225 ILCS 710/40
It shall be the duty of the operator of every mine to provide, in addition to any mechanical means of ingress or egress, at least one means of outlet for the miners by means of ladders from the lowest working of the mine to the surface. All ladders and ladderways constructed after the passage of this Act shall be built as prescribed in rules 33 to 40 of Section 46 of this Act. All ascending and descending manways through stopes and every shaft, winze, raise or incline, steeper than 35 degrees from the horizontal, through which people are obliged to pass, shall be provided with ladders and ladderways as specified in this Section: Provided, however, that where the slope of the working place is such as to permit the installation of stairways that can be easily and safely traversed, such stairways may be substituted for ladders.
Every exit or outlet from a mine shall be marked with signboards plainly showing the direction to be taken wherever more than one course is possible: Provided, however, that no signboards shall be necessary where the exit or outlet does not branch or fork.
Every such exit or outlet shall be marked by colored electric lights wherever signboards are required, as herein specified, and an electric lighting circuit is available within 25 feet. Such lights shall have a color distinct from all other underground lights.
225 ILCS 710/40