The inorganic geochemistry of two western U.S. coals: Emery Coal Field, Utah and Powder River Coal Field, Wyoming

he inorganic geochemistry of coals from the Cretaceous, Emery Coal Field, Utah and the Paleocene, Powder River Coal Field, Wyoming have been determined using XRF, various neutron activation techniques and SEM/EDS. Differences in deposition environments for the two coal deposits results in a higher ash content in the Utah coal (avg., 8.2%) relative to the Wyoming coal (avg., 4.4%). The Utah coal contains higher concentrations of 27 of the 40 elements detected in both coals. The geochemistry of overburden and clinker associated with the Wyoming coal and Fe-sulfide nodules (selected elements) from within the Utah coal is also reported.;Specific mineral phases within the two coals have been identified using SEM/EDS. Discrete grains contained in the surfaces of pellets prepared from crushed whole coal were analyzed and their mineralogies determined based on stoichiometry.;The oxidation of Fe-sulfide to hydrous Fe-sulfates is documented. Paragenesis results in szomolnokite developing on "clean" Fe-sulfide while halotrichite is the typical secondary phase which forms in the presence of clays.;The environmental aspects of coal utilization are discussed. A new term, "The Effective Coal Concentration (ECC)" is proposed to better assess the amounts of potentially harmful (as well as economically important) elements released to the environment as a result of coal utilization.;Some new conclusions regarding the organic/inorganic affinities of the elements are presented based on the physicochemical nature of the element at the time of emplacement. Elements with ionic potentials (IP)...