December 11, 1914.

THE COLLIERY GUARDIAN.

1225

valued at £39,592,981, as compared with 70,160,934
tons, valued at £49,066,231, and 61,070,280 tons,
valued at £38,642,909, in the corresponding periods
respectively of 1913 and 1912. .

The average value of coal, coke and manufactured
fuel exported from the United Kingdom during
November was 13s. 3'09d. per ton, as compared with
14s. 0’5d. in November 1913, and 12s. 11 2d. in
November 1912.

The value of fuel exported in the first eleven
completed months of the present year was 13s. 7'9d.
per ton, as compared with 13s. 11’8d. and 12s. 7’8d.
per ton in the corresponding periods of 1913 and
1912 respectively.

Of the total exports of coal during November, the
mean value of the large coal exported was 15s. 0'6d.;
through-and-through (unscreened), Ils. 11-3d.; and
small coal, 10s. 2'5d. The average value of all
kinds of coal exported was 13s. l’7d., a decrease of
0’4d. as compared with the previous month. Other-
wise divided, it fetched the following:—Steam coal,
13s.	2 2d. ;	gas coal,	11s.	11’9d.	; anthracite,

17s.	7’2d. ;	household,	13s.	0’7d. ; other sorts,

10s. 11-5d. The mean value of the coke exported
was 15s. l-4d. per ton, and of the manufactured fuel
16s. 9*9d. per ton.

It is reported from Denver, U.S.A., that the
miners’ strike in Colorado is now at an end. The
miners, it is said, have been forced to yield. They
struck work on September 23 of last year to enforce
their rights under the existing State law.

The Monmouthshire and South Wales Coal
Owners’ Association and the South Wales Institute
of Engineers have made presentations to Dr. W,
Galloway in recognition of his researches into the
relationship of coal dust to mine explosions.

The result of the Home Office enquiry, conducted
by Messrs. S. Pope and T. H. Mottram, into the
circumstances of the Wharncliffe Silkstone Colliery
explosion, which occurred on May 30 last, and by
which 12 lives were lost, has now been issued. The
opinion is expressed that the explosion was caused
by the stoppage and restarting of the fan with a
defective coal-cutting machine running at the face
causing ignition. The investigators find that in
several respects the pit was not managed in conformity
with the Act. Summonses have already been laid
against the management on these charges. The case
will be heard at Barnsley on Wednesday next.

The introduction of steel props into Yorkshire pits
has gone very much against the grain of the members
of the local miners’ association. The question of
striking over the matter has been referred to the
districts.

A meeting of the executive council of the Mining
Association of Great Britain was held at the
Whitehall Booms, London, on the afternoon of
Friday, December 4, the President, the Earl of
Crawford and Balcarres, being in the chair.

The Government rate for the insurance ot cargo
against war risks is reduced from 2 guineas to
1| guineas as from to-day (Friday).

The Home Office report has been
The issued on the fatal explosion which
Wharncliffe occurred on May 30 last at the
Silkstone Wharncliffe Silkstone Colliery. The
Colliery enquiry was conducted by Mr.
Explosion. Samuel Pope and Mr. Thomas H.

Mottram, and the, circumstances had
already been sufficiently elucidated in the course of
the somewhat protracted enquiry at the coroner’s
inquest. It remains, therefore, merely to dwell
upon the more important lessons which this accident
has afforded, and in this connection it is fortunate
that we know, with a reasonable amount of
probability, what was the apparent combination of
factors which determined this unfortunate result.

We say “ apparent combination ” advisedly, for we
have no proof that other factors did not enter into the
case, and it is by no means certain that an explosion
would necessarily be brought about by a repetition
of the identical circumstances which are now held
responsible for its occurrence. Of this, however,
there can be no possible proof, and we must perforce
admit that the five coincidences enunciated in the

report form a sufficiently dangerous combination to
warrant the conclusions that have been drawn as to
their causative potentiality. One of the most
interesting and important results of this investigation
is the experimental evidence which has been
obtained as to the quantitative effect of ventilation
upon the composition of the air at the coal face.
Four days after the explosion, samples of air were
taken every four minutes. during a period of
20 minutes, during which the ventilating fan was
stopped. While the fan was running normally
the percentage of inflammable gas present was
only 0*65 per cent. This percentage rose, after a
stoppage of only four minutes, to 5'25 per cent.,
after eight minutes to 10’29 per cent. In the
next four minutes this percentage fell to 9’44, but
rose in the succeeding interval to <30'45 per cent., to
be followed, on restarting the fan, by a fall in four
minutes to 5'82 per cent., and a further fall in the
next interval to 3*63 per cent. These experiments
were subsequently repeated by Prof. O’Shea, with
generally confirmatory results, some 10 days later,
after the coal face had remained undisturbed for
14 days.

' This rapid rise in the percentage of firedamp must
be regarded as remarkable, and it would be
interesting to know whether this result is normal or
otherwise in this particular seam, and also how it
compares with the rate observable in other fiery
seams. For it appears to be highly probable that few
colliery managers would expect so sudden an
increase of firedamp after so ‘short a disturbance of
the normal ventilation—a disturbance which might
easily take place in any pit as a result of a fall of
roof or any other accidental circumstance.

This appears to be one of the most practical
lessons afforded by this disaster, and it seems to
point to the desirability of- ascertaining in other
collieries the effect that might be expected under
similar conditions.

