The Department of Labor and Industry shall have the power, and its duty shall be, whenever a difference arises between an employer and his employes with regard to wages, hours, or conditions of employment, to send a representative of the department promptly to the locality in which such difference exists, and endeavor by mediation to effect an amicable settlement of the controversy. If such settlement cannot be effected, and the dispute is submitted for arbitration, the department, in the event of the failure of representatives of employer and employes to name an impartial person to act as chairman of the board of arbitration, shall, if requested by the parties to the dispute, select such person to act as such chairman.