Cloud Peak Energy Inc. Annnounces Proven And Probable Reserves As Of December 31, 2011 And The Schedule For Full Year And Fourth Quarter 2011 Results

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, announced a substantial increase in proven and probable reserves for the year ended December 31, 2011. Following the successful bids for two large coal tracts at the Antelope mine in May and June of last year, Cloud Peak Energy had approximately 1.37 billion tons of reserves as of December 31, 2011, up from approximately 970 million tons as of December 31, 2010.

		Recoverable Reserves
		12/31/2011						12/31/2010
		Proven		Probable		Total		Total
Mine		(tons in millions)
Antelope		519		164		683		252
Cordero Rojo		274		96		370		385
Spring Creek		286		25		311		329
Decker (50% interest)		3		—		3		4
Total		1,082		285		1,367		970

Schedule for Release of 4Q/FY 2011 Results

Cloud Peak Energy plans to announce its full year and fourth quarter 2011 financial results on February 16, 2012, after the markets close.