The recent discovery by Aber Resources (TSE) of several diamondiferous kimberlites further attests to the exploration potential of the Lac de Gras region in the Northwest Territories.
The discovery hole on Aber’s A-21 target has returned 154 diamonds from 154.6 kg of core. Of these, 38 are macrodiamonds measuring greater than 0.5 mm in one dimension.
The hole was drilled to a depth of 169 metres, cutting 123.1 metres of kimberlite. Results from a second hole are pending, along with results from another diamondiferous kimberlite, A-154, also discovered by Aber within its 560,000-hectare Diavik project area. This target area lies between the southeastern portion of the BHP Minerals-Dia Met Minerals block and the TliKwi Cho pipe being bulk-sampled by Kennecott Canada.
Aber President Gren Thomas credits the recent discoveries to company geologists Ira Thomas and Robin Jenkins. A-21 was a geochemical target initially, which became further delineated as the team started zeroing in on the more subtle geophysical signatures in the area. Pipe A-154 was a geophysical target.
The new discoveries by Aber provide Kennecott with prospective exploration targets beyond its 40%-held Tli Kwi Cho pipe where bulk sampling is nearing completion. Results (carats per 100 tonnes and valuations of diamonds) are expected this summer.
Although the results are from only one hole (which may or may not be representative of the pipe), the A-21 kimberlite appears to have macrodiamond counts similar to those encountered by exploration drilling of Tli Kwi Cho. Diamond experts point out that the economics of a kimberlite prospect depend on several factors that can be determined only by bulk sampling — namely grade (carats per 100 tonnes), size distribution, and the quality and value of the diamonds.
“The new discovery boosts Aber into the A team of the Lac de Gras diamond companies,” says Andrew Muir, a mining analyst with Canaccord Research. “The other members of this select club have significant discoveries that are being bulk-sampled to determine economic viability.”
Aber has a 15% interest in Tli Kwi Cho and a 40% interest in the newly discovered A-21 and A-154 kimberlites. Kennecott can earn a 60% interest in Aber’s land holdings (560,000 hectares) by spending $10 million on exploration and development over four years. This is 20% more than the interest Kennecott holds in the claims hosting the Tli Kwi Cho (DO-27 and DO-18) kimberlite.
Thomas declines comment on the quality of the stones being recovered from the new A-21 discovery. “It is premature to (comment),” he says, “but it appears to be typical of what has been reported from the region.”
Aber plans to do more exploration drilling on its new targets as soon as possible. “The A-21 target can be drilled from either the shore or from islands within the lake,” Thomas explains. “We are looking at those options now.”
Aber also plans to drill its (44.4%-owned) C-13 target shortly, to follow up seven holes drilled last year. Previously reported results from C-13 total 15 macros and 40 micros from 269.3 kg of core. Aber is of the view that past drilling did not intersect the main body of the pipe, and recent geophysical work has defined the target further.
“We think more discoveries will come from the Lac de Gras region,” Thomas says. “We’ve only scratched the surface”.
Other companies are planning to drill exploration prospects in the region this summer. The most advanced project remains that of BHP and Dia Met, where large bulk samples are being extracted from three separate kimberlites, including one where gems and near-gems make up the bulk of diamonds recovered from exploration drilling. A feasibility study is expected by year-end. Elsewhere
in the Territories
* A news release says the Drybones Bay geophysical anomaly has been confirmed as a kimberlite pipe. Situated 50 km southeast of Yellowknife on Great Slave Lake, the property is owned by David Smith, a local prospector. Based on geophysical surveys, the pipe’s surface area is estimated at 45 hectares, A vertical hole drilled from the ice in early April encountered kimberlite at a depth of 107 metres. The pipe is covered by 30 metres of water and 77 metres of clay, boulders and sand. Drilling recovered 24 metres of kimberlite core.
Smith says chemical analyses by government geologist Jennifer Pell verify the core is kimberlite. He goes on to say microprobe analyses by Loring Labs “confirm the presence of kimberlitic indicator minerals, including chrome diopsides, ilmenites and both eclogitic and peridotitic garnets.” * The Drybones discovery has sparked a staking rush in the Yellowknife area. One recent entrant, Trade Winds Resources (VSE), has learned that claims it had acquired in the area were overstaked by various stakers. “Until a decision has been rendered by the mining recorder, the full status of these claims is pending,” the company reports.
* Continental Precious Metals (ME) plans to acquire a numbered Alberta company which holds 43 claim blocks totaling 12.8 million hectares on Baffin Island. Continental, which will provide 3.2 million shares in return, plans to spend $3.5 million exploring the ground.
Alberta and British Columbia
* Gwen Resources (ASE) has staked 32 claim groups covering 7,438 hectares in southeastern British Columbia. The claims cover some 43 known or suspected surface occurrences of alkaline and mafic-to-ultramafic rocks. The targets lie within the same tectonic belt that hosts Dia Met Minerals’ (TSE) Mark and Jack pipes, from which limited sampling has returned 2 macros and 13 micros.
Ontario and Quebec
* Diamonds have been identified in a heavy mineral concentrate taken from Noront Resources’ (VSE) Crystal Valley project, near Mont Johnson, east of Montreal.
Elsewhere on the property, in an area where previous sampling located two small diamonds, geophysical surveys have outlined a 1-km circular anomaly. Samples of float obtained near this buried anomaly have been identified as kimberlite.
Based on these encouraging results, Noront has acquired an additional 28,000 hectares, raising to 40,000 the number of hectares it holds in the St. Lawrence Rift diamond region. Follow-up ground surveys are planned in advance of summer drilling.
* Garde, Societe D’Exploration Miniere (ME) is buying all of William Resources’ Quebec diamond plays in return for the issuance of 750,000 Garde shares.
William holds a 25%-to-100% interest in 608 claims in Le Tac and Ailly twps. and a half interest in a 53-sq.-km licence in the James Bay area. * Later this month, Glencairn Explorations (ASE) plans to drill-test a potential kimberlite pipe on its property in the James Bay Lowlands. The target is a large, isolated, magnetic anomaly with a surface expression of about 400 hectares.
Glencairn can acquire the project, subject to a 2% net proceeds royalty. Overseas
* Partners Cliff Resources (TSE), Black Hills Minerals and Triad Minerals report that exploration has begun on their Phillips Range joint venture in Western Australia’s Kimberley region.
During this program, about 5,000 metres will be drilled to delineate the North, Central and Southern kimberlite lobes of the Aries kimberlite pipe. In addition, the North lobe will be bulk-sampled in July using large-diameter drilling. A 2,000-tonne sample will be collected and processed on site at a heavy media-sortex plant.
The budget for the 1994 program is estimated at $4 million, of which Cliff will fund the first $1.3 million to earn its 30% interest.
Triad holds a half interest in the joint venture and is project manager. * Sentinel Resources (VSE) will buy a 70% interest in the Klipdrift diamond prospect from South Africa-based Quatro C. Minerals. The property is near Kimberley.
Under the deal, Sentinel will pay Quatro $180,000 and grant it an option to buy up to 750,000 Sentinel shares at up to $1.45 per share over the next five years. In addition, Sentinel will pay Quatro half of the net profits from the Klipdrift operation until the vendor has received $800,000 (including the initial
$180,000).
Sentinel will also annually issue Quatro one Sentinel share for every $1.45 of net profits generated by the property until a total of 666,550 shares have been issued. The project will be subject to a 5% gross royalty until the $800,000 has been paid and the 666,550 shares issued.
Consultants estimate that the deposit contains 3.7-5.7 million tonnes of kimberlite, and bulk sampling is planned to determine the grade of the pipe.
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