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Code of Federal Regulations

ECFR06afab17eface73

Underground Only

57.8520Ventilation plan.57.8525Main fan maintenance.57.8527Oxygen-deficiency testing.57.8528Unventilated areas.57.8529Auxiliary fan systems.57.8531Construction and maintenance of ventilation doors.57.8532Opening and closing ventilation doors.57.8534Shutdown or failure of auxiliary fans.57.8535Seals.