Rio Tinto reveals US probe into Mozambique writedown

Anglo-Australian miner Rio Tinto on Thursday said that for more than three years it has faced an investigation by top US financial regulator SEC over a writedown of Mozambique assets.

"In response to press reports regarding a US Securities Exchange Commission investigation, Rio Tinto confirms that it is cooperating with inquiries from the relevant authorities relating to the impairment included in the company's 2012 accounts in respect of Rio Tinto Coal Mozambique," Rio said in a statement.

"As the SEC investigation, which started in April 2013, remains ongoing it would be inappropriate to comment further at this time," it added.

In January 2013, Mozambique cast doubt over why the miner made a US$3 billion writedown on its Mozambican assets -- an amount that contributed to Rio chief executive Tom Albanese losing his job the same month.

After spending close to $4 billion acquiring Australian-listed Riversdale Mining in 2011, Rio Tinto said it struggled with the cost of transporting coal from mines to market.

But Mozambique expressed dissatisfaction with the explanation.

Albanese resigned also as Rio suffered impairments of $10-11 billion, mostly related to the 2007 purchase of aluminium firm Alcan.