Aditya Birla Group and state-run Coal India Ltd (CIL) are reportedly among that companies that are planning to place bids for some of Rio Tinto Ltd's Australian coal assets.

Rio Tinto is reportedly offloading a 29 per cent stake in its Coal and Allied business as part of its efforts to reduce its massive debt pile of more than $26 billion and maintain its single-A credit rating. It is also reducing its coal business due to soaring costs and lowering margins.

People familiar with the developments said that Aditya Birla Group and CIL have plans to acquire a stake in Rio Tinto's Australian coal assets.

They also named China's state-run Shenhua Group Corp Ltd as one of the companies that are mulling plans to acquire a stake from Rio Tinto.

As of December last year, Rio Tinto valued its total Australian coal assets at $5.63 billion. This includes the company's Clermont stake plus its 80 per cent stake in Coal & Allied.

Many analysts are of the view that the uncertainty over the future of the company's Warkworth mine could affect the valustion of Coal & Allied business. A court has blocked a planned expansion of the Warkworth mine. The company is appealing the decision.

Michael Evans, an analyst with CIMB, said last month, "In any case, we believe it is highly unlikely Warkworth will be sold until the issue is resolved."

Japan-based conglomerate Mitsubishi Corp, which owns a 20 per cent stake in Rio's Coal & Allied and Clermont mine, has pre-emptive rights to purchase any stakes that the company puts on the block, but it is unlikely to exercise those pre-emptive rights as it has already declared that it has no plans to hike its investments in natural resources.