Update | Rio Tinto sells copper mine to Chinese firm

China Molybdenum, the nation's second-biggest producer of the steelmaking material, has agreed to pay US$820 million for Rio Tinto's Northparkes copper mine in Australia.

The sale is expected to be completed by the end of the year, Rio said yesterday. London-based Rio owns 80 per cent of the mine with the balance held by Sumitomo, which has the right to match the offer. It's valued at about US$800 million, Citigroup said in a February report.

Buying the stake, a transaction which would be the third-largest purchase by a Chinese company of a mining asset this year, gives China Molybdenum control of an operation that provided 43,100 tonnes of mined copper for Rio in 2012 as well as an underground training centre.

The world's second-biggest mining firm is joining global rivals in selling assets after falling commodity prices crimped revenue.

The sale highlights "that there are Chinese companies wishing to invest offshore," said Glyn Lawcock, Sydney-based head of resources research at UBS. "It shows people are looking for copper assets as well."

Rio fell 0.23 per cent to A$57.11 in trading in Sydney yesterday. The stock has dropped 13 per cent this year.