(a)Surface and underground mines. When an abrasive
blasting operation is performed, all exposed miners shall properly use
respirators approved for abrasive blasting by NIOSH under 42 CFR part 84, or
the operation shall be performed in a totally enclosed device with the miner
outside the device.
(b)Underground areas of underground mines. Silica sand or other materials
containing more than 1 percent free silica shall not be used as an abrasive
substance in abrasive blasting.
