Oxford Resource Partners strives to get its customers steamed. An operator and acquirer of surface coal mines, the company produces steam coal used by power plants and other energy producers to fire steam boilers. It owns and operates about 19 surface mines in the Northern Appalachia region and the Illinois Basin. In 2009 the company, which has assets that include more than 91 million tons of proved and probable reserves, produced 5.8 million tons of coal. It serves markets in Illinois, Indiana, Kentucky, Ohio, Pennsylvania, and West Virginia and has counted AEP, Duke Energy, and East Kentucky Power as major customers. Formed in 2008, Oxford Resource Partners filed an initial public offering (IPO) in 2010.