538

THE COLLIERY GUARDIAN.

March 15, 1918.

just on some single props, bore some boles through, put
a spindle through, and run it on a level surface. At first
there was great difficulty in the placing of the coal on
the belt, and a lot fell off before the men adapted them-
selves to the conditions, but at the present time they
had very little trouble in the absence of angle irons or
any side support at all. All the belts they had now—
excepting one or two lengths probably which had
driving gear under just to give the belt a lead on to the
drums—were done with just simply a straight prop
fastened with staples on to the props of the face. With
regard to the installation at a Durham colliery mentioned
by Mr. Jenkins, he would like to ask Mr. Jenkins how
many men were working on that belt at the time. Was the
Work done in the 2 ft. 8 in. section, or in the 18 in.
section ? It would be very interesting to know whether
160 tons were filled off a face 90 yards long, at 18 in.
thick. A 90 yard face of a 2 ft. 8 in. seam, cut to a
depth of 4 ft. 6 in., yielded about 100 tons. Mr. Jenkins
did not say how deep it was cut. If cut 6 ft., it would
yield 125 tons. He was at a loss to understand how
160 tons were got off that face, which was only 90 yards
in length. On the question of flitting, the speaker said
that at the Wbarncliffe Silkstone they had never done
it in two and a-balf hours, even when there had been six
men to remove the belt. Mr. Jenkins said that a belt
conveyor took two men two hours to flit, whilst an
electrical shaker took four men each shift to flit.
At Wharncliffe Silkstone, it took them above two
hours, and required more than two men. Anyone knew
very well that if they had a 90 yds. double belt to
pull up or to thread between the props, it was an
impossibility for two men to do it. He did not know
where the information came from, nor anything at all
about it, but he knew that that was not his experience
at Wharncliffe Silkstone. Dealing with the methods
adopted in the North of England, Mr. Jenkins had
spoken about a mothergate, and keeping one face in
advance of the other by 40 yds. He (the speaker) was
afraid that in the seams in which they worked that would
not do at all. If they had one gate, and a face on each
side of that gate, and they took one face 40 yds. before
the other, they were going to have some cutting up
in the roof, because they had a cutting on the
side of the level, and in the case of Wharncliffe
Silkstone they would not be able to maintain the roof.
With regard to driving a heading forward, in order that
they might run the tubs in and bring the others back,
they commenced with that plan, because, after he had
been round and got as many particulars as he could, he
naturally followed on in the same way that he had seen.
For a month or two they continually had the places in
the conveyors buried and everything upside down. The
results of the adoption of thab plan were still to be seen
in the first twenty yards of the district. It not only
blew the roof down in the headings, but it also set at
liberty the roof down the face on each side, which
was worse than coming in. He determined not to do
any heading, and since then they had cut across the
level; they had it broken in—z.e., the coal taken out—
across the level and about two yards on each side; the
denting blown up or got up, stowed into the goaf, the
flags laid down, and by that meana a corf could be
brought and placed at the back end of the one which bad
already been pulled to the conveyor. There was room
for it. That was the principle they had adopted right
through, and they had not done a yard of heading since.
If there was a sufficiency of corves, there was no need
for the conveyor to stand at all. They did not change
the roads. They still kept one full road only, which
was the low side road. The empty corf came in and
knocked the full one out, twisting it on to the flag
next to the face side, and letting it go away.
This was simple, and there was no necessity in
their case—and he did not think there was neces-
sity in any case—to drive headings for the purpose
of taking the corves and having them at the back.
It was important, in this work, that everything should
go like clockwork, because if by any means they were
stopped in one face, and had the machine held back, it
upset all the arrangements forward, and they had to get
in an extra shift or resort to some other expedient.
That did happen at times, and was a difficulty for the
colliery manager and the under-manager to overcome,
but it could be got over if the thing were tackled in a
proper manner. It was necessary to have plenty of
corves in the level, so that if anything went wrong they
could go on, but not at the same rate as was specified
in the paper—namely; 160 tons a day. With regard to
the shaker conveyor, he believed he started the first in
the Barnsley district; but he noticed that that conveyor
was now on the pit bank. He had heard of conveyors
being taken out at many places, but it did not follow
that because they were taken out, unworkable, it was
the conveyor’s fault. In his opinion it was, in a great
many cases, the fault of the management. If they
would only go in for systematic working and systematic
timbering, in a proper manner, he had not the slightest
doubt that conveyors would come more generally into
use than they were at present. They could be used,
because they could run in very little room. On the
question of removing the belt, Mr. Wroe said that at
Wharncliffe Silkstone the belt had only two joints,
and, when they had “ run the face off,” they drew
out the pin, and pulled the conveyor back into
each gate, one into the delivery end and the other into
the return end. They then moved up the head—which
took, he believed, about an hour and a-half—fastened
the rollers on to the props, pulled the belt to, and put
the pin in. He should say that it would take four men
half a shift to remove one of the belts, which were about
80 yards long.

