225 ILCS 710/45.18

An easily legible copy of the above code, or of any special code adopted in any mine, shall be printed in letters at least one-half inch high, on a board or metal plate not less than 18 by 18 inches, and shall be securely posted in the engine room, at the collar of the shaft and at each level or station. The superintendent of the mine shall be responsible for the carrying out of this rule.