The times dispatch. [volume] (Richmond, Va.) 1903-1914, 1911-09-10

! issued a circular instructlns the miners
to keep the mines clean of dust. and
suggesting that they sprinkle the dust
with water or cover it with rock
clay or sand. DR. Holmes says that dry
coal dust floating in the air will ex-
plode whether there is any innamma BILE
gas present OF not. and that the finer
the dust the greater the explosion.
Some of the dust in the Fittsburg
cylinder was so fine that 1t passed
through q sieve with a mesh OF 200
openings TO an inch. This exploded
when there was only a small proper
ton Of it in the air.
The Bureau of Mines advises that the
coal dust should be frequently washed
from the timbers ard the mines be
kept wet. They say that a dry mine is
dangerous mine and that the finer
the dust the more water requsnas
Under no conditions should coal dust
be used for tamping the holes allied
with other explosives.
The Danger From Dust
Dr.. Holmes tells me that many ex-
and about coal bins and that similar
explosions have happened in coal
crushing rooms. There were some
explosions of that kind last year at
81. Louis and there was one in a ce-
ment plant in Colorado. In the lat
ter case nine mel, were SO badly burned
by the flaming dust that they died
1t must not be thought that coal dust
nis the only kind OF dust that will ex-
plode without inf!a mmable gas. The
dusts OF -four starch and sugar, all
of which contain carbon. will do the
same thing. This Is we'll known in
mills having been blown to pieces by
such explosions. One such instance oc-
CURED at Minneapolis in 1878. and an
other ST Granite City. Ill. in 1910.
Other mineral substances than coal
have 6usts that Will explode. This Is
so of grahamite and gilsonite. both of
which contain carbon. Last December
violent explosion which was due to
dust occurred in one of the asphalt
mines of Oklahoma
Permissible Explosives.
The bushes of making explosives Is
an important one. We have $50 diff
ferent plants engaged In 1t and their
output something like SOC, 900, 900
pounds year. They of different
grades and some so dangerous that
many people are killed by them. In
their transportation alone several mil
ION dollars worth of property Is an
nually destroyed The government is
making tests of the various kinds. the
work done by Professor Charles L.
Munroe. of the George Washington
University who is noted as an expert
in the science. and by Clarence Hail.
of the Bureau of Mines These men
have issued "An Explosives Primer for
Miners" ana they have tested num-
her of explosives in the great Pitts
burg cylinder. which has been filed
with gas and mixtures of gas and
dust and of coal dust alone for this
purpose. The gas and other mixtures
are set off by electris decorators /. the
explosive passes the test, 1t is mark
ed Permissible. The permissible ones
are now. well known to the miners
and mine operators. and the latter
are glad 10 use them to avoid the blame
and dangers that might arise If other
unapproved explosives were used, to
say nothing of their desire for the
good of tho miner
In the European Minea.
So far we have no laws requiring
the use OF approved explosives only.
It is different in Erlrope. Germany.
France. Belgium and Great Britain
have long had commissions studying
and testing the verious explosives, and