BHP Billiton Ltd., the world's largest mining company, may build a plant to process molybdenum at a Chilean mine.

The plant would produce 5,000 to 12,000 metric tons a year of molybdenum concentrate at the company's Escondida mine, according to a March 14 report on the project. The report by mine manager Minera Escondida Ltda. was posted on the Web site of the government's environmental regulator.

BHP owns 57.5 percent of Escondida, located in northern Chile. Rio Tinto Plc owns 30 percent and a group led by Mitsubishi Corp. owns 10 percent. International Finance Corp. owns the rest.