Another matter, which is unfortunately wrapped
in greater obscurity, is the question of flame-tightness
of electric motors. It is assumed, possibly rightly,
that the commutator box cover in this case had
become defective in use, so that it was no longer
flame-tight, and it is suggested that the defect was
caused by hammering the half-moon into position
after it had been removed to replace an armature.
Apparently no test was made to prove whether the
narrow aperture disclosed in the joint and the other
observed defects did in fact destroy the flame-
proofness of this machine. It is concluded that such
was the case as a result of expert opinion, after due
weight had been given to the possibility of outside
sparking at the gear wheels or at the cutter teeth,
and the only comment that can be made upon this
conclusion is that it necessitates a more speedy
diffusion of gas into the motor case than would
have been expected under the circumstances; for it
involves an extremely rapid exchange between the
fresh air with which the machine was filled when
the fan was stopped, and the foul air in the still
atmosphere external to the machine. We do not
say this rapid diffusion through comparatively small
apertures is impossible, especially if the process is
accelerated by convection currents in the motor case,
and the fact, if true, is important to note as a guide
to future conduct under similar circumstances ; for a
motor, which is flame-tight when new, may probably
become gradually less so in use, and the decision
as to when its behaviour should nd longer be trusted
becomes a delicate and difficult one.

Finally a word must be said respecting the
misunderstanding that occurred in connection with
the transmission of instructions respecting the
stopping of the fan. It is generally easy, after an
accident has occurred, to show that more definite
orders might have avoided the disaster, but what is
not easy to explain is how, in the multiplicity of
duties devolving upon the management, necessarily
involving the delegation of responsibilities to the
second and even the third degree, similar occurrences
will not occasionally arise. Such cases are probably
more frequent than we know. They are not inten-
tional, but are rather due to momentary lapses of
rigid discipline, for which the human factor is to be
held responsible. Colliery management can never

become a one-man job ; its tendency is to become
more and more divided, and every delegation,
necessary as it is, adds additional risk of misunder-
standing.

The other matters raised in this report it is not
our intention to discuss at the present time. It is
satisfactory to find that neither the coroner’s jury
nor the Home Office representatives found any
evidence of criminal responsibility. Certain breaches
of regulations are alleged, and these will be investi-
gated in the ordinary course. Bearing in mind the
state of confusion that has been manifest since the
new Coal Mines Act came into force, the continued
impossibility of obtaining some of the prescribed
forms the use of which is compulsory under the Act,
and other considerations, we are greatly afraid that
the Act is being widely infringed throughout the
kingdom at the present time.

It has been the hard lot of electricity
. The Battle that, like most new comers to the
Of the	lists, it has been compelled to win

Lamps. its spurs against agencies of well-
established utility and popularity.
The electrical engineer has had the further mortifi-
cation of seeing electricity, when a solid front of
prejudice and vested interests has been overcome, act
as a stimulus to increased efficiency on the part of
its rivals.

The community, no doubt, is benefited by this
wholesome competition, which helps to amplify and
cheapen the processes of production and at the same
time may contribute to the safety of the worker. In
this vicarious propagandism, however, electrical
engineering has been called upon to make more
than ordinary sacrifices. Chiefly to the electrical
generator and motor have been due the great
improvements in the steam engine and the internal
combustion engine ; the gas industry would doubt-
less have continued to travel on well-worn paths had
it not been for the spur of competition ; and in the
mining industry there have been many instances in
which the introduction of electricity has been
substantially responsible for developments that for
the time have set it back. An example that occurs
to us is the electric winding engine, the arrival of
which encouraged the development of the exhaust
steam turbine and accumulator ; and now the same
process appears to be taking place in regard to the
safety lamp.

To-day we are within a few months of the
centenary of the invention of the miner’s safety
lamp, and, considering that it is 100 years since
Sir Humphry Davy gave his priceless bequest to the
coal mining industry, it is singular that his name
and those of his contemporaries, George Stephenson
and Dr. Clanky, should still remain pre-eminent, even
when all honour has been given those of Marsaut,
Mueseler and others. It would really seem that
the portable electric lamp, which was forcibly brought
to the notice of mining engineers some three or
four years ago, has been the means of spurring the
manufacturers of oil lamps to efforts that are now
meeting with a tangible reward. The electric lamp
owed much to its adaptability for rescue work in
association with breathing appliances, a class of
work in which the paramount virtue of the oil lamp
as a detector of gas is of diminished importance,
and the lamp is eminently suitable for other branches
of mining work such as coal-cutting and haulage;
but we believe that we shall not be contradicted
when we say that the researches of Dr. Llewellyn
on the subject of miners’ nystagmus, which led him
to characterise inadequate light as the chief cause of
the disease and, incidentally, to place on record
some truly remarkable figures proving the great
deterioration of oil lamps under working conditions,
have exerted an influence no less profound.

It is a fact that, perhaps, has not been sufficiently
recognised that the same influence has had its effect
upon makers of oil-flame lamps, some of whom,
notably Mr. Hailwood, of Messrs. Ackroyd and
Best, have made material progress towards meeting
this charge against the oil lamp and to improve its
lighting capacity. Mr. Hailwood’s lamp may not
embody a strikingly novel principle, and it is
probably capable of further improvement, but the