In 10 years of diamond exploration in North America, Ashton has discovered 67 kimberlite bodies, including six in 2003. The company is the operator of a promising exploration campaign in north-central Quebec, where it has so far found 10 diamond-bearing kimberlitic intrusions under a 50-50 joint venture with Soquem (Socit Qubcoise d’exploration minire).
Nine of the kimberlitic discoveries are grouped in the Renard cluster in the south-central part of the Foxtrot property, 400 km northeast of the mining and forestry town of Chibougamau. These bodies are roughly aligned along a 2-km-long north-south axis. Six of the nine bodies — Renard 2, 3, 4, 65, 8 and 9 — are found in a “core area” measuring only half a square kilometre.
The Foxtrot property covers almost 2,000 sq. km in the Otish Mountains region, and is accessible only by air. The nearest all-weather road, 140 km to the north, services a network of hydroelectric dams. About 55 km to the south is the idle Eastmain gold mine, formerly serviced by a 200-km-long winter road from Temiscamie on Lac Albanel.
The Renard 1 through 8 kimberlitic bodies were discovered in 2001 and 2002 as a result of drilling magnetic geophysical anomalies at the head of a prominent indicator mineral dispersion train. Ashton and Soquem had been carrying out regional-scale reconnaissance exploration in northern Quebec since 1996. Renard 9 and 10 were found in 2003, as was the highly diamondiferous Lynx kimberlitic dyke system, a farther 2 km to the west. In all, 29 targets were drill-tested between late 2001 and early 2004, resulting in the discovery of the nine Renard bodies and two Lynx dyke occurrences.
Over the course of 2002 and 2003, the joint venture collected mini-bulk drill samples totalling 57 tonnes from Renard 2, 3, 4 and 65 — four of the bodies in the core area. The last remaining batch of material from the Renard 3 kimberlite was recently processed through Ashton’s newly commissioned 5-tonne-per-hour dense-media-separation (DMS) plant at its new facilities in North Vancouver. The 5.1-tonne sample, collected in 2003 by drilling 11 core holes into Renard 3, returned 7.81 carats of diamonds exceeding a 1.18-mm bottom-size cutoff for an estimated diamond content of 1.53 carats per tonne; the best results to date.
The four largest diamonds each weigh 1.82, 1.01, 0.73 and 0.7 carats. The 1.82-carat diamond is described as a colourless octahedral crystal with uneven surface characteristics, and the 1.01-carat stone is a pale brown octahedral crystal. The mini-bulk sample consisted mainly of kimberlitic breccia, with lesser amounts of hypabyssal kimberlite, country rock and country-rock breccia.
A previous, 4.9-tonne sample, taken from Renard 3 in 2002, delivered a 6.54-carat parcel, using a lower-size cutoff of 0.85 mm, for an estimated diamond content of 1.34 carats per tonne. The largest diamond in the earlier sample was a 0.73-carat colourless composite crystal. Renard 3 is 0.3 hectare in size, with surface dimension of 145 by 25 metres.
The Renard bodies are small kimberlitic intrusions, ranging from 0.3 to 1.5 hectares in size. Each consists of three basic rock types, including kimberlitic breccia, with variable country rock xenolith content, and macrocrystic hypabyssal kimberlitic material that generally exhibits a cross-cutting relationship to the breccia. Contacts with the country rock can be sharp or transitional, with the latter grading into highly fractured and brecciated zones of country rock containing little or no kimberlitic material. This country rock breccia is often crosscut by macrocrystic kimberlitic dykes.
The Renard intrusive bodies exhibit mineralogical and petrographic features common to both kimberlite and melnoite. Based on groundmass features, the Renards are transitional between melnoite and kimberlite, whereas whole-rock trace element chemistry suggests a closer affinity to Group 1 kimberlites.
