25 C.F.R. § 225.28
An amendment, modification or supplement to a minerals agreement entered into pursuant to the regulations in this part, whether the minerals agreement was approved before or after the effective date of these regulations, must be approved in writing by all parties before being submitted to the Secretary for approval. The provisions of § 225.22 apply to approvals of amendments, modifications, or supplements to minerals agreements entered into under the regulations in this part. However, amendments, modifications, or supplements that do not substantially alter or affect the factors listed in § 225.22(c) , may be approved by referencing materials previously submitted for the initial review and approval of the minerals agreement. The Secretary may approve an amendment, modification, or supplement if it is determined that the underlying minerals agreement, as amended, modified, or supplemented meets the criteria for approval set forth in § 225.22(c) .
25 C.F.R. §225.28