Despite its small tonnage implications, the Renard cluster of eight kimberlitic bodies in the Otish Mountains of north-central Quebec shows potential for large commercial-size diamonds at grades comparable to some of the better pipes in the Northwest Territories and Nunavut.
A 4.9-tonne sample of Renard 3 yielded 6.54 carats of diamonds caught by a 0.85-mm square aperture screen, for an implied grade of 1.34 carats per tonne. The five largest diamonds weighed 0.73, 0.31, 0.25, 0.23 and 0.22 carat, for an aggregate weight of 1.74 carats. The 0.73- and 0.31-carat diamonds are colourless composite crystals, whereas the 0.25-carat stone is a colourless single crystal.
The implied grade of Renard 3 is nearly double what was indicated by mini-bulk samples of the nearby Renard 2 pipe (0.69 carat per tonne) and Renard 4 (0.65 carat per tonne). The Renard cluster of eight kimberlitic bodies is confined to an area of 2 sq. km in the Otish region, 275 km northeast of Chibougamau.
The 4.9-tonne sample of Renard 3 consisted of 3.4 tonnes of kimberlitic breccia with minor amounts of country rock. A second component of the mini-bulk sample, weighing a little more than 1.4 tonnes, consisted of hypabyssal kimberlitic material, which is present throughout the body.
Ashton recovered 4.45 carats from the 3.4 tonnes of kimberlitic breccia, giving an implied grade of 1.3 carats per tonne. The remaining 1.4 tonnes of hypabyssal material yielded 2.09 carats of diamonds, for an implied grade of 1.45 carats per tonne.
The two largest diamonds recovered from the hypabyssal units were a colourless, 0.23-carat composite crystal and a 0.22-carat single crystal.
The nine holes drilled to date at Renard 3 suggest that the body is linear, measuring 120 by 20 metres. Kimberlitic material has been intersected to a depth of 201 metres.
Analyst John Kaiser, publisher of the Bottom-Fish Tracker, suggests there is probably at least 1 million tonnes of kimberlite present — a tonnage he considers small in the diamond game.
“The Renard 3 results would be considered spectacular if Renard 3 were a 20-million-tonne-plus kimberlite body, but they are merely interesting in view of the small tonnage implications for Renard 3,” he says.
“Although Ashton has not fully delineated the Renard kimberlites, it looks as if we have a cluster of medium-to-high-grade kimberlite bodies with an aggregate tonnage potential likely in the 5-to-10-million-tonne range, and an outside chance of reaching 15 million tonnes.”
Ashton has approved exploration budgets for winter programs on ground held under the Slave regional joint venture in the Northwest Territories and Nunavut, and also intends to perform winter drilling on the Buffalo Hills joint venture in northern Alberta.
Ashton will conduct mini-bulk sampling programs on the Renard 5 and 6 bodies this winter. Given the encouraging mini-bulk sample results from Renard 2, 3 and 4, further delineation drilling and bulk sampling of these pipes are likely. The results of a further 2.5 tonnes of sample from Renard 2 are expected in January.
This past summer, Ashton and Soquem carried out extensive indicator mineral sampling and ground geophysical surveys on the Foxtrot and other Quebec properties with the aim of finding more kimberlitic bodies outside of the Renard cluster. The results of this work will be used to generate drill targets.
Ashton and Soquem’s joint venture comprises more than 3,800 sq. km of mineral permits in the province’s north-central region.
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