Ashton, Soquem step up work in Otish Mountains

Encouraged by the size of the diamonds recovered from the Renard cluster of kimberlitic intrusions in the Otish Mountains region of north-central Quebec, the Ashton Mining of Canada (ACA-T) and Soquem joint venture is collecting larger samples from some of the recent discoveries and drill-testing new targets.

A seventh kimberlitic body was recently found on the Foxtrot joint-venture property. A vertical hole into a geophysical anomaly, some 1,300 metres north of the Renard 2 intrusion, intercepted kimberlitic rock under 19 metres of overburden. The hole was shut down in kimberlitic material at a depth of 102 metres. At least two other anomalous targets will be tested this summer.

In June, Ashton reported promising results from a small mini-bulk sample designed to test the potential of the Renard 2 kimberlitic body for larger-size stones. A 2.4-tonne sample collected from four core holes, each of which measured 4.8 cm in diameter, returned 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. Two of these stones are colourless; the others are pale yellow or pale brown. Composed of mainly kimberlitic breccia, the mini-bulk sample included several intersections of hypabyssal facies kimberlite and country rock material.

Renard 2 has a geophysical signature measuring 150 metres long and 100 metres wide. The results from drilling suggest the body is up to 65 metres wide at a depth of 80 metres from surface. Covered by approximately 20 metres of overburden, the pipe-like body extends to a confirmed depth of at least 225 metres.

Renard 2 was discovered in the fall of 2001, 1 km south of the diamondiferous Renard 1. In total, 116 micros and 29 macros were recovered from 163.1 kg of discovery core sample, including five stones exceeding 0.5 mm in two dimensions. (A macro is here defined as measuring greater than 0.5 mm in one dimension.)

The drilling of four additional targets during the spring of 2002 resulted in the discovery of four kimberlitic bodies, all of which proved to be diamond-bearing. Each discovery was tested with a vertically drilled hole and a hole angled at 50. Initially, 100-kg representative core samples from each of the discoveries were analyzed for microdiamonds by caustic dissolution methods at Ashton’s laboratory in North Vancouver. However, the Renard 3 sample returned more than 2,500 diamond fragments, which Ashton attributed to the mechanical breakage of at least two larger stones measuring in excess of 3 mm during sample preparation. In addition to the 2,500 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). Ashton’s microdiamond recovery circuit is not typically configured to recover large stones from such small samples during the initial analysis. A second, 54.6-kg sample from Renard 3 was subsequently processed in a manner designed to prevent the 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 Renard 3 sample contained a 4-by-2.7-by-1.9-mm colourless whole crystal weighing 0.13 carat. In total, 21 micros and 17 macros (including 12 stones equal, to or greater than, 0.5 mm in two dimensions) were pulled from 156.1 kg of tested Renard 3 core.

At the time, John Kaiser, publisher of the Bottom-Fishing Report, said these were “the best early stage results ever delivered by Ashton.” By adjusting the microdiamond numbers to reflect a square-mesh-sieve-size-based reporting system, which Kaiser has been rallying the industry to adopt, lab experts arrived at at standard sample size of 1,000 kg and were able to predict the commercial grade potential of the sampled kimberlite. While appreciating that the sample sizes are comparatively small, Kaiser compares the microdiamond size distribution curve with micro results from other kimberlites for which grade is known. “Renard 3 has the potential to have a macro grade of 1 carat per tonne or higher, as may Renard 4 and 5,” predicted Kaiser.

Lukewarm

He added that “the lukewarm reaction by the market and other analysts is due to a poor understanding of microdiamond analysis and an unfortunate obsession with outdated and misguided longest-dimension-based interpretations.”

