The Washington herald., 1921-08-28
By Z. w. COFFIN

twenty feet long shot up 1t in started air
currents, and the flame spread.
The first experiment along this line more OF
a success than the engineers dreamed OF. Hundreds
OF miners representatives OF union labor and opera
tors mine superntendents and other scoffers, made
up the audience. They came to scoof, but remained
to pray after they what happened
For the harmless coal dust. which they themselves
had sprinkled in the mine chamber, and abso-
iuely certain harmless could be, blew up
with mighty bang which drove heavy mine
out OF the mouth Of the mine and it hurting
through the air a ravinc to the hilltop
which they had taken their stand 800 yards away.
Seeing that mine shoot from the hole did more to
convince the miners that coal dust had force when it
mixed with air and spark than all the technical
arguments which the engineering profession had
printed in ten years They back to their respcc-
tive mines with a most wholesome respect ior the
power of coal powder.
MYTH pulverzed Pittsburgh coal it was found
w that the flame travelled about $50 feet in the
first second. The explosion and speed OF the flame
gathers after that second until. point $50 feet
from the origin of the explosion a speed Of 1000 feet
per second is reached and the pressure runs up to
forty pounds per square inch AT $50 feet the
is as high I2o pounds to the square inch, and the
roof OF mine gallery has number of square inches
it.
The beauty OF owning regular mine to work
such experiments is that everyday working cond
tions reproduced at very little cost. Instead OF
building tunnels top of the ground they to be
found already dug with real earth around them This
makes test much practical and the results
very much more useful than when tunnels have to be
built tamped with earth and reinforced with
othes materials to make them sufficiently strong
carry the experiments to real conclusion. The
posions tested at Bruceton exactly the same in
force those in working mines
The wallis the roof and the timbering of a real
mine present conditions which cannot be duplicated in
gallery of wood steel or concrete. Hence preveu-
tive that quite successful under artificial
conditions in a surface gallery not necessarily
successful in mine Arrangements in the expert
mental mine make it possible duplicate any of
an explosion which might in working mine,
and make the results that much more accurate and
valuable As matter of fact scientists and eneeeers
from all parts of the world to the expert
ments at Brueeton, and the results. OF course, are
printed and available for all nations This IS one
public service which the United States performs for
the common good Of all mankind. .... -
Not only mine explosions tested, but the gal
leries deep in the earth provide ways and of
making other Investigations relating to safety which
would be impossible under any other conditions.
Tests of gasoline locomotives for example, of mining
and cutting machinery of electrical equipment and Of
ventilation methods in constant process of tryout
under real conditions. Gas-producer tests and both
physical and chemical tests of explosives can be well
associated with a plant of this kind natures labora
tory" in which the mind OF directs the processes
- here. The Goals ranged from anthracite con-
tanning S per cent of volatile matter to low
grade bituminous Goals ranging up to 40 per cent of
EaNk T.