April 26, 1918.

THE COLLIERY GUARDIAN.

845

soft rocks containing much water. As the sinking
proceeds, the tubbing cylinder, which is built up in
rings at the surface in the usual manner, is forced down
by hydraulic rams. The boring tool is driven by a
percussion engine with oscillating drum, and the driving
performed by a flat rope passing over a pulley in the
headgear over the shaft.

Iiassenberg* Hydraulic Pressure Process.

In the Lassenberg process, at a short distance above
the cutting shoe, the outer side of the tubbing cylinder
is provided with a number of holes formed in the casting
around its periphery, for the purpose of injecting water
under pressure behind the shaft, with the object of
assisting the cylinder to descend.

MANCHESTER GEOLOGICAL AND
MINING SOCIETY.

At the meeting of the Manchester Geological and
Mining Society held on Tuesday, April 16, Mr. W.
Pickup presiding, a discussion took place on the paper
by Mr. H. O. Dixon upon

The Thin Mine Problem.*

The Chairman said Mr. Dixon had made the most
of the favourable conditions in his thin seams. His
haulage was very economical, the endless rope was
more suitable to the larger tub, and better than the
endless chain, which was often in use in thin seam
collieries. He was glad that Mr. Dixon had the
courage of his convictions to change from the smaller
tub to a larger, which was not to go on the faces.
But would it not have been better to have doubled
the size from 5 cwt. to 9 or 10 cwt. ? Personally, he
should prefer the latter weight to the 19 or 20 cwt.
size in use in the Forest of Dean. No road pillars of
any description were left for the support of the main
haulage ways. Had this proved to be the best practice?
In certain thin seams it was often preferred to keep
the main haulage roads in the coal. Generally speak-
ing, and where the circumstances required, one would
expect thin seams to be more suitable, both for
mechanical cutting and conveying, than the thicker
seams.

Mr. John Gerrard said that the goodness of the
roof in the seams worked was largely due to the method
of working; if the ordinary method had been followed
the roof would probably have been very bad. From
that point of view, Mr. Dixon was to be congratulated
on having given an example of good engineering,
because one of the most important points in the laying
out and working of a coal seam was to get pressure
on to the coal so as to facilitate its working and at
the same time maintain the goodness of the roof.

Mr. Dixon said a 9 to 10 cwt. box might be
theoretically more suitable, but it required a stronger
type of drawer than the 7 cwt., and they expected the
dip would be heavier than it had proved to be. There-
fore he thought the 7 cwt. was sufficient. It was in
use in another pit, which was expected to have a long
life, and if those tubs could not be taken into this
pit they would have to be scrapped. He had had con-
siderable experience with heavier types of trams, 19
to 20 cwt. They were taken by horses right to the
coal face in the stalls and were loaded direct from the
collier. There was no hand-drawing; they were very
difficult to handle, and went off the road time after
time, and men often hurt themselves by lifting them.
In South Wales there were more cases of rupture from
this cause than from many other types of accident.
The chairman had asked about there being no road
pillars in the main roads. It was a tremendous
expense to cut the pillars, and strait work had to
be done in each seam, and any strait work done they
made use of by throwing it into the wide work. On
the main road originally they had a creep, which the
first retimbering got rid of. Following on that, none
of the main roads gave any further trouble. One
would have thought thin seams were more adaptable
or more suitable for machine-cutting than the thicker
seams, but this particular seam was very thin, and
had a hard floor. A 2 ft. 6 in. or 3 ft. seam was
easier to cut than an 18 in. or 19 in. seam, because
one was able to get at the machine and past it and
keep it in repair. One could do nothing at a machine
with a face only 19 in. thick.

The Chairman said what he had in mind about the
tubs was that the 4 cwt. or 5 cwt. type, which went
along the face, was as a rule the best. If they went
in for a larger type they needed a young man as
drawer, and then they might as well go up to 9 cwt. or
10 cwt., unless limited in some way, as Mr. Dixon
was, to 7 cwt. For anything above half a ton one
needed horses.

Geology of Manchester.

The paper by Dr. G. Hickling upon “ The Geology
of Manchester as Revealed by Borings” (Colliery
Guardian, December 21, 1917, p. 1184) was also
discussed.

The Chairman said this paper gave part only of the
results of a most important and lengthy enquiry on
which Dr. Hickling was engaged. The geology of
Manchester was very imperfectly known, notwith-
standing the large amount of work done on it in the
past. The peculiar natural difficulties of the problem,
the nature of the rocks and the thickness of the drift
combined to render the results of surface examination
almost nil, and the enquiry had to depend on the
records of deep borings into the rocks. One result of
Dr. Hickling’s investigation was to show that the
upper coal measures were brought very near to the
surface by faulting, both in the centre and the north
of Manchester, so that it was now possible to discuss
in some detail the distribution of the productive
measures under Manchester. The result left little
doubt that workable coals could be reached both under
the centre and northern parts of the city. Another

* Colliery Guardian. October 12, 1917, p. 700.

result of practical importance was to show that the
great chamber fault, which at Bardsley threw down
the rocks more than 700 yards, diminished until it
had no displacement at all within a distance of a mile,
whilst the Irwell fault, which had a proved throw of
1,000 yards at Clifton, had diminished to almost
700 yards in the centre of Manchester. The whole
enquiry was of great value, both as regarded the
knowledge and accessibility of the coalfield under and
around Manchester and the almost equally important
question of the water supply of the city.

