Rio Algom, Inmet expand Antamina deposit

Once again, partners Rio Algom (ROM-T) and Inmet Mining (IMN-T) have boosted the resource estimate of the Antamina copper-zinc deposit in Peru.

The total in-pit resource is now pegged at a minimum of 500 million tonnes grading 1.2% copper, 1% zinc and 0.03% molybdenum, plus 11 grams silver per tonne, with an estimated stripping ratio of 2.8-To-1. The previous estimate was 400 million tonnes at a similar grade.

The current program has also increased the measured and indicated resource by 85% to 370 million tonnes averaging 1.3% copper, 0.9% zinc, 13 grams silver per tonne plus 0.03% molybdenum.

It is believed that, at the anticipated daily production rate of 70,000 tonnes, the total resource will be sufficient for 20 years of production.

These latest figures are derived from the assay results of 140 diamond drill holes, which represent 48,000 metres of core.

So far, 243 diamond drill holes totalling 92,000 metres have been collared at the site, with some 8,000 metres remaining before completion of the current program.

The partners report that the feasibility study is proceeding on schedule and that bulk metallurgical tests are under way at Lakefield Research’s pilot plant. The study should be completed by the end of 1997.

Rio Algom and Inmet each hold a 50% interest in Compania Minera Antamina, which will either invest US$2.5 billion in the project by September 2001 or pay 30% of the unspent portion to the vendor, Centromin Peru.