Rio announces modifications to Argentine copper-gold project

With construction 40% complete, the Bajo de la Alumbrera project in western Argentina is about to undergo some changes.

Operator Minera Alumbrera plans to install a gravity circuit designed to recover up to half of the free gold. As well, the annual capacity of the concentrate slurry pipeline has been increased to 800,000 from 730,000 tonnes to allow for future mine expansion. The storage capacity of tailings and waste rock is also being increased.

Rio Algom (ROM-T) and North Ltd. of Australia acquired a 25% interest each in the project through their joint acquisition of International Musto Explorations last year.

Minera Alumbrera will bump up commissioning of the mine by two months, to the third quarter of 1997. This will increase revenue in the first year, and bring the total capital expenditure (before financing) to US$903 million.

The project has reserves and resources of 766 million tonnes grading 0.5% copper and 0.63 gram gold per tonne. Minera Alumbrera has confirmed production estimates of 180,000 tonnes copper and 640,000 oz. gold per year over a 20-year mine life, with higher metal production in each of the first four years resulting from above-average initial grades.

The remaining half of the project is held by MIM Holdings, under option from property owner Yacimientos Mineros de Agua de Dionisio.