Mr. John Gerrard (referring to a remark by Mr.
Atherton) said he did not think any borehole ever
gave evidence of the volume of water; the only evi-
dence was that of pressure. Numerous boreholes were
put down in Kent, and not one gave evidence as to
the volume of water. The society and the coal owners
of Lancashire were to be congratulated on the services
rendered by Dr. Hickling, and they ought to take
full advantage of them, and in return give him all
the information and assistance in their power. It
was quite an exploded idea that the knowledge
acquired at one colliery with regard to the positions of
seams and faults, and so forth, should be kept secret.
They had always considered the Irwell Valley fault,
the 1,000 yards fault, was a big one, but Dr. Hickling
had proved the existence of a dislocation of 2,000 yards
which no one had previously heard of.

Mr. Dixon said they had been plugging a borehole
that week, and in the course of a conversation the
master borer told him that there never had been a
borehole sunk where one could get from a borehole an
indication of the volume of water which would be met
in sinking.

Mr. Drummond Paton asked whether Dr. Hickling
considered there had been a fixed relation between
marine action and fresh-water action in connection
with the seams. In certain fields he found that
erosions had taken place in a direction north-east to
south-west. If that was observed in the upper seams,
did it afford any guide as to what happened in the
lower seams?

Dr. Hickling said, with regard to mine water, he
was not aware that any of the boreholes he had to deal
with could be said to be actually drawing on the
supplies in the mines; he had no real evidence on
the point. On the whole, his impression was that
certainly the mine water was superior to the waters
which came immediately from the surface. On the
other hand, it would tend to contain a high percentage
of mineral impurity, and for some purposes that would
be more serious than organic impurities. He quite
agreed with Mr. Gerrard as a general proposition that
the volume of water in the borehole had a very remote
relation to the volume which would be obtained
in sinking. That followed from a recognised
rule with regard to boreholes, namely, that the total
water obtained from a borehole was fairly propor-
tionate to the diameter of the borehole, and was
almost invariably increased by enlarging the diameter
of the borehole. On the question of washouts, he
would refer Mr. Paton to a paper by Prof. Fearn-
sides, about three years ago, dealing with the geolo-
gical structure of the Yorkshire coalfields, and
especially with washouts. There was reason for think-
ing a large percentage of washouts were due to the
rock having been squeezed by the sliding of one mass
of rock on another. Probably the residue of washouts,
which were of the nature usually explained in the
text-books, were due to erosion by stream, and there
was no definite information as to their having any
particular constant direction. Where the washout
was due to subsequent earth movement it was probable
that the washouts in a given district would tend to
have a fairly constant direction. Those which Prof.
Fearnsides illustrated had approximately a north-west
south-east direction. So far as the washouts were
true washouts, he should not anticipate that they
would have any washout occurring in successive seams.

Mr. Gerrard said cases of artesian pressure were
quite a different matter from a borehole penetrating
into a seam of water under no pressure at all with no
rise of water and no flow from the borehole. All the
washouts in Lancashire that he knew of had a direc-
tion south-east to north-west. The Hulton Colliery
Company had recently proved a very interesting earth
movement, and he hoped some member would be able
to give them a short paper upon it.

Mr. Atherton said he entirely accepted what Mr.
Gerrard said about artesian pressure. He felt that
Pitman’s men were not doing the work as it was done
in Lancashire, and he showed how they levelled the
surface and did not assume that one water level was
the same as the level in another boring. Pitman’s
reports were in the printed record. He was speaking
of New South Wales, and he expected the same thing
would occur in the Manchester district.

Waste and Inferior Fuels.

The paper on this subject, contributed by Mr.
Drummond Paton (Colliery Guardian, March 22,
1918, p. 585), was discussed.

The Chairman said that at the present juncture the
avoidance of waste of any kind, especially in connec-
tion with the mineral wealth of the country, was
becoming more and more important. He was of
opinion that not nearly as much coal was now lost
or left underground as there used to be; the increased
value had done away largely with what was once
a considerable cause of waste. In obtaining oil from
coal, cannel, and shales which had hitherto not been
regarded as containing it, one felt they were on the
fringe of a great subject which would have an impor-
tant bearing on the future utilisation of mineral
wealth.

Mr. Atherton said he would submit certain infor-
mation to Mr. Paton, and it would be convenient to
adjourn the discussion for the present.

Mr. Paton agreed to this course being taken. He
stated that since he read the paper he had received
more or less definite information that Germany had
been getting fats from coal.

THE CONSERVATION OF COAL.

