((a)) In making an investigation or inquiry or conducting a hearing the deputy commissioner or Board shall not be bound by common law or statutory rules of evidence or by technical or formal rules of procedure, except as provided by this chapter; but may make such investigation or inquiry or conduct such hearing in such manner as to best ascertain the rights of the parties. Declarations of a deceased employee concerning the injury in respect of which the investigation or inquiry is being made or the hearing conducted shall be received in evidence and shall, if corroborated by other evidence, be sufficient to establish the injury.

((b)) Hearings before a deputy commissioner or Board shall be open to the public and shall be stenographically reported, and the deputy commissioners or Board, subject to the approval of the Secretary, are authorized to contract for the reporting of such hearings. The Secretary shall by regulation provide for the preparation of a record of the hearings and other proceedings before the deputy commissioners or Board.