225 ILCS 710/45.20: Shafts to be securely timbered.

Every shaft, incline, slope, tunnel, level or drift and any working place in the mine shall be, when necessary, kept securely timbered or protected to prevent injury to any person from falling material. It shall be the duty of the operator to carry out and enforce the provisions of this rule, but nothing contained herein shall be construed to relieve the miner from the duty of caring for his or her own working place, except as hereinafter provided.