Ohio Rev. Code Ann. § 1567.45
(C) All hoisting equipment at a mine, including automatic elevators, safety catches, and other devices approved by the chief, shall be examined daily, and the examination shall include, but not be limited to, the following:
(E) There shall be at least two effective methods approved by the chief of signaling between each of the shaft stations and the hoist room, one of which shall be a telephone or speaking tube. One of the methods used to communicate between shaft stations and the hoist room shall give signals that can be heard by the hoisting engineer at all times while workers are underground. Signaling systems used for communication between shaft stations and the hoist room shall be tested daily. Other safeguards adequate, in the judgment of the chief or a deputy mine inspector, to minimize hazards with respect to transportation of workers and materials shall be provided. Divisions (E)(1), (2), and (3) of this section set forth the criteria by which the chief or a deputy mine inspector shall be guided in requiring other safeguards on a mine-by-mine basis. The chief or deputy mine inspector shall notify the operator in writing of any additional specific safeguard the chief or deputy mine inspector requires and shall fix a time in which the operator shall comply. If the safeguard is not provided within the time fixed and if it is not maintained thereafter, a notice of violation shall be issued to the operator.