163(1)An employer shall ensure that before any employee returns to the scene of a blasting operation that sufficient air has been introduced into the area so as to ensure that no employee is exposed to air contrary to the requirements of section 47.

163(2)Where blasting is done in a raise or stope, a person who conducts an underground blasting operation shall ensure that precautions are taken to prevent the blast from closing the entrance to or exit from the raise or stope or interfering with the effective circulation of air in the raise or stope.

163(3)Where material from a blast may block the entrance in a single compartment raise or box hole, an employer shall ensure that precautions are taken to assure the adequate ventilation of the area before an employee enters after a blast.