440

THE COLLIERY GUARDIAN.

February 26, 1915.

thought to make the coal cutters popular, they wanted to
give some encouragement to the men to work them, and so
they would be induced to try to get coal cutters placed in
the pit rather than to keep them out. . He was impressed
by the statement that there were many instances where 288
tons were being got in an eight hour shift from 100 yds. face.
Then he noticed that in the three cases cited the charges
for packing, ripping, timber setting, and drawing were left
out of the account. In the case of No. 1, it was said that
the approximate cost at the face was 2s. per ton. The
effect of that would be to make wages 7s. per day. In a
5 ft. 6 in. seam, with a fairly good floor and roof, the coal
would be got for 2s. per ton at the present rate of wages,
to include packing, setting, and drawing timber. Apparently
in Mr. Cashmore’s case, that 2s. was only for getting and
filling coal. But there were seams in that district at the
present time where the charter price for getting was Is. 3d.,
which, with 65 per cent, added, made 2s. Tour tons per
man per shift used to be looked upon as a fair amount to
turn out of any stall, taking that as an average for the
whole of the men. Yet there was shown an amount of three
tons 10 cwt. per man doing nothing else but getting and
filling the whole time; apparently cogging was not included.
Personally, he would have said that a reasonable allowance
for timbering and cogging would be Id. per ton, and there-
fore the price for getting and filling should be reduced to
Is. 8d. That would reduce the advantage of machine holing
to 3|d., and would come much nearer to what he had found
in his own experience. He was hoping to do a little better
than that. ’With regard to cases Nos. 2 and 3, he wanted
some information on the subject as to whether the cases
cited were actual examples. In case No. 3 one man was
employed for every 4^-yds. of face; this seemed rather
crowded. He noticed that the getters and fillers totalled 16.
Was it not the general practice for the getters to break in,
say, every 10yds., and then fill out their own coal? The
author went on to say, “ Beyond the item for interest,
depreciation, and renewals, the cost of stores and power had
been ignored, as where power is already installed for haulage
the slight addition would scarcely be noticed.” With regard
to that, of course, the power for such an output, especially
on the thickest seam given, would naturally be less per
ton, and, as a whole, would not be very heavy, but he did
not think it would be ignored altogether, because, as Mr.
Cashmore had pointed out, the cutting would naturally be
done on the afternoon or night shifts; at that time there
would be no haulage going on, and probably the power
station would be running for that purpose only, except
perhaps for a little pumping. Possibly, with regard to
supervision, it was questionable whether the reduced super-
vision in the roads might not be counter-balanced by more
supervision to look after the machinery and keep it in proper
order. The reduction in the cost of ripping represented a
very important saving. He had had some experience in that
way, his firm having put in a coal cutter and conveyor to
deal with a seam ranging from 3 ft. to 3 ft. 2 in. The seam
had been worked by hand, and the roof was very bad. They
bannocked the seam, and it was of such a nature that it
would not hold its own dirt; and they had saved nearly 3d.
in actual dirt emptying in other parts of the pit. The
reduction in the percentage of small coal was also very
important, and for collieries producing non-coking coal, that
must be one of the chief factors in inducing colliery managers
to adopt coal cutters. He thought it was rather difficult to
make a comparison if they left out the all-important question
of packing and goaf, and he did not think it was a fair
comparison simply to take in the getting and filling. Tor
one thing, it was very difficult to get at. Then it had to
be dealt with in such different ways. He could conceive
that the filling in the case of a thick seam, say 5 ft. 6 in.,
could be considerably more expensive in a machine-holed
stall than filling from a hand-holed stall. If they took the
case of simultaneous coal getting in a hand-holed stall, it
was part of the holer’s prices to do his packing, whereas in
the case under consideration it had to be done on the after-
noon or night shift. He noticed that Mr. Cashmore
proposed to use Continental jigging conveyors, and he pro-
posed using them on the afternoon or night shifts. That
meant that the conveyor had to be going on at the same time
as the coal cutter. But to do that the conveyor would have
to be used right up to the end of the night shift. Really,
the driving end of the conveyor was the thing which took the
most moving, and would have to be done just when the men
would require to fill coal. He did not think Mr. Cashmore
would be able to realise quite the output that he anticipated,
namely, 240 tons, and at the same time stow his goaf
properly.