To date, the 57 tonnes of processed material from the core-area Renard 2, 3, 4 and 65 kimberlitic intrusions have returned a 41-carat parcel of diamonds greater than 0.85 mm, giving an overall diamond content of 0.72 carat per tonne. (See accompanying Table 3 for an analysis of the mini-bulk sampling results.) The four bodies have a cumulative surface area covering 3.4 hectares, the largest being Renard 65, at 1.5 hectares. Ten of the biggest stones are greater than half-a-carat in size, the largest being a 4-carat diamond recovered from Renard 65 that remains embedded in a piece of drill core.
Renard 1, the first kimberlitic discovery on the Foxtrot property, lies just outside the core area, 400 metres to the north. At 1.2 hectares (210 by 94 metres) in size, it is the second-largest body in the Renard cluster. Initial microdiamond results from Renard 1, however, were less encouraging than those from other bodies; as a result, the collection of a mini-bulk sample was deferred until the summer of 2003. Approximately 8.8 tonnes of material extracted from seven holes yielded just 0.78 carat of diamonds greater than 0.85 mm for an estimated diamond content of 0.09 carat per tonne. The largest diamond recovered was a colourless octahedral weighing 0.12 carat. No further work is planned for Renard 1.
Robert Boyd, Ashton’s president and chief executive officer, is encouraged by results to date from the core area bodies, which demonstrate a favourable distribution towards larger-size stones. “The consistently larger stones recovered from relatively small initial mini-bulk samples, the encouraging percentage of relatively clean diamonds, and the favourable initial diamond counts, provide strong endorsement to acquire a larger package of diamonds for valuation purposes,” stated Boyd at the recent annual meeting.
He added: “We have demonstrated that kimberlites with potentially commercial diamond content and commercial-size stones are present on the Foxtrot property. We have also demonstrated that a potentially significant volume of material is present if a favourable rock value can be demonstrated for the core area bodies. Therefore, a bulk sample is justified to help determine the potential range of unit rock values for economic evaluation scenarios.”
In January, the Ashton-Soquem joint venture approved an $18-million bulk-sampling and exploration program, with most of the work focused on the Foxtrot property. The primary objective is to collect a sample of 600 tonnes of kimberlitic material from the Renard 2, 3, 4 and 65 bodies using both core and large-diameter reverse-circulation (RC) drilling. A bulk sample of this size should yield a cumulative parcel of at least 300 carats of diamonds for preliminary valuation.
During the winter phase of this program, completed in early April, a cumulative sample of 220 tonnes was collected. The winter drilling focused on sections of Renard 2, 4 and 65, which are partly overlain by shallow lakes. Ashton recovered 180 tonnes of kimberlite in large-diameter (27-cm) RC drilling, including 110 tonnes from five holes into Renard 65 and 70 tonnes from three holes in Renard 4. In addition, Ashton is using vertical core holes to drill off each of the four bodies on a 20-metre grid pattern to an average depth of 210 metres. This will serve to establish geology and grade control. Approximately 21 tonnes of kimberlitic material were extracted from 15 core holes into Renard 4, while 17 tonnes were pulled from 15 core holes at Renard 65.
Only one vertical core hole was drilled into Renard 2 this past winter, recovering about 2 tonnes of material before the hole was shut down while still in kimberlite at a depth of 219 metres.
The 40 tonnes of drill core will be processed for diamonds at Ashton’s new DMS plant, while the RC portion of the bulk sample will be treated at an outside commercial facility. Another 400 tonnes of bulk sample will be collected from land-based
RC and core drilling later this summer and fall.
During the winter 2004 program, mini-bulk sampling and delineation drilling program were completed on Renard 9, returning an impressive 178 microdiamonds from an initial 212-kg sample. Included was a 0.11-carat diamond described as a pale-brown composite crystal. A more detailed look at the diamond distribution is provided in the accompanying table.
Renard 9 was found 150 metres south of Renard 4, covered entirely by water. About 5 tonnes of kimberlitic material were recovered from nine core holes drilled this past winter. The data suggest Renard 9 is at least 160 metres long and 25-55 metres wide. Mini-bulk sample results are pending.
