72. In an underground mine whose operation begins on or after 1 April 1993, the passages prescribed in section 71 shall:(1) be at least 30 m (98.4 ft) apart;
(2) have a cross-section of at least 1.5 m (4.9 ft) or a diameter of at least 1.5 m (4.9 ft), except for the openings in the rest landings of the ladderways;
(3) have exits on the surface in separate buildings built with non-combustible materials.