Petrographic zonation within the Pittsburgh coal

The Pittsburgh coal was sampled with three columns of oriented blocks in two adjacent surface mines in Harrison Co., WV and one column of 15-cm increment samples from an outcrop 50 km to the northeast in Monongalia Co., WV. Each of the oriented blocks was described as to lithotype. Lithotype bands continuous across the blocks were sampled and analyzed for maceral and mineral matter content. Each of the 15-cm increment samples was also analyzed for maceral and mineral matter. The individual lithotypes were compared as to maceral and mineral matter content between the two benches of the Pittsburgh coal and between the three columns.The data were converted to equal 10-cm intervals by stratified random sampling. Petrographic zones were established based upon stratigraphic variations in maceral group and mineral matter content. The lateral continuity of the zones were observed over short (75 m), intermediate (575 m) and long (50 km) distances.The geochemical environment of deposition of each zone observed in the column samples was interpreted based upon the maceral and mineral matter content and the chemical coal model presented by Renton and Cecil (1979).