Mining giant Rio Tinto says its chief executive Tom Albanese will step down immediately.
Rio Tinto said its iron ore chief executive Sam Walsh has been appointed as the company's new chief executive.
The diversified global miner also announced it expects to book a non-cash impairment charge of $US14 billion ($A13.30 billion) post tax in its 2012 full year results.
The impairments include approximately $US3 billion ($A2.85 billion) relating to Rio Tinto Coal Mozambique as well as reductions in the carrying values of Rio Tinto's aluminium assets, including Alcan Pacific Aluminium, which are in the range of US$10 billion ($A10.45 billion) to $US11 billion ($A10.45).
Melbourne-based Rio made the announcement after the Australian sharemarket closed on Thursday.