Is your home sitting on an abandoned mine?
New DEP report can help you assess subsidence risk
By Rodney L. Sherman
CLARION NEWS Editor
Coal mining in Clarion County is as old as the county itself and collapses in abandoned and forgotten mines can spell costly disaster for homeowners.
A recently completed state Department of Environmental Protection report not only helps identify properties which might be sitting on abandoned mines, but also can guide property owners through the process of obtaining mine subsidence insurance.
What is mine subsidence?
The following definition is from Illinois state mine regulations, but applies to any mine subsidence situation.
Mine subsidence has been defined as lateral or vertical ground movement caused by a failure initiated at the mine level, of manmade underground mines, including, but not limited to coal mines, clay mines, limestone mines, and fluorspar mines that directly damages residences or commercial buildings.
"Mine subsidence" does not include lateral or vertical ground movement caused by earthquake, landslide, volcanic eruption, soil conditions, soil erosion, soil freezing and thawing, improperly compacted soil, construction defects, roots of trees and shrubs or collapse of storm and sewer drains and rapid transit tunnels.
In simpler terms, when the roof of a subsurface mine collapses, it causes the ground above to sink or subside.
Most experts agree that room and pillar mines will eventually experience some degree of collapse, but currently there is no way to know when or exactly where mine subsidence will occur.
Pennsylvania's Act 54 report
The most recent "Act 54" report was prepared by the University of Pittsburgh for the Pennsylvania Department of Environmental Protection.
The report outlines the impacts of bituminous coal mining on land and water.
The new report covers 2013-2018 and is the fifth assessment of the program.
Under the Act 54, the DEP is required to compile data and report findings regarding the effects of underground mining on land, structures and water resources.
The review is done with assistance from professionals with appropriate expertise as stipulated by Act 54.
A Report is prepared and presented to the governor, general assembly and the Citizens Advisory Council every five years.
The Act 54 Report is deemed to be an important audit of Pennsylvania's underground mining program providing the public, organizations, and the mining industry with an opportunity to review and comment on the program and allowing DEP and overseeing parties to consider program edits and improvements.
Underground coal mining, including longwall mining, can have impacts on surface structures like homes and buildings and on water resources like streams, rivers, and lakes.
The report documents these impacts and the actions taken to remediate them.
Report research found mining operations were responsible -- and the company liable -- for 192 impacted water supplies from 2013-2018.
This is down from 371 for the previous reporting period (2008-2013).
The time to resolve operator-liable water supply issues dropped from 415 days in the 2008-2013 report to 302 days in the 2013-2018 report.
DEP has been working with the industry to improve response times.
"This report is a good reminder of the effects of mining, and the need to mitigate those effects to ensure that underground mining can coexist with neighbors on the surface," said DEP Secretary Patrick McDonnell. "This is also a good reminder to residents to check to see if their homes could be at risk of subsidence related to historic coal mining activity."
A total of 28,854 acres were mined in Pennsylvania, with longwall mining accounting for 62 percent of the total acreage, room-and-pillar mining 29 percent, and pillar recovery 9 percent.
This reflects a 7 percent decrease from the previous five-year reporting period, even though more mines are in operation.
Cracked foundations, collapsed walls, and even homes sinking into the ground are all possible impacts of underground mine subsidence, which is not typically covered by homeowner's insurance policies.
A subsidence event can occur at any time and cause sudden, significant damage, often exceeding $100,000 or total loss of the structure.
Mine subsidence occurs when the ground above an old or abandoned mine cavity collapses.
Residents are encouraged to check for risks of mine subsidence on the DEP's website. Interactive maps and search tools can show the user information about their individual properties.
DEP administers low-cost mine subsidence insurance (MSI) coverage through the Commonwealth of Pennsylvania.
The average policy of $160,000 costs about $7 a month, and senior citizens are eligible for discounted rates.