Mining Contract: Development of Heat Mitigation Systems for Refuge Alternatives used in Underground Coal Mines

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Contract #	200-2016-91901
Start Date	9/9/2016
End Date	12/18/2017
Research Concept	As established in previous studies, heat and humidity build-up in refuge alternatives deployed in underground mines can reach uncomfortable and even unhealthy apparent temperatures (values based on heat plus humidity) when occupied. Addressing this heat and humidity build-up is critical if these structures are to be effective at sustaining life up to the full 96-hour rescue rating period. Without mitigating these factors, refuge alternatives could have their occupancy ratings downgraded. Controlling heat and humidity is crucial to the industry’s continued use of these systems.
Topic Area	Refuge Chambers

Contract Status & Impact

This contract is complete. To receive a copy of the final report, send a request to mining@cdc.gov.

The MINER Act of 2006 requires all underground coal mines to install refuge alternatives (RAs). The law was put into effect following a number of mine disasters in which miners lost their lives not due to an explosion or roof collapse, but instead due to the build-up of hazardous gases and lack of breathable air following a mine event. In 2006, little research was available on the heat and humidity effects of miners sheltering in refuge structures.

Formative research performed at the Pittsburgh campus of the NIOSH Mining Program shows that heat and humidity build-up inside an occupied refuge alternative can reach an apparent temperature in excess of 95 degrees F. However, regulations require that an RA be capable of providing a sheltered space up to the maximum occupant capacity for 96 hours. That includes keeping apparent temperatures below 95 degrees F.

This contract will explore using vapor compression refrigeration with an expendable desiccant to remove enough heat and humidity from an occupied RA’s internal air to bring it below the apparent temperature threshold. The system will operate on a rechargeable battery-based power system.

The contractor will fully develop and test a single heat mitigation system for both steel and inflatable tent RAs that can be submitted to the Mine Safety and Health Administration for certification.