Safety Topic: Impoundments and Dams

Impoundments and dams are an integral part of mining.  These structures are used to impound waste, store water for mine use, control runoff, and prevent flooding. Faulty design, construction, or operation can lead to a failure of the dam embankment or the containment system, resulting in the release of water or liquid-borne solid waste. To ensure the safety of miners and others, MSHA personnel regularly inspect all dams at mining operations, investigate construction and operation issues, and conduct training in dam safety.


Safety Dam ImageMSHA also reviews and approves designs for dams at coal mines that meet certain criteria, as defined in 30 CFR §77.216.

Impoundments and dams are classified into three hazard classification levels – low, significant, and high – reflecting the potential damage that a failure could cause. More conservative design and operations criteria apply as the potential for loss of life or property damage from failure increases. High hazard potential dams are designed to the highest standards and are expected to withstand extreme precipitation and earthquake events, as their failure could cause loss of human life.

The classification of a dam can be changed if downstream development increases potential losses. In such cases, the dam may need to be improved or removed.

MSHA has approximately 1,640 dams in its dam inventory. More than 400 of them are currently classified as high hazard potential.


For more information on MSHA's Dam Safety Program or technical information, contact Stan Michalek, DOL Dam Safety Officer, at (412) 386-6233.

For information related to plan submittals or issues related to inspections, contact your District office and ask for the Impoundment Supervisor (Coal Districts) or Impoundment Specialist (Metal/Nonmetal Districts).

MSHA Coal Mine Impoundment Inspection and Plan Review Handbook.

Engineering and Design Manual for Coal Refuse Disposal Facilities*

Design Guide for Metal and Nonmetal Tailings Disposal (1977 Bureau of Mines IC8755)*
*The information in these documents will be made available in alternate formats upon request. Please contact us at

Federal Emergency Management Agency (FEMA), Dam Safety

Department of Homeland Security (DHS), Dam Security

Army Corps of Engineers, National Inventory of Dams

MSHA Regulations on Impoundment and Dam Safety