Mr. J. Ensor said his experience of conveyors had
extended over the last eight years, and had been very
similar to that of Mr. Wroe. Some of the claims put
forward about getting an output of 8, 10 or 12 tons per
man by the use of conveyors were liable to cause trouble
to the colliery manager. His superiors thought that all
they had to do was to put in a conveyor of some sort and
they would get this output, and things got rather warm
if the anticipation was not realised. In his experience, as
in that of Mr. Wroe, they could not drive the advanced
headings, as their roof was too bad. They also had to set

bank bars every two or three feet, which was a detriment
to the conveyors; but they had managed to work for
eight years, because they had found out the proper way.
He was rather disappointed at not finding in the paper
any figures as to what really could be done. The seam at
the colliery with which he was connected varied from 3 ft.
to 3 ft. 6 in., with a bad roof. They had a belt. They had
their gates .110 yards centres, and no middle gate at ail.
They could not take the conveyor and fill the tub at a
lower level than the conveyor, so they ripped down the
bank for a certain distance. Their output varied. He
was in the position of having a conveyor gate, a con-
veyor wall, a machine-cut hand-filled wall, and some
hand work, all running practically side by side, and the
figures which he would give were reliable. They
usually got 230 7-cwt. tubs for a day’s work, filled by 12
men. Those were the men who actually put the coal on
the belt. This worked out at about 7 tons per man.
But if they counted all the men engaged on the face
and engaged on the conveyor, the figure came down to
about 4g tons. In the machine-cut, hand-filled section,
where the coal was filled into tubs, their usual output
was about 4 tons per man, and the hand-cut face
gave them about 2J tons. These were figures that the
ordinary colliery manager would like to get, just to
show what really was done practically, and not a
specially-prepared test, where everything was got ready
for rushing the thing out. It sometimes happened that
a conveyor got buried, and if they took into account the
time in which the ground had to be headed out again,
the figures of large outputs which they saw advertised
were reduced considerably. After his experience, he
would not recommend putting in a conveyor where he
could get a good pit-tub easily.

Mr. Watson Smith said that some time ago he saw
an advertisement that 500 tons were filled off 100 yards
of face, in a seam 3 ft. thick, in a shift. As he could
not get an output like that, he thought it was in the
interests of managers that that statement should be
investigated, so he wrote to the people who were
advertising, asking if they would kindly tell him
where this was being done. They replied that they
were not at liberty to give the information,
but after* some further correspondence they arranged
for him to go and inspect one of their installations in
South Wales. There he found that the average per man
filling on to the conveyors was 4 tons 12 cwt. They
were very proud of that figure, but, at the colliery with
which he was connected, they got as much in tub stalls,
without conveyors. He found that the seam was 3 ft.
thick, and he worked out that, in order to fill 500 tons
in one shift, off 100 yds. of face, they would have to
move the conveyor up four times. He asked the firm
to take the advertisement out of the paper, and he
thought they had done so; otherwise he should have
thrashed the matter out publicly, because statements
like that did more harm than good to any contrivances
that were put on the market. Managers naturally
listened to statements about something that promised
to be of use to them, and on the strength of such state-
ments they might be tempted to buy appliances, only
to find that they got a miserable result compared to
what they expected.

The President said Mr. Jenkins was not able to
be present that day to answer the discussion, but
possibly he would be able to do so at a later date. He
thought they could take it from the discussion, and
from the criticism of the paper that was raised at Leeds,
that they should ask Mr. Jenkins to amplify his figures
with regard to the tons per man produced by conveyors.
There was no doubt that in many cases he had taken
the tons produced actually by the collier, and that, as
had been pointed out both on that occasion and at
Leeds, was misleading. The figures of output should
be based on the total number of men employed at the
coal face, whether they were colliers, machine men,
cleaners up, or men moving the conveyor. He hoped
Mr. Jenkins would give them further information on
that point with regard to the tables in his paper.

The discussion was then further adjourned to the
next meeting.

Cleavage in Coal.—Prof. P. F. Kendall, of the Uni-
versity of Leeds, who is engaged upon important researches
into coal, would greatly value information with respect to
the vertical cleavage in coal, known to English miners as
cleat, slyne or slips. He begs that mining engineers,
mining inspectors and mine managers in all foreign and
colonial coal fields will kindly direct to him a postcard
giving the compass bearing of the principal line of such
vertical cleavage in all mines known to them. If there are
variations in the direction of cleavage in different parts of
the same bed or from one seam to another, a short statement
of the variations would be most useful. The name and the
locality of the mine and the geological age of the coal
deposit should also be mentioned.

