Any power conferred by this Act or regulations F1or health and safety regulations which expressly apply to all mines F2. . ., any class of mines F2. . . or a particular mine F2. . . on F3the Health and Safety Executive or an inspector to grant, give or impose an exemption, consent, approval, authority, direction, requirement, prohibition or restriction or to make a determination shall be construed as including a power exercisable in the like manner and subject to the like conditions, if any, to vary or revoke the exemption, consent, approval, authority, direction, requirement, prohibition, restriction or determination.

Any exemption, consent, approval or authority granted or given under this Act or regulations F1or such health and safety regulations by F3the Health and Safety Executive or an inspector may (subject to any express provision of this Act or regulations F1or such health and safety regulations) be without limit of period or limited so as to expire on a specified date unless renewed, and may be absolute or conditional.