The biggest single-pit open-cut iron ore mine in the world, the BHP Biliton Mount Whaleback mine, 455 km (283 miles) south of Port Hedland is seen in this undated handout photograph obtained August 12, 2009. BHP Billiton Ltd, the world’s largest miner, reported a 30 percent slide in annual profit excluding writedowns, its first fall in seven years, pummelled by a slump in metals prices and demand. REUTERS/BHP Biliton/Handout (AUSTRALIA BUSINESS ENVIRONMENT) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS