Regulation 18

the slopes of walls and faces of excavations shall not exceed safe limits for stability;

where the Licensing Officer is of the opinion that the wall or face of an excavation or the slope of an embankment is unstable, he shall order the employees to be withdrawn from the vicinity thereof, and shall issue such instructions as he considers necessary to reduce risk of injury to the employees or the public or damage to public or private property arising therefrom;

where the Licensing Officer is satisfied that the slopes of the operating faces, or the terminating walls of any excavation as proposed by the licensee in the working plans or developed in the course of excavating, exceed safe limits for stability, he shall issue such instructions as he may consider necessary to the licensee regarding safe slopes.