ECOS Guide to the Ecology of the Northern Rockies

Montana Coal Production

Powder River Basin

The coal industry in Montana supports the generation of electricity. Basically all of the coal mined in Montana eventually is converted to electricity. Coal-fired power plants provide more than half of the electricity in Montana, while most Montana coal is exported to primarily Midwestern utilities.  Although the nation’s reliance on natural gas and wind is increasing, coal continues to provide half of our electricity.

Montana is the sixth largest producer of coal in the United States, almost all of which is mined from the Powder River Basin south and east of Billings.  Montana coal production is almost entirely low-sulfur subbituminous coal, with 17-18 million Btu per ton.  Like most western coal, Montana coal is cleaner but lower in heat content than eastern coal.

The coal beds of the Powder River Basin began to form about 60 million years ago, at the end of the formation of the Rocky Mountains.  The land east of the mountains was under a shallow sea, but began to rise when mountain formation ceased.  During this time, the climate in the region was subtropical, averaging about 120 inches of rainfall a year. For about 25 million years, lakes and swamps covered the basin floor.  Organic matter in the swamps accumulated into peat bogs and was buried by hundreds of meters of sediments eroded from the mountains to the west.  Through this burial, the layers of peat were compressed, forming coal.  Over the last several million years, much of the overlying sediment has eroded away, leaving the coal seams near the surface.

ECOS Program
Division of Biological Sciences
The University of Montana-Missoula | 32 Campus Drive
Missoula, MT 59812
phone: 406-243-6016 | fax: 406-243-4184
ecosproject@gmail.com
Copyright 2003

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