Revisiting the petrology of lower Pennsylvanian (Namurian and Langsettian) coals in southern West Virginia and southwestern Virginia, USA

Namurian and Langsettian coals representing a vertical span of about 650 m were sampled from cores in southern West Virginia and western Virginia. The coal rank ranges from medium through low volatile bituminous. Historically, a significant portion of the production from the region has been for smokeless steam coals and for metallurgical coal. Despite the presence of thrust faults and the potential for fault-induced movement of mineralizing fluids, a depth-of-burial/geothermal-gradient model, as proposed earlier, appears to be sufficient to describe the increase of rank with depth. The coals generally have >70% total vitrinite (mineral-free basis) and a telovitrinite/(telovitrinite + detrovitrinite) ratio exceeding 0.75. Fusinite dominates the inertinite group macerals. An unnamed Langsettian coal had a high liptinite content but, otherwise, in part owing to the difficulty of detecting liptinites in medium and low volatile bituminous coals, liptinite appears to be sparse. Among the coals in the study, not all of them have been extensively mined. The Pocahontas coals represent the most significant economic resource.