The Secretary shall review, within ninety days of December 22, 1982, any existing Minerals Agreement, which does not purport to be a lease, entered into by any Indian tribe and approved by the Secretary after January 1, 1975, but prior to December 22, 1982, to determine if such agreement complies with the purposes of this chapter. Such review shall be limited to the terms of the agreement and shall not address questions of the parties’ compliance therewith. The Secretary shall notify the affected tribe and other parties to the agreement of any modifications necessary to bring an agreement into compliance with the purposes of this chapter. The tribe and other parties to such agreement shall within ninety days after notice make such modifications. If such modifications are not made within ninety days, the provisions of this chapter may not be used as a defense in any proceeding challenging the validity of the agreement.