Safety Standards for Methane in Metal and Nonmetal Mines

Last updated: 3 February 2023

Subpart T of the US Code of Federal Regulations sets forth procedures and safety standards for each metal and nonmetal underground mine subject to the Federal Mine Safety and Health Act of 1977. Depending on which category or subcategory the underground or surface mine is placed into, it shall operate in accordance with applicable standards found in the rules. 

In particular, Subcategory I-A applies to coal mines that release methane with a concentration of 0.25 percent or more. For these mines, the ventilation standards specify that main exhaust fans shall be equipped with methane monitors to give an alarm when methane in the return air reaches 0.5 percent. The regulation also specifies operational standards for main fans, booster fans, auxiliary fans, separation of intake and return air, and seals and stoppings. Methane monitoring devices must be approved by MSHA and maintained in accordance with manufacturer instructions. Methane concentration of the mine atmosphere shall be tested weekly in specified areas of the mine. At atmospheric levels of 1.0 percent, the ventilation changes must be made, electrical power shut off and workers withdrawn until levels are reduced. 

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