Loaded holes to be guarded. Warning whistle

When a charge of explosives has been loaded there shall be a constant guard over same until the blast is fired. Before a blast is fired, a loud warning signal shall be given by the person in charge, who has made certain that all surplus explosives are in a safe place, all persons and vehicles are at a safe distance or under sufficient cover, and that an adequate warning has been given. Said guard shall remain until the person in charge is reasonably certain there have been no misfires.