May 9, 1913.

IHE COLLIERY GUARDIAN.

967

The stoppage in South Wales over the non-
unionist question has not seriously interfered
with the working of the collieries, but in some
instances the collieries have been idle for some
days.

At a meeting of the Manchester Geological
and Mining Society, on Tuesday, an interesting
paper on Chinese coalmining was read by Mr.
Noah Williams.

Sir Alfred Mond, Bart., M.P., on Saturday
morning laid the foundation-stone of the new
Swansea Coal Exchange buildings.

A general strike has broken out in Upper
Silesia on the wages question.

A conference between various traders and the
goods managers of the different railways was held
at the Board of Trade Offices on Wednesday
afternoon, and was presided over by Mr. W. F.
Marwood, the assistant secretary of the Railway
Department. The conference had been arranged
by the Mansion House Traders’ Association with
the view of discussing the new regulations with
regard to demurrage, which came into force on
January 1 last. It was contended on behalf of
the traders that the present flat system of
demurrage was not suitable for all trades, the
chief point made being that different trades
required entirely different treatment. A similar
conference was held in the morning, when
representatives of various Chambers of Commerce
met the goods managers, under the presidency
of Sir Hubert Llewellyn Smith, the Permanent
Secretary of the Board of Trade.

On Wednesday the Court of Appeal delivered
important judgments in the two cases of the
Duke of Beaufort and the Marquis of Anglesey.
The Court decided (against the contention of the
Crown) that income-tax deducted by the lessee
should be deducted from rent for purposes of
assessment to mineral rights duty. They
decided also (in favour of the Commissioners)
that no deductions should be made in respect
of super-tax, and that arrears were taxable.

In South Yorkshire 66,299 men have voted
in favour of a general stoppage to compel the
non-unionists to join the union, and 7,784
against.

On the 1st inst. judgment was reserved in the
appeal of the Commissioners of Inland Revenue
against Mr. James Joicey, in which the former
claimed to assess the latter for mineral rights
duty in respect of compensation paid by the
South Moor Colliery Company to him in
exchange for the right to lower the surface by
the extraction of subjacent minerals which,
however, are not owned by him. Judgment was
issued yesterday dismissing the appeal.

The Fourth Report of the Explosions in Mines
Committee was laid upon the table of the House
of Commons on the 2nd inst.

At a meeting of the joint board of the South
Wales coalowners’ and miners’ representatives
at Cardiff yesterday, the owners granted the
men’s application for an advance of 2J per cent,
in the general wage rate. The wages thus reach
the maximum of 60 per cent, above the standard
of 1879.

The Home Secretary has appointed a Com-
mittee to consider and report what, if any, first
aid certificates besides those of the St. John and
St. Andrew’s associations should be recognised
by the Home Office for the purposes of the
grant of mine managers’ certificates and other
purposes under the Coal Mines Act, and on what
conditions. The members of the Committee
are:—Mr. W. N. Atkinson, I.S.O., LLD., his
Majesty’s inspector of mines for the South
Wales District (chairman) ; Mr. »G. Alfred Lewis,
secretary of the Colliery Managers’ Association;
and Mr. Thomas Richards, M.P.

Several enquiries having
Eskmeals recently been made as to how
Testing	the work of the Coaldust

Station.	Explosions Committee is pro-

ceeding at Eskmeals, we thought
that it would be of interest to our readers to
know what is being done there. So far, three
reports have been issued, but these dealt chiefly
with' work done at the old testing station at
Altofts, the results of which had not previously
been published, and give a very faint notion of
what is now in progress.

Accordingly we applied for permission to pay
a visit to Eskmeals, and the following is some
account of what we saw there. We desire to
express our thanks for the courteous reception
which we received and for the ready response
to our enquiries for necessary information.

A number of experiments were being made
daily in the big tube (7 ft. 6 in. diameter) with
a view of determining with more exactitude
than had hitherto been done, the proportion of
inert dust which it would be necessary to mix
with coaldust in order to render it non-explosive,
and which it would be desirable to use in
practice.

This problem, which at first sight appears
simple, has proved upon trial to be somewhat
complicated. In the first place a distinction
must be made between the effect of inert dust
on the initiation of an explosion, and the effect
of inert dust (or inert dust mixed with coaldust)
upon the progress of an explosion after it has
been established. Moreover, the quantity of
inert dust which it is necessary to mix with the
coaldust depends to a considerable extent upon
the character of the explosion, and upon the
description of the inert dust used.

In some cases a violent explosion, in conse-
quence of the effective way in which it stirs up
the dust, will actually increase the efficacy of
inert dust; so that, contrary to what might have
been expected, a violent explosion entering a
zone containing a mixture of inert dust and
coaldust may sometimes be extinguished more
effectively than one having less violence. This
conclusion is, however, only suggested tenta-
tively, and its correctness has not been proved.

