(a) Oil and gas leases heretofore approved and leases for other minerals now or hereafter in force on land from all of which restrictions against alienation have been or shall be removed, even if such leases contain provision authorizing supervision by this Department, shall after such removal of restrictions against alienation, be operated entirely free from such supervision, and the authority and power delegated to the Secretary of the Interior in said leases shall cease and all payments required to be made to the Area Director shall thereafter be made to the lessor or the then owner of the land, and changes in regulations thereafter made by the Secretary of the Interior shall not apply to such leased land from which said restrictions are removed.

(b) In the event restrictions are removed from a part of the land included in any lease to which this section applies the entire lease shall continue subject to the supervision of the Secretary of the Interior, and all royalties thereunder shall be paid to the Area Director until such time as the lessor and lessee shall furnish the Secretary of the Interior satisfactory information that adequate arrangements have been made to account for the oil, gas or mineral upon the restricted land separately from that upon the unrestricted. Thereafter the restricted land only shall be subject to the supervision of the Secretary of the Interior: Provided, That the unrestricted portion shall be relieved from such supervision as in the lease or regulations provided.