Former Xstrata boss Mick Davis' X2 Resources is in "serious" talks to purchase some of Rio Tinto Plc's Australian coal assets, the Financial Times reported citing people familiar with the matter.

The multibillion-dollar deal talks are at an early stage and have generated solid interest from both sides, the FT reported.

The discussions could also extend to include Rio's metallurgical coal assets in Queensland, the newspaper said.

A spokesman for X2, Michael Oke, declined to comment.

A sale of Rio's thermal coal assets in New South Wales would be the biggest divesture by the company under Chief Executive Sam Walsh, for the past two and a half years, the FT said.

A spokeswoman for Rio Tinto declined to comment.

Earlier in June, Reuters reported that X2, which was long considered a front runner for Barrick Gold's Zaldivar copper mine in Chile, bowed out of the race after it was outbid in the first round of the sale process.

More than a year after he launched his private fund, Davis has been coming under pressure to build a new mining empire with the $6 billion in capital he has raised.

X2 has so far expressed interest in a number of assets in copper, coal and other commodities, but has yet to make its first acquisition.