Petrography of the Middle Pennsylvanian Upper Elkhorn No. 3 Coal of Eastern Kentucky, U.S.A.

Coal rank, maceral composition, ash and sulphur content were determined for 62 channel and borehole samples of the Upper Elkhorn no. 3 coal (Middle Pennsylvanian Breathitt Formation (Westphalian B) of eastern Kentucky. Regional rank trends show an overall increase in rank from high volatile C bituminous in the NW to high volatile A bituminous rank in the SE, but overprinted on the primary rank trend are several high rank anomalies. The high rank overprints occur near specific structural features, suggesting that tectonic forces responsible for the present-day structures, active during post-deposition and possibly syn-depositional time, influenced coalification of the Upper Elkhorn no. 3 coal. The vitrinite maceral group usually comprises > 70% of coals, but relatively lower vitrinites, and concomitant higher inertinites, are found in the vicinity of two high rank overprints, suggesting that structural mechanisms affecting Breathitt coals in post-depositional time may also have been affecting actual peat formation during Breathitt time. Average ash content is 7.7%, with values usually ranging from 4 to 8%. Total sulphur values range from 0.6% to 5.0%, with the average for all samples being 1.7%. Ash and sulphur trends and possible relationship of trends to petrographic characteristics are not readily apparent.