Neb. Rev. Stat. § 66-1103: Neb. Rev. Stat. § 66-1103

When the subsurface or mineral estate has been severed from the overlying surface estate, ownership of the right to develop and produce geothermal resources shall derive from the subsurface or mineral estate, except that no such right shall attach to subsurface or mineral estates granted prior to July 17, 1982, unless the document conveying the subsurface or mineral estate specifically granted the right to develop and produce geothermal resources.