October 25, 1918.

THE COLLIERY GUARDIAN.

861

days, as compared with the rates thereafter in the first
and second experiments. In the third experiment no
such high rate was shown. Obviously the reason for
this is that in the first and second experiment the
desicccation was in vacuo, whereas in the third experi-
ment it was in an atmosphere of nitrogen. Graham,*
however, seems not to have found such an effect in his
experiments.

Conclusions.

The experiments showed that with Illinois coal
thoroughly dried the rate of oxidation at ordinary tem-
peratures was greater than with a comparative sample
of moist coal. On the other hand, a thoroughly dried
sample of Pittsburg coal oxidised at a slower rate
than a comparative moist sample of the same coal.
This difference between the two coals probably explains
the discrepancies in the observations of different
experimenters. Richters found that a German coal
absorbed more oxygen when dry than when moist.
Mahler, investigating a French coal, and Graham,
investigating an English coal, found that moist coal
absorbed more oxygen than dry. Evidently the rates
of oxidation of different coals are not affected uniformly
by moisture.

The investigators named worked with small quantities
of coal in the laboratory and used extreme conditions.
Under actual conditions of storage both the coal and
the air always contain moisture. Hence it seems
doubtful whether water, other than the excess that
actually wets the coal, plays an important part in the
rate at which coal oxidises at the lower temperature,
with consequent increase in the danger of spontaneous
combustion. The experiments conducted on a working
scale by Fayol—who could find no influence of wet
weather on spontaneous combustion—and the New
South Wales commission—which found that actual
wetting of the coal produced a cooling effect during
storage—tend to confirm this idea,

Practical Considerations.

However, the opinion among coal shippers and
consumers that there is more danger of spontaneous
combustion during warm wet weather than during dry

Bottle with PsDs for dry coal

Bottle with.HsO for moist coal

-Thermometer

Stirrer

Motor

•Trapped jiir_

Heater;

E

i
E

2
'I

2

E
o

Plan and Elevation of Apparatus.

may have another basis—the physical changes brought
about by wetting the coal on the surface of a pile.
Such wetting reduces the proportion of voids or open
spaces in the mass. If the coal is divided into particles
fine enough, the water will fill the voids completely and
be held there by capillary attraction. Such a mass of
coal and water on any part of a pile would block the
passage of air at that place. As a result, the conditions
of ventilation in the pile before the wetting would be
changed, so that, in some instances, the heat generated
by the gradual oxidation of the coal would be retained
until the temperature of ignition was reached.

For instance, in a pile of coal formed in the usual
manner—with the fines at the top, because of the rolling
down of the larger particles—there would lea mass
overlaid with an impervious cover through the wetting
of the outside surface. This cover would prevent air
circulating by convection. Under such condit-ons
oxygen would diffuse, as the coal absorbed it, from the
lower parts of the pile to the covered part. The heat
produced would be retained in the pile, and the tempera-
ture of the coal would increase at a rate dependent on
the rate of oxidation alone; ignition temperature would
readily be reached, and a spontaneous fire produced.
The conditions described have been approximated to a
degree in many storage piles of coal. In those piles
moisture had a decided influence in the production of
spontaneous fire.

The only recommendations of practical import to be
made as a result of the matters considered in this paper
is to prevent the segregat’on of the fine coal in building
a pile for storage. This has been proposed befoe as a
means of reducing the danger of spontaneous combus-
tion. The consideration of moisture’ now gives it
further support.

* Colliery Guardian, vol. 109, 1915, pp. 228-229.

MIDLAND INSTITUTE OF MINING, CIVIL
AND MECHANICAL ENGINEERS.

The opening meeting of the Midland Institute of
Mining, Civil, and Mechanical Engineers for the ses-
sion 1918-19, which was held at the University of Leeds
on Thursday, October 17, was of a somewhat novel
character. Instead of being devoted to the reading
and discussion of technical papers, it took the form,
to a large extent, of a visit of inspection to the univer-
sity. The principal business was the presentation of
the Peake medal to Sir William E. Garforth, of
Altofts Collieries, of whose work for the mining
industry a comprehensive account was given by the
president, and who, in reply, dealt with the important
question of the working of deep seams of coal. The
attendance was exceptionally large, including, besides
members of the institute, past and present students of
the mining department of the university. Those pre-
sent were received in the Greek seminar by the pro-
chancellor (Mr. Arthur G. Lupton, LL.D.), and at
the meeting, which took place in the great hall, they
were formally welcomed by the pro-vice-chancellor
(Prof. C. M. Gillespie, M.A.).

In the hall was an interesting exhibition of models,
instruments, etc., including various types of safety
lamp, model of a pulley frame, tubbing model of a
shaft, model showing the method of construction of a
timber dam in a mine to resist a head of 300 ft. of
water, and various surveying instruments. The de-
partment of fuel, gas, and metallurgy had on view
an exhibit showing the products obtainable in the car-
bonisation of 100 lb. of coal, consisting of tar, am-
moniacal liquor, sulphate of ammonia, pitch, creosote
oil, anthracene, naphthalene, carbolic acid, the ben-
zoles, cyanides, and sulphuric acid. Another exhibit
illustrated the synthesis of high explosives from coal
tar products, including picric acid, tetranitroaniline,
trinitrotoluol, and safety explosives used in mining.
There w'ere also displays of refractory materials and
of still heads or fractionating columns used for the
distillation of benzoles, etc.

Mr. W. D. Lloyd (president of the institute) occu-
pied the chair, and was supported by the pro-chan-
cellor, the pro-vice-chancellor, Sir William E. Gar-
forth (chairman of the mining advisory committee),
Mr. G. Blake Walker (president of the Institution
of Mining Engineers), Major G. H. Peake, and others.

Prof. Gillespie, in welcoming the members,
said he did so not as strangers but rather as friends
and co-operators in the great work of the industries
of this country. It had been the pride of the univer-
sity that for many years past it had held the very
closest relation with the industries of the locality and
with many that were beyond Leeds. Thanks to the
co-operation of the industries, it had been possible for
the university to help them by conducting instruction
and research, while the industries themselves had been
able to help the university by telling it what they
wanted. It was particularly appropriate that that
meeting should be held within the walls of the uni-
versity, because the Peake medal was to be presented
to one who for very many years had had the most
intimate connection with the university. Perhaps
il intimate connection ” was not quite the right expres-
sion, for Sir William Garforth was part of the Univer-
sity of Leeds. He held an honorary degree of the
university, granted to him some years ago on account
of his services to the university and to the cause of
specialised knowledge in mining engineering, and
cognate subjects. Besides, he had for many years
been on the mining advisory committee of the council,
the committee which was directly responsible for the
institution and maintenance of the mining’depart-
ment ; and he had not only been a member of that
committee, but had all through shown the warmest
interest in regard to all the details of the work done
by the department. He had helped them by his advice,
by his purse, and not least by the presentation of
some most valuable scientific apparatus and a certain
series of unique cuttings of the Barnsley coal seam,
now to be found in the university. It was therefore
particularly gratifying to those connected with the
university that the presentation to Sir William should
be made within its walls.

The President heartily thanked the authorities of
the university for their kind reception and for allow-
ing the members of the institute the opportunity of
inspecting the various departments. He was sure that
an occasion of that sort would do a great deal to
further the interests which both the university and
the institute had with regard to the advancement of
mining science.

The following elections were then made :—Members :
Mr. T. Noden, Highfield View, Tingley, Wakefield:
Mr. D. A. West, Wyndyate. Bradford-road, Wakefield :
and Mr. M. Koyama, 21, Harcourt-road, Sheffield.

PRESENTATION OF THE PEAKE MEDAL TO
SIR WILLIAM GARFORTH.

The President said that, the council having unani-
mously decided to award the Peake medal to Sir
William for the excellent services he had rendered to
the Midland Institute and to the mining industry, it
was his pleasant duty to make the presentation. It
was a great pleasure to him that this award had been
made during his term of office as president, as he had
been closely associated w’ith Sir William for over 20
years, and, although Sir William’s work was so well
known to the members of the institute, and he had
a world-wide reputation amongst mining engineers,
he (the president) was possibly in a position, from per-
sonal knowledge and acquaintance, to lay before them
a more complete account of the work Sir William had
done for the advancement of mining than could other-
wise have been given.

Throughout his mining career, Sir William’s motto
had been “safety first.” Both at the collieries he
had had under his charge and in the papers he had
written the question of safety had been his first con-
sideration. The first paper he contributed, nearly
40 years ago, to the Manchester Geological and Mining

Society, described a method which he had successfully
devised for breaking down coal by the use of com-
pressed air instead of gunpowder, and though the
method was not to any great extent adopted in prac-
tice, it showed that even at that time he was interest-
ing himself in methods to increase the safety of coal
mining.

The first paper he read before that institute, on
May 3, 1882, described the method of working the
Silkstone seam at Normanton, with suggestions for
winning deep coal, and recommended “the straight
line of face, as it afforded the best line of fracture
and allowed the subsidence of the superincumbent
weight to be more regular, besides taking the pressure
from the coal fac a and minimising the liability to
sudden outbursts of gas.” The increased safety and
other advantages to be gained from working longwall
faces on as straight a line as possible had been one of
his pet theories, and had had far-reaching results.
, In 1884 he gave to the institute a description of a
contrivance he had devised to increase the safety of
the operation of testing for gas with a safety lamp.
This device, which was known as the “ Garforth ”
detector, consisted of a small indiarubber ball or bulb
fitted with a brass nozzle, in which a sample of air
could be obtained from close to the roof. The nozzle
of the bulb was then inserted in a tube, fitted with a
valve and gauze in the bottom of an ordinary safety
lamp, and the sample was tested while the lamp was
in fresh air and also in a convenient position for obser-
vation. Incidentally, the contrivance also enabled
samples to be taken from the breaks in the roof, and
by this means it was a simple operation to detect where
gas was issuing from the strata (which could not be
done by a safety lamp alone), thus enabling the gas
to be dealt with before it could accumulate. The
detector had been in constant use ever since at all
the collierie sunder Sir William’s charge, and greatly
increased the safety of the mines. Although it wars
favourably reported on by the Royal Commission on
Mines in 1886, it had not been so generally adopted
as its usefulness warranted.

In 1885 he contributed a paper to the Manchester
Geological and Mining Society on the longwall system
of working coal on a straight line of face, and also
described a system for draining the gas from a sub-
jacent seam by means of boreholes to prevent sudden
outbursts of gas. This method was very effective in
the seam particularly described, and was capable of
wide application to prevent outbursts and improve the
roof or floor where there was another seam, possibly
of an inferior quality and thickness, lying near the
main seam which was being worked.

On October 2, 1886, an explosion occurred in the
Silkstone seam at the Altofts Collieries, which were
under Sir William’s charge. This explosion, although it
caused the regrettable loss of 22 lives, and gave him
many months of anxious and dangerous work in the
recovery of the pit, was undoubtedly turned, by his
faculties for observation and deduction, into a blessing
in disguise, of which the whole coal mining community
would derive the benefit, as it was from the informa-
tion he then obtained of the effect of stone dust on
a coal dust explosion that he was led to propose the
stone dust remedy to prevent explosions. In his
evidence before the Royal Commission on Explosions
from Coal Dust in Mines on July 2, 1891, he suggested
that experiments should be made on the different
kinds of coal dust and dirt dust, and stated that he
believed that “ dirt dust would be the means of pre-
venting an explosion on some roads—more so than
water.”

It was not until 16 years later, after he had con-
firmed the recommendations made in 1891 in his evi-
dence before the Royal Commission on Mines in March
1907, that any real progress was made. He then
showed how experiments on a large scale might be
conducted, and subsequently, having impressed on the
Mining Association of Great Britain the advisability
of such experiments, he was entrusted by the Mining
Association with the conduct of the British coal dust
experiments, which were carried out at Altofts from
1908 to 1911.

In May 1908, having proved that coal dust was
explosive without the presence of inflammable gas, and
so settled the controversy as to whether coal dust per
se was explosive, thus ending a discussion which had
been carried on for 30 years, Sir William, having
obtained the consent of the Mining Association ami
the committee who with him had been entrusted with
the experiments, proceeded to put to the test his
theory that fine stone dust would extinguish an ex-
plosive flame. In July 1908 he was able to demon-
strate this fact, which was subsequently confirmed by
later experiments at Altofts and Eskmeals, and also
at testing stations in other countries.

He then proceeded, in September 1908, to introduce
the stone dust remedy underground, and showed not
only that it was easily and cheaply applied to ex-
tinguish an explosion, but also that by treating all
coal dust with stone dust the possibility of explosions
could be reduced to a minimum at an inconsiderable
cost and without introducing any additional danger
to the health of the miners.

He subsequently read numerous papers and de-
livered addresses on the subject, and although the
mining profession had been somewhat slow in recog-
nising the merits of his discovery, there could be no
doubt that the generations to come would with grati-
tude always associate the name of Sir William
Garforth with the discovery of the stone dust remedy,
by the proper application of which disastrous explo-
sions of coal dust would be rendered impossible.

From the experience gained after the Altofts explo-
sion, Sir William drew up a code of rules for the
assistance of explorers in recovering mines after ex-
plosions, and these he presented in the form of a
paper read before the Institution of Mining Engineers
in June 1897. The rules were subsequently revised by
him and published in book form, and they had been
taken as a basis for the rules adopted at various rescue
stations in this country and abroad.