702

THE COLLIERY GUARDIAN.

October 13, 1916.

MIDLAND INSTITUTE OF MINING,CIVIL
AND MECHANICAL ENGINEERS.

A paper on “ The Widening of the Upcast Shaft at
Tinsley Park Colliery, Sheffield,” and a further discus-
sion on ” Fuel Economy at Collieries,” were the features
of a general meeting of the Midland Institute of Mining,
Civil and Mechanical Engineers, which was held at ibe
Great Northern Hotel, Leeds, on Thursday, October 5,
Mr. C. C. Ellison (president) occupying the chair.

Widening the Upcast Shaft at Tinsley Park Colliery.

The paper (see Colliery Guardian, Oct. 6, p. 651),
which was read by Mr. H. J. Atkinson, a student
member of the institute, was submitted for a prize
offered by the president, and gained the award.

Discussion.

The President said they had listened to a most
interesting and very practical paper. If anybody was
going to undertake similar work, he felt quite sure he
would find the information in the paper of considerable
value. Theoretically, after hearing the paper read, the
work of widening a shaft sounded a very simple matter,
but they knew how difficult it was in practice, how many
little troubles had to be overcome which did not occur
to them at the time of starting. He was sorry that that
paper was the only one contributed for the students’
prize. Fie was sure there wore a great many young men
who could contribute similar papers. He proposed a
hearty vote of thanks to Mr. Atkinson for the trouble
he had taken in preparing the paper.

The resolution was carried.

Mr. J. FI. W. Laverick (managing director of the
Tinsley Park Colliery Company), in a letter expressing
regret at his inability to attend, more especially as a
junior member of his staff was reading a paper, said
they did not claim any originality in using the boiler
shell shield for supporting the sides and for the safety of
the men working on the widened off ledge. He remem-
bered some years ago reading in one of the technical
journals of this method being adopted elsewhere—he
believed in North Staffordshire. It struck him then as
being a very simple and effective safeguard, and this
they had proved it to be; and he would not hesitate to
recommend it to anyone who contemplated doing
similar work, i.e., where it was not possible to fill up the
shaft before commencing the widening.

Col. H. Rhodes said the paper was so absolutely prac-
tical, and seemed to cover every point so completely,
that it was difficult to criticise it. He should like to
ask why they put in one oak crib. It would be interest-
ing to have the exact quantities of air, both before and
after the widening. With a quantity like 150,000 cu. ft.,
even if they got an increase of 15,000, and the water
gauge went down 0*2 in., it showed that they had got
some considerable improvement.

The President referred to the firing of only two shots
at a time, and to the fact that only a few men were
working. He supposed this was on account of the
danger of the weight of earth which would fall on to
the scaffold. He noticed that the sinkers were allowed
to ride on the top of the cage. He wondered why they
could not go into the cage, after the tubs came out.
The rate of progress described in the paper seemed to be
very satisfactory.

Mr. Blake Walker said at Wharnpliffe Silkstone they
carried out a very similar job, enlarging a 10 ft. shaft
to 15 ft., but they did it by filling it up, which, of course,
was a somewhat easier process than that described by
Mr. Atkinson. He was sorry he had not the particulars
of the cost with him, but as the case was so absolutely
parallel, he should be pleased to contribute the figures
to the discussion. The excellent paper which Mr.
Atkinson had given them, showed that some of the
younger members could, if they only would, and if they
would have confidence in themselves, do something to
help the institute with papers. Most of the older mem-
bers, especially at present, were very hard pressed, and
had not time to write papers. That did not apply in
quite the same way to the younger members—such of
them as were left at home—and they would be very glad
if Mr. Atkinson’s example proved catching.

The President said there was another question he
would like to ask : Whether it was feasible, and, if so,
whether an estimate was made as to what it would have
cost, to sink an entirely new shaft, instead of widening
the existing one? When he was at Wharncliffe Silk-
stone, they had a staple pit from the Silkstone to the
Whinmoor, and they sank from the top on to the top
of the staple pit. The surveying was made by two or
three people, chiefly by Prof. Hardwick, and great care
was taken in making it, because it had to be made round
a lot of buildings—they could not get any direct sites at
all. He believed the shaft was not 4 in. out.

New Shaft v. Widening.

Mr. W. D. Lloyd said the discussion raised in his
mind the question how fully those imcharge at Tinsley
Park discussed the question of whether it would be
cheaper to sink a new shaft or not. Of course, each
problem had to be settled on its own peculiar difficulties.
At Altofts, about five years ago, they were confronted
by an almost identical problem, and their solution of it

was to sink straight from the surface. He believed he
could give the cost of sinking per yard, which he would
send to the secretary. The conditions were very
similar to those described in the paper. They had an
upcast shaft, with about 150,000 cu. ft. of air passing
per minute, and they had to keep it open to maintain
the ventilation. It had been worked as a furnace shaft
for 40 or 50 years, and the sides were, at any rate, no
better than they ought to have been; and the risk and
the delay in carrying out the work decided them to
start straight away from the surface. Of course, a new
fan engine had to be put down at the .same time, and
there was no possibility of putting it to the old pit. New
winding engines were also required; and these circum-
stances influenced greatly the decision as to sinking
from the surface. He thought that, taken all round,
there was a good deal to be said for making a fresh job
entirely; it all depended on the conditions.

