coal trade bulletin - Clpdigital.org

30 THE COAL TRADE BULLETIN.
This miners circular discusses the means of preventing
accidents in driving tunnels, levels and
drifts for mining purposes, such as drainage, transportation
and development, in which the entire
cross section is excavated in one operation. The
precautions apply also to the driving of nearly all
tunnels that are used to carry water for power.
irrigation, or domestic use, because in such work
practically the same kinds of risks are incurred
as in the driving of mine tunnels.
Complete statistics in regard to the number
of tunnel accidents cannot be obtained, but a study
of the data collected indicates that the number of
fatal accidents in proportion to the number of
men employed is somewhat greater than in either
coal or metal mining taken as a whole. The
result obtained by averaging reports, which extend
over periods of 1 to 10 years, for 16 representative
mining and water tunnels was 4.7 deaths
annually per 1,000 men employed, as compared
with 3.73 per 1,000 for coal mining and 4.19 per
1,000 for metal mining during 1911. In addition
to the men killed outright more than three times
as many more (or 16 per 1,000) have annually
been seriously injured or maimed for life, and 13
times as many more (or 62 per 1,000) have annually
been slightly injured by accidents in tunnel
work.
A large number of these deaths and injuries have
resulted from ignorance or carelessness and
COULD HAVE BEEX AVOIDED
by a knowledge on the part of every underground
employe of the proper precautions to be taken and
by strict attention to the observance of these precautions.
This applies not only to the driller or
the mucker but to the foreman and superintendent
as well, for each has his duty to perform, and
it is only by co-operation between all parties concerned
that the number of deaths and injuries now
resulting from tunnel work can be reduced. The
following paragraphs are therefore written directly
to the men interested, in the hope of bringing
home to them once more some of the more important
preventive measures.
The greater responsibility always lies with the
man who has the broader vision and you. the
superintendent, are in duty bound to see that the
working places of your men are made as safe as
possible, regardless of the time required to do so,
and you are equally bound to see that the men
themselves exercise the greatest care and caution
in conducting their work. Do you realize that
accidents are costly, not only in life and limb but
also in actual money? For in most cases an acci-
*Miners Circular No. 13. United States Bureau ol Mines.
SAFETY IN TUNNELING*
By David W. Brunton and John A. Davis
dent seriously hinders the work, even a single
death causing a suspension of operations for two
or three shifts, whereas a larger catastrophe may
cause the tunnel to be shut down entirely for
months at a time, as, for instance, after fire, or
flood, or cave-in. Many such accidents could have
been prevented altogether if even ordinary precautions
had been exercised beforehand. So for
both humanitarian and economic reasons you
should make safety the first and all-important
consideration.
By far the greatest source of danger in tunnel
work at present is from falls of rock. These can
be prevented in a large measure by promptly and
adequately supporting the roof. Insist that necessary
timbering be done at once and always keep
a supply of lumber at hand for this purpose, so
that no delay may ensue for lack of it. True,
timbering is laborious and it either takes the
men of the tunnel crew from their regular work
or requires extra men. If extra men are used
they add to the confusion in the heading, and as
their work is done at the same time as the other
work of the tunnel it seriously hinders either the
drillers or the shovelers, or both. So. although
you may suspect that the roof is dangerous, you
may be tempted to delay timbering—possibly until
an accident brings the necessity forcibly and unavoidably
to the front. Remember that all necessary
timbering cannot be done too soon, and that
any delay seriously
JEOPARDIZES THE LIVES
and limbs of the men who have to work under a
roof improperly supported.
Do not permit any disregard of the proper percautions
in handling, storing, or using explosives,
as referred to herein, and provide each man with
a copy of these or similar precautions.
Provide suitable magazines and thaw houses for
explosives. Specifications for such buildings
recommended by the Bureau of Mines are to be
found in Technical Paper 18, which is published by
the bureau for free distribution.
Have careful tests of the burning rate of the
fuse made periodically, especially whenever a newbrand
is purchased. Different makes and brands
of fuse burn at greatly varying rates, and a miner
accustomed to a slow-burning fuse will perhaps
not realize the necessity of cutting the fasterburning
fuse longer so that he may have time to
reach a place of safety before the detonation takes
place. Experiments conducted by the Bureau of
Mines, and described in Technical Paper 6, show
also that there are several causes that may increase
greatly the rate of burning of the same