The Helena independent. [volume] (Helena, Mont.) 1875-1943, 1891-09-22
DANGERS OF COAL MINING.

In my last choke-damp, after-damp n
Rzote as dangerous elements in coal mining
were briefly considered, and some infor-
nation was promised respecting the ex-
plosive properties OF coal dust in mines.
While We do not know all the conditions
in which coal dust produces explosions in
mines, or aids in producing them, it is we'll
settled that coal dust has acted an i'm
portant part in the largest number of the
most disastrous explosions of the last few
years, or since this subject has been under
investigation in this country and Europe.
Various operations in coal mines do con-
stantly reduce portions of the coal to 80
fine q powder that it floats in the air of the
mine. Drilling, breaking and handling the
coal makes GOAL dust; so also the trampin0
of men and animals and the wheels of cars
are constantly reducing coal to the dust
that floats in the air and becomes the most
dangerous element in coal mines, for when
such coal dust is dry and mixed with the
air in any considerable portions, explosions
of the most disastrous nature may be ex-
pected.
Until late years, it had been believed that
coal dust and air would not form an explo-
sive mixture; but it is now known that pure
coal dust and pure air will form a very
powerful and dangerous explosive. But it
is very evident and still firmly believed
tAuu l1ul1 ~ Va 1AoNAa ANACN W.
a mixture of air and coal dust will render
its ignition more easy, and will greatly in
crease it's destructive owe 1t is also we'll
established that a mixture of air and fire.
damp will not explode with any dangerous
force unless the proportion of fire-damp be
moro than five per cent, and less than
twenty per cent. But the addition of dry
, coal lust to such nOn-explosive mixtures
will render them most dangerous explosives.
In fact, it ia now generally believed among
- f.: 5000 - A1oA Ahn .r,.o, ,>,,.~lor
of the disastrous explosions in the coal
mines of the world, has been caused by the
presence of dry coal dust.
While it is true that the dust from some
Goals are highly explosive when mixed with
air alone, the dust from other Goals form
from still other Goals will not form explo-
sive mixtures with air alone. Unfortunate
ly we have as yet no tests by which we can
determine whether any given coal will
yield an explosive dust save by actual ex-
pertinent.
But it should never be forgotten that q
dust, which will not explode in pure air
alone, is endered highly explosive by the
addition of very small quantities of fire.
damp. As little az 1.5 per cent of fre-damp
dust and air highly explosive: and on the
other hand II small proportion of non
explosive coal dust will render a non-
explosive mixture of ~tire-damp and mir
highly explosive. In fact there appears to
be such an affinity between tre-damp II
coal dust that their union becomes extreme
ly dangerous.
II has been fully established that coal
dust is explosive in proportion to its dry
ness. Hence damp and wet mines are sell
dom troubled with coal dust; and when it
does appear in such mines the moisture
soon renders it harmless or lays it alto
gether.
II is also we'll known that an explosion
III which coal-dust forms any considerable
element causes greater heat than an explo-
sion produced by tire-damp n air alone.
Hence All explosion of coal dust Ia moro
likely to set fire to tho mine and to pro-
duce more painful injuries to the men and
amin ais in the mine, and produce more
dangerous and troublesome after-dRmps.
The miners will scarcely need any special
dust save what his lamp and his own senses
Supply,