Kaiser remains critical of the longest-dimension reporting system, a common industry-wide practice of dividing the total number of recovered diamonds into “macros and micros” according to whether the stone exceeds 0.5 mm in the longest dimension. Any attempt to correlate the longest-dimension macros to commercial grade is flawed, said Kaiser, because it allows a sliver-like fragment to be counted as a macro even though its weight contribution may be substantially lower than a stone with the same length in three dimensions. While high “macro counts” gave an early indication of the high-grade Diavik pipes, Kaiser warned that many high-potential kimberlites that underwent bulk sampling delivered disappointing commercial macro grades, pointing to the Tli Kwi Cho, Torrie, Wawa and Torngat kimberlites.

The Renard 3 kimberlite, which consists of solely hypabyssal material, sits just 200 metres east-southeast of Renard 2. It has a geophysical signature measuring 125 by 60 metres. The original six Renard kimberlitic intrusions form a tight cluster, and all the intrusions occur within a diameter of roughly 1 km.

The microdiamond results for Renard 3, 4 and 5 all show a high macro-to-micro ratio and suggest the potential for larger stone populations. Ashton and Soquem are carrying out further mini-bulk sample delineation drilling on each of the Renard 3 and 4 discoveries. A 4-tonne sample will be extracted from each of these bodies, whereas a further 1-tonne sample will be taken from Renard 2.

The Renard 4 kimberlite delivered 21 micros and 14 macros, including 11 stones exceeding 0.5 mm in two dimensions, from 102.1 kg of tested core. The dimensions of the largest diamond recovered was 2.4 by 2.1 by 0.9 mm. Renard 4 has a geophysical signature of 120 by 120 metres. Renard 5 has also shown promising results, yielding 15 micros and 20 macros from 100.3 kg of sample. Thirteen of the macrodiamonds are greater than 0.5 mm in two dimensions, with the largest measuring 2.5 by 2 by 1.8 mm. Renard 5 also warrants further work, but because the body lies partially under a small lake, Ashton will wait until winter before collecting a mini-bulk sample. The Renard 5 geophysical anomaly measures 80 by 80 metres. (Note: Ashton cautions that drilling data suggest that each of the Renard bodies may be smaller than the corresponding geophysical anomaly.) At present, no further work is planned for Renard 6, which yielded 25 micros and six macros, including two stones greater than 0.5 mm in two dimensions, from a 101-kg sample.

Ashton and Soquem, a Quebec Crown corporation, are 50-50 partners in a joint venture that holds more than 3,800 sq. km of mineral permits in north-central Quebec. The permits are broadly held in two areas: the Otish Mountains, 275 km northeast of Chibougamau, and the Caniapiscau region, 500 km east-northeast of Radisson.

Foxtrot and Tichegami

The joint venture’s current 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, which covers 1,168 sq. km about 125 km north of Foxtrot.

Ashton kicked off this summer’s field program by completing a helicopter-borne geophysical survey on the Foxtrot property, followed by reconnaissance and heavy-mineral sampling, as well as ground geophysics over selected targets. In the Caniapiscau area, where the joint venture holds 57 sq. km of mineral claims, two targets were drilled without intersecting kimberl
ite.

Ashton’s original staking of the Foxtrot property was followed shortly thereafter by several phases of staking activity by other junior and major companies, culminating in a major staking rush in December 2001, when Ashton announced that its first two kimberlite discoveries were diamond-bearing.

The Canadian diamond division of BHP Billiton (BHP-N) has been exploring properties immediately south of the Foxtrot property in joint venture with Majescor Resources (MAJ-V). BHP Billiton has the right to earn up to a 56% interest in the Portage project by funding all costs through to production. Earlier this year, an aggressive drilling program by BHP Billiton failed to hit kimberlite in any of the 18 various geophysical anomalies drilled. This summer has been spent conducting geophysical surveys and further heavy-mineral sampling designed to increase the density of sample sites in anomalous areas of kimberlitic indicator minerals.

Mistassini

Farther to the south, Majescor and Canabrava Diamond (CNB-V) are jointly exploring the Mistassini project, which covers 1,724 sq. km of mineral claims between the northern part of Lake Mistassini and the Eastmain River. Canabrava can earn a half-interest by spending $1.3 million on exploration over three years. Majescor is the operator.

