The Division of Mineral Resources Management (DMRM) regulates mining in Ohio while also protecting the public, the minersand the environment.
Subsidence in Area of Active Mining
Determining Subsidence Shadow Area
For room and pillar mining (where subsidence is not expected), the shadow area is comprised of the surface area above the area where the coal is removed (called the underground workings.) For longwall mining or pillar extraction (where planned subsidence will occur), the shadow area is comprised of the surface area above the area where the coal is removed (the underground workings) as well as the surface areas that are within the angle of draw of the underground workings. The angle of draw is determined by a series of equations and analyses of the underlying strata. Subsidence is anticipated to occur within the shadow area. Please see the following Planned vs. Unplanned Subsidence discussion, below, for more information.
Planned vs. Unplanned Subsidence
Planned subsidence occurs when a permittee anticipates that mining will cause the ground to lower in a predictable manner. Generally, subsidence occurring after longwall mining or pillar extraction is planned subsidence. Room and pillar mining operations are designed to prevent subsidence; such permit applications are required to show that the size of pillars and the amount of coal removed will result in a stable underground mine opening and will be expected to not subside the ground surface. However, some pre-law room and pillar operations have resulted in unanticipated, unplanned subsidence.
Subsidence Outside the Shadow Area
Based on the application/hydrology map and mine plan, the permittee cannot subside beyond the approved shadow area limits.
Subsidence Prevention
Room and pillar mining operations are designed to prevent subsidence from occurring; enough coal is left in place to support the rock above to prevent subsidence. Where the method of mining requires planned subsidence in a predictable and controlled manner (longwall or pillar extraction), the coal company is required to repair or compensate a homeowner for any material damage caused by subsidence. If the coal company and homeowner have no agreement for repair or compensation, the coal company must correct material damage caused to any non-commercial building or occupied residential dwelling and structures related thereto that existed at the time of mining by repairing the damage, or the company shall compensate the owner in the full amount of the diminution in value resulting from subsidence. Repair of damage includes rehabilitation, restoration, or replacement. Highwall mining and auger mining are activities that take place as part of a surface mining operation. Similar to room and pillar mining, highwall and auger mining leaves coal in place to support the rock above to prevent subsidence.
Reporting a Subsidence
If a property is not within the shadow area of an active coal mining operation but is being affected by a current coal mining operation, the Division encourages reporting the subsidence to the permittee.
Generally, a permittee will work with a landowner to resolve any problems associated with mining. If the permittee does not correct the problem, the landowner should then notify the inspector assigned to the permit, who will work with the Division’s engineers to investigate the complaint. Contact the inspector at the appropriate Division regional office.
If a property is not within the shadow area of an active coal mining operation but it is being affected by a current coal mining operation and the preference is not to report the problem to the permittee first, report it directly to the Division. It is possible that a house is instead affected by subsidence from an old abandoned underground coal mine. Check ODNR’s OhioMinesLocatorinteractive map to see if there is an abandoned underground mine nearby that may be causing the subsidence. If an active mine or an abandoned underground coal mine may be involved, contact the appropriate Division regional office,under the tab for Field Office Phone Numbers. It is also possible that a house is affected by factors unrelated to mining. For example, a variety of non-mining factors can cause cracking in floors or walls including, but not limited to, construction on slip-prone soils, poor foundation construction, settling of the foundation, or water not properly draining from around the home.
Underground Mines
The specific mining plan for each underground mine is part of the permit for that mine.
- For active permits, a copy of the permit is maintained in the Columbus Division office and in the Division regional office closest to the mine site. Contact the supervisor for the appropriate Division regional office.
- For permits for which all performance security has been released, a copy of the permit is available either in the Columbus Division Office or State Archives. Contact the Columbus office at (614) 265-6633.
- For abandoned underground mines, mine maps can be viewed on ODNR’s Ohio Mines Locator interactive map. Copies of underground mining maps with specific information regarding the location and the coal seam mined is available by contacting Geographic Information Management System (GIMS) Specialist Chris Freidhof/Email at the Division's New Philadelphia regional office, (330) 339-2207.
Subsidence vs. Something Else
Cracking in basem*nt floors or walls is a common occurrence in mining and non-mining counties in Ohio. A variety of factors cause cracking which include but are not limited to, subsidence, construction on slip-prone soils, poor foundation construction, settling of the foundation, or water not properly draining from around the home.
Current underground coal mining operations that may cause damage to structures in the shadow area due to subsidence are required to have a subsidence control plan which can include monitoring of subsidence to prevent, reduce, or correct damage.Surface owners are to be notified prior to underground mining of their property.
If a structure is damaged by subsidence from an active mining operation, the permittee is required to repair or replace any non-commercial building or occupied residential dwelling and structures related thereto that existed at the time of mining or compensate the owner for the diminished value of such structures.
Some signs of mine subsidence include:
- Hairline cracks in one or more basem*nt walls
- Some cracks in the perimeter walls causing loss of water tightness
- Repointing required in some or all walls
The most severe signs are:
- Cracks typically in all basem*nt walls, as well as the floor slab
- Possible instability of several walls and loss of superstructure support, requiring extensive shoring and bracing
- Possible significant tilt to home
- General reconstruction of basem*nt walls, footings and floor slab required
Subsidence in Abandoned Mine Land (AML) Area
Mine Subsidence Reporting
- If the occurrence of a sinkhole or mine subsidence is a life-threatening event, call 911.
- If a sinkhole or mine subsidence is NOT related to a current coal mining operation, you should contact the Division's Abandoned Mine Land (AML) staff at the nearest AML regional office,under the tabs for Field Office Phone Numbers/Abandoned Mine Lands. Calls received after regular business hours will be returned the next business day.
- If a sinkhole or mine subsidence IS caused by a current coal mining operation, first report this issue to the coal mining operator (permittee). Generally, a permittee will work with a landowner to resolve any problems associated with mining.
Mining History of a Property
Check ODNR’s OhioMinesLocator interactive map to see if there are any mines or other resources on or near the property. Or contact the Geographic Information Management System (GIMS) Specialist Chris Freidhof /email at the Division’s New Philadelphia regional office, (330) 339-2207.
Mine Subsidence Insurance
Mine subsidence insurance is mandatory for homeowners in 26 eastern and southeastern Ohio counties. Optional coverage is available in 11 additional counties. See website pages for Mine Subsidence Insurance.
Subsidence vs. Something Else
Cracking in basem*nt floors or walls is a common occurrence in mining and non-mining counties in Ohio. A variety of factors cause cracking which include but are not limited to, subsidence, construction on slip-prone soils, poor foundation construction, settling of the foundation, or water not properly draining from around the home.
