WRIGHT, Wyo. (December 17, 2004)  - Arch Coal, Inc. (NYSE: ACI) announced its Black Thunder mine in Wyoming achieved a one-billion-ton shipment milestone on Friday, Dec. 17, 27 years after the mine's first coal shipment on Dec. 14, 1977. Today, Black Thunder produces nearly 10 percent of the U.S. coal supply. That's enough coal to provide electricity to 5.8 million American households.

"We're proud to be the first coal mine to ever achieve this milestone," said Paul Lang, president of Thunder Basin Coal Company and general manager of the Black Thunder mine. "It's especially rewarding for our employees and retirees who all worked so hard to make this happen in a safe and environmentally responsible manner."

Coal provides the fuel to generate more than 50 percent of our nation's electricity. "This shipping milestone is also significant for Americans, who use nearly 7,500 pounds of coal per person each year in the form of electricity," said Lang. "Black Thunder Mine has proven over the last quarter-century that we can keep pace with the growing energy demands."

On average, Black Thunder produces nearly three tons of clean-burning, low-sulfur coal per second, 24 hours a day, 365 days a year. During the life of the mine, roughly 71,428 trains, or 9.3 million cars, have been loaded with coal. Stretched end-to-end, the railcars would circle the equator more than three times.

Arch's Black Thunder operation in Campbell County is one of the world's largest and most efficient coal mines. Black Thunder's low-sulfur coal is shipped to more than 23 states and two foreign countries. Nearly all of Black Thunder's customers use the coal to generate electricity, including more than 100 U.S. coal-fired units.

St. Louis-based Arch Coal is the nation's second largest coal producer, and employs 850 people in Wyoming. Through its subsidiary operations in West Virginia, Kentucky, Virginia, Wyoming, Colorado and Utah, Arch provides the fuel for approximately 7 percent of the electricity generated in the United States.