St. Louis-based Arch Coal is one of the United States largest coal producers. The company exclusively mines clean-burning, low-sulfur coal. In total, Arch Coal contributes more than 10 percent of America s coal supply from its complexes in West Virginia, Wyoming, Kentucky, Virginia, Colorado and Utah. With more than 140 million tons of pro forma coal sales in 2004, the company provided United States utilities with the fuel for more than 5 percent of the nation s electricity. Arch Coal also controls a vast domestic reserve base totaling more than 3.5 billion tons. Of that, 90 percent is low in sulfur. Arch Coal has a location at the West Elk Mine in Somerset, Colo.