Whenever an appeal shall be taken on the ground that the referee's award or disallowance of compensation was unwarranted by the evidence, or because of fraud, coercion, or other improper conduct by any party in interest, the board may, in its discretion, grant a hearing de novo before the board or one or more of its members, or assign the petition for rehearing to any referee designated by it, or sustain the referee's award or disallowance of compensation. If the board shall grant a hearing de novo, it shall fix a time and place therefor and notify all parties in interest.

As soon as may be after any hearing de novo by the board, it shall in writing state its findings of fact, and award or disallow compensation in accordance with the provisions of this act.