Petrographic, mineralogical and chemical characterization of certain arctic Alaskan coals from the Cape Beaufort region

Abstract

Coal seams for the Cape Beaufort region of Arctic Northwestern Alaska were sampled by drilling by the U.S. Bureau of Mines, Juneau and the U.S. Geological Survey, Anchorage). Samples from the drill holes were supplied to the Mineral Industry Research Laboratory. These are Cretaceous coals ranging in rank from high volatile bituminous A to B. A total of 48 samples from 18 drill holes intersecting 14 seams were studied. Floatsink separations were made at 1.50 specific gravity for ten of these samples. Raw coals and float-sink pr'oducts were characterized for proximate analysis, ultimate analysis, ash fusibility, vitrinite reflectance, coal petrology in reflected light, quantitative determination of mineral matter by x-ray diffraction and infrared spectrophotometry of low temperature ash, major minor and trace elements by atomic absorption and emission spectrochemical analysis. Influence of beneficiation and geological significance of these characteristics, and organic affinity of trace elements are discussed. A generalized scheme for analysis of coal ash by atomic absorption and emission spectrochemical methods is presented.