[Code of Federal Regulations] [Title 30, Volume 1] [Revised as of July 1, 2002] From the U.S. Government Printing Office via GPO Access [CITE: 30CFR70.100] [Page 421] TITLE 30--MINERAL RESOURCES CHAPTER I--MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR PART 70--MANDATORY HEALTH STANDARDS--UNDERGROUND COAL MINES--Table of Contents Subpart B--Dust Standards Sec. 70.100 Respirable dust standards. 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 Sec. 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 Sec. 70.206 (Approved sampling devices; equivalent concentrations).