Ohio Rev. Code § 1567.10
Every outside fan installed after September 2, 1941, at any coal mine shall be placed at least twenty feet from the side or mouth of the shaft entry or slope with which it is connected for ventilating purposes and shall be of fireproof construction. Explosion doors shall be provided in a direct line with the mine opening.
Upon the written order of the chief of the division of mineral resources management, all main mine fans installed after September 2, 1941, shall be so arranged that the ventilating current can be quickly reversed. No fan shall be reversed while workers are in the mine unless authority to do so is given, preferably in writing, by the mine foreperson, superintendent, state inspector, or other responsible person. The fan shall be inspected at least daily.
Every main ventilating fan at nongaseous mines shall be kept in operation continuously day and night, unless operations are definitely suspended, except when written permission is given by the inspector to stop it. The permission, or a copy thereof, shall be posted by the mine foreperson in a conspicuous place at the entrances of the mine, and shall state the particular hours the fan may be stopped. The inspector may withdraw or modify such permission at any time and in any manner the inspector deems best. In all cases in which permission has been given by the inspector to stop the ventilating fan, the fan shall be started a sufficient length of time prior to the appointed time for any person working therein to enter, to clear the mine of explosive, poisonous, and noxious gases, and shall be kept in operation a sufficient length of time after the appointed time for such employees to leave their working places, for all persons to be out of the mine.
Every main ventilating fan at gaseous mines shall be kept in operation continuously day and night unless operations are definitely suspended. Should it become necessary to stop the fan at any mine, gaseous or nongaseous, because of an accident to part of the machinery connected therewith, or by reason of any other unavoidable cause, the mine foreperson or the foreperson in charge shall, after first having provided for the safety of the persons employed in the mine, order the fans stopped for necessary repairs. Should the ventilating fans be stopped at any time for any reason at any gaseous mine for a period of time sufficient to cause a serious interruption of the ventilation, the source of electric power shall be forthwith disconnected from the mine, and the source of electric power shall not be reconnected with the mine until the fans have been started, and the mine has been examined by the mine foreperson, foreperson, or fire boss, and reported safe. A record of such examination shall be entered in the fire boss record book. The person in charge of the mine at the time of the examination is responsible for the execution of this latter provision.
No operator of a mine shall refuse or neglect to comply with this section.
R.C. §1567.10