Marius Kloppers, chief executive of BHP Billiton.

BHP Billiton on Tuesday was granted a four-year extension by the South Australian state government to come up with a cost-effective plan to expand its Olympic Dam copper and uranium mine.

As part of the deal, BHP has committed to spending A$650 million on pre-project research and community work, according to a statement by South Australia state premier Jay Weatherill.

The world's biggest miner scrapped a $20 billion-plus plan to expand the mine in August, saying its proposal to dig an open pit was too expensive and it was going to start from scratch to find a cheaper way to extract copper. - Reuters