Anglo-Australian giant was forced to book a $7.2bn writedown in shale operations last year. : Mining giant BHP Billiton has unveiled plans to sell its US shale operations, after pressure from investors to get rid of the business took its toll on the board. Shareholder Elliott Management, which owns 5% of the company's London-listed shares, has actively campaigned since April for BHP to offload its shale assets in the US and the FTSE 100 company confirmed on Tuesday (22 August) that it was "actively pursuing options to exit".