[=Inexperienced miner.=] The provisions of this section shall not prohibit a person not so qualified from working in a mine by himself, or with another inexperienced person, when such person or persons work under the direction of a competent overseer, as hereinafter prescribed. Until such person or persons have been employed in a mine for a period of not less than three months, the overseer shall visit the working place of such persons not less frequently than once in each four hours that such persons are in the mine, and instruct them as to their work and safety, and assist them in caring for their safety. After such persons have been employed in a mine for a period of three months, and until they have been employed not less than six months, the overseer shall examine the working place not less frequently than once during each six hours that such persons are in the mine, and shall instruct them as to their work and safety, and assist them in caring for their safety. After such persons have been employed in a mine for a period of not less than six months, the overseer shall examine the working place not less than once each day until such persons become qualified by having worked the period of time hereinbefore provided. The overseer shall instruct such persons not to handle or use any explosives, except in his presence, until they have been employed in a mine not less than three months, and not then until he is satisfied that such persons are fully competent to handle and use same with safety. The overseer shall visit the working place of such persons oftener than required herein, when, in his judgment, it is necessary to do so for the proper safety of such persons. (Sec. 954; Penalty, Sec. 976.) Sec. 966. [=Oath and bond of weigh-master.=] Any person employed to weigh coal at a mine in which ten or more miners are employed, and upon the weight of which the earnings of the miners depend, shall take and subscribe to an oath before an officer authorized to administer the same, that he will correctly weigh all coal taken from such mine under existing contracts between the owner, lessee or agent, and the miners, and give due credit for same; and when required by existing contracts between the lessor and lessee, he shall give due credit to such lessor. He shall also give a bond in the sum of three hundred dollars, with two sureties approved by the clerk of the township in which such mine is situated, conditioned for the faithful discharge of his duties, and payable to the state, with the oath indorsed thereon, which shall be deposited with such township clerk. (Penalty, Sec. 976.)