30 C.F.R. Subpart B—Dust Standards
Title 30 - Mineral Resources
Authority: Secs. 101 and 103(h), Federal Mine Safety and Health Act of 1977, Pub. L. 91–173 as amended by Pub. L. 95–164, 91 Stat. 1291 and 1299 (30 U.S.C. 811 and 813(h)).
Source: 45 FR 24001, Apr. 8, 1980, unless otherwise noted.
(a) Each operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active workings of each mine is exposed at or below 2.0 milligrams of respirable dust per cubic meter of air as measured with an approved sampling device and in terms of an equivalent concentration determined in accordance with §70.206 (Approved sampling devices; equivalent concentrations). (b) Each operator shall continuously maintain the average concentration of respirable dust within 200 feet outby the working faces of each section in the intake airways at or below 1.0 milligrams of respirable dust per cubic meter of air as measured with an approved sampling device and in terms of an equivalent concentration determined in accordance with §70.206 (Approved sampling devices; equivalent concentrations). When the respirable dust in the mine atmosphere of the active workings contains more than 5 percent quartz, the operator shall continuously maintain the average concentration of respirable dust in the mine atmosphere during each shift to which each miner in the active workings is exposed at or below a concentration of respirable dust, expressed in milligrams per cubic meter of air as measured with an approved sampling device and in terms of an equivalent concentration determined in accordance with §70.206 (Approved sampling devices; equivalent concentrations), computed by dividing the percent of quartz into the number 10. Example: The respirable dust associated with a mechanized mining unit or a designated area in a mine contains quartz in the amount of 20%. Therefore, the average concentration of respirable dust in the mine atmosphere associated with that mechanized mining unit or designated area shall be continuously maintained at or below 0.5 milligrams of respirable dust per cubic meter of air (10/20=0.5 mg/m3 ).
Title 30: Mineral Resources
PART 70—MANDATORY HEALTH STANDARDS—UNDERGROUND COAL MINES
Subpart B—Dust Standards
§ 70.100 Respirable dust standards.
§ 70.101 Respirable dust standard when quartz is present.
