St. Louis, Missouri – June 6, 2000 - Arch Coal, Inc. (NYSE:ACI) announced today that the U.S. Mine Safety and Health Administration (MSHA) had approved a ventilation plan for the company’s West Elk mine. The West Elk mine, which is located in Gunnison County, Colorado, has been idle since January 28, 2000, when combustion-related gases were detected there.

"The approval of the ventilation plan represents one of the final steps in our efforts to resume production at West Elk," said Gene DiClaudio, president of Arch’s Mountain Coal subsidiary and general manager of the West Elk mine. "We expect to complete rehabilitation work at the mine in the next two to three weeks and resume production with the longwall before the end of June."

Arch had previously determined that the combustion was occurring in the mine’s old workings. The affected area was subsequently sealed off from the active mining area and flooded with water. West Elk shipped 7.3 million tons of coal last year and employs approximately 300 people. Most of the mine’s output is sold to electric generating stations in the western and midwestern United States.

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including Arch Coal’s expectations concerning the timing of certain operating events. Although Arch Coal, Inc. believes the expectations reflected in such forward-looking statements are based on reasonable assumptions, it can give no assurance that its expectations will be attained. Factors that could cause actual results to differ materially from expectations include changes in local or national economic conditions; changes in mining rates and costs for a variety of operational, geologic, permitting, labor and weather-related reasons, including equipment availability; and other risks detailed from time to time in the company’s reports filed with the Securities and Exchange Commission, including quarterly reports on Form 10-Q, reports on Form 8-K, and annual reports on Form 10-K.

Arch Coal is the nation’s second largest coal producer, with subsidiary operations in West Virginia, Kentucky, Virginia, Wyoming, Colorado and Utah. Through these operations, Arch Coal provides the fuel for approximately 6% of the electricity generated in the United States.