Mr. Langford Ridsdale said that with regard to hydraulic
stowing, he thought he could prophesy that Mr. Cashmore
would not make any of the experiments suggested—at least
at present. He had so far had no experience with coal
cutting himself, but with regard to hydraulic stowing, the
facts that had been published in the public Press were
sufficient to make them all extremely cautious before com-
mencing any experiments in that direction.

Mr. N. Forrest said that with regard to the analyses of
figures from the annual reports of the inspectors of mines,
while there was no doubt Mr. Cashmore had given the
figures quite accurately, he had an impression that if they
were examined they would show that the coal cutting was
very much located in certain districts. Taking the year
1909, they were told that the amount of coal obtained was
13-7 million tons. But he knew practically for a fact that at
least 600,000 tons, or one twenty-sixth of the total, was
produced from one colliery alone. That rather pointed to
the fact that coal cutting had progressed in certain districts
where the conditions were exceedingly favourable, while other
districts had left such machines very much alone, and he
thought the latter course rather applied to the Cannock Chase
district. He could thoroughly endorse what Mr. Sopwith
had said about the increasing inefficiency of the coal face
staff. The standard mentioned by Mr. Sopwith for fillers,
he was afraid, could hardly be equalled at Holly Bank.
There had been a notable retrogression in the production
per man. He had been taking figures of production over a
considerable period of years, and he was satisfied that the
retrogression was continuous. With regard to two collieries
in which he was interested, producing 900,000 tons of coal a
year, the retrogression during the last six months had been
considerably more than it was in the six months a year ago.
That pointed to the fact that the slackness was increasing.
He could also endorse Mr. Sopwith’s remarks as to the
great opposition which they had to meet whenever they
introduced mechanical appliances. They had a good taste
of it at Holly Bank. His firm introduced “ Diamond ” coal

cutters in 1899, in the face of very considerable opposition.
It was introduced into a seam varying in thickness from
6 ft. to 6 ft. 6 in., and it showed a clear saving of 7d. per
ton, excluding the cost of power, which was never deter-
mined—they used compressed air. Of course, one had to
select the right seam for the working of that machine, and
this could only be determined by experiment. In some cases
he had tried during the last three years three different seams
with mechanical coal getters. He had failed in one of them,
one of them was a distinct success, and the other only a
fair average. Possibly the last-named paid its way on the
round coal that was produced. With regard to Mr.
Cashmore’s figure on the cost of cutting, that depended
entirely on the nature of the cutting. At the large collieries
in Yorkshire where machines were extensively used, they
generally avoided cutting in the coal, because that neutralised
the percentage of round coal. In cutting in a seam about
2 ft. 10 in. thick, and taking an average of 45 yds. cut per
shift, excluding the fixing of the machine, the cost came out
at 5^d. per ton. With regard to getting and filling, he
agreed with Mr. Sopwith that it was a difficult matter to
arrive at the cost of the getting and filling exactly. In the
above-named seam, 2 ft. 10 in. thick, he paid the men
Is. 9d. net for the whole operation on the face, including
cogging and timbering, but not for the cleaning up of the
dirt from the machine. It cost him altogether to get that
seam on the face, and put it into tubs at the face, practically
2s. 3d. per ton. That was when all the different items were
added together. The hand price for that seam was 3s. 4d.
net, so that there was a considerable saving. He agreed
with Mr. Cashmore that if they got the right seam they
would get a much larger production of coal per man, and
they would get an increase of about 20 per cent, in the
round coal. With regard to the conveyors, his firm had
installed a jigging conveyor, but the results had not been
all that he expected when he got it, but he had put it down
partly to the inherent opposition of the men. The men
persistently held back when it was first put in, and for some
time the actual cost of getting exceeded the cost of working
in the old way. He believed it was much the same seam as
Mr. Sopwith was working. The men were working on
“ company,” and the results were as everybody knew who
had worked on that system—extreme slackness. He rather
questioned whether the experiment had paid, except as to
the round coal, and he did not think he had saved in actual
wages.

