142.3(1)Despite section 142.2, a minor blast to dislodge a single rock or unclog a chute may occur without evacuating the underground mine providing that all employees are located in a safe area and the employer ensures that the blast avoids endangering anyone in or about the mine.

142.3(2)An employer shall establish a code of practice for the blasting operation referred to in subsection (1), ensure that the code of practice is followed and make a copy of the code of practice available to an officer and the committee on request.