(225 ILCS 725/20) (from Ch. 96 1/2, par. 5431)
    Sec. 20. No oil or gas well shall be drilled hereafter nearer than 250 feet to any opening to a working coal mine used as a means of ingress or egress for the persons employed therein or which is used as an air shaft, except by mutual agreement between the person owning or operating the mine and the oil or gas operator.
(Source: Laws 1941, vol. 1, p. 934.)