1164

THE COLLIERY GUARDIAN.

December 15, 1916.

970yds. long, 6|in. circumference; weight, 301b. per
yd.; weighted same as conductors; breaking strain, 140
tons; factor, 6’8. The above ropes were all made of
the best plough steel by Messrs. Latch and Batchelor.

Mr. A. H. Steele, H.M. inspector of mines, said he
agreed with what Mr. Curley had written in his contri-
bution to the discussion. He knew the colliery where
Mr. Curley had been, and he was aware of the condi-
tions there, as well as those at a similar colliery in the
same district. The depth of the .shaft at both these
collieries was about 900 yds. The details Mr. Curley
had given were accurate.

Round y. Square Shafts.

Mr. G. L. Kerr said he did not suppose the author
had any intention of seeking to convince anyone as to
the merits or demerits of the circular compared to the
rectangular shaft. Nevertheless, he felt it would be a
good thing if either Mr. Nisbet, or some other member
of the institute who had sunk circular shafts, would
take a certain size of shaft, such as described in the
paper, and give details of the cost of sinking, so that
these details might be compared with the cost of sink-
ing a rectangular shaft dealing with the same output.
If Scottish colliery managers were to make a decision
as to the type of shaft they ought to adopt in sinking,
it was essential, in the first instance, that they should
have information regarding the comparative costs. If
these comparative costs were given, it would greatly
help colliery managers in Scotland to make a decision.

Mr. Wm. Ross (Auchengeich Colliery, Chryston) said
he would be glad to hear the author’s views as to
whether, in every case, he would use the system of
having two guide ropes, Mr. James Black, for example,
having said that it would be better to use four guide
ropes for a depth of 300 fms.

Mr. John Gibson, Kilmarnock, said it struck him that
possibly -a factor that would require to be considered,
besides the actual first cost of the sinking and equip-
ment of the relative shafts, would be the cost of the
mid-windings. He did not see very well that ordinary
rope guides in a circular shaft, with a mid-winding
arrangement, were so simple and safe as in a rectangular
shaft. In Scotland, too, they were in favour of wooden
slides, and the men were most experienced in handling
wooden slides. If they had knowledge that a colliery in
all likelihood would last for probably 100 years at a great
depth, it might be better to spend the extra money in
sinking and equipping a circular shaft. In districts,
however, where the life of the collieries was an uncer-
tain quantity, the type of shaft showing the lowest first
cost was always the one that would be accepted.

Mr. Richard M‘Phee, Bothwell, said he had no
experience whatever of round shafts, but he had given
Mr. Nisbet’s paper a considerable amount of thought.
The paper would be a most valuable one to the younger
members of the Mining Institute of Scotland. He
believed its value would be still further enhanced if the
president, or some other member of the Summerlee
Company, would give them the benefit of the firm’s
experience in converting a rectangular shaft into a
round shaft.

The President said he was pleased to hear read the
communication which had come from Mr. Curley.
Although he did not know the shaft Mr. Curley was
writing about, he had seen a shaft fitted in exactly the
same way as had been described. The question of
stripping a rectangular shaft and converting it into a
round shaft was one which depended altogether on the
size of the shaft. The shaft Mr. M‘Phee referred to
was a smaill shaft, and the matter of stripping was not
difficult.

Guide Ropes.

