On petition and proof and in its discretion, the Supreme Court or Superior Court may grant leave to enter an appeal from an order of the Commissioner of Labor in cases where the petitioner has been prevented by fraud, accident, or mistake from taking or entering an appeal within the time allowed by law. On granting leave, the court shall order the petitioner to give sufficient security to prosecute the appeal to effect and pay any costs awarded against the petitioner.
21 V.S.A. § 673