coal trade bulletin - Clpdigital.org

28 THE COAL TRADE BULLETIN.
The bureau has endeavored to extend the move­
ment for the establishment of rescue stations
Iiatterned after its own, at which miners may be
locally trained in mine-rescue and first-aid work,
so that there will be immediately available in
times of disaster groups of organized men trained
in scientific and rational rescue and recoverymethods.
There are now in the different parts
of the country several hundred such groups of
men. A number of the larger mining operators
have established 76 rescue stations; mine operators
now own 12 and two states own 4 rescue cars
equipped somewhat after the manner of those
operated by- the Bureau of Mines; and the movement
has otherwise been vigorously developed not
only in the coal-mining but to some extent in the
metal-mining districts.
A revolution has been brought about in the
explosives used in coal mines containing inflam­
mable gas or dust.
At the time of the inauguration of this work
black powder, with its long flame and poisonous
gases, was almost universally used in coal-mining
operations in the United States. One of the first
investigations undertaken by the bureau was thai
looking to improvement in the character of tne
explosives used. As a result of conferences with
mine owners, miners, and manufacturers of explosives
a number of these
MAM 1 ATI* REUS AGREED
to undertake the making of a new type of explosive
that would have for its special character­
istics an explosion flame of short duration and
relatively low temperature.
The bureau co-operated in the development of
this new type of explosives by establishing the
necessary standard with regard to safety, and
by testing the explosives submitted from time
to time to determine whether they had reached
such standard, or the manner in which and the
extent to which they failed to reach such standard.
As a result of this work, within a little
more than three years' time, the use of the new-
type of explosives, termed "permissible explosives,"
has become general in those mines where
the risk of gas or dust explosions was a serious
one. So rapid has been the introduction of the
permissible explosives that, during 1912, more
than lS.ooo.ouo pounds of these explosives were
used in the coal mines of this country. The
present work of the bureau along these lines is
to assure further improvements in these explo­
sives, and especially to reduce the quantity of
poisonous gases given off in firing shots, and to
reduce the shattering effect of these shots; and
also to bring about safer methods of handling
and tiring whatever explosives may be used in
mining.
Notwithstanding the large increase in the use
of electricity in coal-mining operations, and also
the increase in the number of mines in the past
few years, there has been no increase in the number
of fatalities from electric shock or burns, as
the following table shows. But the ignition of
gas and dust by electric short circuits has, it is
believed, been the cause of certain great explo­
sions that resulted in a large number of fatalities
not included in this list.
Fatalities in coal mines due to electricity and
to gas and dust explosions:
I Figures for 1907-1909 based on those of United
States Geological Survey. Figures for 1910-
1912 based on those in Bulletin 69.
Bureau of Mines).
Number killed
per 1,000
^_ employed.
Year.
3
O
1907.. _-
1908..
.
3,125
2,450
1909.. . 2,412
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be _
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947 _ — 0*a - *
1.39
396 * .57 *
341
.51 *
1910.. . 2.S40 5 1 8 79 .71 0.11
1911.. . 2,719 379 87 .51 .12
1912.. . 2.360 3111 70 .40 .10
::
Electricity not given as separate cause.
The bureau has conducted an investigation concerning
the insulation of electric wires in coal
mines and has recommended a number of im­
provements. It has conducted a series of investigations
with a view of developing explosion-proof
motois, approved types of fixed and portable electric
lamps, and better electric signals in mines,
regarding all of which there is serious need of
additional research.
The mine-safety appropriations of the Bureau
of Mines have been more largely devoted to a
possible reduction of mine explosions than to
any other phase of mine-safety work. Congress
made its first appropriation for investigation into
the causes and possible prevention of mine ex­
plosions in 1908, and appropriations for carrying
forward such an investigation have been made
each year since that time. Extended laboratory
tests have shown the differences in explosibility
of coal dust collected from different coal mines
in different parts of the country, and this particular
line of research
HAS BEEN MUCH FACILITATED
by the opening of the experimental mine at Bruceton,
Pa., which has, however, been ready only
within the past few months for the making of
serious investigations. As a result of these researches
and the educational campaign carried
on by the engineers of the bureau with the co­
operation of state mine inspectors, mine operators,