PART XXIX UNDERGROUND OPERATIONS — Air supply for hoist operator
568
Where, in an underground or tower mounted hoist room, the normal air supply could become contaminated in an emergency, the employer shall provide and keep available uncontaminated air available to the hoist operator by means of
568(a)
an enclosed booth with a positive supply of uncontaminated air; or
568(b)
one or more self-contained breathing apparatus, together with a fully charged cylinder of breathable air to allow safe evacuation of all underground workers.
Not legal advice. Verify the cited article against the signed agreement.