The Outlook for Pit wood.—If all requirements are to
be met during the year 1918 without encroaching upon the
necessary tonnage for the conveyance of food, the supply of
the Navy and Army, munitions, and other essential
commodities, it is estimated that the home production will
have to be not less than 2,900,000 tons of sawn wood, and
3,100,000 tons of mining timber, or an aggregate of six
million tons, according to the Board of Trade Journal.
Before the war the requirements of the mines, aggregating
something like 3| million tons of mining timber annually,
were satisfied to the extent of probably 90 per cent., or
even more, by imported woods. Now the greater part of
the pitwood required has to be cut from home woods, and
the supply has come forward in a satisfactory manner. In
spite of the fact that imports of mining timber fell from no
less than 3,451,328 loads in the pre-war year of 1913, to
roughly one million loads in the year just ended, the
stocks in the hands of merchants and collieries together
are now at very much the same level as they were at the
end of 1915, the first year-end at which a stock census of
mining timber was taken. This year at least three million
tons of mining timber will have to be produced in these
islands The home production of pitwood last year was a
little less than two million tons. So that one and a-half
times as much will have to be cut in this country during
1918 if the requirements of the mines are to be met and the
output of coal maintained.

A “RESPONSIVE” SHAFT SIGNAL
DEVICE.*

By B. Angwin.

In order to obviate the continual cost caused by the
need for renewal of the bell wires in the “ knocker
line ” system at East Pool, the author started some 18
month ago a search for an efficient, and at the same
a cheap, form of answering signal. The device here
illustrated and described was the result.

Tie term “responsive.” in the sense of meaning
simply answering, does not fully denote the capabilities
of the appliance. Allowing that the operators are
acquainted with the “dot-and-dash” method of sig-
nalling, a conversation can readily be carried on between
them by means of this instrument.

It relies for its operation on the ready transmission
of a pulsation of air through a pipe, in conjunction
with the fact that a comparatively low pressure of air
is required to sound a whistle. It may be mentioned
that, whilst carrying out various tests during the course
of the experiments, it was found that an air pressure
equal to in. of water, or lb. per sq. in., gave a clear
note; on the other hand, a pressure of 30 lb. per sq. in.,
or over, produced simply the sound of escaping air.

The drawings show the “shop details” for the cast
work required in a working set, and the various parts
assembled, with the necessary connections. Slight
differences in the details of the shop patterns and the
assembled device are due to developments in the design.
The present set consists of bored wrought iron pipes for
cylinders, wrought iron reducers for cylinder covers,

“ Responsive ” Shaft Signal Device.

A, Cast iron cylinder and valve box ; B, cast iron air-pump
rod; C, cast iron air-pump rod cap (with 5 in. cup leather);
D, cast iron lever fulcrum; E, cast iron rod stay; F, cast
iron lever; G, gunmetal 4-way branch pipe; H, whistle
made of 6in. of 1 in. pipe; H1, silencer made from electric
wire tube.

two smaller wrought iron reducers and nipples for
valve boxes, and levers, fulcrums, plungers, rods and
rod stays made on the mine, as was also the brazed
four-way junction pipe carrying the whistle attach-
ment. These built-up contrivances, six in number, have
been in constant use for upwards of 12 months, and
are as good now as when first put to work.

The details illustrated are for the most part self-
explanatory, but it may be well to mention that the 1 in.
holes bored in the cylinder near the bottom are to
provide inlets for the air at the end of the stroke.
A hole is tapped at the bottom end of the pump
plunger to facilitate attachment of an extra weight
should this be required to bring the pump plunger to
its normal position at the bottom of its stroke. It will
be noticed that the whistle is shown to be provided with
a sliding sleeve silencer. It is not desirable to have
a silencer fitted to the whistle in the engine room, as
there is a prime necessity for the engine driver to hear
the signals transmitted from the shafts, and to be able
to reply to them. Silencers may, however, be fitted
to all shaft whistles, and the cage or skip onsetter
should be instructed to slide the silencer over the
whistle hole directly he has finished at one level. This
is not absolutely imperative, but it ensures a more
distinct sound for other whistles subseqxiently engaged.

To comprehend the utility of this “ responsive ”
signal in actual working conditions, one may quote
some such case as the following :—Let us suppose that
the onsetters were at work on the 150 fm. level, and that
something requiring immediate attention occurred at
the 300 fm. level; a man in the latter level
who was conversant with the Morse code could
at once send the S.O.S. signal (-----------...--------)

consisting of three full, three half and three full
strokes of the plunger, together with the distinc-
tive number of the level; these signals would be
heard both at the 150 fm. level and in the engine room,

* Paper presented to the Institution of Mining and
Metallurgy on March 7.