THE DIAMOND PAGE — Yamba Lake diamond exploration results

The Lac de Gras region of the Northwest Territories was back in the spotlight as results were released of a mini bulk sample from the Yamba Lake joint venture of Tanqueray Resources (ASE) and Mill City Gold Mining (VSE).

The results were discouraging in that only 19 diamonds, weighing an aggregate 0.635 carats, were recovered from a 24.5-ton bulk sample taken from the 1.5-hectare Torrie pipe. The sample was treated at Dia Met Minerals’ treatment plant at Fort Collins, Colo., with De Beers overseeing the analysis of concentrates.

No diamonds were recovered from the Ptarmigan pipe. This 27.8-kg sample was processed by Lakefield Research by means of caustic dissolution. The juniors also announced that De Beers is no longer required to subscribe for shares of Tanqueray or Mill City. But the South African-based major has agreed to undertake a general exploration program on the entire Yamba Lake concession, which will include drilling of certain defined targets by the end of 1995.

If De Beers decides to bring a mine into production, it will arrange financing of up to $500 million for the first mine and thereby earn a 60% interest in the concession.

The disappointing news from Yamba Lake follows on the heels of poor results from a larger bulk-sampling program by Kennecott Canada on the Tli Kwi Cho kimberlite, also in the Lac de Gras region. That leaves the BHP Minerals Canada-Dia Met Minerals joint venture clearly in the lead in the race to develop Canada’s first diamond mine.

Elsewhere in the Northwest Territories

* Kennecott has shifted its focus from Tli Kwi Cho to two recently discovered kimberlite pipes on ground held by Aber Resources (TSE) near Lac de Gras. Results to date from the A-21 and A-154 pipes indicate that both are significantly diamondiferous, with the latter having the greatest potential. As Aber President Gren Thomas explains, the company is particularly encouraged by the size of the stones encountered during exploration drilling. Two stones observed during core logging have weights of about 1.76 and 0.28 carats.

To date, A-154 has yielded 402 macrodiamonds and 894 microdiamonds from 750.8 kg of core. Of the 402 macros, 112 are greater than 1 mm and seven of these have a weight exceeding 0.2 carats each. The largest stone recovered in the fusion process was 1.18 carats.

Core drilling of the A-21 pipe returned 38 macros and 116 micros from 154.6 kg of core.

Kennecott’s next step is to carry out delineation drilling of A-154 using a barge-mounted rig; it will also carry out delineation drilling of A-21 from the ice. The pipes are 5 km apart and off the east end of an island in Lac de Gras. Should the results of this work prove satisfactory, large-diameter drilling of the two pipes will be undertaken from the ice.

Kennecott’s first-phase program, budgeted at $1.7 million, will involve bulk samples totaling 60-80 tonnes, to be trucked to Yellowknife for processing. These samples will provide Kennecott and Aber with a preliminary idea of the grade, gem-

content (quality) and size

distribution of the diamonds within the A-21 and A-154 kimberlites. Drilling is expected to begin shortly. The partners hope to have results in hand so that a decision to mine a 5,000-tonne bulk sample can be made in time to use the winter road to bring equipment to the site. Mining of the larger samples could then take place in the spring and summer. British Columbia

* Consolidated Venturex Resources (VSE) has collected two bulk samples, totaling 38 tonnes, from the Jack property in southeastern British Columbia. The samples were trucked to Dia Met’s recovery plant in Colorado, with results expected in late September. The two most prospective phases in the Jack pipe were tested —

25 tonnes of hematitic breccia and 13 tonnes of grey-green breccia. Previous bulk samples yielded two macros, including one 0.1145-carat diamond fragment recovered by Venturex in 1993. The company notes, however, that the previous samples were from the “least prospective” crater fill phase. Saskatchewan

* Drilling is expected to begin shortly on the Montreal Lake-Candle Lake joint venture properties, according to partners Consolidated Pine Channel Gold (VSE), June Resources (VSE) and Tutko Development. Additional ground has been staked in the region to cover anomalies which were identified by geophysical and geochemical techniques.

Overseas

* Australian-based Ashton Mining has discovered a diamond province in Finland, which is the result of a broad exploration effort covering several countries in the Nordic-Baltic region.

The company informed the Australian Stock Exchange that two kimberlite fields and several isolated kimberlite

occurrences had been found. The discoveries to date total 21 kimberlites, four of which are dykes. The majority contain diamonds and range in size from 1 to 4 hectares.

One 2-hectare pipe yielded 26 carats of 0.8 mm diamonds per 100 tonnes from a 23-tonne sample, and Ashton says a “significant number are clear and colorless crystals.”

A 9.4-tonne sample from another pipe (exceeding 1 hectare in size) yielded grades from 13 to 26 carats per 100 tonnes, with a weighted average of 19 carats per 100 tonnes.

New targets are being defined, with current activity focused on extending regional exploration coverage. Ashton owns the venture outright but is considering bringing in a partner to share the risks and rewards.