Map of coal-mining features, Allegheny County, Pennsylvania

This map is one result of a series of studies sponsored by the Appalachian Regional Commission as part of a larger U.S. Geological Survey program of environmental analysis of a part of southwestern Pennsylvania. The map summarizes surface features resulting from coal mining. The distribution of surface features is largely from 1973, 1:12,000 scale aerial photographs verified by field reconnaissance in 1973 and 1974. Supplementary interpretations relative to surface subsidence were done using 1939 aerial photographs.