Great Lakes Minerals keys on advanced-stage projects

One of the new juniors growing by leaps and bounds is Great Lakes Minerals (TSE). Listed last July, the company already has three promising copper properties in the Keweenaw Peninsula of northern Michigan and the rights of first refusal over another 1,520 acres on the peninsula. President Nicholas Tintor says that successful fund raising for the juniors means “you have to give investors what they want — advanced-stage projects with reserves in the ground.” The company also talks like a major with its strategy of acquiring minority interests in, and production royalties of, operating mines, as well as acquiring, exploring and developing mineral properties in the U.S. and Canada, like a junior.

Under the initial joint venture agreement with Michigan Mining and Manufacturing, Great Lakes had the right to earn a 50% interest in the Keweenaw copper project by spending $1.5 million on exploration.

By December, 1990, the com- pany had spent approximately $320,000 on an 8000-ft. diamond drilling program and, encouraged by the high-grade intersections, was already planning a prefeasibility study on the 543-S deposit, which got under way this January. The company is now looking for a joint venture partner to fund a proposed underground exploration program on the 543-S project this summer.

Meanwhile, in early January the company acquired the right to purchase 100% of Keweenaw Copper Company, a private Michigan-based company, in exchange for 550,000 Great Lakes shares. The purchase was completed by late February and in the process Great Lakes increased its interest in the 543-S, G-2, and St. Louis copper projects from 50% to 75%.

Through Keweenaw Copper’s two subsidiaries, Michigan Mining and Manufacturing and Michigan Copper, the company also acquired the right to explore, develop and mine several other copper deposits along the Keweenaw Peninsula.

The most advanced of these projects is the 50%-owned Centennial copper mine and the 1000-ton-per-day Key mill built by Homestake Mining (NYSE) in the mid-1970s. Great Lakes expects Centennial to begin production in the third quarter of 1991 at an annual rate of 8.5 million lb. copper (TNM, Jan.7, 1991).

Through a recent restructuring proposal, Great Lakes is now negotiating to acquire 100% of the 543-S, G-2, and St. Louis properties.

The 8000-ft. drill program in 1990 tested mainly the 543-S deposit with excellent results. Designed to upgrade reserves and confirm 1970 drilling results by previous owners, Inco (TSE) and Homestake Mining (NYSE), results included high-grade intersections of 15 ft. averaging 5.6% copper, within lower-grade intersections of 68 ft. averaging 2.0% copper in drill hole 543-90-5.

Inco and Homestake completed more than 80,000 ft. of drilling on the 543-S deposit before terminating the program in 1977 due to low copper prices. Metallurgical studies completed by Inco also indicated a recovery of 93% to produce a concentrate averaging 40% copper.

The 543-S deposit contains probable reserves of 3.1 million tons grading 2.9%, including a core of 1.3 million tons grading 4% copper.

The satellite G-2 deposit contains an additional preliminary reserve of 520,000 tons grading 4% copper. Most of the reserves are above 500 ft. in depth and would be accessible by decline ramps. Copper mineralization occurs mainly as chalcocite.

The St. Louis native copper deposit, 20 kilometres west of the 543-S, is estimated to contain (yet to be confirmed by drilling) an inventory of open pittable 8 million tons grading 0.8% copper.

Tintor says that “no other mining companies have explored the Keweenaw Peninsula since the mid-1970s.” The company is planning a major compilation survey on its Keweenaw copper properties this spring.

The company is looking at copper projects in Arizona which would be amenable to the low-cost SX-EW processing technology, an acid-leaching process followed by solvent extraction and electrowinning.