Renard 10 was discovered in the fall of last year when two angle holes were drilled in opposite directions across a subtle, irregularly shaped magnetic anomaly, 1.5 km north of the core area. The discovery hole intersected a 25-metre section of kimberlitic material between 237 to 262 metres down-hole. The intercept represents a true width of 16.2 metres.
The second hole was drilled to test the kimberlitic zone at a higher level. It cut a section of kimberlitic breccia and macrocrystic kimberlite from 85.2 to 95.5 metres down-hole for a true width of 6.6 metres. Ashton only just recently announced the caustic-fusion results for the Renard 10 discovery. A 187.8-kg sample returned 64 microdiamonds, including one stone exceeding a 1.18-mm sq. sieve size. (See Table 1 for a breakdown on stone-size distribution.)
Of the $18 million budgeted this year for Quebec, $12 million is being spent on bulk sampling. The remainder is being used to conduct further exploration on the joint venture’s holdings.
This past winter, several targets were drill-tested on the Foxtrot property, resulting in the discovery of additional kimberlitic dykes 1.3 km north of the original Lynx dyke. Lynx is a strong, 2.5-km-wide indicator mineral train that contains a “healthy population of G10 or diamond-friendly garnets.” Kimberlitic float material was discovered on surface at three different sites in the Lynx area anomaly at the end of last year’s field season.
Last fall, a new kimberlitic dyke system was discovered 2 km west of the Renard cluster as a result of drilling two angle holes across a broad, weak geophysical anomaly in an area up-ice of where three microdiamonds were recovered from two widely spaced till samples. The body is interpreted to be a 4-to-5-metre-wide zone of narrow hypabyssal kimberlite dykes, the largest of which is 1 metre thick.
Abundant kimberlitic cobbles and boulders measuring up to 2 metres wide in diameter were found on surface 100 metres down-ice of the discovery holes. A 3.9-tonne sample of the boulders was treated by DMS and returned 4.63 carats of diamonds larger than 0.85-mm, giving an estimated diamond content of 1.2 carats per tonne. The two largest diamonds are a colourless composite crystal weighing 0.96 of a carat and a 0.28-carat pale-brown octahedral.
A 238.7-kg surface sample from this same site was tested by caustic fusion analysis, yielding a significant 594 microdiamonds, including three stones caught on the 1.18-mm screen size fraction (see Table 1).
A second sample, comprising 77.2 kg of kimberlitic material, was collected from a surface site 1.2 km northwest of the Lynx occurrence; it held 289 microdiamonds.
During the winter program, two additional holes were drilled in the vicinity of the discovery holes to collect more material for diamond analysis. The drilling confirmed the dyke complex to be 3.4 to 9.4 metres wide. The longest single intercept of kimberlite in each hole ranged from 1.1 to 2.7 metres thick. A second target in the Lynx anomaly, 1.2 km northwest of the first occurrence, was tested with two angle holes; the drilling encountered a zone of narrow kimberlitic dykes.
The first hole intersected a 3.9-metre-wide zone at a down-hole depth of 130 metres. The largest kimberlite intercept was 1.2 metres wide. A second hole intercepted a 6.8-metre-wide zone at a depth of 123 metres. The widest section was 0.45 metre.
“The encouraging indicated diamond content to date for the Lynx boulders and excellent microdiamond results encourage the joint venture to explore the Lynx anomaly for larger blows and strike continuity to the Lynx dykes,” stated Boyd. “In addition, there are strong unexplained anomalies at north and southeast anomalies, which contain diamonds in till samples at the north anomaly, plus cobbles of kimberlite in both anomalies.”
The two anomalous areas of indicator minerals are 6 km north and 3 km southeast of the core area.
An extensive summer program of geological mapping, sampling, trenching is planned on the balance of the Foxtrot property to identify drill targets. In July of last year, the joint venture tied on an additional 456 sq. km of mineral claims to the Foxtrot property, and picked up 82 sq. km of new claims in the Monts Otish area, 50 km southeast of the Foxtrot property.
