STATISTICS AND INFORMATION. 2791

gencies and at a speed limited to six miles per hour, in which case the
leading car shall bear a signal light. The rear car of any trip shall carry
a signal light, and all trips hauled by endless cable shall carry a white light
on the leading car. A safety catch or other safety device shall be placed on
the rear end of the last car of all trips passing up steep grades or planes.
Where cars or trips pass through automatic doors the trip rider shall ob-
serve that such doors close, and if they fail to do so, he shall immediately
return and close the same. The transportation of tools and materials in
and out of the mine shall be under the direction of the mine foreman.

1922, ch. 307, sec. 94.

95. No person shall travel on foot to or from his work on any slope,
plane or haulage road, unless no other roads are provided or available for
that purpose, and then only at such times as permitted by the mine fore-
man. No person except officials and repairmen shall be permitted to travel
on slopes or planes while cars are in motion thereon.

1922, oh. 307, sec. 95.

96. In every such mine wherever the condition of grade, weight to be
moved, and distance of movement or any of them render placing of mine
cars liable to physically injure the miners if they are required to place
such cars by their own exertions, the Bureau may by general regulation
require that such cars, by mechanical or animal power, be placed at such
point in the heading, room or other excavation where the miners are at
work as shall be convenient without being further moved for loading.

1922, ch. 307, sec. 96.

97. The Bureau shall regulate and may prescribe conditions for the
installation, maintenance and operation of internal combustion engines, at
or within any such mine.

1922, ch. 307, sec. 97.

98. The Bureau shall prescribe such regulations for the installation,
maintenance and operation of coal cutting machinery, including periodic
examinations thereof, adequate guarding of dangerous moving parts, pro-
tection from electric shock, and proper support of roof and warning of
bystanders, as may assure reasonable protection of persons who may be
endangered by such machinery.

CHAPTER XIV—Ventilation.
1922, ch. 307, sec. 98.

99. The operator of every such mine, whether operated by shaft, slope
or drift, shall provide and hereafter maintain ample means of ventilation
by the circulation of air through the main and cross-entries, rooms and
all other working places of such mine, to an extent that will dilute, carry
off and render harmless all noxious or dangerous gases, affording in non-
gaseous mines not less than one hundred cubic feet of air circulation per