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Title: Pyrite in coal: its forms and distribution as related to the environments of coal deposition in three selected coals from western Pennsylvania

Book ·
OSTI ID:5905769

The environment of peat deposition (marine-brackish vs. fresh water) effects the amount of morphology of pyrite in the resultant coal. Three coal samples were studied; two of the Lower Kittanning seam, one marine influenced and the other fresh water deposited, and one sample of the Upper Freeport coal, also fresh water deposited. A microscopic pyrite classification scheme was used to quantitatively describe pyrite occurrences in columns of these three coals. The seams were examined by megascopic and microscopic techniques for both organic and inorganic constituents. Results of the study show that most, if not all, pyritic sulfur was fixed in the peat stage as syngenetic pyrite by anaerobic sulfate reducing bacteria. Sharp contrasts in pyrite amount, morphology, and distribution were delineated in the three coals studied. A marine-brackish water environment of peat deposition favored the formation of pyrite, and coals so influenced were higher in pyritic sulfur than fresh water coals. Pyrite tended to be concentrated in dull layers of the seams, however, the overwhelming majority of pyrite in these layers occurred in the thin vitrain bands. Certain microscopic pyrite types preferentially formed in marine-brackish water influenced coals, and certain types preferred fresh water coals.

OSTI ID:
5905769
Country of Publication:
United States
Language:
English