Cominco Resources underground on Mexican Copper project

The Maria property is located in Sonora and has high grade reserves of 850,000 tons grading 10.6% copper, which immediately overlies a lower grade zone containing 950,000 tons of 1.8% copper.

A jointly owned Mexican operating company, Minera Maria S.A. de C.V., expects to spend $3.6 million(US) to develop the mine for production with financing to be provided by Empresas Frisco. Cominco Resources’ 49% share of production is estimated to exceed 5,000 tons per year of copper metal from the proposed 300-ton-per-day operation.

Work will begin with the driving of a 700-m decline to provide access to the high grade portion of the deposit. The partners are considering various ore processing options, including shipping the high grade ore directly to a smelter or upgrading it in available concentrating facilities.

Five kilometers to the west of the Maria deposit, Cominco Resources has resumed work on the Mariquita copper prospect where a feasibility study is expected to start later this year. The project has inferred reserves of about 20 million tons grading 0.6% copper as outlined by previous operators.

The deposit occurs as near- surface copper enrichment and is well suited to open pit mining. Cominco Resources said the deposit also appears to be amenable to heap leaching and low-cost solvent extraction-electrowinning. The company’s preliminary studies indicate that its share of production could total 5,000 tons per year of cathode copper.

According to Cominco Resources, two step-out drill holes completed on the Mariquita deposit last year demonstrated the potential for substantial additional reserves. A drilling program is now under way to confirm and expand reserves, and metallurgical tests are continuing.

Cominco Resources is owned 58.6% by Cominco Ltd. (TSE) and has an international portfolio of gold and base metals projects. Among its key assets is a 76.4% interest in the producing Buckhorn gold-silver mine in Nevada and a 25.7% interest in the Marte heap leach gold mine in Chile scheduled for production in the second quarter of 1989.

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