Peru Antamina raises reserve estimate by 77 pct

LIMA, Nov 6 (Reuters) - Peru's growing Antamina zinc and copper mine on Thursday raised its mineral reserve estimate by 77 percent, and said it was pushing ahead with expansion plans.

Antamina, a joint venture between BHP Billiton Ltd (BHP.AX) (BLT.L), Xstrata Copper (XTA.L), Teck Cominco Ltd (TCKb.TO) and the Mitsubishi Corporation (8058.T), said it raised its reserve estimate for the deposit by 325 million tonnes of ore to 745 million tonnes.

It said it raised contained copper in reserves by 69 percent and contained zinc by 35 percent.

"Both grades and tonnages have increased for all reserve categories," the mine said in a statement.

"Antamina is now engaged in studies for the evaluation of expansion alternatives based on the increased ore reserves base, with expanded production capacity of around 30 percent already indicated from the pre-feasibility study."

The mine is one of the world's largest copper-zinc pits. (Reporting by Maria Luisa Palomino; Writing by Dana Ford; Editing by David Gregorio)