The 2010 regulation on approval of safety rules in coal mines outlines requirements regarding the monitoring and control of atmospheric methane gas and carbon dioxide concentration levels within mines for worker safety. This regulation applies to mines at all stages of operation, construction and closure, regardless of ownership. The requirements stipulate maximum thresholds for methane concentration for specific equipment, as well as ambient levels in the mine workings. Under the regulation, electric machine operation is only permitted at methane concentrations of 1% or less, and electricity is shut off and workers evacuated at concentrations of 1.3% and above. Degassing procedures are to be approved by the chief engineer of the mine. Combustion of methane extracted through degassing measures is prohibited without the use of approved devices.
Appendix 4 details additional applicable standards. Table 4 categorises mines by relative methane content (cubic m/t), where category III mines are considered dangerous due to cases of local accumulations, flares or explosions. A forecast of methane breakthroughs must be carried out for mines of category III and above. Table 5 establishes maximum concentrations of methane in different parts of the mine, including degassing pipelines, pipelines for insulated removal, and at the exit from mixing chambers.