Ohio Rev. Code § 5713.05
On or before the thirty-first day of March, annually, the county auditor shall make a list of petroleum, oil, and natural gas wells, coal and ore mines, limestone quarries, fireclay pits, and works designed for the production of minerals which have been begun or constructed since the last preceding appraisal.
If, by reason of the discovery of such minerals, the construction of such works, the commencement of such operations, or the development of such minerals, or otherwise, within the year, the value of the lands containing or producing such minerals or the value of any right to such minerals, listed and taxed separately from such lands, has increased in value to one hundred dollars or more, the auditor shall increase the assessment of such land or right to the minerals therein to its taxable value in the name of the owner thereof. If the auditor finds that rights to minerals contained or produced in or upon any lot or parcel of land have been previously created and not separately assessed for taxation, he shall apportion the aggregate valuation of the lot or parcel and the right to minerals therein as provided in section 5713.06 of the Revised Code.
If the value of any lot or parcel of land containing or producing petroleum, oil, natural gas, coal, ore, limestone, fireclay, or other minerals, or of any right to the minerals therein shall decrease within one year because of the exhaustion of any such minerals or the failure to find or develop such minerals, the auditor shall determine the decrease in value of such lot or parcel in consequence of such exhaustion or failure to find or develop, if the fee of the soil and the right to the minerals is owned by and assessed for taxation against the same person. If the title to the fee of the soil is in one or more persons and the right to the minerals therein is in another person, the auditor shall determine the decrease in value of such right to the mineral therein by reason of such exhaustion or failure to find or develop. If the auditor finds that the value of any such lot or parcel of land or any such right to the minerals therein has decreased by one hundred dollars or more by reason of such exhaustion or of such failure to find or develop, he may reduce the valuation of such lands or of such rights to the minerals therein so as to place such valuation at its taxable value.
R.C. §5713.05