25 C.F.R. § 215.7
Upon authority being granted by the Secretary of the Interior to the superintendent to offer for sale at public auction a lead and zinc mining lease of any tract or tracts of restricted or trust allotted and inherited Indian lands, the superintendent shall cause a notice to be published once a week for at least 4 weeks in some designated newspaper of general circulation in the county in which the land is located, setting forth that upon a certain day, which shall be not less than 30 days from the first publication of such notice and at a place to be named in the notice, the superintendent or other duly authorized representatives of the Secretary of the Interior will offer for sale at public auction a lead and zinc mining lease of such lands to the highest and best bidder, subject to the rules and regulations prescribed by the Secretary of the Interior, notice to be in such form as may be prescribed by the Secretary of the Interior.
25 C.F.R. § 215.7