CFR > Title 30 - Mineral Resources > CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR > SUBCHAPTER O—COAL MINE SAFETY AND HEALTH (parts 70 to 90) > PART 74—COAL MINE DUST SAMPLING DEVICES > SUBPART B—Approval Requirements for Coal Mine Dust Personal Sampler Unit (§74.3 to §74.6)