(a) On and after March 30, 1971, in mines operated entirely in coal seams which are located at elevations above the water table:
(1) All junction or distribution boxes used for making multiple power connections inby the last open crosscut shall be permissible; and
(2) All handheld electric drills, blower and exhaust fans, electric pumps, and all other electric-driven mine equipment, except low horsepower rock dusting equipment, that employs an electric current supplied by either a power conductor or battery and consumes not more than 2,250 watts of electricity, which is taken into or used inby the last open crosscut shall be permissible.
(b) On and after March 30, 1974, in mines operated entirely in coal seams which are located at elevations above the water table, all electric face equipment which is taken into or used inby the last crosscut shall be permissible.