Ashton and Soquem also hold 546 sq. km of scattered claims in the Techigami area, 75 km south of the Renard cluster, where geophysical targets associated with indicator mineral dispersion trains have been identified. Drilling is planned this summer.
Other junior companies active in the Otish Mountains region include
In return for investing $500,000 in a private placement financing of Majescor earlier this year, Stornoway will have the right to acquire a 51% interest in the Portage project upon Majescor’s completing a $1-million exploration program. Majescor is performing till sampling on the project, which sits down-ice of Ashton’s Foxtrot property. Despite promising indicator mineral chemistry, both the Canadian division of
De Beers Canada Exploration can earn an initial 51% interest in the 33 Carats project by spending $5.5 million on exploration before the end of 2008. By completing a feasibility study, De Beers can boost its interest to 60%. The 33 Carats project covers 918 sq. km. Dios, which was spun off from
Reconnaissance till sampling by Dios revealed favourable G10 pyrope garnets, picroilmenites and high-magnesium olivines in selected samples. Last year, De Beers completed 11,761 line km of airborne magnetic surveys, with follow-up ground investigations on 14 targeted areas. Further infill and regional sampling resulted in 715 glacial sediment samples, which are being collected for indicator mineral processing.
Dios exploration also holds a 100% interest in the 530-sq.-km Hotish claim group, 100 km south of the Renard cluster and just north of Lake Mistassini. Last year, it discovered two narrow kimberlitic dyke occurrences while drilling targets 10 km apart. A third kimberlite occurrence was found a few kilometres away from the first discovery by prospecting. Neither a 20.5-kg core sample from the first discovery nor a 148-kg sample from the surface showing contained any diamonds. The other kimberlite occurrence was too narrow to provide a sufficient enough sample for testing.
geting some 30 airborne anomalies on its 30-sq.-km Marusia property, 25 km south of Foxtrot. Under the supervision of Roscoe Postle Associates, some 60 samples, each weighing 20-30 kg, were collected (two per site) down-ice from target anomalies. Twenty-six of the samples contained at least one kimberlite indicator mineral grain, with a total of 63 recovered mineral grains, including three low-calcium G9 pyrope garnets and an assortment of picroilmenites, chromites, olivines and clinopyroxenes.
TABLE 1: Microdiamond Results for the Renard 9, 10 and Lynx Discoveries
Renard 9Renard 10Lynx
TABLE 2: Caustic Fusion Microdiamond Results
KimberliticApproximateSample#Totalin twoRecovered (mm)
Renard 1210 by 94 m205.85900.9 by 0.5 by 0.3
Renard 2120 by 65 m163.114531.6 by 1.6 by 0.5
Renard 3145 by 25 m206.681*64.0 by 2.7 by 1.9 (0.13ct)
Renard 4180 by 70 m152.75432.5 by 2.1 by 0.9
Renard 65300 by 60 m2969032.5 by 2.0 by 1.8
Renard 7150 by 60 m101.13300.4 by 0.4 by 0.2
Renard 875 by 40 m111.8900.6 by 0.6 by 0.5
Renard 9160 by 40 m212.41781(0.11 carat)
* In addition, about 2,500 diamond fragments were recovered from this sample. These fragments are attributed to the breakage of one or more stones during sample processing.
TABLE 3: Mini-bulk Sampling Results
Renard 22.214.171.124*1.82, 1.01, 0.73, 0.71.53
4.886.540.73, 0.31, 0.251.34
Renard 20.613.538.720.91, 0.39, 0.380.64
Renard 41.015.078.040.66, 0.31, 0.280.53
Renard 651.518.4410.04, 0.92, 0.77, 0.460.54
Total Core area3.457.0341.110.72
Lynx boulders3.874.630.96, 0.281.2
* Note: All diamonds are larger than 1.18 mm using a square aperture screen.