Any minor over 16 and under 18 years of age engaged in an occupation approved by the department of labor and industry as required by section 11 of Act No. 285 of the Public Acts of 1909, as amended, shall, within the meaning of said act, be considered to be legally employed, and shall in all cases be subject to Act No. 10 of the Public Acts of 1912 (extra session), as amended, known as the workmen’s compensation law, provided that the employer has filed the required permit or certificate for said minor.