Revised numbers pave way for new study at Chapada

Revised resource and preliminary reserve estimates for the Chapada copper-gold project in Brazil’s Goias state will provide the basis for a new feasibility study planned by Yamana Gold (YRI-T).

The revised calculations, made by Tucson-based International Mining Consultants (IMC), place the resource at 421 million tonnes grading 0.31% copper and 0.23 gram gold per tonne in measured and indicated categories. There is a further inferred resource of 68 million tonnes at 0.2% copper and 0.14 gram gold per tonne.

A prefeasibility estimate, based on a gold price of US$325 per oz. and a copper price of US85 per lb. (US$1,870 per tonne), puts the reserve at 263 million tonnes at 0.36% copper and 0.27 gram gold per tonne. An additional 47 million tonnes of stockpiled material, grading 0.3% copper and 0.22 gram gold, are classified as a probable reserve.

Chapada, a flat-lying tabular deposit, would be mined by open-pit methods; as designed by IMC, the pit would have a low stripping ratio of 0.65-to-1. A starter pit, with a 5-year life, would have grades of 0.46% copper and 0.43 gram gold per tonne.

Yamana plans to update the 1998 feasibility study to provide definitive capital and operating cost figures. The study will start this month and should be completed by mid-year.

Yamana acquired Chapada, an 84-sq.-km property 250 km northwest of Brasilia, in a deal with Brazilian-based Mineraao Santa Elina in August 2003. Santa Elina had previously been advancing the project in a joint venture with Echo Bay Mines, now part of Kinross Gold (K-T). A feasibility study in 1998 proposed production of 12.7 million tonnes annually from a reserve of 187 million tonnes grading 0.39% copper and 0.31 gram gold per tonne.