As used in KRS 353.462 to 353.476, the following definitions shall apply:
(1) A "severed mineral interest" is any whole or fractional interest in any or all minerals which have been severed from the surface estate by grant, exception, reservation or other means.
(2) An "unknown or missing owner" is any person vested with a severed mineral interest and whose present identity or location cannot be determined from the records of the county in which the land is located or by diligent inquiry in the vicinity of the owner's last known place of residence, and shall include his unknown heirs, successors and assigns.