25 C.F.R. § 215.8
At the time of public auction bidders may submit their bids in person or by authorized agents, but in the latter case the bids must be accompanied by power of attorney duly executed by the real party or person in interest. Sealed bids may be submitted by mail or otherwise to the superintendent at his office at Miami, Okla., or delivered to him at the place set for the sale at any time prior to the hour fixed for offering the lease for sale. At the time and place of the public auction and before receiving the public bids the officer in charge shall announce the amounts and terms of all sealed bids received by him and the names of the bidders. The persons present, including those, if any, who may have theretofore submitted sealed bids, shall then be allowed to offer public bids. Bids must contain the offer of the stipulated and fixed royalty (see § 215.5 as to royalty) and, in addition thereto, the offer of a bonus payable as follows: 25 percent at time of sale and the balance before or at time of execution of the lease contract. Bidders shall be required to submit with their bids a draft or certified check payable to the order of the superintendent covering the advance rental for the first year on the proposed leasehold and 25 percent of the amount of the bonus offered. The superintendent shall, in each case, determine the highest and best bid, said determination, however, to be subject to the approval of the Secretary of the Interior. Upon approval by the Secretary of the Interior of the award, the successful bidder shall, within 30 days from notice thereof, enter into and execute the lease contract in accordance with said bid and the regulations in this part. The lease so executed shall be subject to the approval of the Secretary of the Interior and may be accepted or rejected by him when submitted for his approval. The right is reserved to the Secretary of the Interior, in the event of the rejection of such lease, to authorize and instruct the superintendent to accept the offer of some competitive bidder or to readvertise the land for lease. The report of the superintendent to the Commissioner of Indian Affairs relative to the auction sale shall contain full information as to all bids received for the lease rights on the land. If any person or party fails or refuses to execute a lease after being declared the highest bidder or after being awarded such lease, the amount tendered with his bid shall be forfeited to the superintendent for the benefit of the owner of the land.
25 C.F.R. §215.8