WAC 296-52-67115
Excavation work in pressurized air locks. (1) Receiving, handling, storing, and transportation.
(a) The blaster in charge or powder person is responsible
for the receipt, unloading, storage, and on-site transportation
of explosives and detonators.
(b) Explosives in transit cannot be left unattended.
(c) Detonators and explosives for each round must be taken
directly from the magazines to the blasting zone and immediately
loaded.
(2) Wet holes. Explosives appropriate for use in wet holes
must be:
(a) Water resistant
AND
(b) Fume Class 1 or other approved explosives.
(3) Bonding. All metal pipes, rails, air locks, and steel
tunnel linings must be:
(a) Electrically bonded together and grounded at or near the
portal or shaft.
(b) Cross bonded together at not less than one thousand-foot
intervals throughout the length of the tunnel.
(4) Air locks.
(a) No one is allowed to enter the air lock when detonators
or explosives are brought in, except:
(i) The blaster in charge.
(ii) The powder person.
(iii) The lock tender.
(iv) Employees needed to carry explosive materials.
(b) Primers, detonators, and explosives must be taken
separately into pressure working locks.
(c) Material, supplies, or equipment cannot be brought into
air locks with explosive materials.
(d) Detonators and explosives not used after loading a round
must be removed from the working chamber before connecting the
connecting wires.
(5) Grounding. Each air supply pipe must be grounded at its
delivery end.
(6) Mixed face.
(a) Light charges and light burdens must be used for each
hole when tunnel excavation in rock face is approaching or is in
mixed face.
(b) Advance drilling must be done when tunnel excavation in
rock face approaches mixed face to determine the:
(i) General nature and extent of rock cover
AND
(ii) Distance to soft ground as excavation advances.
[Statutory Authority: RCW 49.17.010, [49.17].040, and[49.17].050
. 02-03-125, § 296-52-67115, filed 1/23/02, effective
3/1/02.]