Cloud Peak Energy Inc. Provides Third Quarter 2011 Cordero Rojo Mine Production Data to Correct MSHA Site Information

Cloud Peak Energy Inc. (NYSE:CLD), one of the largest U.S. coal
producers and the only pure-play Powder River Basin (PRB) coal company,
is providing third quarter 2011 production data for its Cordero Rojo
mine. It has come to the company′s attention today that due to an
administrative error the production data presented on the Mine Safety
and Health Administration (MSHA) website was inaccurate. For the third
quarter of 2011, Cordero Rojo produced approximately 9.9 million short
tons.

Cloud Peak Energy will announce its third quarter 2011 results on
October 27, 2011, after the markets close. Refer to the company′s
October 17, 2011 press release for access information regarding the
company′s upcoming quarterly earnings announcement.

About Cloud Peak Energy ^?

Cloud Peak Energy Inc. (NYSE:CLD) is headquartered in Wyoming and is one
of the largest coal producers in the United States. As one of the safest
coal producers in the nation, Cloud Peak Energy specializes in the
production of low sulfur, sub-bituminous coal. The company owns and
operates three surface coal mines in the Powder River Basin, the lowest
cost major coal producing region in the nation. The Antelope mine and
Cordero Rojo mine are located in Wyoming and the Spring Creek mine is
located near Decker, Montana. With approximately 1,550 employees, the
company is widely recognized for its exemplary performance in its safety
and environmental programs. Cloud Peak Energy is a sustainable fuel
supplier for approximately 4 percent of the nation′s electricity.

Cloud Peak Energy Inc.

Karla Kimrey, 720-566-2932

Vice
President, Investor Relations