Any person whose interest is substantially affected by the adjudication of the Secretary under § 6212 of this title may appeal to the Environmental Appeals Board within 20 days after the Secretary has announced his or her decision. The Board may affirm, modify or reverse the decision of the Secretary. If the decision of the Secretary is overruled or modified by the Board, then the Board shall state reasons for its decision. No decision of the Board shall be valid unless signed by a minimum of 5 members.