Renard 8 was found just 350 metres away from the Renard 2 kimberlitic intrusion. Two angle holes were drilled across a small geophysical anomaly measuring 75 by 40 metres. The holes drilled through the pipe-like body and intercepted 67 metres and 102 metres of kimberlite breccia, respectively.
Ashton and Soquem, a Quebec Crown corporation, are 50-50 partners in a joint venture that has been exploring for diamonds in Quebec since 1996. Today, the joint venture holds more than 3,800 sq. km of mineral permits in the north-central part of the province. The permits are broadly held in the Otish Mountains and the Caniapiscau region.
The holdings in the Otish Mountains are subdivided into Foxtrot, a large claim block covering 1,536 sq. km in the north, and Tichegami, which covers a scattering of claims totalling 1,040 sq. km in the southern region. In late 2001, the partners staked the Taiga property, consisting of 1,168 sq. km about 125 km north of Foxtrot.
This summer’s discovery of Renard 7 and 8 brings to eight the number of kimberlitic bodies found in the past year on the Foxtrot property. The bodies occur in a tight cluster within a 700-to-800-metre radius. Two additional geophysical anomalies were drilled this summer at Foxtrot without intersecting kimberlite.
Renard 7 was uncovered 1.3 km north of the Renard 2 intrusion by drilling a complex geophysical anomaly, with surface dimensions of 150 by 60 metres. A vertical hole into the anomaly intercepted what was initially reported as being kimberlitic rock under 17 metres of overburden. Upon closer inspection, the hole was found to have intersected chewed-up brecciated gneissic country rock with minor stringers of kimberlite and a few dykes of hypabyssal kimberlite, up to 3 metres thick, before passing into hypabyssal kimberlitic material at 87 metres of depth. The hole was shut down early while still in kimberlite at a depth of 102 metres. A follow-up angle hole intercepted 8 metres of hypabyssal kimberlite at 21-29 metres downhole, followed by a 98-metre section of brecciated country rock.
Results from caustic fusion microdiamond analysis of samples collected from Renard 7 and 8 will be announced before year-end.
Ashton has been encouraged by microdiamond tests from the first six discoveries. The initial results were particularly encouraging for Renard 2, which was discovered in the fall of 2001, 1 km south of the diamondiferous Renard 1. A total of 116 micros and 29 macros were recovered from 163.1 kg of core, including five stones exceeding 0.5 mm in two dimensions. (A macro here is defined as equal to or greater than 0.5 mm in one dimension.) The largest stone recovered measured greater than 1 mm in two directions.
To test the potential for larger-size stones, the joint venture extracted a 2.4-tonne mini-bulk drill sample from Renard 2 in the spring. The sample delivered a 1.69-carat parcel of diamonds larger than a 0.8-mm bottom-size cutoff, for an implied grade of 0.693 carat per tonne (or 69.3 carats per 100 tonnes). The five largest diamonds ranged in size from 0.1 to 0.16 carat.
This summer, Ashton collected an additional 1.8 tonnes of kimberlitic material from three holes in Renard 2 for further evaluation. Based on the drilling to date, the pipe-like body measures 120 by 65 metres at surface.
The drilling of four additional targets during the spring of 2002 resulted in the discovery of four kimberlitic pipes, all of which proved to be diamond-bearing. Each discovery was tested with a vertically drilled hole and a hole angled at minus 50. Initially, 100-kg representative core samples from the vertical hole in each of the discoveries were analyzed for microdiamonds at Ashton’s laboratory in North Vancouver.
During the microdiamond testing of Renard 3, at least two stones greater than 3 mm were broken, accounting for some 2,500 fragments. In addition to the fragments, the original 101.5-kg sample returned 10 micros and nine macros, including seven stones greater than 0.5 mm in two dimensions (the largest being 2.8 by 1.5 by 0.7 mm). A second, 56.4-kg sample from Renard 3 was subsequently processed in a manner designed to prevent crushing of larger stones. A further 11 micros and eight macros were recovered, including five diamonds equal to or greater than 0.5 mm in two dimensions. The second sample contained a 4-by-2.7-by-1.9-mm colourless whole crystal weighing 0.13 carat.
The initial microdiamond tests for Renard 3, 4 and 5 all show a high macro-to-micro ratio and suggest the potential for larger stone populations. The partners completed additional mini-bulk sample delineation drilling on each of the Renard 3 and 4 discoveries this past summer, collecting a further 4.3 tonnes and 4.2 tonnes of sample, respectively. Based on drill results, Renard 3 is believed to be a linear body with a minimum surface expression of 120 by 20 metres. The Renard 4 pipe measures 140 by 60 metres.
Dense-media-separation (DMS) tests on the mini-bulk samples should be completed before the end of 2002. Renard 5, which lies partially under a small lake, will be mini-bulk-tested in the spring of 2003 during colder conditions.
Ashton has reported additional microdiamond results from further 50-kg samples taken from the original angle holes into Renard kimberlites 3 through 6. In addition, the remaining core from the discovery holes on Renard 1, 5 and 6 kimberlite was processed through Ashton’s DMS plant to provide an early indication of the potential for larger diamonds. The initial microdiamond counts from Renard 1 and 6 were not as favourable as the other discoveries. “We had the material, and we wanted to learn a little more about those bodies,” explains Brooke Clements, Ashton’s vice-president of exploration. “We want to use all the tools we have at our disposal.”
q The Renard 1 discovery originally delivered 54 micros and five macros from 205.8 kg of tested core, including one stone exceeding 0.5 mm in two directions. A follow-up, 296-kg sample tested by DMS proved to be barren of stones larger than a 0.85-mm bottom size cutoff.
q In total, from Renard 3, 48 micros and 33 macros have been found in 206.6 kg of core tested by caustic fusion methods. Seventeen of the stones are greater than or equal to 0.5 mm in two dimensions, including six diamonds exceeding 1 mm in two directions.
q In total, a 152.7-kg sample of Renard 4 returned 29 micros and 25 macros, including 19 diamonds greater than or equal to 0.5 mm in two dimensions and three stones measuring 1 mm or more in two directions.
q In total, 21 micros and 32 macros were recovered from 143.9 kg of tested core from Renard 5. Twenty-one stones measure 0.5 mm or more in two directions, and two stones exceed 1 mm in two directions, the largest being 1.9 by 1.3 by 0.6 mm. A further 364 kg were processed by caustic fusion methods, returning four diamonds with an aggregate weight of 0.95 carat. The largest diamond is a grey composite crystal weighing 0.92 carat.
q Renard 6 initially returned 25 micros and six macros from a 100.9-kg sample. A further 51.2 kg contains four micros and two macros. The two samples combined to deliver a total of 29 micros and eight macros from 152.1 kg, including three diamonds greater than or equal to 0.5 mm in two dimensions and one stone measuring 1 mm or more in two directions. In addition, a 457-kg sample processed by DMS returned a single translucent colourless diamond crystal weighing 0.26 carat.
Clements is optimistic about the latest DMS results that seem to indicate the potential for larger stones but realizes diamonds are notoriously subject to “nugget effect.”
“We see some bigger stones, but these samples are so small that we don’t make any allusions to grade,” Clements says. “We’re waiting for the next bigger sample results, which will be much more meaningful.”
The past summer’s program also consisted of heavy-mineral sampling. More than 1,000 samples from the Foxtrot, Tichegami and Taiga properties were collected. Several targets were investigated with ground geophysics in preparation for drilling in 2003.
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