Contamination bill stalls BHP sale BHP Billiton is exploring the potential sale of its old Mount Goldsworthy iron ore project in the Pilbara to a company that plans to reopen the mine, but the deal could be stymied by revelations that BHP faces a potential $100 million clean-up bill after the discovery of acid contamination at the site. Documents obtained by The Australian show BHP has held confidential talks with private company Nimbus Mines as part of a deal in which Nimbus would reopen Mount Goldsworthy -- once a jewel in BHP's Pilbara crown -- as an underground mine.