Mine Subsidence: What You Should Know Before You Buy
Most of the homes, businesses and residential lots in southwestern Pennsylvania sit atop coal and mineral deposits. Some of these subterranean areas were
mined decades ago, others remain untouched today. Over the past 200 years, the mining of coal has been commonplace and essential to the economic growth of
the region. Safety and reclamation standards were non-existent to voluntary until the early 20th Century. Some mining companies took care to provide
adequate support for the above-ground buildings by leaving columns of coal unmined. Other companies simply mined the coal out of the earth, leaving hollowed
out columns unable to support surface weight. This could lead to mine subsidence.
Not all structures in southwestern Pennsylvania are in danger
of mine subsidence, but the threat is real nevertheless. The best way to assure the land beneath a building is solid is to have an inspection.
The Department of the Interior is responsible for investigating the surface and subterranean impact and potential damage of mines. By appointment, an
inspector will come to the property and evaluate the risk of mine subsidence. There is no obligation to purchase insurance from the inspector and the
inspection is free-of-charge.
Generally, buildings that have less than 100 feet of earth between the surface and the mine are at risk. If there
are several hundred feet of earth between the mine and the property, the risk is lessened. Preliminary research by the Department of the Interior and an
onsite inspection are the best ways to determine the risk of subsidence.
For more information on subsidence inspections and insurance contact:
The Pittsburgh Mine Map Repository has over 90,000 maps available for public use by appointment only. This office does not handle inspections or insurance.
of Environmental Resources
3913 Washington Road
McMurray, PA 15317
Mine Map Repository
Office of Surface Mining Reclamation and Enforcement
Ten Parkway Center
Pittsburgh, PA 15220
Ownership of Coal and Mining RightsMost of the coal deposits in Allegheny County were purchased decades ago when the surface was forest or
farmland. Although ownership of the surface overlying the coal may have changed many times, the ownership of the coal and mining rights beneath the surface
may have stayed the same. Prospective homeowners and builders should be aware of the ownership of the land beneath their property and the owners intentions.
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The information presented in this publication is general in nature; it is not our intention to provide specific
advice to individuals or a comprehensive discussion of the subject matter. We suggest that you consult with your
financial or tax advisor, accountant or attorney to obtain specific advice or comprehensive information.