If an appeal is filed, the administrative law judge shall, as soon thereafter as is practicable, transmit the record of the proceeding to the Assistant Secretary for review. The record shall include: the petition; the MSHA investigation report; any request for hearing on the petition; the transcript of testimony taken at the hearing, together with exhibits admitted in evidence; any documents or papers filed in connection with prehearing conferences; such proposed findings of fact, conclusions of law, rules or orders, and supporting reasons, as may have been filed; and the administrative law judge's decision.