Homeowners, realtors, geo-technical consultants, land-use planners and others interested in the location and extent of Ohio’s underground mines – both active and abandoned – will find many uses for a new Web-based map available through the Ohio Department of Natural Resources. The Underground Mine Locator Web site at ohiodnr.com/geosurvey puts an interactive map of Ohio’s known underground mines, along with potential areas of subsidence, as close as a personal computer.
Ohio currently has about a dozen active underground mining operations; abandoned mines are found in 44 counties. The ODNR Division of Geological Survey has information on 6,675 abandoned underground mines in Ohio, including detailed maps for 4,346 mines – most of which are coal mines.
The division’s extensive database on abandoned underground mines has been combined into an Abandoned Underground Mine Geographic Information System.
Ohio has a history of mining underground that dates to the early 1800s. Coal, clay, limestone, gypsum, conglomerate, and, in one unusual instance, even sand and gravel, were mined underground in the state during the last 200 years. The heyday of underground mining activity occurred in the late 1800s and early 1900s, when more than 1,110 underground mines were in operation. Much of this mining led to subsidence, a lowering of the earth’s surface due to the collapse of bedrock and other materials into mined-out voids.
Subsidence can damage the foundations of homes, buildings and roads; disrupt underground utilities, and can be a potential risk to human life. An unfortunate consequence of more than two centuries of underground mining, subsidence is a geologic hazard that can strike with little or no warning and can result in very costly property damage. While underground mining has occurred in many parts of Ohio, the vast majority of underground mining took place in the coal and clay-producing regions of the east and south where subsidence continues to be a problem for property owners today.