Coal Mine Subsidence
Coal mining in Iowa dates from 1840. Most of Iowa's coal mines were underground mines, possibly as many as 6,000 in 38 counties, potentially affecting 80,000 acres. Long-lasting detrimental effects of underground mining includes subsidence, the process by which the land surface sinks from collapse of the mine roof or failure of the support pillars. Subsidence has caused damage to buildings and property in both rural and urban areas in Iowa. A 1984 national publication estimated that 3,800 urban acres in Iowa are threatened by mine subsidence; a conservative cost estimate to alleviate subsidence problems, just in these areas, was $114 million (Gray and Bruhn, 1984).
Gray, R.E., and Bruhn, R.W., 1984, Coal mine subsidence - eastern United States in Holzer, T.L., ed., Man-induced land subsidence: Reviews in Engineering Geology, v. VI, Geological Society of America, p. 124.
Coal Mine Subsidence Publications: