Report of the Bureau of Mines of the Department of Internal Affairs of ...

Ixxviii MINING LAWS OF PENNSYLVANIA. Off. Doc.
Section 9.
All doors used in assisting or in any way affecting the
ventilation shall be so hung and adjusted that they will close automaLically.
Section 10, All main doors shall have an attendant whose constant
duty it shall be to open them for transportation and travel and
prevent them from standing open longer than is
necessary for persons
or cars to pass through.
Section 11. All main doors shall be so placed that when one door
is open, another, which has the same effect upon the same current,
,>^hall be and remain closed and thus prevent any temporary stoppage
of the air current.
Section 12. An extra main door shall be so placed and kept standing
open, so as to be out of reach of accident, and so fixed that it can
bo at once closed in the event of an accident to the doors in use.
Section 13. The frame work of such main doors shall be substantially
secured in stone or brick, laid in mortar or cement unless otherwise
permitted in writing by the inspector.
Section 14. All permanent air bridges shall be substantially built
of such material and such strength as the circumstances may require.
Section 15. The quantities of air in circulation shall be ascertained
with an anemometer or other efficient instrument; such
measurements shall be made by the inside foreman or his assistant
once a week at the inlet and outlet airwaj's, also at or near the
face of each gangway and at the nearest cross-heading to the face of
each gangway and at the nearest cross-heading to the face of the inside
and outside chamber or breast where men are employed, and
^he headings shall not be driven more than sixty (GO)
face of each chamber or breast and shall be entered in
feet from the
the colliery
report book.
Section 10. A report of these air measurements shall be sent to the
inspector before the twelfth day of each month, for the preceding
month, together with a statement of the number of persons employed
in each district.
Section 17. All ventilators used at mines shall be provided with recording
instruments by which the speed of the ventilators or the ventilating
pressure shall be registered for each hour, and such data
siiall be preserved at the colliery for future reference, for a period of
three months.
Section 18. Any person or persons who shall neglect or fail to
comply with the provisions of this article, or who shall make any
false report in regard to air measurements, shall be guilly of an offense
against this act.