The signaling apparatus shall be a cord or wire actuating a knocker, bell or an electrical system.
225 ILCS 710/45.13
Every shaft, if exceeding 50 feet in depth shall be provided with an efficient means of interchanging distinct and definite signals between the lowest level and the top of the shaft and the various intermediate levels from which hoisting is being done
Known as the Fluorspar Mines Act
The act spans §§ 225-710-1 to 225-710-9-02 (122 sections).
Laws 1945, p. 1035.
Official source: Illinois General Assembly. Reproduced from public-domain Illinois statutes; confirm against the official source for the current text. Not legal advice.