September 13, 1918.

THE COLLIERY GUARDIAN

547 .

difficulty kept down to 87 degs. Fahr. He was in-
formed that at the last of these collieries many of
the men suffer from boils and ansemia, and their work-
ing efficiency was reduced by 20 per cent. Could these
conditions be mitigated on a practical scale so as to
make physical exertion healthy and efficient?

It might be assumed that the temperature of the
air at the bottom of a downcast shaft 3,000 ft. deep
was 6 to 7 degs. higher than at the surface in cases
where a large volume of air was passing. If the sur-
face temperature was 50 degs. Fahr., the air would enter
the mine at, say, 57 degs.; but in hot weather the
rise in the temperature of the air at the pit bottom
would not be as much as 6 or 7 degs. In a case
which came under his own observation—the Sydney
Harbour Colliery in Australia, where the summer
temperature was 80 degs. Fahr, and upwards on the
surface—the temperature at the pit-bottom (depth,
about 2,500 ft.) was sometimes a degree or two less
than at the surface, and in the workings (1,500 yards
in-bye) the temperature was only 86 degs.—not very
much more than the surface temperature.

Influence of Ventilation.

It was of great importance that the oxygen of
the air carried into the mine for ventilation should
act as little as possible on the strata; and airways
which have a smooth surface caused less friction and
resistance to the ventilating current than those which
were less smooth. Cement linings of airways had
been used largely in the mines of Courrieres and other
French collieries, and were said to have been quite
economical. The airways were roughly reduced to a
circular or oval form, and were coated with a thin
shell of cement a few inches thick. This cement gave
some support to the roadway, but its principal value
was in preventing the air from leaking into the goaves
or the roof, and the heat from passing from these
and raising the temperature of the intake air. A
description of this system had just been published
by the United States Bureau of Mines, and an
abstract had been circulated to the members of two
of the local institutes under the title of the “ Cement
Gun.”

In the Doncaster district, a seam underlying the
Barnsley Bed (the Dunsil) was being utilised for the
purpose of constructing intake or return airways
independent of the main seam. By this means the
separate ventilation of districts and panels of workings
was being carried out in such a way that the tempera-
ture prevailing in any panel or district could be kept
down to the minimum, and the best conditions for
the workmen secured. This system seemed to lend
itself to the introduction of cooling (or refrigerating)
apparatus which might at some future time be con-
sidered worth introducing. From what he had been
able to ascertain, a large volume of air could be
reduced in temperature by 10 degs, with a compara-
tively small expenditure of pow’er. If, therefore, such
a system as the employment of a subsidiary seam were
adopted, and communications were made between the
subsidiary and the main seam at any required number
of points, a supply of cooled air could be carried to
these various points of communication between the
seams, and the general temperature of the mine
thereby reduced to a reasonable degree. It was in
some such direction as this that the solution of this
difficult problem might be found. It would be pre-
sumptuous on his part to offer any suggestions to
the eminent engineers who were already dealing with
this matter, but it was only right to mention what
was being done.

Mechanical Appliances.

If we had already reached a point at which human
energy became ineffective, and the working of coal
was to be continued under such conditions, muscular
effort would have to be supplanted by mechanical
appliances. Already a great deal of machinery was
employed in the working of coal where in days gone
by the miner’s pick was the only implement. Coal-
cutting machines had for many years been in use,
but it had generally been for other reasons than those
of high temperature. It had been hitherto mainly
in the thinner seams that these appliances had been
called in, and their use had not appeared to be
economical in seams thicker than 4 ft., but when they
had to be used mainly on account of the excessive
temperature of a mine, they would no doubt be applied
to the thicker seams. The same machines as were
employed in thin seams would, of course, not be as
a rule suitable, and special devices would have to be
designed in order to meet the new conditions. In
Canada and America percussive picks were largely
used in seams of 8 ft. thick and over, and probably
something of the kind would be made use of here.
Explosives would probably not be required, as at
great depths the coal came down very easily. The
use of ponies in the mines had been reduced a great
deal in recent years, and small mechanical haulage
appliances had been substituted. This would be neces-
sary in an increasing degree in very deep mines. The
ponies suffered very much from the heat, and the
manager of one of the deep mines near Doncaster told
him they had taken out all their ponies for this reason,
and small haulages and conveyors had taken their
place. For these mechanical appliances compressed
air would be required, or it might be a combination of
compressed air and electricity. To carry compressed
air great distances underground was most expensive,
and perhaps it might be found permissible to have
air-compressing plants distributed throughout the
workings and supplied with electric power.

Cost of Sinking.

