Coal Valley Quadrangle

The earliest record of coal mining in Rock Island County is 1867, when 68,000 tons were mined (indicating that mining started considerably before that year), although production records were not reported until 1882. An 1877 History of Rock Island County states that 46 mines operated in the previous year, producing almost 300,000 tons. All the mines in the Coal Valley Quadrangle mined underground using the room and pillar method. The longwall method was tried prior to 1885 by the Eureka Coal Company (mine index 4949, in the unlocated mines at the back of the report), but that attempt failed due to geologic conditions in the area. The coal was near the surface, often accessed directly from the outcrop at the surface into the hillside. Shafts were rarely 80 feet deep, more commonly 30 to 40 feet.

The only seam mined was the Rock Island Coal. However, the lenticular and discontinuous coal, known locally as the Caseyville Coal (stratigraphically below the Rock Island Coal), may have been the seam mined in some cases, especially by low-volume short term local mines. Both coals undulate and vary considerably in thickness, thickening and thinning from both the top and the bottom of the seam. Coal balls were common in some mines, ranging in size from 1 to 8 inches in diameter. The roof in most mines was reasonably good, although in some mines clay slips would make blocks of roof material prone to failure. Usually the roof material was a hard black shale, sometimes with a competent limestone above the shale. The coal ranged from 1.7 to 6 feet thick, and averaged 3.5 feet.

Coal Mines In Illinois Coal Valley Quadrangle