Minnova examining Chu Chua for possible copper production

The Chu Chua massive sulphide deposit near Kamloops, B.C., is being evaluated by Minnova Inc. (TSE) for potential open pittable, high grade copper ore that might supply additional feed to the Samatosum mill. The project is further evidence of copper’s recent comeback, particularly noticeable in British Columbia, which during 1987 turned out 45.4% of the metal produced in Canada, more than any other province.

Conveniently for operator Minnova, the Chu Chua deposit is located only 50 km by road from its 70%-owned Samatosum mill due to begin producing silver and secondary amounts of lead, zinc, copper and gold next spring. The company is earning a 50% interest in Chu Chua, while Pacific Cassiar (TSE) is sharing the remaining 50% interest equally with Quinterra Resources (VSE), a company in the Noramco Mining fold, and International Vestor Resources (VSE).

In 1988, Minnova completed a drill program to test a zone in the central part of the deposit, representing a portion of the known reserves estimated at 2.75 million tons of 2% copper, with zinc, silver, gold and cobalt values. With results now in, the 13-hole program appears to be confirming high copper grades over appreciable widths for at least 558 ft of length. The deposit is open to depth, and has yet to be fully delineated in both directions along strike.

Selected assay results for copper from the recent drill program include: 19.3 ft of 4.52%, 36.4 ft of 2.89%, 33.7 ft of 2.0%, 93.5 ft of 4.25%, 40.3 ft of 2.15%, 64.9 ft of 2.62%, 51.8 ft of 3.35%, 48.2 ft of 4.59%, 82 ft of 4.13% and 49.2 ft of 3.25%.

Ian Pirie, senior exploration geologist, said Minnova is now evaluating results of this year’s program and those from earlier programs in order to evaluate the possibility of a potential open pittable reserve. The company is reported to be considering a possible pit depth of 328 ft.

“At this stage it’s something that wouldn’t go on its own, but given its proximity, within trucking distance of our mill (500 tons per day), we may be able to do something,” he said, noting that the key factors for viability will be grade (hopefully in the 4% range) and low cost mining. Trucking costs aren’t seen as a major concern, he added.

Although it is still too early to talk production and production scheduling, Michael Kenyon, director of International Vestor, said Minnova has expressed some interest in mixing ores from both projects early on in order to maximize its copper recoveries. Silver is the metal of primary interest at Samatosum, but the deposit has copper values of 1.2%

Also potentially available with a shallow pit at Chu Chua is an incompletely delineated zone of massive magnetite previously estimated at 0.5 million tons. Magnetite is used in the coal industry for heavy media separation processes.

The Chu Chua property was staked in early 1978 by the junior companies to cover anomalies resulting from a reconnaissance geochemical survey to cover a 600-mi volcanic belt. Craigmont Mines optioned the property later that year (to 1984 when the joint venture re-acquired it) and outlined a vertical to steeply dipping deposit within a siliceous tuff continuous from surface to a depth of about 2,000 ft. Most of its drilling, however, was concentrated within the upper 600 ft of the deposit.

Since taking on the project in July of 1985, Minnova’s efforts were concentrated on exploration for deposits similar to the Samatosum high grade silver deposit optioned from Rea Gold (TSE), part of a regional effort continuing today on a number of joint-ventured projects in the area.

But improved prices for copper motivated the company this year to drill a series of short diamond drill holes as fill-in holes between earlier grid holes on the main Chu Chua deposit in order to establish a near surface average copper grade. Drilling is expected to resume in the spring.