In order to reach coal at a depth of 3,000 ft. and
over, very large expenditure on sinking shafts must
be incurred. Shafts were now made very large, 20 ft.
in diameter and upwards, and a pair of such shafts
might cost as much as £60,000, irrespective of the
equipfnent. To justify such expenditure, areas up to
5,000 acres were designed to be worked to a pair of
pits, but the difficulties of temperature would limit
the distances to which the workings could be extended.
Shafts would have to be more numerous, so for private

enterprise such expenditure might be prohibitive; but
if the collieries became the property of the State, the
element of cost became one of secondary importance.
So long as private capital was employed in coal mines
the question of the return on it must decide what
expenditure could be incurred; but the State would
not be concerned primarily with the question of profit,
and the expenditure would only be limited by the rate
at which the money expended on winning and working
the coal could be borrowed. The price of the coal
would be eventually the amount necessary to pay the
interest, and here we had, of course, to remind our-
selves that there was a limit beyond which it would
not be worth while to produce coal. The cost of pro-
duction must not exceed what the general trade of
the country could bear. The collieries existed for the
benefit of the country, not the country for the col-
lieries. Often a good deal of the capital put into
colliery enterprise was lost. Companies were wound
up or reconstructed, and the newcomers acquired the
property for a fraction of what had been spent on it.
That would not be the case with State mines: the
country would be responsible for every pound expended,
and the interest would have to be* regularly provided
by Parliament. The general trade of the country, and
more particularly the export trade, must be done at
competitive prices. We had to meet the competition
of the whole world. It could hardly be questioned
that the chief material basis of the great industrial
and commercial expansion of this country during the
past century had been its abundant supplies of easily
obtainable coal, which, until recent years, had given
us a position of advantage over all other countries. It
was also equally true that we could no longer claim
any advantage in this respect over our two closest
competitors.

Limit of Working.

The International Geological Congress held during
1913 issued a report on the world’s coal resources,
according to which the geographical distribution of
the world’s possible and probable reserves of coal of
all kinds available within 6,000 ft. of the surface,
amounting in all to 7,397,550 million tons, should
make us realise that, large as the quantity of coal was,
it was not limitless. The fact that the available
reserves of coal in Great Britain amounted to only
about a fortieth, whilst those of the whole Empire did
not amount to more than one-fourth of the world’s
estimated total, was one which ought to be brought
home to everyone responsible for the economical
development of our national and imperial resources,
especially in view of the fact that the United States,
whose competition in the immediate future would
probably be more severely felt than ever before,
possessed more than half the estimated world’s store
of coal. This estimate of 7,397,550 million tons was
based on the possibility of following the coal to a
depth of 6,000 ft. from the surface.

The British Royal Commission on Coal Supplies
adopted a depth of 4,000 ft. as the limit at which
coal-mining could be advantageously prosecuted. He
ventured, however, to suggest that these depths were
altogether fallacious, and that the available quantities
of coal were largely overstated. The quantity esti-
mated by the Royal Commission on Coal Supplies in
their report was 39,483,000,000 tons. If this quantity
were reduced by 20 per cent., it left 31,586,400,000
tons. The quantity of coal produced in this country
during the quinquennial period 1910-1914 was
270,000,000 tons per annum, and if we adopted the
reduced quantity our coal w’ould be exhausted at this
rate in 116 years.

As the conditions of temperature in the pits in the
neighbourhood of Doncaster (which had not actually
reached 3,000 ft.) already made human labour in-
effective, it seemed to be useless to estimate what
coal there might be between 3,000 and 4,000 ft., and
to count upon it as if it were actually workable, much
less at the greater depths of 5,000 and 6,000 ft. which
had been confidently spoken of as within the limits
of practicability.

Labour Problems.

As lately as the seventeenth century coal miners
had only the status of serfs, and were attached to
the mines, which they were not allowed to leave; their
hours were long, the conditions of their service very
bad, and the payment they received very niggardly;
but in the times in which we were living these con-
ditions had been completely reversed; the coal miner
was now the best paid member of the community, and
there seemed to be no limit to the wages which they
might demand in the future. Mr. Smillie, at the
Southport Trades Union Conference, declared that if
the miners claimed £2 or £2 10s. per day they would
not, from the point of view of their importance to
the nation, be claiming too much. It was not, how-
ever, only in the direction of wages that extraordinary
claims had been made. It had been suggested that
the working days should be limited to five per week
and the working hours to six per day, payment to
be made- as for six days and eight hours per day
as at present. Possibly it might be in view of the
more arduous conditions to which he had already
referred that these shortened periods of work were
demanded; but the miner was not superior to economic
law, and he would not be able to extract from the
coal industry more than the coal industry would pro-
duce. We had had “boom” times before, when
wages had risen to a very high level, but they had
been succeeded by times when wages fell to a very
low point. We were told that the collieries would
not revert to their old owners after the war. That
remained to be seen, but whoever worked the collieries
must obtain for the coal at least what it cost. The
cost of coal had doubled during the last six years,
and so had the price to the public. If, therefore,
the high rates of pay continued after the war, the
price to the public would have to remain at its present
very high figure, and the cost of manufacture'! articles
would also remain very high in price. How this
country with this serious handicap was going to com-
pete for its share of the trade of the world was at
present a conundrum. It was an important part of

