St. Louis - December 13, 2001 - Arch Coal, Inc. (NYSE:ACI) today announced that it will invest an additional $100,000 in ZECA Corporation, successor to the Zero Emission Coal Alliance, over the next two years. ZECA is comprised of coal producers, power generators, mining companies and scientific organizations that are working together to develop an emission-free process for producing electricity from coal. Arch is a founding member of ZECA.

"We are excited about the work that the alliance is doing," said Steven F. Leer, Arch Coal's president and chief executive officer. "The power generation industry has made tremendous strides in reducing emissions at coal-fired power plants in recent years, and we expect that progress to continue in the future. The ultimate goal is a zero emission coal plant, and we are increasingly confident that such a plant is achievable."

Zero emission coal technology is based on new applications of well-known science and has the potential to provide low-cost, clean and copious fossil energy to meet increased U.S. and world energy demands. The Department of Energy is a strong believer in the future viability of zero emission coal technology and has implemented a program entitled Vision 21 in pursuit of this objective.

"Coal is our nation's most abundant energy resource and the fuel source for more than 50% of the electricity Americans use each day," Leer said. "By pursuing increasingly clean ways to use this plentiful and low-cost resource, we are making an investment in both the environment and America's long-term energy security."

Coal represents 85% of America's hydrocarbon resources. At current consumption rates, the United States has an estimated 250-year supply of coal.

Additional information on ZECA can be found at www.zeca.org.

Arch Coal is the nation's second largest coal producer and mines low-sulfur coal exclusively. Through its subsidiary operations in West Virginia, Kentucky, Virginia, Wyoming, Colorado and Utah, Arch provides the fuel for approximately 6% of the electricity generated in the United States.