Every insurance company or mutual association which insures employers against liability either under this chapter or for damages imposed by law arising out of any other liability to employees because of personal injuries including death at any time resulting therefrom, or both, shall file with the commissioner of banking and insurance its classification of risks and premiums and rules pertaining thereto, together with the basis rates and system of merit or schedule rating applicable to such insurance which system of merit or schedule rating shall be applied as hereinafter provided. Neither classifications of risks, rules pertaining thereto, basis rates, nor system of merit or schedule rating shall take effect until the commissioner of banking and insurance shall have approved the classifications, rules, basis rates, and system of merit or schedule rating, as reasonable and adequate for the risks to which they respectively apply. The commissioner of banking and insurance may withdraw his approval of any classification, rule, basis rate, or system of merit or schedule rating if he shall find that such classification, rule, rate, or system of merit or schedule rating is unreasonable or inadequate for the risks to which they respectively apply. To secure the impartial application of such approved classifications, rules, rates, or system of merit or schedule rating, the commissioner of banking and insurance is hereby authorized to create, organize and supervise such rating and inspection bureau with such jurisdiction under his supervision as hereinafter provided. No insurance company or mutual association writing workmen’s compensation or employer’s liability insurance in this state shall issue, renew, or carry any insurance against the liability of an employer either for compensation or for damages imposed by law, because of personal injuries, including death at any time resulting therefrom, sustained by his employees, or for both, except in accordance with the classifications, rules, basis rates, and system of merit or schedule rating approved by the commissioner of banking and insurance as aforesaid and applied by the rating and inspection bureau; provided, however, that any departure from the basis rate filed with and approved by the commissioner of banking and insurance on account of the application of a system of merit or schedule rating approved by the commissioner of banking and insurance shall be clearly set forth in the insurance contract or indorsements attached thereto. If any insurance company or mutual association authorized to write workmen’s compensation or employer’s liability insurance in this state shall violate any of the provisions of this act, the commissioner of banking and insurance, may, in his discretion, after public hearing, suspend the authority of said insurance company or mutual association to transact workmen’s compensation or employer’s liability insurance in this state for such period as said commissioner shall fix.