Fire Extinguishers to Supplant Rock Dust in Underground Anthracite Mines
MSHA moved today to change its standard governing the quantity and location of firefighting equipment and materials underground to ensure they are readily available during fires. The proposed rule would allow the use of portable fire extinguishers in working sections of underground anthracite coal mines that have no electrical equipment at the face and produce less than 300 tons of coal per shift. The rule also would require an additional extinguisher in lieu of rock dust at temporary electrical installations in all underground coal mines.
As with today's proposed update of OSHA's shipyard rules, the current fire protection mining standards are old, having last week revised in November 1970. MSHA wants to eliminate the requirement that an operator petition MSHA for a modification of an existing safety standard in order to permit the use of portable fire extinguishers in lieu of rock dust and other firefighting materials in the working sections of underground anthracite coal mines that produce less than 300 tons per shift and use no electrical equipment at the face. The rule would eliminate the requirement for rock dust and instead would require portable fire extinguishers at underground temporary electrical installations.
Rock dust, a non-combustible dust such as crushed limestone, is spread on coal surfaces to reduce the chance of stirring up an explosive suspension of coal dust. It works as a fire suppressant but has a major drawback: bagged dry and placed at the ready for fires, the dust may absorb moisture through the bag and solidify, making it useless in a fire. Miners may have a false sense of security from a handy bag, only to find it won't help in a fire, MSHA said. Anthracite is hard coal mined laboriously in steeply sloped veins, with little mechanization and little room for firefighting equipment, and mining conditions are usually wet, MSHA said.
30 CFR part 75, subpart L--Fire Protection, contains the current requirements. Existing 75.1100-2 requires at working sections 240 pounds of rock dust, two portable fire extinguishers, and a ready supply of water or dry chemical. Today's proposed rule would add 75.1100-2(a)(3) to provide an additional compliance option for underground anthracite coal mines and make nonsubstantive format changes to 75.1100-2(a)(2).