Again, if an explosion has gathered strength
by proceeding for some distance along a zone
containing pure coaldust, it will, as has been
repeatedly observed, traverse, for a considerable
distance, a zone of coaldust mixed with inert
dust. In this case, however, the distance that
the explosion will traverse the latter zone is
distinctly diminished by an increase in the
quantity of inert dust. From this point of
view, if mere zones are treated with inert dust,
it appears as if perfect safety could not be
obtained without the use of an enormous
proportion of inert dust.

As the result of experiment, however, we were
greatly impressed by the powerful extinguishing
effect of a mixture of 2 parts of inert dust with
1 of coaldust, though to what extent this, or
a greater or less, proportion could be used in
practice without unduly clogging up the road-
ways of a mine, is a question of mining practice
which will need investigation.

A new method of igniting the dust is now
being used, and appears to be successful.
Formerly the methods employed had been either
a dynamite shot, as used in France, or two
cannons—one to raise the dust, and the other,
fired about two seconds later, to ignite it. The
latter method was adopted at Altofts.

The method now in use at Eskmeals consists
in firing a charge of black powder from a cannon
into a tube, 3 ft. in diameter and 10 ft. long,
placed in the large gallery, and strewn internally

with coaldust. For some distance the resultant
flame is allowed to traverse a zone treated with
lib. of pure coaldust to the linear foot. It then
encounters a zone treated with a mixture of
stonedust and coaldust, in varying proportions,
and the effect is observed. In some’ experiments
the whole of the coaldust is laid on the top of
the stonedust.

The results have been encouraging, and, while
it may be said that an explosion of coaldust will
always penetrate a zone of mixed stonedust and
coaldust to a certain distance, the distance is
remarkably diminished as the proportion of inert
stonedust is increased.

It is premature to say what quantity of stone-
dust will prove to be desirable for use, but it
will probably be between the limits of one to
three times the quantity of coaldust. Upon this
point, however, the Committee have not as yet
expressed an opinion.

One thing, however, appears to be reasonably
certain, and that is, the establishment of the
utility of stonedust as a flame extinguisher.

The effect of the presence of gas upon a coal-
dust explosion remains to be investigated, but
there are reasons for the belief that the influence
of this, as a factor, has been greatly over-rated.

The considerable force developed by explosions
of mixtures of coal dust and air has recently
received further illustration by the bursting, in
three places, of the small tube (1 ft. diameter),
which is constructed of steel T5^in. in thickness.

The Fourth Report of the Coaldust Explosions
Committee has been presented to Parliament,
and will soon be in the hands of the public.

The work which is being done at Eskmeals is
thoroughly practical in character, and is being
pressed forward with all reasonable speed. It
is, however, obvious, especially to those who
have had an opportunity of seeing the operations,
that experiments on such a large scale require
very careful preparation and every precaution
when being made. This necessarily occupies
considerable time, but it is unavoidable.

Our observations, however, lead us to a belief
that coalowners will not have to wait much
longer before they will be placed in possession
of carefully-tested information which should
enable them to increase the safety without
unduly increasing the cost of working their
collieries.

Trade Summary.

The London coal trade is slow and in many cases pit
prices are weakening. The weather continues cold and wet,
but the demand is small and from hand to mouth. Contract
renewals are slowly progressing, and all prices are higher
than last year. The general demand for Is. above last year
is, however, strongly resisted. Lowest summer prices are
likely to be settled directly after the holidays. Bakers*
nuts are firm, and kitchener cobbles and steam coals fairly
steady, but all house coals are weak.

Prices at Newcastle are firm, but supplies are rather more
plentiful owing to the abstention of buyers.

The Durham coal trade is strong all round. Coke is
steady.

The Lancashire house coal demand is now easing off. The
call for bunkers is pressing in view of the Whitsun holidays.
Slacks are rather plentiful.

There is still a fair demand for West Yorkshire house
coal, and manufacturing sorts continue to find a ready
outlet.

The pressure for supplies of South Yorkshire hard coal is
considerable, and shipments are on a large scale. House
coal is not markedly easier.

Derbyshire house coal prices are steady. Deliveries
of gas coal are heavy, whilst the demand for manufacturing
coal is exceptionally strong.

Non-unionist troubles in South Wales have given an
impetus to prices at Cardiff. Small coals are firm. Mon-
mouthshire coals are scarce.

The Scottish coal trade is busy in all departments.

The owners of the Buckley Collieries, near Chester, have
informed their workmen that work will cease in a fortnight.
Quite 1,000 men and boys will thereby be thrown out of
employment.