Cal. Code Regs. tit. 8, § 7111 – Shaft Work, Maintenance, and Repair--General.

(a) (19-107) Before maintenance or repair work is begun in a shaft, the person in charge of such work shall inform the hoistman of the nature of the work to be done.
(b) (19-108) Signs marked “Men Working in Shaft” shall be hung on the signal device in the hoist room and on or near the hoist brake during the time men are at work in a shaft compartment. The sign shall not be removed until the shaft men have notified the hoist operator that they are in the clear.
(c) When men are working in any compartment of a shaft, the shaft conveyance in any adjoining compartment shall not be operated except in an emergency or as directed by the shaft repair crew.
The hoisting conveyance of any adjoining compartment shall be spotted at the working place to prevent workers from falling into such compartment.
(d) All planks, timbers, bulkheads, and other materials used in repair work shall be removed to a safe place before regular hoisting operations are resumed.
They shall not be placed in a manway compartment in such manner as to impede safe and ready passage through the shaft.
(e) Wherever practical, maintenance work shall be carried on from the hoisting conveyance used in the shaft.
(f) If maintenance work is carried on from the top of the conveyance, a substantial platform or other safe footing securely fastened to the conveyance shall be provided for the workers.
In vertical shafts, an auxiliary bonnet shall be secured to the hoisting rope as closely above such platform as is practical for the work being done.
(g) (15-5) Unless protected by other means acceptable to the Division, approved safety belts shall be provided employees while working:
1. (1) In or over shafts or winzes inclined more than 45 degrees from the horizontal.
2. (2) In any portion of any shaft where, because of slippery footing or other local conditions, a serious fall may result.