Cordero Rojo

Overview

Located approximately 25 miles south of Gillette, Wyoming, Cordero Rojo Mine is in the southern portion of the Powder River Basin. In 1993 Rio Tinto Energy America (RTEA) acquired the Cordero Mine from the Sun Oil Company. RTEA then purchased the adjacent Caballo Rojo Mine from the Marigold Land Company, a subsidiary of Drummond Company, Inc. in 1997. RTEA subsequently merged the two facilities operationally and those synergies continue today under Cloud Peak Energy.

In 2010, Cloud Peak Energy acquired Rio Tinto's interest in the Cordero Rojo coal mine therefore becoming its sole owner.

Cordero Rojo mines the Wyodak seam, the principal economic coal seam in the Wyoming portion of the Powder River Basin. The average seam thickness is between 55 to 70 feet. The typical average heating quality of the subbituminous coal is 8,425 Btu.

Cordero Rojo Mine utilizes a highly efficient combination of dragline open-pit operations with truck-shovel assist to produce significant volumes of coal each year.  In 2010, Cordero Rojo mined and shipped more than 38.5 million tons of coal.

Cordero Rojo is permitted to mine 65 million tons of coal per year. Cordero Rojo sells its coal primarily to electric utilities in the west, midwest and southeast United States.

The Cordero Rojo Mine full-time workforce total was 545 employees at year-end 2010. Cordero Rojo has won the Sentinels of Safety Award five times. The Sentinels of Safety is an award given by the U.S. Department of Labor. This award recognizes the surface coal mine in the United States with the best safety performance for the year.

From 1996 to 2006 Cordero Rojo was recognized four times by state agencies for accomplishments in reclamation and wildlife habitat development.

Location

Located approximately 25 miles south of Gillette, Wyoming, Cordero Rojo Mine is in the southern 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

Cordero Rojo mines the Wyodak seam, the principal economic coal seam in the Wyoming portion of the Powder River Basin. The average seam thickness is between 55 to 70 feet. The typical average heating quality of the subbituminous coal is 8,425 Btu.

Mining & Operation

Cordero Rojo Mine utilizes a highly efficient combination of dragline open-pit operations with truck-shovel assist to produce significant volumes of coal each year.  In 2010, Cordero Rojo mined and shipped more than 38.5 million tons of coal.

Cordero Rojo is permitted to mine 65 million tons of coal per year. Cordero Rojo sells its coal primarily to electric utilities in the west, midwest and southeast United States.

The Cordero Rojo Mine full-time workforce total was 545 employees at year-end 2010. Cordero Rojo has won the Sentinels of Safety Award five times. The Sentinels of Safety is an award given by the U.S. Department of Labor. This award recognizes the surface coal mine in the United States with the best safety performance for the year.

Processing

Processing consists of crushing and washing of coal prior of stockpiling and getting it ready for railway shipping to customers. Customers are electric utilities in the west, midwest and southeast United States.

Environment & Community

Based on the average sulphur content of 0.69% coal produced at the Cordero Rojo mine is considered to be compliance coal under the Clean Air Act.

Cloud Peak Energy works with the Thunder Basin Grassland Prairie Ecosystem Association in development of greater sage-grouse conservation approaches specifically adapted to northeast Wyoming, an area encompassing their Antelope and Cordero Rojo mines.

During 2011 the company provided stable groupings of trees to help eagles and hawks with perching, nesting and roosting sites in prairie dogs habitats near the mine.

Land disturbed by mining is continuously reclaimed in sequences concurrent with mining.