U.S. coal giant Peabody Energy said it will increase seaborne export coal volumes at its Wilpinjong and Millennium mines in Australia by 3 million tonnes to 5 million tonnes after expanding both operations.

"The successful expansions of Wilpinjong and Millennium increase our annual thermal and metallurgical coal supplies to serve the highest-demand regions by a combined 3 million tonnes to 5 million tonnes," Gregory H. Boyce, Peabody Energy Chairman and Chief Executive Officer, said in a statement.

"With the recent acquisition of Macarthur Coal and additional Australian mine expansions over the next several years, Peabody Energy plans on a rising share of our earnings to come from the world's largest coal exporting nation."

The company recently acquired 90 per cent of Australian miner Macarthur Coal.

Upon completion of a preparation plant and coal handling facility expansion, the Wilpinjong thermal coal mine in New South Wales will increase expected annual yield by 2 million tonnes to 3 million tonnes beginning in 2012 from the 9.2 million tonnes in 2010. The mine is among Australia's most productive surface operations and supplies export and domestic markets. Capital requirement for the project is expected at approximately $95 million.

The Millennium Mine in Queensland is forecast to expand its PCI and semi-hard coal production by 1 million tonnes to 2 million tonnes annually when full production is reached in 2013.

Peabody Energy has so far invested $20 million for the expansions of the two mines. Project cost is pegged to total up to $275 million over the next two years, the company said in a statement.