Anglo-Swiss miner Xstrata Plc. said Wednesday it has added another year to the mine life of its Alumbrera copper operation in Argentina, ensuring metal production until at least mid-2016.

The extension comes via an additional 40 million metric tons of ore reserves and a subsequent mine plan optimization, resulting in an increase in contained metal reserves of more than 10%, the company said.

The upgrade equates to an additional 120,000 tons of contained copper and around 400,000 ounces of gold over the life of the mine, it said.

"The reserves addition is an important complement to the mill expansion, which will be completed in the second half of this year," said Xstrata Copper Chief Executive Charlie Sartain in a statement.

By the end of the year, a four-year US$45-million expansion at Alumbrera's concentrator will have increased throughput capacity 54% to 40 million tons, the company said.