredor kimberlites reveal more stones (October 08, 2002)

Partners Rio Tinto Mining (RTP-N) and Trivalence Mining (TMI-V) have recovered more diamonds from the latter company’s Aredor concession in Ghana.

Rio, which operates the project, recently sank 8 holes into a promising geophysical anomaly lying north of the known K14N kimberlite. To the immediate south, 4 other holes were sunk in an area previously sampled by Russian geologists in the 1960s.

All 12 holes cut kimberlite, and 4 of those returned elevated diamond counts. Results include:

• hole 40, which averaged 0.119 carat over 95 metres, including 14 metres at 0.166 carat, 24 metres at 0.337 carat and 13 metres at 0.147 carat;
• hole 41, which averaged 3.124 carat over 62 metres, including 25 metres at 2.973 carat, 20 metres at 5.958 carat and 6 metres at 3.87 carat;
• hole 42, which ran 2.588 carat over 79 metres, including 32 metres at 7.117 carat; and
• hole 43, which ran 1.371 carat over the first 38 metres, including 23 metres at 1.683 carat and 12 metres at 1.061 carat.

Each interval begins from the start of the hole, and their grades include only those stones having at least two dimensions greater than 1 mm. The largest stone of 0.889 carat, which came from hole 41, was excluded from the grade estimate.

Rio notes that core recoveries were generally low, averaging 42% overall, and thus the reported grades may be up to twice as high as if 100% of the core had been recovered. To overcome the problem, the major will sink several large-diameter holes into the K14N kimberlite.

Drilling at the K4, K7 and K19 kimberlites failed to return any significant diamond counts. The K4 kimberlite is one of a cluster of four that sit in the central part of the concession. Kimberlites K3 and K6 have not been drilled yet, and the heaviest stone from the K5 kimberlite weighed 0.38 carat.

Rio also has flown 4,700-line km of airborne electromagnetic and magnetic surveys over central and southern portions of the property. Any notable drill targets will be drilled in an upcoming campaign.

Rio can earn up to a 58% stake in any kimberlite body by advancing it to production. Nearby alluvial deposits, which Trivalence has been mining since March 1998, are excluded from the deal.