25 C.F.R. § 215.11
In cases where the lands have heretofore been leased and lead and zinc ores have been discovered but the mines and mining operations have been abandoned and the leases have been canceled or forfeited or have expired, special arrangements in the matter of the leasing and mining of said lands may be made provided the consent thereto of the Secretary of the Interior be first obtained. Applications containing special offers as to the terms and conditions may be considered by the Secretary of the Interior and the leasing of said lands may be made upon such special terms and conditions as the Secretary of the Interior may in each case deem to be for the best interests of the Indian owners of the land. If, however, in any case, it shall appear to the Secretary of the Interior that the granting of such lease would not be to the best interest of the Indian owners of the land, the Secretary of the Interior may cause the mining lease rights on said land to be offered for sale at public auction to the highest bidder. If the lead and zinc mining lease on said land be offered for sale at public auction, the same procedure shall be followed as provided in §§ 215.7 through 215.9 .
25 C.F.R. §215.11