Sec. 939. [=Notice must be sent to chief inspector in certain cases.=] The owner, lessee or agent of a mine shall give notice to the chief inspector of mines in the following cases: When a change occurs in the name of the mine, in the name of the owner, lessee or agent thereof, or in the officers of an incorporated company owning or operating such mine; when a working is commenced for the opening of a new shaft, slope or mine; when a mine is abandoned, or the working thereof discontinued; when the working of a mine is commenced, after an abandonment or discontinuance thereof for a period of more than three months; when the pillars of a mine are about to be removed or robbed; when a squeeze, crush, or fire occurs, or a dangerous body of gas is found, or any cause or change that may seem to affect the safety of persons employed therein. (Sec. 940; Penalty, Sec. 976.) Sec. 940. [=Notice of accidents.=] The owner, lessee or agent of a mine at which loss of life occurs by accident, shall give notice thereof, by telegram, forthwith, to the office of the chief inspector of mines, and to the coroner of the county in which such accident occurs; and, within twenty-four hours next after loss of life or personal injury has occurred, the owner, lessee or agent of the mine shall send to the chief inspector of mines a report in writing, of the accident, specifying the character and cause thereof, the names of the persons killed or injured, and the nature of the injuries. If a personal injury thereafter results in the death of the person injured, as soon as such death comes to his knowledge, the owner, lessee or agent shall give notice thereof forthwith, in writing, to the chief inspector of mines, and to the coroner of the county in which such accident occurred. (Sec. 907, 921, 934, 951; Penalty, Sec. 976.) [=Return of owner, lessee or agent.=] The owner, lessee or agent of a mine, shall, on or before the thirty-first day of January of each year, send to the office of the chief inspector of mines, upon blanks furnished by him, a correct return, specifying with respect to the year ending on the preceding thirty-first of December, the quantity of coal mined, and the number of persons ordinarily employed at, in, and around such mine, distinguishing the persons below and above ground, and give such other information as required by such blanks. (Penalty, Sec. 976.) Sec. 941. [=Test weights to be provided.=] The owner, lessee or agent of a coal mine, at which the earnings of ten or more persons depend upon the weights of coal mined, shall provide and keep accessible for the purpose of testing the weigh scales as provided elsewhere in this act, the following standard test weights, properly sealed: Where the coal mined is weighed upon hopper or pan scales, two standard test weights of fifty pounds each; where the coal mined is weighed upon railroad track scales, ten standard test weights of fifty pounds each. (Sec. 910.)