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U.S. Department of Labor

Mine Safety and Health Administration
201 12th Street South, Suite 401
Arlington, VA 22202-5450
ISSUE DATE: August 16, 2010
LAST VALIDATED: 03/31/2021


FROM:             KEVIN G. STRICKLIN  
                       Administrator for
                       Coal Mine Safety and Health

SUBJECT:     Maintaining Methane Monitors in Permissible and Proper Operating
                   Condition for Mining Equipment

This Program Information Bulletin (PIB) applies to coal mine operators, miners and miners' representatives, independent contractors, Mine Safety and Health Administration (MSHA) enforcement personnel, and other interested parties.

The purpose of this Program Information Bulletin (PIB) is to provide information to the mining community on requirements to maintain methane monitors in permissible and proper operating condition to ensure that the monitors provide miners with a warning when excessive quantities of methane are liberated in the working face.

Under 30 C.F.R. § 75.342, methane monitors on mining equipment must be maintained in permissible and proper operating condition. In addition, under 30 C.F.R. § 75.503, all electric equipment that is taken into or inby the last open crosscut must be maintained in permissible condition. Some mine operators are defeating the purpose of a methane monitor either by placing material over the sensor head of the monitor or "bridging out" the electrical safety components of the monitors. Placing material over the sensor head will prevent the monitor from detecting excessive and dangerous concentrations of methane in the mine. Similarly, "bridging out" the electrical components of the monitors will prevent the mining equipment from shutting down when methane reaches the two percent cut-off level. Methane ignitions and potential explosions could occur if these practices continue.

Methane monitors are critical safety devices designed to protect miners from methane explosions. These monitors provide the first warning of elevated levels of methane by providing a visible warning at one percent and automatically shutting down mining equipment when methane concentrations reach two percent. Mining equipment that continues to operate under such conditions could result in a violent explosion.

MSHA maintains an anonymous hotline for reporting hazardous conditions, including tampering with methane monitors. The phone number is 1-800-746-1553. Persons may also report hazardous conditions to their MSHA District office. MSHA will promptly investigate any report of a hazardous condition at a mine.

On April 21, 2010, MSHA launched inspections at 57 coal mines whose enforcement history indicated a significant number of violations related to methane accumulations, ventilation, rock dusting and mine examinations. These impact inspections followed the April 5, 2010, explosion at Upper Big Branch Mine in Montcoal, West Virginia, and focused attention on mine ventilation, rock dusting, methane monitoring and mine examinations.

In addition, on May 24, 2010, the House Education and Labor Committee conducted a hearing on the Upper Big Branch explosion. The Committee heard testimony from deceased miners' families. The testimony addressed issues regarding safety conditions in existence prior to the explosion including inadequate ventilation, intentional changes to ventilation systems, high levels of methane, excessive coal float dust, "bridging out" methane monitors on mining equipment, advance notice of MSHA inspections, and retaliation for miners who raised safety and health issues.

This PIB emphasizes that MSHA intends for mine operators to fully comply with the Mine Act and MSHA's regulatory requirements.

The Federal Mine Safety and Health Act of 1977, as amended, 30 U.S.C. § 801 et seq.;
30 C.F.R. §§ 75.342 (a)(4) and 75.503.

Internet Availability
This PIB may be viewed on the Internet by accessing MSHA's home page at (, choosing "Compliance Info" and "Program Information Bulletins."

Issuing Office and Contact Person
Mine Safety and Health Enforcement
Rodney Adamson, (202) 693-9549

MSHA PPM holders
Underground Coal Mine Operators
Coal Miners' Representatives
Independent Contractors
Special Interest Groups