is not provided, the owner, lessee or agent shall be required to
lower or hoist persons, as above prescribed, but when such stairway
is provided, the hoisting of persons shall not be required.


Sec. 930. [=Owner, lessee or agent shall provide second opening.=]
The owner, lessee or agent of a mine shall not employ or permit any
person to work therein except as hereinafter provided, unless to
every seam worked in such mine there are at least two openings,
separated by natural strata of not less than one hundred feet in
breadth at any point, by which distinct means of ingress and egress
are always available to the persons therein employed. Such openings
need not belong to the same mine so long as the persons employed
therein have safe, ready and available means of ingress and egress,
by not less than two openings, provided, however, that no air shaft
with a ventilating furnace at the bottom be designated or used as a
means of ingress or egress. The provisions of this section shall not
apply to opening a new mine while being worked for the purpose of
making the second opening and the communication therewith, and the
making of the landing or bottom and extending of the main entries
one hundred feet while such communication is being made; to a mine
in which the second opening has become unavailable from any cause
while said second opening is being restored or another is being
made; nor to a mine in which the second opening has become
unavailable by reason of the final robbing of the pillars previous
to abandonment, so long as not more than twenty persons in either
case are employed therein at one time.


[=Fire protection to shafts.=] At each mine at which the only means