BHP Billiton

Mining giant BHP Billiton has written down its US shale assets by $7.2 billion (£5bn) as a result of crumbling commodity prices.

The latest move means BHP has now written down the value of around two thirds of its investment in shale gas in the US.

Falling iron ore, coal, copper and other commodity prices caused BHP's profits to fall 86% last year. And the latest blow comes recently after its Brazilian assets were frozen when a dam burst, causing one of the worst mining disasters in history.

BHP chief executive Andrew Mackenzie said: "Oil and gas markets have been significantly weaker than the industry expected.

"Although we expect prices to improve from their current lows, we have reduced our oil price assumptions for the short to medium term. Our long-term price assumptions continue to reflect the market's attractive supply and demand fundamentals."