(a) Tamping shall not be done directly on a primer. (b) Rigid cartridges of explosives or blasting agents that are 4 inches (100
millimeters) in diameter or larger shall not be dropped on the primer except
where the blasthole contains sufficient depth of water to protect the primer
from impact. Slit packages of prill, water gel, or emulsions are not
considered rigid cartridges and may be drop loaded.
[58 FR 31908, June 7, 1993; 58 FR 69596, Dec. 30, 1993]
NOTE: At 58 FR 69596, December 30, 1993, the effective date of §56.6304(b) is
stayed until January 31, 1994.