(225 ILCS 705/33.04) (from Ch. 96 1/2, par. 3304)
Sec. 33.04.
Each underground map shall show, in feet and decimals thereof, the elevation of the floor of the coal at reasonable intervals on the main entries and cross-entries from the bottom of the shaft to the face of the workings; such elevations shall be referred to the floor of the coal at the bottom of the hoisting shaft.
(Source: Laws 1953, p. 701.)