Omaha daily bee. (Omaha [Neb.]) 187?-1922, 1911-09-10

One of the most interesting results of these tests
has been to show that coal dust alone is even more
deadly than fire damp dust mixed with fire damp
the past both miners and mine operators have be-
lieved that the dust would not ignite unless from
fire damp explosion and that dust in mine free
from gas could not explode. To test this a lot of
dust put in the steel tube, which was then free
from gas. The loaded with black powder
tamped with clay and discharged. The result was
terrible explosion, which threw open the manholes
and sent great volumes of smoke and flames into
the air.
Indeed, the danger from this is great that
Director Holmes has issued circular nstructng the
miners to keep the mines clean of dust and suggest
ing that they sprinkle the dust with water cover
it with rock, clay sand. Dr. Holmes says that dry
coal dust floating in the air will explode whether
there is any infammabe gas present not and
that the finer the dust the greater the explosion Some
of the dust in the Pittsburgh cylinder so fine
that it passed through a sieve with a mesh of 200
openings to inch. This exploded when there was
only small proportion of it in the air.
The bureau of mines advises that the coal dust
should be frequently washed from the timbers and
the mines be kept wet They say that dry mine is
a dangerous mine and that the finer the dust the
more water required. Under conditions should coal
dust be used for tamping the holes filled with other
explosives.
DR.. Holmes tells me that many explosions of coal
dust have occurred in and about coal bins and that
similar explosions have happened in coal-crushing
rooms There were soma explosions of that kind last
year at St Louis and there in a cement plant
in Colorado In the latter nine
badly burned by the flaming dust that they died
II must not be thought that coal dust is the only
kind of dust that will explode without inflammable
gas The dusts of flour, starch and sugar, all of which
contain carbon will do the thing. This is we'll
known in the flour milling centers, many of the mills
having been blown to pieces by such explosions. One
such instance occurred at Minneapolis in 1873, and
substances than coal have dusts that will explode
This is of grahamite and gilsonite. both OF which
contain carbon. Last December a violent explosion
which due TO dust occurred in of the asphalt
mines of Oklahoma.
Permissible Explosives.
The business Of making explosives is an impor-
tant We have $50 different plants engaged in it
and their output is something like 500 pounds
a year They of different grades and so
dangerous that many people killed by them In
their transportation alone several million dollars
worth OF property is annually destroyed. The gov
eminent is making tests Of the various kinds the
work being done by Prof. Charles e. Munroe of
the George Washington university, who is noted
expert in the science, and by Clarence Hall
Of the bureau Of mines. These have issued
"An Explosives Primer for Miners" and they have
tested number Of explosives in the great Pittsburgh
cylinder which has been filed with gas and mix
lures of and dust and of coal dust alone for this
purpose. The gas and other mixtures are set off
by electric decorators II the explosive passes the
test It is marked permissible. The permissible
well known to the miners and mine oper-
ators and the latter glad TO use them to avoid
the blame and damages that might arise II other
unapproved explosives used to say nothing OF
their desire for the good OF the miner
5 In the European Mines.
So far we have no laws requiring the use of ap-
proved explosives only. It is different in Europe
> Germany, France. Belgium and Great Britain have
long had commissions studying and testing the va
rous explosives and they have prohibited those knowr
a to be dangerous There about fifty different
kinds which safe, and some of these have beer
found incapable or igniting mixture OF fire damr
and air. even with . charge forty tines as gysa