Coal being excavated at a U.S. mine earlier this month. Coal mining is one of the activities BHP Billiton still considers a core business. SYDNEY—The head of BHP Billiton Ltd. ‘s coal business signaled confidence in the outlook for the strained global coal industry, forecasting increases in world demand for decades to come. Dean Dalla Valle said he expects most demand growth to come from outside China, which has been the primary driver of global commodity prices in recent years. China currently accounts for about half of the world’s coal consumption. “Over the next couple of decades we expect global growth in demand for both energy coal and metallurgical coal,” he said in a speech in Brisbane Wednesday. Although “the likes of India, a country not overly endowed with metallurgical coal, [is] anticipated to be the most significant source of new demand” for coal used in steelmaking, he said. […]