U.S. MINING REPORT — Nevada’s Carlin Trend supports numerous

One would be hard-pressed to name a richer North American gold mining complex than the Carlin Trend in Nevada.

The Goldstrike property of American Barrick Resources (TSE) contains about 22.5 million oz. grading 0.18 oz. gold per ton (at the end of 1993). At its adjacent operations, Newmont Gold (NYSE) reports reserves as being 19.5 million oz. (to be updated shortly).

Newmont holds an extensive land position in the area and surrounds Barrick on all sides. The company is fortunate in that 94% of its proven and probable reserves are on private land and would therefore not be subject to proposed royalty taxes.

Newmont operates five mines in the area, its largest being the Gold Quarry which was commissioned in 1986. All production from the mine is either heap leached or sent to an oxide mill. Since deeper ore is refractory, Newmont is constructing an 8,000-ton-per-day roaster to treat the material prior to milling. This upgrading is expected to cost about US$285 million and the company expects to commission the roaster in the latter half of this year. It should reach design capacity in 1995.

Newmont is continuing to test a bioleaching process for treating low-grade, refractory material which cannot be milled economically. Newmont Mining (NYSE), 90.1% owner of Newmont Gold, received a patent in 1993 for the process, which involves using naturally occurring bacteria to mimic and speed up oxidation of sulphide ore. The contained gold is rendered leachable, using cyanide.

Newmont’s non-reserve material totals 13.6 million oz. of contained gold and includes low-grade sulphidic material, as well as material containing active carbon. The carbon removes gold from solution once it has been leached and, as a result, prevents its recovery. Tests are being performed on a second bioleaching process, designed to block the carbon’s ability to remove gold. If the company can prove both processes are commercially viable, 4 million oz. of gold would be added to reserves. (That material is already included within current reserves and must be moved, in any event.)

If the process proves viable, numerous low-grade, sulphide gold deposits in North America would be rendered economic.

Newmont Gold is already involved in a joint venture with Barrick with regard to low-grade, refractory mineralization and the company hopes to form partnerships with other companies if the tests prove successful. Results from the bio-oxidation leach tests have yet to be released and the company expects to continue tests on gold mineralization containing active carbon.

Production at Goldstrike has grown steeply since Barrick bought the property in 1987. Following a major expansion which began in 1988, the mine now has six autoclaves operating with a combined processing capacity of 15,000 tons of sulphide ore per day. (An expansion to 16,000 tons is in the works.) All oxide ore at the mine is heap leached.

The additional mill capacity is needed to process ore from the huge Betze-Post pit encompassing both Barrick’s Betze deposit and the Deep Post orebody, which straddles the Barrick-Newmont property boundary. The two companies reached an agreement in December, 1992, to extend the original Betze pit to include the Deep Post. Mining of sulphide ore in Betze began in earnest in 1992 and is expected to reach the Deep post ore in 1997. Further production growth at Goldstrike is expected to come out of Barrick’s rich, underground deposit known as Meikle (9.7 million tons grading 0.68 oz. gold per ton).

Shaft-sinking was to have started in June, 1993, but construction was postponed as Barrick had not yet received land patents and the final permit for the mine. The company notes that it has complied with all aspects of the patenting process and is seeking a court order requiring that its application be processed promptly.

If patents are issued, Barrick would not be subject to royalties, proposed by the government, for mines operating on federal land. The application was filed in August, 1993, and the court has not yet published an opinion on the matter. Despite the delay, Barrick still hopes Meikle to be in production, at more than 400,000 oz. annually, by 1996.

Barrick, which turned out more than 1.6 million oz. in 1993, is projecting total output of 1.8 million oz. in 1994 and 2 million oz. in the following year.