Any person who knowingly works in or at a mine without a certificate issued under the provision of this article, any person who knowingly employs an uncertified miner to work in or at a coal mine in this state, or, any operator who fails to insure the supervision of miners holding a certificate of apprenticeship as provided for in section five of this article, is guilty of a misdemeano, and, upon conviction thereof, shall be fined not less than $50 nor more than $500.