Code of Federal Regulations Title 43. Public Lands:  Interior § 43.5511.3–5 Removal of improvements

Upon expiration of the permit period the permittee will be given 90 days to remove equipment, personal property and any improvements he has placed on the land, except roads, culverts and bridges are to be left in place, in good condition and will become the property of the United States upon expiration of the 90–day removal period.