such, in the opinion of the chief inspector of mines, that the
provisions of the preceding section do not provide the required
protection from shock to persons employed therein, such additional
safeguards shall be employed as may be required by the chief
inspector of mines, and the district inspector of mines, jointly.
(See. 911, 947; Penalty, Sec. 976.)


Sec. 949. [=Relating to construction of new mines.=] Any person,
firm or corporation beginning the opening of a mine, whether such
person, firm or corporation be the owner, lessee or agent of the
property upon which such mine is located, or not, shall observe the
following in the construction of such mine: If the opening be a
slope or vertical shaft, no explosive used therein shall be fired by
means of a squib or fuse after the same is extended more than
twenty-five feet from the surface, and thereafter and until the
slope or shaft reaches the seam, and the entry or landing be
extended beyond a breakthrough or other place driven at right angles
thereto, no explosive shall be fired except by means of an electric
battery operated from the surface after all persons are on the
surface. A substantial structure to sustain sheave wheels or
pulleys, ropes and loads, shall be provided, and if the opening be a
shaft, the same shall be placed at a height of not less than twenty
feet above the tipping place. A landing platform shall be arranged
in such manner that no material can fall into the shaft while the
bucket is being emptied, and in no case shall the shaft be sunk to a
depth of more than thirty feet without such structures. If the
bucket used for hoisting material is to land on a truck, the track
on which said truck is operated, and the platform, shall be so
constructed that material cannot fall into the shaft. Rock and coal