Evening star., 1915-07-11

Electricity, which has proved such a
boon to most branches of nodern in
dustry. has had
Devices to Reduce its undoubted use
Mining Perils. opera tIons 10 e tenn.
pered by the fact that it has caused
many deaths among the miners. both
through shock and through the igni-
ton of explosive gases by sparks and
flashes. The bureau of mines, in the
work to promote mine safety. in which
it has been steadily engaged since its
creation in 1910, has recently been
making a special study of electrical
problems. 1t has succeeded in formulat-
ing specifications for electric motors
and accessories and electric lamps that
when followed will insure the produc-
tion of equipment practically free from
danger.
The bureau has no authority to en-
force the use of apparatus of partic-
ular type, but it has found weapon in
modern business organization and ad-
vertising that is highly effective. The
method adopted is to make tests OF
safe as permissible" the govern
ments sanction being indicated by a
plate bearing the official seal of the
bureau attached to the larger pieces OF
apparatus. Manufacturers who re.
their wares advertise the fact widely,
and mine operators and miners work.
ing in dangerous mines are beginning
to demand the use of permissible"
equipment only.
The greatest danger in the use of
electricity in mines is from explosions.
Practically all electrical motors and
accessories in ordinary use above
ground give off sparks at some point
at times. In gaseous mines such a
condition might result in the loss Of
hundreds of lives. The bureau there
fore demands that permissible motors
shall have all dangerous parts in
closed in chambers that. keep sparks in
interior explosions in case gas finds
it's way into the machinery. The mo-
tors are placed in metal boxes or rooms
filled with highly explosive gas. and
are rigidly tested as to their behavior
under the most dangerous conditions
before being listed as permissible.
Many tests of electric hand-lamps and
cap-lamps for use by miners have also
been made recently in the laboratories
of the bureau. The officials and ex-
perts of the bureau are desirous OF
bringing about general use of such
lights to replace the open flame, and in
large part the safety flame lamps which
give much less light and at the same
time may cause explosions.
All permissible electric mine lamps
are equipped with safety devices which
automatically break the electrical con-
nections the instant the bulb is broken
thus preventing the ignition of gas by
the glowing flaments In testing the
lamps, numerous attempts are made to
break and jam the safety devices In
gas-f1lled chambers before the lamps
are listed as permissible.
Before taking up the electrical studies
the bureaus experts attacked the prob
lem of producing safer explosives and
worked out formulas for permissible
explosives for coal mines. More re-
Gently formulas for such explosives foI
metal mines and quarries have been
promulgated. These are coming Into
general use, and will effect consider.
able saving of life, it is believed.
The need for the safety work of the
bureau is shown by the fact that In
coal mines alone more than 1000 men
are killed each year. In 1913 the num-
Der was 2,7S5, and in 1919 2.451. 1t is
believed that the educational work OF
the bureau of mines, its introduction OF
safer methods and its rescue work by
means of it's eight mine rescue cars
were important factors in bringing
about this reduction. and that such
work will make itself felt more and
more in the future.