History

Arch Coal was formed in July 1997 through the merger of publicly traded Ashland Coal, Inc. and privately held Arch Mineral Corporation. Arch Mineral had its origins in 1969, when it was formed as a partnership between Ashland Oil (now Ashland Inc.) and the Hunt family of Dallas, Texas; Ashland Coal was formed in 1975 as a wholly owned subsidiary of Ashland Oil. With the completion of the merger, Arch became the leading producer of low-sulfur coal in the eastern United States.

In June 1998, Arch Coal expanded into the western United States with the acquisition of the coal assets of Atlantic Richfield. Included in this transaction were the Black Thunder and Coal Creek mines in the Powder River Basin of Wyoming; the West Elk longwall mine in Gunnison County, Colorado; and a 65% interest in Canyon Fuel Company, which operates three longwall mines in Utah.

In October 1998, Arch added to its Powder River Basin reserves when it was the winning bidder on Thundercloud, a 412-million-ton federal reserve tract adjacent to the Black Thunder mine.

In July 2004, Arch Coal solidified its position as a leading producer of high-Btu, low-sulfur western bituminous coal with the acquisition of the remaining 35% interest in Canyon Fuel Company and its 161-million-ton reserves.

In August 2004, Arch again expanded its position in the Powder River Basin with the acquisition of Triton’s North Rochelle mine adjacent to Arch’s existing Black Thunder operation. By integrating the North Rochelle mine with Black Thunder, Arch created the premier mine in the nation’s fastest growing coal supply region.

In September 2004, Arch again added to its Powder River Basin reserves when it was the winning bidder on Little Thunder, a 719-million-ton federal reserve tract adjacent to the Black Thunder mine.

In December 2005, Arch Coal sold select eastern assets to Magnum Coal Company to unlock the value of some of its Central Appalachian holdings, sharpened its focus in that region, and strengthened its balance sheet in preparation for future growth.

In August 2006, Arch Coal acquired a one-third interest in Knight Hawk Coal, a growing coal producer in the Illinois Basin.

Today, Arch Coal is one of the nation’s largest and most efficient coal producers. The company’s core business is providing U.S. power generators with clean-burning, low-sulfur coal for electric generation. Through its national network of mines, Arch supplies the fuel for approximately 6 percent of the electricity generated in the United States. The company is listed on the New York Stock Exchange (NYSE: ACI) and maintains its corporate headquarters in St. Louis, Mo.