30 C.F.R. § 57.22209 Auxiliary fans (I-C mines).
Title 30 - Mineral Resources
Electric auxiliary fans shall be approved by MSHA under the applicable requirements of 30 CFR part 18. Tests for methane shall be made at electric auxiliary fans before they are started. Such fans shall not be operated when air passing over or through them contains 0.5 percent or more methane.
Title 30: Mineral Resources
PART 57—SAFETY AND HEALTH STANDARDS—UNDERGROUND METAL AND NONMETAL MINES
Subpart T—Safety Standards for Methane in Metal and Nonmetal Mines
Ventilation
§ 57.22209 Auxiliary fans (I-C mines).