Mr. J. Brindley said that, as a mechanical engineer, he
had been very much interested in listening to the paper and
the criticisms on machine coal cutters and conveyors, the
general effect of which was that those machines were, as one
might say, damned. But he thought the two subjects were
scarcely to be mixed together, and it might be that the con-
veyor should be regarded as a kind of appendix to the coal
cutter, and might be of some benefit, particularly in a thin
seam. He understood that conveyors were first introduced
into the thin seams in Durham. It was difficult to get a
large number of small tubs about in very low places, and it
did not pay to make big roads, and so they used a conveyor,
and brought the coal through the small roads into the main
haulage road instead of having to cut out roads large enough
to accommodate the ponies and men. His experience of
workers underground did not warrant him saying that the
men were slackers, and deliberately placed obstacles in the
way of the success of machines. He had found that if a
man was put to work on a machine his idea was to show
what he could get out of it. Often enough it was the machine
that did not carry out what it was supposed to be able to do.
As an engineer, he knew there •were inherent defects in the
design of some of those machines. They had to be put on
the market cheaply, and the effect of that was that on
account of mistaken economy the weakness came out at a
critical moment, and the machine broke down. At the same
time, the cost of keeping up those machines, however good
they might be, was very considerable, and as soon as they
introduced them into a colliery they were bound to increase
their mechanical engineering or electrical engineering staff,
because the supervision of the machines must be put into the
hands of someone who had a knowledge of such matters. If
they provided the machine, and put it in the hands of an
underground workman having no special knowledge of the
subject, it was no use expecting him to keep his machine in
order. Certainly some of the men knew no more about the
machines than the machines knew about them. If they got
a man with mechanical knowledge, naturally he wanted
more wages to remunerate him for his expert knowledge.
Depreciation and wear and tear were naturally very great
on all such machines on account of the rough and trying
conditions under which they were worked. There was the
presence of dust, sometimes the difficulty of giving them
proper lubrication. Another important point was that such
machines were only worked for a very small fraction of the
whole time. For instance, they would be cutting for
perhaps five or six hours a day, and the machine would be
lying idle all the rest of the day, and, so to speak, eating its
head off in interest; and that, of course, had to be taken
into account. He noticed that Mr. Cashmore had put down
33| per cent, for “ interest, depreciation, repairs, and
renewals of machine, cables or pipes, and accessories.” But
it was not very clear what was meant by that, or whether
he had made a fair allowance for the short life of the
machines. They would not find one working regularly for
more than five years, and, if it was, there would not be
much of original machine left. If they were getting their
power down at 2d. per hour per horse-power, they were
doing very well. If the coal cutter was to have an
undercut of 4J ft., they would require a wheel of 7 to 8 ft. in
diameter, and they could not drive that with less than 30
to 40-horse power, which would represent about 6s. 8d. per
hour, and if that was spread over 30 tons of coal it became
a serious item. The cost of power could not be ignored in
respect of the coal cutter, to say nothing of the conveyor.
Apparently the figures showed that the cost of machine-got
coal was a little over half the cost of hand-got coal. Per-
sonally, he thought there would be very little change out of
those figures, and he thought if they made all allowances
for power, which might very well be put at 3d. or 4d. per
ton, and apparently the best case was that of No. 3, then
they got into the neighbourhood of Is. 5d. per ton, and, of
course, if anything happened to the cutter, the whole process
was stopped for a day or two, and the pit was thrown out
of gear. In that way a month’s gain might be very quickly
lost in a single stoppage. He was not quite sure, but he
believed there was more trouble with dust where coal cutters
were used. Certainly that was the case in some districts
of South Wales, in which the dust was tremendous in dis-
tricts where cutters were employed, as compared with those
employing hand cutting. In connection with hydraulic

stowage, they must consider that the material required to be
pumped was about the worst mixture that a pump could
possibly deal with, and he would suggest that something
other than a centrifugal pump should be used.

