Cal. Code Regs. tit. 8, § 7044 – (11-1). Manways and Ladder Installations.

(a) Every mine shall have at least one means of outlet for the miners by means of ladders, stairways, or runway from all active workings of the mine to the surface.
(b) (11-55) No ladder or stair need be provided in a passageway if the slope is less than 20 degrees from the horizontal and the footing is such that men can walk safely.
(c) Every ladderway having an inclination of more than 60 degrees from the horizontal, and where the distance between the top and bottom of the ladderway is more than 30 feet, shall have substantial platforms at intervals of not more than 20 feet. If possible, the sections of the ladders shall be staggered at each platform so that no section shall be directly in line with the section above or below it.
(d) The ladder opening in any platform shall be large enough to permit ready passage of rescue men wearing breathing apparatus, and in no case shall such opening be less than 24 inches by 24 inches.
(e) Distance from the step to the nearest permanent object on the climbing side of the ladder shall not be less than 24 inches.
There shall be a clear width of at least 12 inches from the center line of the ladder on each side across the front of the ladder.
(f) (11-5) The front side of the step of a ladder shall in no case be less than 4 inches from any obstruction.
(g) (11-6) Ladders shall project at least 3 feet above every platform in the ladderway, and at least 3 feet above the collar of the shaft, winze, or raise, unless convenient and secure handholds are fixed at such places.
(h) (11-5) All ladders shall be securely fastened.
(i) Under no circumstances shall any ladder be installed in such manner that it leans backwards from the vertical.
(j) In all shafts which are in the process of sinking or enlarging, a fixed ladder, stair, or ramp shall be provided to within such distance from the bottom of the shaft as will secure it from the danger of blasting.
Access shall be provided from the bottom of the shaft to the bottom of the fixed ladder, stair, or ramp. Such access may be by means of an extension ladder or flexible ladder or by a handline or chain.
(k) Ladders, stairways, and ramps shall be installed at such distance from power and light wires that a person on them cannot accidentally contact an electric conductor.
(l) Every shaft shall be provided with a continuous means of egress from the bottom of such shaft to the nearest active mine level. Such means of egress may be by stairs or fixed ladders or ramps, or by a combination of the above.
(m) (11-3) Any manway through which employees are required or permitted to pass shall be kept in good repair to allow ready passage.
(n) (11-36) Trap doors or adequate guarding shall be provided in ladderways at each level. Doors shall be kept operable so that they are easily opened.