Anglo-Swiss miner Xstrata is investigating a major expansion of thermal coal mining in Australia's northeast, the company said on Monday.

Xstrata's communications manager James Rickards confirmed a report in The Australian newspaper on Monday that the investment in Queensland state could cost 15 billion Australian dollars ($13 billion) and create one of the country's largest coal-producing regions.

But plans for the 110 million U.S. tons (100 million metric tons) a year four-pit operation near the town of Wandoan, 240 miles (390 kilometers) northwest of the state capital Brisbane, were not finalized and faced several hurdles, Rickards said.

Xstrata is the world's largest exporter of thermal coal which is used to power electricity generators.

Development of the main Wandoan mine was well advanced and was expected to produce 33 million U.S. tons (30 million metric tons) of thermal coal a year after production begins in 2014, he said.

But development of another three nearby mines, each with a 28 million U.S. ton (25 million metric ton) annual output, was not expected to be completed within the next decade, he said.

"We are currently exploring three other areas outside of that mine within the Wandoan region," Rickards said.

"It is still (at) very early stages, and we are yet to complete any of the feasibility, pre-feasibility or environmental studies of those other regions," he said.

The initial Wandoan mine is expected to cost AU$6 billion to build.