A detailed comment on the Interim Report on Electric
Power Supply in Great Britain by the Coal Con-
servation Sub-committee has been made to the New-
castle-upon-Tyne Municipal Parliamentary Committee,
by Mr. Ernest Hatton, engineer and general manager
of the Newcastle Tramways and Electricity Under-
taking.

Mr. Hatton states that every one is, or should be,
interested in conserving the national coal supplies. No
body of men have been so enthusiastic or have laboured
to attain this object more than the engineers of municipal
power stations, who have a record of success for many
years of lower and lower coal consumption per unit
generated. A cheap supply of electrical power is not
solely dependent upon low fuel costs, which is the only
aspect of the case emphasised in the report; the deter-
mining factor being in many cases capital expenditure.
Waste heat is, undoubtedly, a factor that should be taken
into consideration, but those acquainted with the manu-
facture of iron and steel must know that for generations
this source of power has always been taken advantage
of in driving the works plant. There is, therefore,
nothing new in this proposal.

The report mentions, in Appendix D, that the north-
east coast district “ occupies a unique position, owing
to the extent to which its power requirements have been
met by electricity produced as a by-product of two of
its largest industries—the making of pig iron and the
making of coke.” This area is the premier coke pro-
ducing district of the country, owing to the superior
qualities of Durham coal for this purpose. Notwith-
standing the extensive use of waste heat in the district,
the report states that large main coal-fired power
stations are erected to deal with such portions Of the
load as could not be supplied with electrical energy
generated by waste heat. Many coal-producing areas
are not coke-producing. Therefore, most areas in the
kingdom cannot have the advantages enjoyed by the
north-east area of utilising waste heat to the same
extent; therefore, power stations in such areas must be
largely coal-fired, as at present. The report recom-
mends the utilisation of coal at or near the pit mouth.
Unless waste heat can be utilised in all other areas of
the country as a factor in the production of cheap
electric power, the figure of 1'54 lb. of coal per horse-
power hour quoted in the report cannot be realised.

Waste Heat Utilisation.

The report states that there are now 11 waste
stations in operation in the north-east coast area,
and that the total saving due to the utilisation
of waste heat in the district amounts to some
150,000 tons per annum. Assuming, for the sake
of illustration, that waste heat was nationally
available to the same extent as on the north-east
coast, Mr. Hatton calculates that there could be a
saving 6f 750,000 tons of coal per annum—a very small
factor towards the saving of 55 million tons quoted in
the report. Though such sources of power have not
always been taken full advantage of in the past, it is
surely unnecessary to revolutionise the production of
electric power in the manner proposed, nor does the
present time appear opportune to scrap in a wholesale
manner plant which, whilst slightly less efficient than
the most modern, will, when all matters are taken
into consideration (i.e., the capital in the case
of municipal authorities being largely redeemed
on such plant, buildings and mains) enable even
small undertakings to supply power at much
cheaper rates than are now in vogue, and thus lead
in time to further and greater development of the
plant, with correspondingly increased efficiency and
lower costs of production. Against this natural deve-
lopment it is now proposed to throw overboard these
stations, to add their purchase value to the immense
sums that must be spent upon the erection of proposed
large power stations and distribution systems, to borrow
money now at high rates of interest, and, with Govern-
ment assistance, to obtain a monopoly, the Government
to have only partial control—a most audacious
proposal.

The report states that “ The capacity of plant
installed represents about one-ninth of the total plant
installed in public supply stations in the United
Kingdom, but, as the north-east coast power companies
are working at a more constant load, i.e., a better ‘ load
factor,’ the electricity actually generated is about one-
fifth.” Mr. Hatton comments that the better load
factor is primarily due to the nature of the industries
in the area. The figure of one-fifth agrees very closely
with the proportionate amount of coal mined, as com-
pared with the national output. As to the statement,
in Appendix D, that “ the total saving due to utilisation
of waste heat in the north-east coast now amounts to
some 150,000 tons per annum,” as the output of the
area represents one-fifth of the whole, the remaining
four-fifths must represent 600,000 tons per annum.
Therefore, eliminating waste heat, a figure of 2T4 lb. of
coal per horse-power hour delivered at consumers’
terminals is arrived at for the coal-fired stations.
Taking 560 million horse-power hours as representing
one-fifth of the total output of the United Kingdom, as
the report states, the remaining four-fifths must repre-
sent 2,240 million horse-power hours.

Probable Saving of Coal.

Assuming, for the purpose of illustration and con-
ceding the benefit of low coal consumption to the power
companies in the north-east coast area, the liberal
allowance of |lb. of coal average per horse-power hour
delivered at consumers’ terminals is made, a figure of
500,000 tons is obtained as representing the coal now
consumed in excess of that which would have been the
case had the power companies in the area supplied the
whole output of the United Kingdom on the basis of
the figures set out in the report. Adding that figure to
the 600,000 tons of coal that would have been saved by
using waste heat on the north-east coast basis in the
remaining four-fifths of the power supply of the
kingdom, there is a total probable saving of 1,100,000
tons of coal which, at the 10s. per ton stated in the
report, is equivalent to £550,000 per annum. This