India's largest aluminium maker, the Aditya Birla group's Hindalco Industries Ltd, said on Friday it would buy copper mines in Australia from Straits Resources Ltd for A$79.80 million (US$47.11 million).

Hindalco has signed a purchase agreement with Straits Resources, an Australian coal and copper producer, which owns the Nifty mines through Straits (Nifty) Pty Ltd, the Indian group's chairman, Kumar Mangalam Birla, told a news conference.

"We would ideally like to source about 25 per cent of our copper concentrate requirements from our own mines," Birla said, adding that the Nifty mines would supply 12 to 13 per cent of the group's raw material requirements.

The group's copper making company, Indo Gulf Corporation, expects to raise its capacity to 250,000 tonnes a year from 150,000 tonnes in the next two to three months, for which the mines will prove useful, Birla said.

Hindalco is in the process of taking over Indo Gulf's copper business as a part of the group's restructuring exercise, which is likely to be completed by March.

Kumar Mangalam Birla said the group was also looking at other mines, but did not provide details.

As part of the deal with Straits, a Hindalco subsidiary will take over Nifty's operations, which are in the eastern Pilbara region of western Australia, the Aditya Birla group said in a statement.

The Pilbara mines are estimated to have 148 million tonnes of ore containing 1.3 per cent of copper, the statement said.

The sulphide in the ore can produce up to 100,000 tonnes a year of copper in concentrate. Nifty also makes 27,500 tonnes of copper cathodes a year.

The Indian company will get rights to explore the Paterson range, which has copper and gold reserves.

Hindalco also plans to buy Strait's entire 50 per cent stake in its Maroochydore joint venture in Australia for A$10 million.

The venture has mines with 51 million tonnes of ore with 1.1 per cent of copper.

The purchases still require approvals from the Reserve Bank of India and the Australian government, Birla said.