Ohio Rev. Code § 1563.39: Precautions when working place approaches completed or abandoned workings.

When any working place approaches within fifty feet of accurately surveyed completed workings in the same mine, or within two hundred feet of any other abandoned workings, that cannot be inspected and which may contain dangerous accumulations of water or gas, boreholes shall be drilled at least twenty feet in advance of the face, and forty-five degree angle rib holes shall be drilled at least twenty feet deep and not more than eight feet apart in one or both ribs as may be necessary for adequate protection. Completed workings are accurately surveyed when a competent engineer or surveyor has certified as to the surveying and recording thereof.

No operator of a mine shall refuse or neglect to comply with this section.