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THE COAL TRADE BULLETIN. 53
BRITISH EXPLOSIONS IN MINES COMMITTEE ISSUES ITS REPORT
ON COAL DUST.
While many of the mining engineers of the world
have for a number of years recognized the danger
of coal dust in mines, the increasing number of
fatalities from this cause impelled the British
government in 1906 to plan a series of large-scale
experiments, "if only for the purpose of concentrating
the attention of the mining world upon
the danger that coal dust constitutes."
The British Explosions in Mines committee,
which has charge of these experiments, has just
issued its first report to the Secretary of State for
the Home Department, which report will be of
interest to American operators ancl engineers in
view of similar experiments being conducted by
the United States Bureau of Mines.
The committee in its report states: "The effect
of these experiments was, in the first place, to
demonstrate conclusively the fact that coal dust,
in the complete absence of firedamp or other inflammable
gas, is explosive when raised as a cloud
in air and ignited under conditions which may
exist in a coal mine, and moreover is capable of
producing such destruction as is observed after a
colliery disaster. In the second place, the experiments
indicated that the admixture of increasingproportions
of an incombustible dust with the coal
dust rendered the initiation of an explosion increasingly
difficult to accomplish; and that, therefore,
a means of preventing coal dust explosions
in mines might possibly exist in the
TREATMENT OF THE ROADS
with incombustible dust such as stone dust. In
the third place, the experiments on the mode of
propagation of coal dust explosions gave an indication
of the manner of their development during
the initial stages, and suggested a way for a more
complete study of the problem. * * * It wdll be
seen that provision has been made for complete
investigations into the initiation and spread of
coal dust explosions, whereby we hope to ascertain
the means of preventing or limiting them. It may
therefore be some time before we are able from
our own experiments to recommend definite precautions.
There is, however, one point to which
it is desirable to draw attention—the proposal
to use an inert dust as a preventative. It is difficult
to state the exact date- of the idea of using
stone dust as a protection against coal dust explosions,
and we do not pretend to give complete history
of the progress of thought upon the question.
We may, however, mention a few instances in
which it was brought prominently into notice.
That an inert dust might prevent the ignition of
coal dust seems to have been suggested by the
tacts observed in several mine explosions such as
that at Seaham in 1880. The possibility that fine
sand strewn over coal dust might prevent the eoal
dust being raised in an inflammable cloud is re
ferred to in the Prussian Commission's Report,
1884. It is also alluded to in the Report of the
Royal Coal Mines Commission in 1886. *****
As soon as the Altofts gallery had been constructed,
experiments on the large scale
WITH STONE DUST
were commenced on July IS, 1908, under the supervision
of Mr. Garforth, and continued in 1909 and
in subsequent years.
In the record of the Mining Association, pp. 105
to 10S, details are given of experiments upon the
effect of mixing stone dust with coal dust. They
show that the liability of dry coal dust to ignite
is largely reduced by an admixture of fine stone
dust.
In our opinion further experiments upon the
action of stone dust are essential before any final
recommendation can be made. For instance, it
has not yet been proved that a name of coal dust
that has attained full explosive violence in a mine
wdll be extinguished on reaching a region where
stone dust had been strewn over the coal dust, nor
that an explosion of fire-damp would not be "extended"
by a thin layer of coal dust deposited on
stone dust. Further experiments also are needed
to test the correctness of Sir F. Abel's conclusion
that the presence of an incombustible dust niay
increase the danger of a gas explosion. The latter
experiments we have already started.
We think, however, that we ought to call attention
to the steps that have been taken not only at
Altofts in Yorkshire, but also at the Charlaw.
Sacriston and Kimblesworth collieries in Durham,
at the New Moss colliery near Manchester and elsewhere,
to put this theory into actual practice.
At the present time inert dust is not put on In
zones, but is
SCATTERED BY HAND
over the whole surface of such haulage roads as
require it.
This application of rnert dust needs no considerable
expenditure of capital, nor laying down
of plant, ancl is not a costly operation, and we are
of opinion that even in the present incomplete
state of our knowdedge as to the exact action of
inert dust, those who are working and carrying
coal along dry and dusty roads would be well advised
to take into consideration this means or
obviating danger.
We do not, of course, question the utility of wat-