Ottumwa semi-weekly courier. [volume] (Ottumwa, Iowa) 1899-1903, 1902-03-04

Hydroaeu 400 1l.o7 o.
S STygss 7S.sS ss.os 2 2s.s
.2S.97 90
Sulphur. ....,..l2sO 81
ASH ............- u.4U USo
When gunpowder is burnt or eXplod-
ed the heat is produced by the union
of carbon with the oxygen. When
fire-damp is burnt or exploded, the
heat is produced by the combination
of the carbon and hydrogen with the
oxygen, and when coal-dust is burnt
the heat is by the combination of car
bon, hydrogen and oxygen.
The reason why fire-damp and air is
explosive is that the nature of gases
is such that the particles of carburated
hydrogen can be mixed with the oxy-
gen, so that exceedingly minute parti-
cles of one gas are in contact with
particles of the other gas, and there is
nothing to prevent instantaneous I'M
ion between the two gases. In the
case of gun-powder the carbon and
sulpher are ground up exceeding fine
and then mixed with the saltpetre
(Which contains the oxygen) which is
also ground very fine SO that each min
ute particle of carbon and sulphur has a
particle of oxygen touching 1t, so that
there is no reason why all the par
ticles should not burn at once. And
this simultaneous burning produces
the expansion which accompanies the
explosion. If the particles of carbon
and saltpetre instead of being ground
up small were mixed in large pieces
they would burn if a light were applied
but not so rapidly as to produce an eX-
plosion. In the same way Jumps oil
coal will burn if light is applied, if
there is supply of air, but will not
explode, because there is no natural
quantity of oxygen in the composition
of the lump, nor is it possible to get
sufficient quantity of oxygen into
such immediate contact with lump
of coal that there could possibly be
instantaneous combustion, and in the
case Of ordinary coarse coal dust the
particles of carbon are not small
enough to permit of instantaneous un--
ion with the surrounding oxygen. If,
however, the dust is exceedingly fine
so that it will float in the air in dense
clouds, then each minute particle of
dust may be surrounded with suffi-
GENTLY large proportion of oxygen to
burn, and there is no reason why the
fame should not extend with extreme
rapidity from particle to particle so as
to produce all the effects which are
known as explosions. The expert
ments conducted by numerous mining
engineers and chemists have demon
strated that if the air is mixed with
fire-damp in the proportion of per
cent Of fire-damp to SO per cent of air.
This mixture is harmless, but if
into this mixture is put dense cloud
of coal dust and this is then ignited by
a flame from pistol violent explo-
sion will follow, showing beyond dis
pute that an atmosphere previously
non-explosive becomes explosive when
mixed with coal dust. This is suffi-
Gent to place coal dust among the dan
gerous elements of a mine, but there is
evidence to show that coal dust is the
prime cause of the explosions in the
mines of Iowa.
In my thirty years experience in
Iowa mines there has never come to
my notice any evidence of fire damp
but the evidence of the several mine
explosions seems to establish the fact
that coal dust and air are terribly ex-
plosive without any mixture of fire.
damp. When an explosion occurs, it
invariably travels toward the down
cast shaft or against the air. This is
partly accounted for by the air being
purer in that direction, and in part by
the current of air carrying the dust to-
wards the place where the explosion
starts And what first starts the ex-
plosionis the agitation in the air caus-
ed by the disc large of shots which
shakes the ist loose, which may have
accumulated on he sides and timbers
of the mine, md if a shot is fired
where the dus 2 thick in the air and
| it HAPPIER + re blown out shot, or
one that has cot done its work proper
Ily, it isJliable to have flame attached
which ignites the dust, and one par
ticle communicates flame to the next
and the result is an explosion But in
order to arrive at the theoretical force
of dust explosion7it must be borne
in mind that no matter how much coal
dust there may be, only as much of it
can explode as enters into the combin-
alton with the OXYGEN and the only
oxygen available in a mine for an eX-
plosion is that contained in the air
Wherever there is a great deal of dust
there Is much more Of it than can be
burnt blythe oxygen in the air in that
locality, and it is safe to assume the
force Of the explosion may be measur.
ed by the, amount of oxygen. III
/, think enough has been said about
explosions and their causes. T. j,
Phillips says to use the pick more anG
use flrsclay tampingy then fire the
shot with "a squib If explosions are tc
be avoided will say here that the
shots whIieh caused the explosions al
Cedar, Jack Oak, Pekay b, and Lost
Creek mines were all fired with squibs
We may infer frem these facts that
Phillips isiineerror. II or
The remedy which Izthink would be
effective isethis: Ifs,steam were in
jected into the downcast shaft in cold