Ohio Revised Code Title XV. Conservation of Natural Resources § 1563.27

The mine foreman shall examine or have examined the working place of each person working in the mine on each coal-producing shift that such person is working in such working place or more often when the circumstances so require. In case the mine foreman should delegate such duty of inspecting working places, when men are at the faces, the person to whom he delegates such authority shall be certified. As evidence of such examination, the mine foreman or the certified person delegated by him for such examination shall mark with chalk upon the face of the coal or upon some other conspicuous place, his initials and the time and date of the month upon which such examination is made. During such examination of the working places, the condition of the roof and timbering shall be observed, and when necessary, instructions shall be issued to the workmen therein as to the proper method of timbering for the security of the roof. He shall instruct pick miners and machine men regarding the width of the working places. The examination provided for in this section shall be made at least once each coal-producing shift by a certified man.

No person shall refuse or neglect to comply with this section.