A total of 453 coal samples from Northern Great Plains subbituminous coal beds, and 92 samples from the Gulf Coast lignite beds were chemically analyzed and studied from 1975 to 1979. These samples were analyzed for major, minor, and trace elements by the U.S. Geological Survey. In addition, ultimate, proximate, and Btu analyses were performed by the Coal Analysis Section of the U.S. Department of Energy.

Of the 18 elements reported in the summary, the geometric means for F, Zn, and S are as much as two-fold higher in ligite, compared with subbituminous coal. The elements Mn, Cr, and Se are more than four-fold higher in lignite than in subbituminous coal. All other reported elements are two to four-fold higher in lignite than in subbituminous.

About 8 metric tons (8 Mg) of Gulf Coast lignite are required to produce 1 billion Btu; in contrast, approximately 6 Mg of Northern Great Plains subbituminous coal are required to produce the same quantity of Btu. According to these comparative tonnages, 1.7 Mg of ash will be produced by combusting 8 Mg of lignite and 0.5 Mg of ash by 6 Mg of subbituminous coal. During the production of 1 billion Btu from lignite, 27,000 g of sulfur will be mobilized and a similar Btu production from subbituminous coal will mobilize 76,000 g of sulfur. Approximately 2,700 g of the other elements will be mobilized during the combustion of lignite and about 730 g will be mobilized from the combustion of subbituminous coal.

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