Section 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: (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.(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.Wash. Admin. Code § 296-52-67115
Amended by WSR 17-16-132, Filed 8/1/2017, effective 9/1/2017Statutory 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.