Mr. James Nisbet, in replying, said, with reference
to Mr. J. B. Thomson’s question, that on account of
the shaft being sunk upwards, kettle guide ropes were
not required. It was intended, however, to introduce
these, had the sinking been continued to the depth at
first proposed. The ropes were to be hung from crowns
on the pithead frame, and their lower ends respectively
passed through two parallel beams, fixed across the
shaft at a depth of 50 fms. or thereby. Close below
these beams, a gland was to be fixed to each rope, and
tension applied to each rope by a weighted lever ful-
crumed to the underside of each beam, and bearing on
the afore-mentioned gland. On these beams the rider
would rest while the kettle travelled below. These ropes
were to be equi-distant from the winding ropes, and far
enough apart to provide free travel of the kettle in
between. Since there were no guide ropes introduced,
there was no rider used. The construction of a rider
was, however, considered, particularly from the point of
view of preventing risk. Mr. G. L. Kerr had asked why
they in Scotland should adhere so rigidly to the rect-
angular form of shaft. Well, until recent years, Scot-
tish pits had been comparatively shallow. They had
been sunk to work comparatively small leaseholds, and
their life was, therefore, correspondingly short; where
pumping plant was installed, it was usually of the bucket
or plunger type. A rectangular shaft was more easily
partitioned off for the accommodation of such winding
and pumping plant. Scottish mines, generally speak-
ing, were less fiery than those across the border, and
less consideration had to be given to the question of the
obstruction offered to the passage of large volumes of
air in shafts than was necessary in the case of gassy
mines. It was common knowledge that the circular
form of shaft offered least obstruction, more especially
when fitted with wire rope guides. In the case of the
larger, deeper, and more recent sinkings in Scotland,
thev had been gradually getting away from the rect-
angular form of shaft- and were sinking shafts of the
circular or elliptical type. Mr. G. L. Kerr and Mr.
James Black both remarked on the comparatively small
clearance between the cages. That result had been
arrived at in the present case by having guide ropes on

only one side of each cage, and, as Mr. Black observed,
having only | in. of clearance between buffer ropes and
the buffer blocks, the faces of which were only 2| in.
out from the sides of the cage. The buffer rope, placed
in the position described, was able to check the ten-
dency to side-swing, as well as to form what its name
implied—a buffer or rubbing rope. Only two guide
ropes were provided for each cage, because with four
guide ropes'—two on either side of each cage—the cages
would require to be further apart to avert the fouling
of the inner guide shoes on the cages when the latter
were passing each other in the shaft. To a consider-
able extent, this was averted by packing out the rubber
blocks beyond the line of the shoes, but the freedom of
the cages to twist, and the possibility of fouling must
be greater, in consequence of the buffer ropes of neces-
sity being hung closer together, and therefore further
away from the ends of the cage than they could be
placed if no inner guide ropes were used. It might
meet Mr. Black’s contention to suggest that the com-
bined weight which would be hung on four ropes could
be applied to two outer ropes, even if these had to be
put in strong enough to sustain the greater load. The
shaft described was not the only winding pit where out-
side guide ropes alone were provided. It was, however,
the only one known to him (Mr. Nisbet) where the
clearance between the cages was not more than 6 in.
Mr. Kirkby thought it would be better to put in steel
rails, fitted to steel buntons, than have rope guides, and
though more costly, he (the speaker) agreed that would
probably give a more rigid and durable job, and be more
suitable for mid-landing winding. On the other hand,
the common practice in England was to instal wire rope
guides'—even in deep shafts, drawing heavy loads with
fast winding. He knew one large English colliery
where the main winding shaft was 17 ft. in diameter.
Wire rope guides were installed there, and four-decked
cages carrying two hutches on each deck were raised
from a depth of 450 fms. in 55 seconds. There could
be no slowing down at the meetings there. With regard
to the relative cost, as a result of his experience, he did
not think there was much difference between sinking a
circular shaft and sinking and timbering a rectangular
shaft. With regard to the question by Mr. Ross, he was
not prepared to say that he would limit the number of
guide ropes to two in deep shafts, in view of the experi-
ence of men who all their life had been dealing with this
sort of work. In regard to mid-landings, he was of the
opinion that a rectangular shaft was more suited to mid-
landing winding than a circular shaft. He had seen
mid-landings, and he had to confess, that he never
desired to have anything to do with them.

The discussion was closed, and, on the ’call of the
President, Mr. Nisbet was thanked for his paper.

The Hurlet Sequence.