Canabrava entered into the option agreement based on the results of some 250 heavy-mineral samples collected from the project area. The samples revealed several discrete indicator mineral dispersion trains. The mineral assemblage is dominated by ilmenite, with lesser amounts of garnet and chromite. Some rare G10 garnets, diamond inclusion chromites and mantle-derived olivine grains are also reported. The joint venture is targeting some of the higher-priority targets generated from an airborne survey with further glacial sediment sampling and geological mapping. A drilling program is scheduled for the fall.

The Mistassini project is west of the Beaver Lake area, where Uranerz Exploration & Mining discovered a kimberlite body in 1978 while exploring for uranium. Ditem Explorations (DIT-V) optioned a 49% interest in the Beaver Lake discovery in 1998 by agreeing to spend $1.5 million over four years. Ditem initially tested the kimberlitic intrusion with six holes and recovered four macros from 511 kg of sample. Drilling showed that the weakly diamondiferous body was not uniform but rather a stockwork-like system. A follow-up, 7-tonne mini-bulk sample to test for larger-size stones proved barren.

Pure Gold deal

After acquiring more ground in the area, Ditem struck a deal with Pure Gold Minerals (PUG-T), which can earn a 60% interest in the Tichegami property and a half-stake in mineral claims surrounding the Beaver Lake kimberlite. During a spring drilling campaign, Pure Gold discovered a kimberlitic body, known as H-1, on the Tichegami property, 20 km northeast of Beaver Lake. Test samples from the discovery hole returned no diamonds. Pure Gold recently found a second kimberlite, about 350 metres southeast of H-1. Based on the results of two holes and the interpretation of geophysical data, Pure Gold believes it has intercepted a multi-phase kimberlitic dyke at least 65 metres wide. Selected samples will be analyzed for microdiamonds.

Bard Ventures (CBS-V), a sister company to Pure Gold, is conducting ground investigations on several airborne anomalies at its Otish 3 and 6 properties in the Beaver Lake area. Bard is hitting the ground with prospecting and till sampling.

Majescor’s diamond holdings in Quebec exceed 7,500 sq. km. The junior has teamed up with Randy Turner’s Diamondex Resources (DSP-V) to explore the Lac Gayot area, 85 km north of the Caniapiscau reservoir, on a 50-50 basis. Reconnaissance till sampling conducted independently by both companies resulted in the identification of a regional anomaly of kimberlite indicator minerals. The joint venture currently covers a 328-sq.-km land position, forming a large block oriented in a northeasterly direction. A summer program entails sampling and ground follow-up of selected geophysical airborne anomalies.

Wemindji

Majescor recently received disappointing results from what has been considered a high-priority project by the junior: the wholly owned Wemindji, 400 km west of the Otish Mountains. In March, 17 drill holes (in a program spanning 22 holes) intersected a series of subhorizontal kimberlite sills extending over an area of 400 by 500 metres at depths ranging from 4 to 32 metres. The cumulative thickness of the kimberlite intervals is 2 metres. Microdiamond analysis on 190 kg of material yielded just two micros.

Majescor retrieved 8.5 tonnes of kimberlite from blasted trenches to test the potential for larger-size stones. The mini bulk sample returned no diamonds greater than a 0.85-mm bottom-size cutoff. The company continues to target the source of six other distinct dispersion trains at Wemindji.

Another junior working in the James Bay area of Quebec is Dianor Resources (DOR-V), which carried out a helicopter-supported program of regional exploration, including prospecting, soil and till sampling, geophysics and geological mapping.

Elsewhere in the Otish Mountains, Northern Empire Minerals (NEM-V) is conducting a reconnaissance-style program of till sampling across the La Croix and Premier properties. Roughly 65 samples in total will be collected from the two properties. Under the terms of an option agreement with Blackstone Ventures (BLV-V), Northern Empire can earn a 75% interest in the Premier property by spending $1 million over four years. BHP Billiton retains a back-in right on the property, which lies 7 km northwest of Majescor’s Mistassini project.