Geochemical characteristics of the Springfield (western Kentucky No. 9) coal in western Kentucky
L. Lynn Chyi, Jack H. Medlin, 1990. "Geochemical characteristics of the Springfield (western Kentucky No. 9) coal in western Kentucky", Recent Advances in Coal Geochemistry, L. Lynn Chyi, C.- L. Chou
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Bench samples from the Springfield (western Kentucky No. 9) coal bed have been analyzed for 25 major, minor, and trace elements, including Au and Pt, by instrumental and radiochemical neutron activation analyses. The elemental enrichment trend of this coal bed, compared with crustal abundances, is similar to the Pittsburgh coal bed. Except for Mn, all the other elements in the western Kentucky No. 9 coal have a larger or comparable range of variation when compared with the Pittsburgh bed. The coefficients of variation increase with decreasing concentrations, or remain constant and independent of concentrations. They could be used in evaluating the mode of occurrence of chemical elements.
The abundance of the chemical elements, particularly those at trace concentrations, are believed to have several sources. There are quantities inherent from plant debris, those derived from coal-forming processes, and quantities added from or lost to enclosing rocks during ground-water processes. The quantities from each source are not easily determined, but their source can be approached through the use of elemental ratios of coherent pairs. Analytical data are compared to values interpolated from U.S. Geological Survey isochem maps. Among the eight elements compared, the content of Al, Cr, Na, and Sb appear to correlate well.
Three kinds of elemental abundance variation can be recognized. These are regional, local, and in-bed variations. On the basis of study of elemental distributions within mine locations, five variation types are identified. Only types I and V can be contoured directly with simple channel sampling. Local variation of the elements should be assessed for other variation types and composite channel samples should be collected to draw meaningful regional distribution contours. For the purpose of bed identification, coherent triads are presented. The triad Al-La-Sc is the best in characterization of a bed. The triads Br-Cs-Na and Co-Ga-Th are not useful for bed fingerprinting, but they are probably useful to identify coal beds locally.