225 ILCS 710/30
The sheave carrying the hoisting rope shall be placed upon a headframe so designed as to resist a pull in the direction of the hoisting engine greater than the breaking stress of the hoisting rope employed. The headframe shall be of sufficient height to allow room for a set of automatic safety chairs, and also for a humble hook in connection with the hoisting rope or some equally practicable device for releasing the hoisting rope in case of over-winding.
The operator of a mine employing more than 100 people underground shall install upon the headframe both a rope-releasing device and a set of automatic chairs to hold the cage, skip, or man car in case the hoisting rope is broken or released through over-winding. Such safety chairs shall be placed at such distance below the releasing device as will equal 3 feet more than the height from the bottom of the cage, skip or man car to the clevis at its top. Immediately below the sheave a strong stop shall be put in to prevent the cage, skip or man car from being drawn over the sheave.
The operator of a mine employing more than 100 people underground shall install in every shaft in which people are hoisted by cage, skip or man car, a device which shall give a warning signal in the engine room whenever the cage or skip in ascending reaches a point 100 feet below the collar of the shaft. This device shall be independent of the usual indicator or any other device directly connected with the hoisting engine.
Provided, however, that the rope releasing device, safety chairs, and the warning signal required by the terms of this Section need not be installed if the hoisting engine is equipped with a device that will automatically stop the engine if the cage, skip, or man car passes a certain point, and provided further that such automatic stopping device be kept constantly in good working order.
225 ILCS 710/30