Mr. A. Naylor (Shirebrook) said he had no doubt that
the question of sinking a new shaft had been thoroughly
considered. The shaft pillar would have to be taken
into account in deciding whether a new shaft was to be
sunk, or the existing shaft widened. In one particular
case that he had carried out for Mr. Laverick, they sank
a new shaft 15 ft. diameter. They also sank another
shaft 150 yds. deep, and bottle-necked it from the bottom
so as to make it into an upcast shaft. In the case of
the 15 ft. shaft, the sinking cost £6 10s. per yd., the
fixing of the bricking curbs £2 10s., and the bricking he
believed 35s. In the case of the other shaft, which was
9 ft. finished, the actual sinking cost was £4 10s. per yd.,
the fixing of the bricking curbs £2, and the bricking
between 27s. and 35s., according to the nature of the
brickwork. The 15 ft. shaft was from the surface down
to the Silkstone. The other shaft which they deepened
was 7 ft. diameter from the surface to the Deep Hard,
and 9 ft. from the Deep Hard to the Silkstone.

Mr. Blake Walker said, in 99 cases out of 100, sink-
ing was done backwards, but at his colliery they had had
occasion lately to carry a staple pit upwards to a higher
seam, and had done it on a principle that was new to
him. He would try to get a short'paper on it. It might
form an interesting supplement to Mr. Atkinson’s
contribution.

Mr. Atkinson, in reply to the discussion, said the oak
crib mentioned by Col. Rhodes was only put at a depth
of 4 or 5 yds., and was done temporarily. He could not
give any actual figures as to the quantities of air. It
would be rather difficult to do so, as an auxiliary fan was
also installed whilst the work was in progress, and that
would help to increase the ventilation. They had not
got a very great increase of air as the result of the
widening. He should think they had gained 15,000 ft.
He would try to get the figures, and supply them to the
secretary. The reason why only two shots were fired
at once was that there was very little resistance. Very
small charges were put in, and quite a quantity of
material was brought down. The men were allowed to
ride on the top of the cage simply as a matter of expedi-
ence, for getting them down. He could hardly give any
figures in connection with the sinking of a new shaft.
This would necessitate different arrangements both at
the surface and underground in connection with the fan
drifts. Moreover, at Tinsley Park they had the larger
size of shaft for the lower part, and they wanted to
utilise that. They had only 214 yds. of sinking to do,
whereas a new shaft would have meant sinking 548 yds.

Fuel Economy at Collieries.

The meeting then resumed the discussion on Mr. F. F.
Mairet’s paper on “ The Economical Production and
Utilisation of Power at Collieries,” which was read on
July 18. (Colliery Guardian, July 21, 1916, p. 114.)

Discussion.

Mr. W. D. Lloyd said that on the last occasion he
suggested that the figure given by Mr. Mairet for the
percentage of the total heat units produced from the
fuel burnt which were utilised in work at an average
colliery was star tingly low. He was now able to give
the corresponding figure for the Altofts collieries as a
result of an investigation made by the National Boiler
Insurance Company in March last. It was estimated
that 3-34 per cent, of the heat units produced from the
fuel burnt were utilised in work done, as against 1’7 per
cent., the figure given by Mr. Mairet—that was to say,
practically twice as much work was obtained out of the
heat produced at the one colliery as at the other. The
investigation at Altofts covered the working of five
plants, consisting of 28 boilers, over a fortnight, and was
carried out by the same people who made the report on
the Wharncliffe Silkstone collieries; therefore the figures
were strictly comparable. It was only fair, However, to
point out that, at Altofts, the winding engines were only
used for drawing coal eight hours per day, and that only
9 per cent, of the heat units used were utilised for wind-
ing, which was a comparatively low proportion, as the
winding engine was practically the most extravagant
large engine at a colliery. On the other hand, 44 per
cent, of the heat units were utilised for air compressing
in fairly modern engines, and 30 per cent, in constant
running fan engines; so that nearly three-quarters of the
steam was used in constantly running engines. But he
should also state that, although the results of the boiler
tests at Altofts were better than those given by Mr.
Mairet, they were capable of considerable improvement.
All the auxiliaries were steam-driven, steam was taken
down two pits to drive haulages, and three out of the
five boiler plants had no economisers; they had no super-
heaters and no exhaust steam turbines. Therefore, there
was considerable scope for improvement, and yet they

