USCHEM, a geochemical data file, is a part of the U.S. Geological Survey's computerized National Coal Resources Data System, NCRDS. The purpose of this data file is to store and retrieve geographic, geologic, and chemical-analytical information for each coal and coal-related rock sample submitted for analysis to the USGS. Each sample is analyzed by the USGS for major-, minor-, and trace-element, and oxide concentrations; splits of coal samples are also analyzed by the U.S. Department of Energy for proximate and ultimate data, forms of sulfur, free-swelling index, ash-fusion temperatures, and Btu information.

Data for samples of the Waynesburg coal bed in the Appalachian region are useful to demonstrate the capabilities of USCHEM as an aid to geologic, geochemical, environmental, and technological studies. Available techniques for presenting and manipulating the data are: sorting, listing, mathematical redefinition, tabulation, statistical analysis, and graphic displays. Graphic displays include: plots of point locations, trend surfaces of single and multiple variables, isoline maps, histograms, and two- and three-dimensional graphs. Data in USCHEM can be used to delineate geographical areas that meet (1) specific individual criteria, for example, areas where arsenic is < 10 ppm, or (2) multiple criteria, for example, areas where sulfur is < 3%, ash is < 10%, and Btu is > 10,00 . Trace-element data can be presented on an ash or whole-coal basis, and proximate and ultimate data on an "as-received" or "dry" basis.

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