Guidelines for Permitting, Construction, and Monitoring of Retention Bulkheads in Underground Coal Mines

Many mining operations rely on retention bulkheads to provide a barrier between impounded water and active mine workings. However, bulkhead failures can cause catastrophic flooding that puts the underground workforce at risk. Underground observations and evaluations of existing bulkheads indicate that a systems approach is required when building an underground water or slurry retention system. In addition to engineering the bulkhead, the designer must ensure the quality control of materials and workmanship of the bulkhead, the reaction of the mine strata when exposed to water under pressure, and methods to monitor the performance of the retention system. Researchers from the National Institute for Occupational Safety and Health (NIOSH), with the assistance of the Mine Safety and Health Administration (MSHA), conducted an extensive review of bulkhead permits submitted to the MSHA Technical Support office in Bruceton, PA. In addition, the researchers visited accessible bulkhead installations at underground mining operations to gather information related to construction practices, maintenance issues, and monitoring and emergency response procedures. The guidelines in this report are to be used as a tool to identify areas or conditions that could impact the long-term stability of an underground fluid retention system and to give direction in addressing these situations.