the problem on which the future of the country
depended. If we could not keep our trade because
our coal was too dear, it would cease to be in demand;
the price would fall, and as the price fell, wages would
follow. Doubtless the collier would always be one of
the best paid men in the country, but his wage would
be limited to what the country could afford to pay
him. In some ways he welcomed the State ownership
of mines; it would then be possible to get at the facts
of the cost of production. To-day the miners’ leaders
seemed to question the necessity of raising the price
of coal in order to meet advances in wages. The Con-
troller was worried as to how he Was to make ends
meet. Some experience of State ownership would
open many eyes as to the actual profits of collieries,
and there was probably a great surprise in store for
those who thought the average colliery made a lot of
“ plunder.”

Importance of Output.

There had been a great deal said during this war-
time about restriction of output. The output of
colliers had decreased at the present time to about half
what it was twenty years ago. Reference to old books
would verify this. If the colliers worked as hard as
their grandfathers worked, they could earn double
their present wages. At the present day wages were
so high that miners did not care to earn all they might
earn. Some were satisfied with the “ minimum wage ”
—the most pernicious* piece of industrial legislation
ever inflicted on the country. In the future if the
country was to survive it must produce its coal cheaply,
and if miners were to enjoy high wages they must be
earned consistently with this condition.

He feared these observations on the qutlook were
the reverse of cheerful, but there was no doubt that
there was much in the future to cause anxiety to every
thoughtful man. The organisation of society was in
the melting-pot, and power was passing more and more
into the hands of men who were lacking in experience,
and rather rejoiced in the fact—whose idea was rather
to pull down and destroy than to build and recon-
struct ; and, as we had seen in Russia, the elements of
discontent and jealousy had immense powers for
destruction. This country had reached a magnificent
position of prosperity and wealth. We could only
hope that the sturdy common sense of the British
people would keep them from wrecking the edifice
which our forefathers had reared stone by stone
throughout the centuries.

ANALYSIS OF COAL, COKE, AND
BY-PRODUCTS.

The chemists’ committee of the United States Steel
Corporation has compiled standard technical methods
for the sampling and analysis of coal, coke, tar,
ammonia and gas. The methods selected for coal
and coke are those regarded as the most useful in
steel and coke works practice, but the by-products
industry being of comparatively recent introduction
into America, it was not so easy to compile standard
methods of treatment, and therefore preference has
been given to those methods which have given the
most consistent results and harmonise best with large-
scale plant practice.

With regard to taking samples for analysis, special
precautions are recommended in the case of coke from
the ovens, so that the analysis will yield results con-
cordant with calculations based upon the analysis of
the coal from which it was made—e.p., if the ash in
the coal is 7 per cent, and the gross yield of coke and
breeze is 70 per cent., then the ash in the coke should
be 10 per cent. Owing to the liability of coke samples
to contamination with iron from the crusher, the com-
mittee recommend the use of a crusher fitted with
manganese steel jaw plates for reducing to | in size,
and a roll machine for further reduction to a 40 mesh
powder is advised. Small laboratories are advised to
/Crush coke on a chrome steel plate and complete the
powdering in a diamond steel mortar.

Analysis of Coal and Coke.

The use of large samples is recommended for the
various determinations of coal and coke, at least
10 lb. being dried at 105 degs. Cent, for ascertaining
the percentage of moisture.

Volatile matter is determined either by the muffle
furnace method or by direct heating over a Meker
burner at 950 degs. Cent. It is considered, however,
that the value of this determination is merely com-
parative, since, in by-product coking practice, the
actual yield of coke has been found greater than that
indicated by calculations based on laboratory deter-
minations of volatile matter. There is at present no
standard method which will harmonise actual coke
yields with the theoretical laboratory yields, though
the progressive distillation method gives results quite
comparable with those of actual practice when the
determination is conducted as far as possible under
practical conditions.

The determination of metallic iron from the crusher
is based upon the solvent action of copper salts, which
leave combined iron unaffected. The Eschka method
is advised for the determination of sulphur, and either
the hydrofluoric or fusion process for the determina-
tion of phosphorus. The ash constituents determined
include silica, iron oxide and alumina, titanic acid,
manganese, calcium, magnesium, alkalies, and SO3, all
by the usual standard methods.

For ultimate analysis the standard method, using
a gas furnace of 25 burners, is recommended. Nitro-
gen is estimated by the Kjeldahl method, and oxygen
by difference in the usual manner. Direct determina-
tion of calorific value is made by means of the Mahler
or the sodium peroxide bomb calorimeter.

The committee consider that the only satisfactory
formula for the calculation of thermal values of fuels
from proximate and ultimate analyses is one in which
a variable factor is ascertained by the operator for
each kind of coal based on the ash-free, dry sample.