Discussion was resumed on the paper read by Mr.
David Ferguson (Glasgow), on “ The Hurlet Sequence
and the Base of the Carboniferous Limestone Series in
the Districts of Campsie and Kilsyth.”

The Secretary (Mr. G. L. Kerr) said he had received
a letter from Mr. H. M. Cade-11, of Grange, Linlithgow,
to the effect that Mr. Ferguson’s paper enabled the
somewhat confusing sequence of the strata to be under-
stood. In the East of Scotland there seemed to be a
regular succession upwards from the oil shale series to
the carboniferous limestone series, and no interruption
to indicate local upheavals or volcanic movements. In
the west there was no volcanic activity after the Hurlet
period, but in West Lothian the volcanic activity which
began at the Hurlet period or earlier, was continued
right on to the end of the carboniferous limestone
period, and did not end until the date of the index lime-
stone. A local volcanic bank or ridge was formed,
which must have been a considerable island for a time
in the swampy waters when coal seams were being pro-
duced. The Hurlet coal gave opportunity for chemical
research, as Mr. Ferguson had pointed out, and now,
when we must turn to the fullest advantage all our
resources, he (Mr. Cadell) thought that chemists should
direct their attention to the profitable elimination of the
sulphur, or its extraction from this seam, of which there
was still much left to work. The old process of making
alum from the accompanying shale might, with the high
prices now ruling, be revived with advantage, and a hunt
for ironstone in that section, when iron is so much
needed, might prove fruitful. The working of lime for
cement and for agriculture might be resumed in some
places. It was important to know all the places where
good lime could be got, and it might be that some lime-
stone beds were better than others. At present, all
scientific research should be directed into practical and
economic channels, so that we might help to make up
the vast loss due to the war, by aiming at an increased
production of wealth of every kind; and tire sooner we
began to improve our output and methods the better.

Prof. J. W. Gregory (Glasgow University) also testi-
fied, in a brief speech, to the geological value of the
paper; and the discussion was adjourned to a future
meeting of the institute.

A paper on ” The Summerlee Visual Indicator,”
which was- read by Mr. D. M. Mowat (president), will
be given next week.

Partnerships Dissolved.—The London Gazette announces
dissolution of the following partnerships :—J. E. Gomersall,
J. W. Fisher, J. C. Towler, R. Lees, and H. Ross, trading
as the Flockton Moor Colliery Company; H. E. Jackson and
S. Mills, trading as Barlow, Jackson and Mills, coal mer-
chants, Miles Platting; A. Holmes, H. Holmes, and H.
Midgley, trading as Henry Holmes and Company, machine
tool makers, Halifax; F.‘ 0. Russell and G. EL Pearson,
trading as F. 0. Russell and Company, metal workers and
brass founders, Price-street, Birmingham; F. Baker and
W. A. Baker, trading as George Baker, at the Cecil-street
Wire Works, Birmingham.

SOME CAUSES OF DECAY OF
TIMBERS IN COAL MINES.*

By J. Mitchell, A.R.C.Sc.

On taking up the subject of decay of timbers in coal
mines, the author was -somewhat astonished to find how
little was the attention directed to fungi as a possible
direct factor in decay; and no computation of the rela-
tive amount of wastage of timbers caused by the various
factors seems to have been made in this country, though
in the mines of the United States it has been estimated
that 5 per cent, is due to wear, 20 per cent, to breakage
under pressure or squeeze, 25 per cent, to miscellaneous
causes, and the remaining 50 per cent, directly or
indirectly to fungal attack. Opinion will doubtless differ
as to whether such an estimate would apply to this
country. There is no doubt that the proportions of each
will vary greatly in different mines, but as an estimate
applying -to all mines, it is probably roughly accurate.
As a general proposition, it may be assumed that 50 per
cent, of the wastage of timbers in the coal mines of
this country is due to fungal attack, and therefore a
more intimate knowledge of the fungi causing thi-s decay,
their method of attack, and mode of spread, is neces-
sary, in order to arrive at any reliable methods of
checking this wastage.

