RESOURCE ASSESSMENT OF THE SPRINGFIELD, HERRIN, DANVILLE AND BAKER COALS IN THE ILLINOIS BASIN

The goals of this assessment were to provide overviews of the geologic setting, distribution, quantity, and quality of the major producing Pennsylvanian coals in the Illinois Basin. These coals are the Springfield, Herrin, Danville, and Baker Coals. This assessment was a cooperative effort between the state geological surveys of Illinois, Indiana, and Kentucky and the U.S. Geological Survey. The main products of this assessment are digital databases that contain all publicly available point-source data on thickness, depth, and coal quality. From these databases, regional and statewide digital maps were prepared that depict coal extent, thickness, elevation (structure), mined-out areas, areas where the coal may potentially be mined at the surface or underground, and geographic distribution of ash, sulfur, and major, minor, and trace-element contents.

Coal-bearing rocks in the basin underlie 36,800 mi² in Illinois, 6,500 mi² in southwestern Indiana, and 6,400 mi² in western Kentucky. Coal production from all coals in the basin in 2000 was about 88.4 million short tons (mst), down from 104 mst in 1999. Remaining resources (>14 in thick; <2,000 ft depth) of the Springfield Coal are estimated at 80,700 mst (61,700 mst in Illinois, 12,100 mst in Indiana and 7,000 mst in western Kentucky). Approximately 65,700 mst (81 %) of these resources are in relatively thick coal (>42 in). In general, the Springfield Coal has medium ash (11.2 %) and high sulfur (3.5 %) contents. Mean, as-received, calorific value is 11,280 Btu/lb. Remaining resources of the Herrin Coal are estimated at 81,600 mst (78,900 mst in Illinois and 2,600 mst in western Kentucky). Approximately 68,700 mst (84 %) of these resources are in relatively thick coal. In general, the Herrin Coal has medium ash (10.9 %) and medium to high sulfur (3.0 %) contents. Mean, as-received, calorific value is 11,170 Btu/lb. Remaining resources of the Danville and Baker Coals are estimated at 27,400 mst (17,900 mst in Illinois, 6,300 mst in Indiana, and 3,400 mst in western Kentucky). About 10,800 mst (39 %) of these resources are in relatively thick coal. In general, the Danville and Baker Coals have medium ash (11.9 %) and medium to high sulfur (2.9 %) contents. Mean, as-received, calorific value is 10,920 Btu/lb.