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Subchapter 20. Tunnel Safety Orders
Article 16. Mechanical Tunneling Methods, Machinery and Equipment

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§8459. Mechanical Hazards.

(a) An audible and visual warning shall be given before starting excavating or conveyor machinery.

(b) A thorough examination of the heading shall be made before starting excavation equipment to insure that all employees are in a safe location.

(c) Excavating machines shall be equipped with a deadman control.

(d) Power transmission equipment, hazardous moving parts, and conveyors shall be guarded as required by Title 8, Group 6 of the General Industry Safety Orders.

(e) Cleaning, repairing, and servicing of machinery, equipment and prime movers shall be in accordance with Section 3314 of the General Industry Safety Orders.

(f) Emergency stop switches within reach of the operator shall be provided for emergency shutdown of all underground conveyors. Unguarded conveyors with access shall be equipped with emergency stop devices or cords along their full length.

(g) An automatic device to prevent inclined conveyors from rolling backward shall be provided.

(h) Guarding shall be provided where workers are exposed to shear hazards from erector arms and other moving equipment.

(i) Erector arms shall be operated with a power up and power down system and shall have provisions for locking devices or safety pins.

(j) Tunnel support systems shall have adequate strength to resist the thrust of hydraulic jacks.

(k) Safety cables shall be provided on jacking shoes located above the spring line.

(l) Where wire rope is used to tow tunnel machines, trailing gear and other similar equipment, all components used shall provide a safety factor of at least 2.5 to 1 and be equipped with means to prevent whipping in case the wire rope or connection fails.

(m) Employees shall not be permitted between the tunneling machine and any associated trailing equipment during the towing cycle.

(n) An audible alarm shall be provided that distinctly warns employees of the movement of tunneling machines and trailing gear such as during the regripping and towing cycles.

(o) Employees shall not be permitted on the deck area of a training gear system where they may be exposed to being injured by railed equipment unless physical safeguards are provided for their protection.

NOTE: Authority cited: Sections 142.3 and 7997, Labor Code. Reference: Sections 142.3 and 7997, Labor Code.


1. Amendment of section and new Note filed 3-5-96; operative 4-4-96 (Register 96, No. 10).

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