Refuge chambers, or emergency shelters, are now required by federal law to be included in every US mine’s emergency response plan.

MSHA says the four basic aspects of refuge chambers are structural, breathable air, air monitoring, and harmful gas removal.

Every unit will have different designs of these elements, beginning with the protective structure that encompasses the internal atmosphere of the shelter. Manufacturers have provided various materials and thicknesses to their respective units.

All refuge chambers will allow for an uncontaminated flow of breathable air, which is generated inside via cylinders, compressed air lines, or boreholes equipped with compressors or fans. Under MSHA guidelines, all miners will have adequate breathable air in the unit for 96 hours.

Once inside during an emergency, crews will need to closely watch the unit’s air monitors, designed to measure oxygen levels as well as carbon monoxide, carbon dioxide and methane both inside and outside.

Chemical scrubbing material or other processes will remove harmful gases such as CO2 (from exhaled breath), CO (mine fire gas), or CH4 from the inside environment.

“Your knowledge of how to examine, transport, maintain, deploy and use these units can save your life,” MSHA noted in its safety briefing.

“It is imperative that you know how to deploy and operate these units should an emergency arise and you are not able to escape from the mine, therefore miners should receive comprehensive training for all aspects of refuge alternatives.”

The agency reminded operators that quarterly training was required for all individuals as well as annual expectations training; details can be referenced under MSHA’s 30 CFR 75.1504(b) ruling.

For a printable version of the safety alert, visit MSHA’s website.