Antelope

Overview

Antelope Mine is located fifty-five miles north of Douglas, Wyoming in the south-central portion of the Powder River Basin.

Rio Tinto Energy America acquired the mine in 1993 from Northern Energy Resource Company, a mining and natural resource company of PacifiCorp.

Antelope Mine is now owned and operated by Cloud Peak Energy.

It is a surface coal mining operation producing low sulphur 8,880 Btu thermal coal from an operation permitted for the production of 42 million tons of coal annually.

Location

Antelope Mine is located fifty-five miles north of Douglas, Converse County, Wyoming, USA in the south-central portion of the Powder River Basin.

The Powder River Basin is sandwiched in between the Black Hills and the Big Horns Mountains and is a result of their uplifting, an event  that ended 45 million years ago. At that time the region indulged in a rainy subtropical climate that favored the development of large palm  trees on the land and crocodiles in very large swamps and lakes that riddled the flat basin floor.

Over the next 25 million years rivers and heavy tropical rains transported and deposited huge amounts of dead vegetation in the swamps,  thus creating thick layers of extremely pure peat. In time the peat got  buried under subsequent sediments and by being subjected to high  pressure and temperature was transformed into one of the world's lowest ash content coals - the Fort Union and Wasatch Formations. During the  last million years the sedimentary layers lying on top of the coal seams  were eroded away thus bringing the coal close to the surface.

Geology and Mineralization

Antelope Mine is located at the south end of the Wyodak seam, the principal economic coal seam in the Wyoming portion of the Powder River Basin.

Two different seams of the Wyodak are mined at Antelope: the Anderson and the Canyon.

The Anderson coal seam is 44 feet thick and the Canyon coal seam is 36 feet thick. The coal's typical average quality is 8,850 Btu subbituminous thermal coal

Mining & Operation

Antelope Mine utilizes a highly efficient combination of dragline open-pit operations with truck-shovel assist to produce significant volumes of coal each year.  In 2009, Antelope mined and shipped nearly 34 million tons of coal.

The Antelope Mine employee total was approximately 500 at year-end 2009. Antelope’s annual production rate has continued to increase each year for the last 24 years. The mine is permitted for production of 42 million tons of coal annually.  Coal mined from Antelope is shipped primarily to electric utility customers in Illinois, Oklahoma, Michigan and Texas.

 Antelope mined and shipped 37.1 million tons of low sulfur, 8,880 Btu coal in 2011.

Processing

Coal is washed of impurities prior of being shipped.

Environment & Community

Antelope Mine received two prestigious awards: the State of Wyoming Mine Safety Awardin the Large Surface Mine category, and the Safe Sam Award, for safety performance records as the safest large mining operation and the safest coal mine inWyomingduring 2007 and 2008. Antelope was also awarded the Sentinels of Safety award in 2000 by the U.S. Department of Labor. The Sentinels of Safety is an award that recognizes the surface coal mine in theUnited Stateswith the best safety performance for the year. Antelope was also recognized for the best safety performance in the U.S.in the surface coal mine category in 2000.

In 2003, 2009 and 2010 the Antelope Mine won awards from state and national organizations recognizing excellence in mine reclamation and wildlife stewardship.