BHP Billiton Limited is a global resources company. The Company is engaged in exploration, development, production, processing and marketing of minerals, such as iron ore, metallurgical and energy coal, copper, aluminum, manganese, uranium, nickel, silver and potash. It is also engaged in exploration, development, production and marketing of conventional and unconventional oil and gas. The Company operates through segments: Petroleum and Potash, Copper, Iron Ore and Coal. The Company's Petroleum and Potash segment is engaged in exploration, development and production of oil and gas and potash pre-development. The Copper segment is engaged in mining of copper, silver, lead, zinc, molybdenum, uranium and gold. The Iron Ore segment is engaged in mining of iron ore. The Coal segment is engaged in mining of metallurgical coal and thermal (energy) coal.