Section 7113 - (19-110). Protection Against Falling Materials(a) When a bucket or skip is used for hoisting while sinking a new shaft or deepening a shaft already in operation, workers in the shaft shall be protected against falling rocks and materials by one or both of the following means:(1) Trap doors shall be installed at the shaft collar over openings in pentices and bulkheads, and under dumping points in the shaft for buckets and skips. Such trap doors shall be substantially constructed and so arranged that they can be readily and easily opened and closed. It is recommended that trap doors at the collar be operated by compressed air and that the controls be located convenient to the hoistman.
(2) Some other equally effective means acceptable to the Division.Cal. Code Regs. Tit. 8, § 7113