The Washington herald., 1921-08-28
PRACTICAL STUDIES OF MINING HAZARDS
ss Synthetzed Explosions in Bruceton, Pa Colliery

possibility in sizes corresponding to the average nness
OF the road dusts obtained in the mine from which the
sample of coal taken and also in size OF standard
fness for comparison with other Goals So II mms
in Wyoming, for example. wanted to find out how
best stop coal explosions they simply ship samples
OF their coal the direction Of the Bureau OF Mines
and let the experts reproduce conditions in the expert
mental station.
All the tests made in the standard test zone"
part OF the mine, which is lined with concrete This
lining facilitates cleaning after explosion and pre-
particles Of coal dust from the ribs and roof
affecting tests with coal from the outside beds At
intervals of feet throughout the mine strong
instrument stations, built into the solid ribs
The measuring devices used during the tests
placed in these stations where the result may be
recorded without danger Of damaging the machines
and not being able that account to find out what
happened besides the fact that big explosion took
place Smaller intermediate stations placed be-
tween the large at every point the force OF
the explosion may be permanently recorded Not only
the force, but the time that the flame of the explosion
passes the instruments is recorded Photographic
film Thus the speed Of the dangerous force be
calculated and designed to prevent the spread
OF the explosion can be perfected from this data.
Two methods were discovered of preventing dust
explosions. First by weng the coal dust and second
by adding enough rock dust other noncombustible
dust of any to the coal particles render the
i
common use, and the second is comparatively new.
In it ordinary rock dust is simply blown into the
tunnels to- cover the coal and very light covering
is sufficient to prevent danger. Rock dustng is also
carried on by 'barriers," which will tip their
into the air when the first force OF the explosion is
felt and thus put up fine which curiously
enough prevents the flames from spreading
A NOVEL method of warning miners of danger
n by turning foul-smelling gas into compressed
air lines has been developed at the experimental mine.
One of the most promising stenches tried is prep
aration of butymcrcaptan isomercapan its pungent
and disagreeable odor gives timely warning of
unsafe coalition and allows the miner time to escape
Its manufacture involves the replacement of the oxygen
of alcohols by sulphur, compounds known as hydro
sulphides Inercaptans being formed
In the event of sudden danger such as a fire on
the surface the mouth of the mine, in of
the upper levels with large number of in the
next level below any condition necesstating hasty
escape of the men. the engineer the surface
once by means of simple device, introduce this
pungent substance the compressed-ar pipes. Its
odor is unmistaabe and is instantly detected by the
miner. who has been told to regard the odor as a
danger signal The odor reaches him through the
drill that he using the hoists where he is working
the pump that he is controlling and through all forms
simple and direct; it replaces expensive telephone
equipment, and is dependable than electric bells
and signals. 2'.f
Perhaps the most curious use to which the mine
is being put is for the storage Of helium gas This
gas non-inflamabfe and very light formerly was pro-
duced in laboratories only at a cost of about S.
pound too expensive for in ordinary mechanical
processes. 1t is the ideal gas for balloons, being
nearly as light as hydrogen and incombustble During