In the discharge of the duties imposed by this act, the secretary, the members of the board, any agent duly authorized in writing by the board, and any referee shall have power to administer oaths and affirmations, take depositions and certify to official acts. The department and the board shall have power to issue summons or subpoenas to compel the attendance of witnesses and the production of books, papers, correspondence, memoranda, and other records deemed necessary as evidence in connection with a disputed claim or the administration of this act. Such summons or subpoenas shall be signed by the secretary or the chairman of the board, as the case may be, or some person duly authorized in writing by the secretary or the board. Witnesses subpoenaed pursuant to this act shall be allowed reasonable fees and expenses at a rate fixed by the department. Such fees and all expenses of proceedings involving disputed claims shall be deemed a part of the expense of administering this act and shall be paid from the Administration Fund.