(1) Employee evacuation. The blaster must make sure all employees are out of the blast area before firing a blast.

(2) Guarding entrances. All entrances:

(a) Leading into the blasting area must be carefully guarded.

(b) To any working place where a drift, raise, or other opening is about to hole through must be carefully guarded.

(3) Warning signals. A warning must be given before firing an underground blast. See Table T-1 for signaling requirements.

TABLE T-1
warning signal	A 1 minute series of long blasts 5 minutes prior to blast signal.
blast signal	A series of short blasts 1 minute prior to the shot.
all clear signal	A prolonged blast following the inspection of the blast.