A. All drill holes shall be of greater diameter than the diameter of cartridges of explosive used.
B. Drilling shall not be done in an area already blasted until all remaining butts of old holes are examined for unexploded charges and the total area has been thoroughly examined to make sure that there are no additional unexploded charges remaining. A drill, pick or bar should never be inserted in such holes even if examination fails to disclose explosives.
C. Drilling and loading operations generally shall not be carried on in the same area.
D. Where drilling adjacent to previously loaded areas or holes is essential, the minimum clearance shall be equal to or greater than the deepest hole in the area. (Ord. A-348, 6-4-1979)