Abstract: Coal Resources of Illinois

James E. Palmer, Colin G. Treworgy

The identified bituminous coal resources of Illinois are 161 billion tons (145 billion MT), according to a recent estimate by the Illinois State Geological Survey, and exceed the bituminous resources of any other state. About two-thirds of Illinois is underlain by coal-bearing strata of Pennsylvanian age. Major coal seams crop out along the margins of the Illinois basin coal field and are at depths of about 1,000 ft (300 m) in the deep part of the basin in southeastern Illinois. Over 20 billion tons (18 billion MT) of potentially surface-minable coal (<150 ft or 45 m deep, >18 in. or 45 cm thick) have been mapped, of which 5 billion tons (4.5 billion MT) are estimated to be economically recoverable at present. Identified deep minable coal resources occur primarily i two thick, uniform seams-the Springfield-Harrisburg (No. 5) Coal Member and Herrin (No. 6) Coal Member--and underlie most of the Illinois basin coal field. These coal seams and others of Illinois commonly are overlain by black shale or limestone which provides a relatively stable roof for modern, high-speed underground mining. Little exploratory drilling has been done on the Jamestown, Seelyville, De Koven, Davis, Assumption, and other coals which may represent a substantial additional coal resource. Only 4% of the state's identified coal resources are relatively low in sulfur (<2.5%). However, as deeper parts of the basin are explored, new discoveries of low-sulfur coal are expected. At present in Illinois, more than 60 million tons (54 million MT) of coal are produced annually from about 60 mines. At least 12 new mines are expected to open during the next several years, and annual production may exceed 90 million tons (81 million MT) by 1985. The industrial climate for coal mining in Illinois remains hospitable, and continued expansion of mining activity is expected.

AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma