June 12, 1914.

THE COLLIERY GUARDIAN.

1299

trouble at all about getting a 2,000-horse power steam
turbine, but there was a good deal of trouble in getting
that power in gas engines. On the other hand, he
would have no hesitation whatever in putting in steam
turbines up to 10,000-horse power, or more if necessary.
The whole boiler problem had been altered quite recently
by the introduction of the new gas fired boiler of Prof.
Bone, which had an efficiency of 94 per cent. An
efficiency of 94 per cent, would make a difference in the
figures in the paper if those were based on the 85 per
cent, efficiency. As to whether it paid to instal
by-product plant, that depended very largely on the size
of the plant. In conclusion, he suggested that the
author should put in the price of sulphate. He did not
think that sulphate of ammonia was going to remain at
its present high price. There were so many nitrogenous
fertilisers coming on the market that he thought there
would be a slump in the price of sulphate of ammonia.

Mr. Maurice Deacon thought it very important that
they should state the price of sulphate, as Mr. Kilburn
Scott had suggested, and also the price of sulphuric acid.

Mr. John Davidson, in reply, said that he would
answer in writing the questions as to the details of the
preparation of the tables. With reference to the difficulty
in starting, the only way of starting a large engine, or
nearly the only way, was by compressed air. With
regard to the method of cleaning cylinders, it certainly
was a great advantage to be able to take the top oil and
clean them, but in the case of the two-cycle gas engine,
which he believed would be the type of engine which
would supersede others in the end, one could run it for
two years night and day without cleaning, and when
that stage was reached it was not very serious if a few
more covers had to be taken off to get at the cylinders.
As to the reliability of gas engines, turbines and steam
engines, the figures given by Mr. Hiller had come as a



Obverse.

1

v'-

Medal awarded by the Institution for Conspicuous Service to the Progress of Mining.

The medal, which was designed by Mr. Allan G. Wyon. the King’s Medallist, is of oxidised silver 2f in.
in diameter, and is now on view at the Royal Academy Exhibition, Burlington House.

The first medal has been awarded to Sir William Garforth.

bit of a surprise to most people, but still, he believed,
they were based on the results of engines which they
had covered, and they had certainly covered a great
number. People, had an idea that turbines were only
revolving vanes and caused very little trouble; but
turbines were not the only things which gave no trouble.

Geology of the Kent Coalfield.

In the afternoon the paper for discussion was “ The
Geology of the Kent Coalfield,” by E. A. Newell Arber,
M.A., Sc.D., F.G.C.* Dr. Arber gave an abstract of
his paper, and illustrated it by lantern slides.

The President , in moving a very hearty vote of thanks
to the author, said there was little doubt but that in
the near future that large area of coal in Kent would
become of very great commercial value, and would have
to be taken into serious account by the other coal pro-
ducing areas in the country. It was interesting to know
that there was no connection between the Kent coal-
field and the Pas-de-Calais coalfield. His experience of
that coalfield, gained during several visits, was that there
were a great number of faults.

Mr. John Gerrard (Manchester), in seconding the
motion, remarked that it was not by any means the first
time that mining had been indebted to geological science
for enlightenment.

The resolution was carried with accclamation.

Mr. John Morison (Neweastle-on-Tyne) said that
having been for some time associated with the Kent
coalfield in the way of its development, he had read the
paper with very great interest, and had added to the
information he already possessed from the facts given
there. In the course of his practice in developing one
of those collieries, he had been, of course, compelled to
study the geology as far as possible, but while recog-
nising that all those theories were very valuable, he
thought that the way to develop a hidden coalfield like
the Kent coalfield was not by boreholes entirely, or to

* See Colliery Guardian, June 5, 1914, p. 1242.

any large extent, but by putting money and “ back ”
into it, and getting the collieries down to the coal.
Anyone reading the description of the boreholes might
think that they were at too great a distance apart to
enable one to come to a conclusion as to the lie of the
field; but one who had been engaged in other coalfields
would have been struck very much, not by the distance
apart of the boreholes, but by their frequency; and he
would have been further struck by the small amount of
information which had been derived as to the correla-
tion of the seams from those boreholes. In the Brady
borehole were found two seams of 2 ft. thick each, one
seam of 2 ft. 9 in., and another seam of 4 ft. They had
taken the trouble in making the borehole to analyse the
cores, and they had also proved that the Kent coal was
of very high quality. How much further had we got
since that? They had under-estimated two features
which were found in the Kent sinking; first, the
treacherous nature of the top ground, and, second, the
large quantity of water at a very great depth. In Kent
water had to be encountered at a depth hitherto unknown
in Britain, so far as his experience went. In the map
which Dr. Arber had presented, he had shown the propo-
sition from which he derived his conclusions as to the
dip and as to the strike. Examining that map, he could
not follow why the author had drawn his outcrop form-
ing the outline of his field to the east in the direction
he had done. To his mind, there was no evidence of
that. He did not think that point had any practical
effect, but if it could not be substantiated it destroyed
the theory that the coalfield was not a continuation of
the Pas-de-Calais coalfield. He could not see, from
anything he knew about the field, why that abrupt line
was drawn down from the east going in a southerly direc-
tion; he saw no evidence to show that that was the true posi-
tion. Coming down to the coastline, where borehole
No. 10 was shown, there was an outcrop of the limestone
there, which, according to everything he had seen in
Kent, was the natural outcrop of an under-rock such as



Reverse.

the carboniferous limestone, and that applied also right
down the dotted line which was shown as the middle
coal measures. There was nothing to the east of that
line, and nothing could be got, because it was out at
sea, which, to his view, made that direct south outcrop
line a practical conclusion. The whole of the coalfield
was within a moderate distance from the sea-board; it
was proved that the coals were of very high quality,
and that in the southern area of the field there was a
very important deposit of iron stone which he had not
the slightest doubt, would in course of time be
developed. Although that iron stone might not extend
further north, still it was known to extend within such
an area north from the coastline that there was an
immense amount of workable iron stone there to assist
the coal. There was a market for the coalfield, although
he did not agree to any great extent as to the value
locally or even in London. There was a power behind
the coalfield, however, once the difficulties of sinking
were overcome, which, in his opinion, put it beyond
any possible prophecies or theoretical considerations.

Sir Henry Hall (Chester) thought that the author of
the paper had made an admirable use of the information
that he had obtained from the boreholes. Whether the
author was correct in his surmises or not, at any rate
they felt they had his real opinion upon the matter from
a scientific point of view. At the present moment, to
practical men, the Kent coalfield was in this position :
Recently two collieries had been sunk at a quite ordinary
outlay, and there was no doubt that the collieries to be
sunk there in the future would be sunk at an ordinary
outlay; and if that were so, it seemed to him that it
offered a field of great prosperity. He had never quite
made out what the coal produced in Kent up to this
time was worth in the market, but he had an idea that
there must be something like 2s. or 3s. in hand as com-
pared with any other district.

Prof. Henry Louis (Newcastle-on-Tyne) said he was
not quite at one with the author in the way he drew
his carboniferous limestone outcrop. He (Prof. Louis)
had been very closely connected with the particular bore-

hole which had, to a great extent, decided the matter,
viz., the Ebbsfleet borehole, and his own impression was
that the evidence of the existence of a definite outcrop
of limestone there was by no means certain. He was
much more inclined to think, both from the appear-
ance of the cores, and from the general tectonic consider-
ations, that they were dealing there with an upthrow
fault. He was inclined to think that there was a con-
siderable pre-secondary fault which had probably thrown
up the carboniferous limestone and the coal measures
with it, of course, to the north. If that were so,
obviously there was no reason to despair of boring further
north, because it was perfectly imaginable that there
might be, still further north, a downthrow fault and a
continuation of the coalfield. Whilst" he was not pre-
pared to estimate a dip from a borehole core, he would
judge of the absence of dip from a borehole core. If he
found in the borehole core that the strata were lying
horizontally, or practically horizontally, he was not going
to find any very great dips when he went down. So far
he had never known a case in which that experience of
his has been at fault. If the Ebbsfleet boring were
really on the edge of the outcrop, he could not imagine
the strata thinning so rapidly, normally, that from
4,000 ft. the coal measures were going down to some-
thing very little over 2,000 ft., without there being steep
dips, and the Ebbsfleet cores showed practically no dips
at all. They showed certain appearances which might
very well be ascribed to faulting, and, on the whole, he
was inclined to think that the limestone there came out,
not as a normal outcrop, but as the result of faulting. If
that were so, he would be inclined to agree with Mr.
Morison that the eastern edge of the coalfield was by no
means at all certain, and that it was a very vague hypo-
thesis as to where the limestone would run to the east-
ward. He agreed with the author fully when he spoke
of the impossibility of correlating the coal seams. He
had tried repeatedly and had never managed to get any-
thing like reasonable correlates. He also agreed with
him when he spoke of the excessive false bedding of
those seams. It had been his experience throughout in
examining the work that the seams were exceedingly
false bedded, but he was not sure that false bedding
alone would explain all the phenomena with regard to
those seams. He would not be in the least surprised if
in the future it was found that the field was traversed by
very flat overthrust faults, which would easily escape
notice in a boring, and which would, of course, have the
effect of producing the appearance of false bedding.
What strengthened that view was that in the other coal-
fields, which were, he would not say a physical continu-
ation, but, if he might use the phrase, a genetic
continuation of that, the Radstock and the Pas-de-
Calais, the overthrusts were very marked. He could
hardly imagine overthrusts occurring in the east and
extreme west of the area, and leaving the centre
untouched. That seemed to be contributory evidence
towards the tectonics of that very difficult coalfield. He
did not quite agree with Mr. Morison's statement that
the field was exceedingly well, bored over. He was
rather inclined to take the author’s view, and say it
wanted far more bores, and far closer together, simply
because this after all was a coalfield concealed beneath
a greath depth of secondary measures. In all other
cases they had been able to do with many fewer bore-
holes, because they had had outcrops to help them. In
the present case they had nothing at all except the
borings, and it was quite evident therefore that they
must have very many more borings. The iron stone to
which Mr. Morison referred was up in the secondaries,
and therefore it did not contradict the author’s state-
ment in the least.

Dr. E. A. Newell Arber, in reply, said that wherever
he went he always met with great kindness from mining
engineers. In that instance they had put their finger
at once on the weak point of the whole argument. There
were many difficulties which he did not attempt to con-
ceal, about which there was some evidence at present,
but not so much as they would like to have. He was
quite aware that the eastern boundary was a difficulty
at the present time. There really was not as much
evidence as they would like in support of a curve round
to the south, which had been disputed, or at any rate
doubted, in the course of the discussion. In a few
years’ time they would know more about it, but they
had the very definite fact that the measures were
thinning in to the east, which had some significance. He
merely stated that, in his opinion, the most probable
solution was that it was thinning to some sort of boun-
dary in the east or the south-east. That again was a
matter on which further light was wanted. He was
much interested to hear a possible explanation of Ebbs-
fleet which he had not seen stated before, but which had
already occurred to him. Whether the fact that the
boring there was only 100 ft. odd of coal measure was
due to a fault had, of course, crossed his mind. But it
was very extraordinary, if that were so, that as one pro-
ceeded northward the measures were thinning. It was
only a case of palseobotanical considerations, but they
had gone through the measures into the carboniferous
limestone at ever-decreasing depths as they went north-
ward, so that the supposition was that they were
approaching an outcrop. There was no doubt all these
boundaries were connected with faults of one sort or
another. The most reasonable view, having regard to
the result in those northern bores, and the fact that
they had already penetrated the carboniferous limestone
at ever decreasing depths, was that they were approach-
ing an outcrop, and that it was not a quesion of a fault.
That was his view at the present time, which he was
quite prepared to alter in the future. It would be well
worth while to put down bores still further north at
Ebbsfleet, on the chance that it really was not through
a fault. In that case some other explanation would