The Xstrata and Anglo American joint venture that owns the Chile Collahuasi copper mine said mineral resources at the mine increased by 40% to over seven billion tons.
Minera Dona Ines de Collahuasi said mining reserves have increased by 315 million tons to 2,453 billion tons.
The increase in mineral resources is the result of new drill results, modelling changes and metal price assumption adjustments.
The mine's output is expected to expand to over one million tons a year.
Mine expansion studies are expected to be completed by the first quarter of 2011.
Collahuasi, one of the world's biggest copper deposits, produced 535,853t of copper in 2009.