Ohio Rev. Code § 1567.76: Maintenance of hydraulic lines and roof support units.

(A) An operator shall ensure that all hydraulic line repairs are performed in accordance with maintaining the functioning of the line at a level consistent with that at the time of initial installation of the line.

(B) An operator shall ensure that all hydraulic roof support units and associated apparatus on a longwall working face are visually inspected at least once each day, at any time of the day, by a qualified person as part of one of the on-shift examinations of the longwall working sections. The person conducting the inspection shall enter the inspection into the preshift examination book and shall note any hazards or problems that he encountered.