Anyone who has spent a few hours in a warm, damp
coal mine will have been impressed by the luxuriance of
certain fungal growths on the props, bars, or couplings,
and even on the walls and ceilings of the roadway,
especially in small excavations on the sides of roadways
where the air is “ slack,” and where there is usually a
good deal of timber. It is a general experience that
where these fungi are most prevalent, decay is rapid,
and the timber has to be replaced very frequently. The
purpose of the present paper is to show what certain of
these fungi are, and how they spread through the mines.
Also to make suggestions for lessening the prevalence
of these growths, and therefore the rate and amount of
decay caused by them.

These fungi commence their life history as micro-
scopic spores, which are blown about or are carried by
insects, etc. Under suitable conditions of warmth and
moisture, they germinate on the surface or in the cracks
of the timber, and produce threads which penetrate and
feed on the substance of the wood. By the action of
certain enzymes excreted by the fungus threads, the
wood is rendered more fragile or brittle, so that it
eventually breaks under pressures much less than those
which it can bear when healthy, e.g., the timber is
rendered useless for mining purposes. This is known
as the vegetative stage of growth, and the threads are
known as mycelia. Then, certain growths, in the form
of cushions, brackets, or incrustations, appear on the
surface of the affected timber, and produce microscopic
spores. This is known as the reproductive stage, and
the various growths are known as fructifications. The
ripe spores become detached, and the cycle re-com-
mences.

Mine Fungi.

The fungi found in mines can be roughly grouped
under two types, based on the method of growth of the
mycelium, and those who are responsible for the tim-
bering in mines should be familiar with the charac-
teristics of the two types. Between these two there are
certain forms which are intermediate in character,
inclining to one or the other according to local condi-
tions, but a little experience will allow of these being
placed correctly for practical purposes.

Type 1 comprises those fungi which are characterised
by an excessive development of surface mycelium. This
grows over the timber in widespreading sheets or in long
strands or cords; and it is this type which attracts most
attention in mines. The following species have been
found in Lancashire and Yorkshire mines, and illustrate
* the characteristics very markedly :—Polyporus vaillantii
(Fries), Polyporus vaporarius (Fries).

Intermediate in character, but closely allied to type 1,
are the following species, also from mines in the same
districts : Paxillus acherontius (Schr.), Lentinus lepideus
(Fries), Fomes annosus (Fries).

Type 2 includes those fungi which show little or no
external mycelium. They commence their growth in
the cracks of the timber, but instead of growing out-
wards to form sheets or cords, the mycelium remains
inside the wood. Eventually the fructification appears
on the surface of the wood as a cushion or bracket, and
until this happens there is little to show that the timber
is affected. A little consideration will show how
dangerous the members of this type may be, particu-
larly when we consider the question of falls of roof__

the fragile or brittle state of the timber not being
realised in time. The following species of this type
have been found in the mines visited :—Lenzites sept-
aria (Fries), Trametes odorata (Fries), Trametes mollis
(Fries), Polystictus versicolor (Fries), Polystictus stip-
ticus (Pers.), Phytogaster albus (Sacc.), Phytogaster
rubescens (Sacc.).

It is probable that one or more of these forms will be
found in every mine in this country, the one or other
predominating in accordance with the relative tempera-
ture and moisture, and, to a less extent, with the nature
of the timber in use.

Spread of Infection.

The significance of each of the above-mentioned
types in relation to the decay caused by them, may
now be considered.

Type 1.—From the nature of growth of this type, it
will be seen that, given a starting point for growth, all
the timber in the vicinity is liable to become involved.
Thus, if the fungus is growing on a prop, it becomes a
simple matter for it to spread on to the adjacent coup-

* From a paper read before the Midland Institute of
Mining, Civil and Mechanical Engineers.