Deseret evening news. [volume] (Great Salt Lake City [Utah]) 1867-1920, 1903-10-09
COAL DUST EXPLOSIONS.
Experiments Conducted by English In.
speetors Proved Beneficial.

Mr.. Hall, inspector Of mines, ex-
perlmented for the English commits
sion appointed to enquire into explo-
siOns from coal dust in mines. He
proved that when a gunpowder shot
was fired In pit 80 yards deep and
feet in diameter and ventilated by an
air-curront of $50 cubic feet per min
ute-that % minutes after coal dust had
been thrown into the pit and only the
finest dust remained In suspension
that under these conditions very vio-
lent explosion might result and flame
be forced out Of the shaft 60 a height OF
go feet. The photographs OF the ex-
ploslons, as they appeared above the
pit top, showed that when only the
fine dust was In suspension the smoke
and dust We're less dense, and the flame
more intense. Experiments were also
made by firing shots In the pit 30 to As
minutes after the previous explosion
without adding any additional dust.
and the resultant explosions shot up
10 Ia 80 feet above the pit top.
Fortunately record was kept during
these experiments Of the state of the
weather, and Mr. Hall reports. that
the experiments occupied ~ days, the
weather throughout being most favor
able, and on several days there was an
unusual difference between the wet and
dry bulb thermometers showing the
atmosphere to be very dry" The OBJ
iect of this note Is clearly to point out
that the coal dust was dry, and the air
also dry, and therefore both were In
the most favorable condition for dem
onstratlng the explosibllity OF coal
dust We must however probe a lit
Tie deeper to get at the facts which are
Of the first value In this investigations
we shall be astonlshed to find that the
water content OF the air varied during
these days from SO grains TO 90 grains
per cubic foot, and on one day II was
within II per cent OF absolute satura-
ton We also find that on the Sth day
Of July, 1898. a charge Of ne hundred
weights OF dust was thrown into the
pit and three minutes afterward a
charge Of 10 ounces OF ammonte was
ired without causing an explosion, II
minutes after this charge Of eight
ounces OF rohurlte was also fired with
out adding any more dust, and no ex.
plosion resulted, and then 20 minutes
after the last shot charge OF ~
pounds Of gunpowder was fired again,
without adding fresh coal dust with
the result that very violent explosion
occurred and flame shot up GO feet above
the pit top. This experiment proved
that 30 minutes after dust was put In.
the two shots had been fired, each OF
which would blow n considerable duan-
tlty OF dust out OF the pit. and when
the air was carrying ts greatest load
Of water OF any day during the expert
ments-vi2,, go grains per cubic foot
the most violent explosions might oc-
cur Nearly all the explosions on this
particular day are reported as very
violent" II Ia unfortunate for a con-
tlnuance Of this argument that expert
meuts were not made with similar dusts
on days when the water contents was
mt its lowest, ms well as when at its
highest or vice versa; still we maycare-
fully note that on the 23rd of June,
when rain was falling nearly all day,
and the thermometer heats were low
viz, "a and 50. the water content was
Al grains per cubic foot, or only G
grain under absolute saturation. very
violent explosions occurred forcing the
flame GO feet above the pit top.
In reference to these experiments Mfr.
Han remarks that 'mines which are
naturally Of d?y and dusty character
cannot be artincialy damped so as IN
render gunpowdcr safe, and II Is do.
serving OF consideration and expori.
ment to test whether coaldust ex.
plosion would be stopped In It's course
by o certain length OF roadway being
constantly Kept IN a wet condition. Per.
sonally ! think such plan would moi
prove effective In consequence OF ,yhnt
may be termed the pioneering cloud OF
dust which precedes the flame" As n
further proof that a pioneering cloud
or dust Is unnecessary we may note one
Of Professor DiXOns remarks british
Coal-Dust Commission regarding Tho
Radstock eNplosion-vlx., that the pnth
Travelled by the fame was not dusty
IN the sense In which that word is or
for pioneering cloud OF dust is there,
fore. as quoted above and as proved bv
Mr. Halls own experiments. q negligi-
bic factor In the initiation of coal-dIst
explosions, james Ashworth In Octo-
bor Mines and Minerals