Leases of allotted lands for mining purposes

All lands allotted to Indians in severalty, except allotments made to members of the Five Civilized Tribes and Osage Indians in Oklahoma, may by said allottee be leased for mining purposes for any term of years as may be deemed advisable by the Secretary of the Interior; and the Secretary of the Interior is authorized to perform any and all acts and make such rules and regulations as may be necessary for the purpose of carrying the provisions of this section into full force and effect: Provided, That if the said allottee is deceased and the heirs to or devisees of any interest in the allotment have not been determined, or, if determined, some or all of them cannot be located, the Secretary of the Interior may offer for sale leases for mining purposes to the highest responsible qualified bidder, at public auction, or on sealed bids, after notice and advertisement, upon such terms and conditions as the Secretary of the Interior may prescribe. The Secretary of the Interior shall have the right to reject all bids whenever in his judgment the interests of the Indians will be served by so doing, and to readvertise such lease for sale.