Mr. J. W. McTrusty said his own experience was that
most modern machines were well designed and would stand
a fair amount of hard work. He would like a little further
information with regard to the achievements of coal cutting
machines referred to in the paper. In one place the author
spoke of the machine cutting 250 sq. yds. per shift, and at
another he said that the cutting would be 50 yds. per shift.
Apparently there was a discrepancy in these statements. He
ventured to suggest that the greatest difficulty was not
mechanical, or a question of design, or of transmission of
power. What they wanted was trained men to deal with
machines. Mining engineers would persist in looking at the
matter of training from a theoretical point of view, and failed
to realise that training was a separate problem. If a man
had spent the earlier part of his life in hand cutting at the
coal face, and had no mechanical instinct, it was unreason-
able to expect that he would get the best out of a machine.
They had found in Scotland the necessity of training, and
in that district they accordingly got good results. Probably
these were the facts underlying what had been described as
the prejudice and inefficiency of workmen. It was unreason-
able to expect the ordinary miner to appreciate the uses
of electrical machinery; in fact, many of them were very
much afraid of it, as they did not understand the factors
making for safety or danger. That accounted largely for
the opposition of the men’s unions and associations, and
it appeared that if men understood the safeguards which
could be provided, much of the difficulty would be removed.
Undoubtedly the success of the coal cutting machine largely
depended on mines being specially laid out with a view to
their working. The more highly developed the organi-
sation and the more skilled the workmen, the greater would
be the success realised; and it appeared to come down to the
question of the better training of the men, so as to deal
with this higher organisation. A certain amount of educa-
tional work was being done among miners by county councils
and other authorities, but that work was not what it might
be if practical mining men would take more interest in the
instruction conveyed, and assist to correlate pit work and
Uass work. Greatly improved results would be realised.
His impression was that machine mining would gradually
become inevitable, because of the increasing depth of mines.
At a temperature of 80 degs. it was physically impossible for
a man to do a hard day’s work equal to that he would do in
a temperature of 60 degs. The fact alone would press
forward the development and the increasing adoption of
machine mining. A most important matter was to take a
selection of young men and give them time to obtain proper
mechanical training, and if that were done he had great
hopes that machine mining would be a success, if and when
economic circumstances demanded the introduction of
machines.

Mr. N. Forrest said he would like to add another word to
what he had already said, in view of Mr. Brindley’s
remarks. Apparently he had 'been misunderstood, and he
would like to make it clear that he was not an opponent of
conveyors. As a matter of fact, the cheapest coal he had
ever seen obtained was dealt with by conveyors. He knew
a case where men were filling 10 tons of coal per man from
a hand-holed face by means of a conveyor. The amount of
coal got per shift was 80 tons from 45 yds. of face. That
certainly was the cheapest coal he had yet seen got. But
the conditions were eminently favourable, because the seam
was level, and generally the coal very suitable for easy
getting. But at his own colliery he had the greatest diffi-
culty to get the men to give the suggested charter price a
•trial; and it was some weeks before it got a fair chance.

Mr. C. Fenn said that he considered that it was the most
interesting paper he had ever listened to. For some months
past he had been hesitating about putting in an electrical
coal cutter, and apparently the chief difficulties suggested
were those to be expected from the workmen. From the
particulars given with regard to the saving, .it was clear
there was a case for consideration by the mining engineer,
and, if possible, he should endeavour to put the machines into
operation, especially where the seams were thin. Where the
thickness was not more than 2 ft. it was clearly impossible
to make a success of hand cutting. On the other hand, the
machine cutting was the natural and proper thing for a seam
of that sort. Obviously coal cutting was the thing for the
future and rapid progress was being made, and the result
of that paper would be to lead him to extend his own
experiments in that direction.

Mr. Cashmore, replying to the discussion, said he was
much obliged to Mr. Sopwith for his kind remarks. But
apparently that speaker questioned very much whether 240
tons for a face of 100 yds. could be obtained. Personally,
he had before his mind an instance where, under very
favourable conditions, in a 4 ft. 6 in. seam 18 tons per man
were being dealt with daily by means of a conveyor on a
face 130 yds. long. He was not permitted to see the seam
being worked, but he could accept the statement, and the
same manager assured him that the cost, including timber,
packing, and everything at the face, was Is. 3d. There-
fore, he concluded that an estimated cost of Is. per ton
should be well within the mark, excluding charges for pack-
ing and timbering. With regard to Mr. Sopwith’s sugges-
tion concerning output, he (the speaker) purposely put
this rather on the under side than over, and he had
taken the same course with regard to other figures, and
where the best methods were adopted it was possible to do
better than the figures cited showed. With reference to the
number of men employed, Mr. Sopwith appeared to have
the idea that the men would be crowded. He did not think
that was the case, and the system he had seen adopted was
to work in pairs, one acting as buttocker, and the other as
filler. With regard to the conveyor, he had taken what he
had heard described as a comparatively high rate for interest
and depreciation, although he had neglected to include any
figure for power. Apparently Mr. Sopwith thought that the
cost of supervision would be greater than had been shown.
That appeared to be so, because they had to have skilled
men ; but where the system was largely employed, the general
cost of supervision was almost invariably less. In respect
of the packing, Mr. Sopwith seemed to think that a mistake
had been made, because he thought the cost of packing
would be more in the case of machine than in hand holing.
Speaking from experience, he thought a large amount of