“…Highly carbonaceou.8 aaterials (rider coal, parting•, leona.rdite and carbona.ceoua aha.lea) have been attributed vi.th producing acidity upon oxidation. Acid production from carbona.ceou.8 aateriala baa been identified in overburden and abandoned coal apoils in Wyoming, Kew Mexico, Montana, Utah, Colorado and Texu (Bola and llaore, 1986;loon, 1986;Hagener, 1985;Boon and Saith, 1985;Piaher and Munshower, 1984;Miller et al, 1976;Arora et al, 1980). Sulfide minerals occur in significantly higher concentratioUB in the finer grained aedillentary rocka aaaociated with coala: roof ahales, floor aaterial and parting • (Arora et al, 1980;Valkovic, 1983).…”