Northern Great Plains lignites

North America.. In the United States, lignite deposits are located in the northern Great Plains and in the Gulf states. Subbituminous coal is found along the Rocky Mountains. The western half of North Dakota has about 74% of the nation s resources, Montana 23%, Texas 2%, and Alabama and South Dakota about 0.5% each. The lignite resources to 914 m represent 28% of the total toimage of all coal deposits in the United States. The lower cost and low sulfur content have contributed to rapid growth in production. 

The U.S. has vast coal resources of various geologic age (Carboniferous to Tertiary) and rank (lignite to anthracite). The regions with major coal resources in the conterminous U.S. are divided into six provinces Eastern, Interior, Rocky Mountains, Northern Great Plains, Gulf, and Pacific Coast. In addition, there are Alaskan coal fields (1). Information concerning geographic area, age, rank, reserve base, and sulfur abundance in coals from major basins in these provinces is summarized in Table I. 

The Structure and Reactions of Northern Great Plains Lignites... 

Table I. Average Analyses of Northern Great Plains Lignite and...

The aromaticity for several samples of Northern Great Plains lignites, as measured on run-of-mine material, lies in the range of 0.61 to 0.66. A sample of Australian brown coal had an aromaticity of 0.56 a sample of Minnesota peat had an aromaticity of 0.50. Samples of vitrinite concentrates from the Northern Great Plains lignites were more aromatic, with measured values from 0.72 to 0.74. 

Exhaustive analyses of the products from liquefaction of Northern Great Plains lignite at 400°C and higher in the presence of tetralin (see (9) for example) have never identified diphenylmethane or related compounds. Absence of diphenylmethane constitutes strong circumstantial evidence for the relative unimportance of methylene linkages between aromatic clusters. 

Analysis of the Northern Great Plains Province Lignites and Their Ash A Study of Variability," U.S. Bureau of Mines Report RI 7158, 1968. 

Stone LR, Erdman JA, Feder GL and Holland HD (1983) Molybdenosis in an area underlain by uranium-bearing lignites in the Northern Great Plains. J Range Manage 983 280-285. 

Table II. Average Ash Compositions of and Bituminous Coals, Northern Great S03-Free Basis Plains Lignites...

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