225 ILCS 705/19.05
The escapement shaft at every mine opened after the passage of this Act shall be equipped with a substantial stairway, set at an angle not greater than forty-five degrees, which shall be provided with hand rails and with platforms or landings at least 2 feet wide and 4 feet long at each turn of the stairway. However, circular escapement shafts may be equipped with a substantial spiral stairway equipped with hand rails, and set at an angle not greater than 45 degrees, and platforms or landings are not required except at the top and bottom of such spiral stairways. Subject to the approval of the Mining Board, at any underground mine constructed with 3 or more shafts all of which are within a radius of 400 feet and containing 2 or more hoisting systems, one of which has an independent auxiliary power source, such mine may be equipped with a substantial ladder system instead of the substantial stairway as required by this Section. Such ladder system shall have intermittent platforms at intervals not exceeding 20 feet. Such platforms shall be at least 2 feet wide and 4 feet long with adequate handrails. Each section thereof shall be staggered and be provided with backguards extending from a point not more than 7 feet from the bottom of each section of the ladder to the top of that section.
225 ILCS 705/19.05