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Subchapter 20. Tunnel Safety Orders
Article 19. Shafts and Hoisting Systems
§8496. Shafts and Raises Under Construction.
(a) Shafts under construction exceeding 200 feet in depth shall be provided with guides, which extend within 75 feet of the bottom of the shaft.
(b) Where guides and safeties are used, the maximum rated speed for hoisting shall not exceed 600 feet per minute.
(c) In areas of shaft construction where buckets or cages without guides are used for handling personnel and material, the arrangements must be such that:
(1) All parts of the rigging shall provide a safety factor of 10 or more when personnel are being transported or working below a suspended load.
(2) Adequate level landing areas shall be provided for the use of personnel getting on or off buckets or cages.
(3) The travel speed for personnel hoisting shall not exceed 200 feet per minute.
(4) For mine-type hoists, a governor system set for a maximum speed of 200 feet per minute shall be installed in the control system and shall be used during personnel hoisting. The governor shall be tested, operated, and maintained in accordance with the manufacturer's recommendations.
(d) During sinking operations, no cage, skip, bucket or other conveyance shall be lowered directly to the bottom of a shaft or incline steeper than 20 degrees from the horizontal when personnel are working there. All such equipment shall be stopped at least 15 feet above the bottom of such excavation, and remain there until the signal to lower further is received from the bottom of the shaft.
(e) During sinking operations in shafts steeper than 20 degrees from the horizontal, no other work in any other place in the shaft shall be executed, nor shall any material or tools be hoisted in the shaft while personnel are at work in the bottom of the shaft, unless they are covered by a well constructed barrier or otherwise protected from the danger of falling material.
(f) Open pilot raises in shafts being enlarged shall be covered or railed except when necessarily open for passage of muck. Safety belts and lifelines shall be worn when the raise is not guarded.
(g) Means of unplugging shafts and/or raises, such as chains or cables that can be worked up and down, shall be provided. Hand placed “Bombs” shall not be permitted to unplug shafts and/or raises from the bottom.
(h) Shaft bottoms shall be cleaned of muck and an examination made for misfires before resuming drilling.
(i) Blasting holes shall not be drilled through blasted rock or water.
(j) Employees in a shaft shall be protected either by location or by suitable barriers if powered mechanical loading equipment is used to remove muck containing unfired explosives.
(k) Explosives used in shafts shall only be fired by blasting systems which provide for initiation from a safe and remote location away from the blast site.
(l) Powder or blasting caps shall not be taken into any shaft or raise until holes are drilled and are ready for loading.
(m) After each blast, a qualified person shall determine if the walls, ladders, timbers, blocking or wedges have loosened, and if such is the case, they shall be repaired before employees other than those assigned to make the repairs are allowed in or below the affected areas.
(n) Unless a raise-climber, suspended drill cage or similar method is used, raises over 30 feet in length and steeper than 30 degrees with the horizontal shall have separate compartments for muck and ladderway during the driving operation.
(o) Suspended Drill Cage Method of Raise Driving.
(1) Hoisting operations and equipment involved in moving the cage shall comply with Section 8495.
(2) Arrangements must be made so that the cage is adequately braced against lateral sway or spinning while cage is in work position.
(3) Each cage shall be provided with a protective canopy which may have hinged sections or other arrangements to provide partial protection, when needed, even if sections of the bonnet must be open for work purposes. The cage must be fully covered during first access after blasting so that the face can be safely inspected for loose material and barred down.
(4) Arrangements shall be such that a rope ladder can be promptly placed into position, or equivalent steps taken if the need should arise.
(5) Adequate means of communication, protected against damage or failure, shall be provided between hoist operator and drill cage.
(p) A method using raise-climbing machinery is acceptable, provided that the degree of protection for employees are equivalent to that required for the drill-cage method.
(q) During raising operations, no work or other activity shall take place beneath an open raise. The area around the bottom of the open raise shall be effectively barricaded and posted against entry. Where a raise bore is used, the area barricaded shall be extended a sufficient distance from the centerline of the raise to provide protection should the cutterhead and/or drill rod assembly accidently fall down the raise.
(r) During raise boring operations and/or shaft enlargement, muck shall not be permitted to accumulate closer than 12 inches from the bottom collar to prevent plugging.
(s) Mucking operations shall not be conducted concurrent with raise boring except those operations conducted by employees in a remote location providing protection from the hazards associated with a failure of the drill rod, cutterhead assembly or falling material.
Note: Authority cited: Sections 142.3 and 7997, Labor Code. Reference: Sections 142.3 and 7997, Labor Code.
1. Amendment of section heading, repealer of section and new section and Note filed 3-5-96; operative 4-4-96 (Register 96, No. 10).
2. Amendment of subsection (c)(3) and new subsection (c)(4) filed 1-9-2014; operative 4-1-2014 (Register 2014, No. 2).
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