were getting 3’34 per cent, out of the heat that was
given out by the fuel. The investigation was carried
out to see what they were actually doing, and also what
improvements they could make. The biggest waste
occurred in the surface auxiliaries, of which they had a
tremendous number, all taking a big quantity of steam
per indicated horse-power. They also had long ranges
of steam pipes. It was estimated that by driving these
auxiliaries by electricity, fitting some of the boilers with
superheaters, and making certain other alterations, the
power required could be produced with slightly over half
the fuel which was at present being used. That was to
say, after the improvements were made, over 6 per cent,
of the heat units produced should be utilised. He was
of opinion that many modern collieries were, or should
be, getting somewhere about 6 per cent, of efficiency.
There was much room for improvement in fuel economy
at the majority of collieries, but he maintained that the
figure given by Mr. Mairet for the percentage of efficiency
obtained at an average colliery was too low. The follow-
ing were the main results of the Altofts investigation :—
Thermal efficiency of five boiler plants, 64’3, 53-2, 43’4,
57’6, and 52-6 per cent, respectively; total amount of
fuel (not all coal, by a long way) used per week, 850
tons; total British thermal units produced from fuel
burnt, 19,956 millions; average calorific value of fuel
burnt per lb., 11,062 British thermal units; British
thermal units utilised in work done, 666’92 millions;
total indicated horse-power hours per week, 262,100;
total pounds of steam generated, 10,215,100; total
pounds of steam used in engines, 9,081,500; average
pounds of steam used per indicated horse-power per
hour, 34’6; average pounds of fuel used per indicated
horse-power per hour, 7’26; pounds of steam
raised per pound of fuel burnt, 5’36. He might
point out that the average calorific value of the
fuel used was comparatively low, and the average
weight of fuel used per horse-power hour was, therefore,
correspondingly high. If they had been using fairly
decent coal all the while, they would not have used
quite so much per indicated horse-power hour. It
should also be noted that the investigation was made
during the war, that the proportion of steam used for
winding and hauling was below the normal, and that
the boiler firing and the condition of the engines were
not so good as they would have been in peace time.

Misleading Estimates.

Mr. H. F. Smithson said that some people worked on
the percentage of output that they drew, and others
worked on the cost per ton; but he thought all these
figures were more or less misleading, and that the only
accurate way of finding out whether a colliery was doing
well or badly was to ascertain how much coal was burnt
per indicated horse-power. Ten years ago, the collieries
with which he was connected were drawing about 10,000
tons of coal per week, and for that tonnage they had 17
Lancashire boilers. Just prior to the w’ar they were
drawing 17,000 tons a week with five Lancashire
boilers. Since then they had increased their power
plant. They had put up some new compressors, and
consequently they had put up another boiler, so that
now they had six boilers running. Their output was
not up to 17,000 tons at the present time; but two years
ago, which was during the period of the war, they had
tests made, and these showed that they were burning
5 lb. of coal per indicated horse-power. He agreed with
Mr. Lloyd that Mr. Mairet’s figure of 1’7 per cent,
thermal efficiency was extremely low. The results of
the tests referred to proved conclusively that the plant
was open to several improvements, many of which had
since been made, and a later test showed that their
thermal efficiency was 5 per cent.—in fact, he should
think that to-day it was rather better than that. The
efficiency of the boiler plant was just over 60 per cent.,
which was not too good. Therefore, if they could
improve that, and they already had a thermal efficiency
of a little over 5 per cent., there was no reason, in his
opinion, why the thermal efficiency of a colliery plant
should not be got up to at least 6 or 7 per cent. They
had been able to increase the efficiency at the collieries
w’itli which he wras connected by the use of exhaust
steam turbines. He would suggest that the ideal
method, at a colliery where there wras a washery and no
coke ovens, was to try and arrive at a balance of power.
Suppose, for the sake of argument, that they had 2,000
horse-power to run the whole of their plant; if they could
divide that up into a proportion of about 1,200 horse-
power steam, and from that 1,200 could get back another
800 horse-power of electricity, he could not conceive any
conditions more ideal or more efficient. A question that
had been raised in the discussion wras that of the use of
w’ashed fuel. Well, they had been burning washed fuel
for three years or a little more, and he thought it w’as a
proper thing to do. If they had a washery, and could
wash all their output, he could not see why the pro-
ducing side should not be treated exactly as customers
buying from the colliery. His experience showed that
customers nowadays preferred washed fuel to dry fuel
with a lot of dirt in it; and he did not see why a colliery
•should not do exactly the same thing. By doing that
they economised in capital cost, they had fewer boilers
and fewer men, the labour cost w’as reduced, and he
thought, speaking generally, one had less trouble all
round. The crux of the whole question, he thought,
wras that, as producers at a colliery, the only thing that
counted was how much of their output they could hand
over to the selling department. Mr. Beach suggested
that comparisons should be made in £ s. d., or so much
per ton; but that w7as hardly the point, because the
selling department at one colliery might like to charge
a ton, whereas the selling department at another
might only like to charge 2s. 6d. They could not get
comparisons that way. The real thing that counted was
how’ much of the output they could hand over to the
selling department, and the more they handed over the