FILE - In this July 2, 2014 file photo, smoke billows out of a chiming chimney stack of BHP steel works at Port Kembla, south of Sydney, Australia. BHP Billiton, the world's biggest miner, reported an 86 percent drop in annual profit on Tuesday, Aug. 25,2015, amid plummeting commodity prices, as the company warned that China's slowing economy would lead to further market volatility. BHP saw a net profit of $1.9 billion for the 12 months to June 30, down from $13.8 billion a year ago.(AP Photo/Rob Griffith, File)