August 11, 1916.

THE COLLIERY GUARDIAN.

255

Society of South Australia, South African Engineering,
and the Northern Engineering Institute of New South
Wales.

The lectures for colliery engineers, enginewrights, and
apprentice mechanics, arranged to take place at Arm-
strong College, were suspended on account of the war.
Mr. Thos. Douglas continued to represent the institute
as a governor of the college, and Mr. J. H. Merivale, in
conjunction with the president (Mr. Greener), were on
the council of the college as representing the institute.
Mr. T. E. Jobling continued to represent the institute
as a director of the Institute and Coal Trade Chambers
Company Limited. The president continued as a repre-
sentative governor of the University of Durham College
of Medicine during his term of office. Under the will
of the late Mr. John Daglish, funds were placed at the
disposal of Armstrong College for founding a Travelling
Fellowship, to be called the “ Daglish ” Fellowship,
candidates for which must be nominated by the insti-
tute. No application was made for the Fellowship for
the year 1916. G. C. Greenwell gold, .silver, and bronze
medals might be awarded annually for approved papers
"recording the'results of experience of interest in
mining, and, especially where deductions and practical
suggestions are made by the writer for the avoidance of
accidents in mines.” No medal was awarded this year.
A prize had been awarded to Mr.

A. S. Blatchford for his paper on
“ The Influence of Incombustible
Substances on Coal Dust Explo-
sions.” The bequest of the late
Mr. Geo. May was for the pur-
pose of purchasing a prize or
prizes to be given annually to
any of its students as the council
might think fit. No excursion
meetings had been held during
the year. The council hoped to
re-arrange the postponed excur-
sion to Eskmeals on the conclu-
sion of the war. During the year
Messrs. Jas. Wilson, John Rivers,
and J. Straker Nesbit presented
lamps to the collection which the
institute is forming to replace that
destroyed by fire at the Brussels
Exhibition.

The report was adopted, on Mr.
Greener’s proposition.

The following gentlemen were
elected as representatives of the
institute on the council of the
Institution of Mining Engineers :
Messrs. R. S. Anderson, Sidney
Bates, W. C. Blackett, W. C.
Carr, Frank Coulson, Benjamin
Dodd, T. Y. Greener, Reginald
Guthrie, Samuel Hare, A. M.
Hedley, T. E. Jobling, J. P.
Kirkup, Philip Kirkup, C. C.
Leach, Henry Louis, J. H. Meri-
vale, W. C. Mountain, R. E.
Ornsby, Walter Rowley, F. R.
Simpson, John Simpson, J. R. R.
Wilson, W. B. Wilson, and E. S.

Wood. The representation is the
same as for last year, save that
the Duke of Northumberland,

bustible dust can, we believe, be regarded as proof
against ignition by the flame of the most violent firedamp
explosion.” Prof. Dixon stated that these words appeared
to him to bear a meaning which went beyond the facts
experimentally established. Otherwise he was in entire
agreement with his colleagues. Possibly and not impro-
bably the committee trad tired of the investigations, and
had made up their minds that these had been carried as
far as was practicable, and, moreover, to a successful
conclusion. So, also, thought the Coal Dust Commission
when they recommended watering in various forms as
the cure-all of coal dust explosions. Most people out-
side the United States of America now knew that water-
ing would not afford the safeguard against coal dust
explosions that the Commission thought. Even before
the Seventh Report of the Explosions in Mines Com-
mittee was published, one of the members had found it
necessary to express his doubts on the principal conclu-
sion of his colleagues. The doubt expressed by Prof.
Dixon would carry more weight, because he was known
as a very high authority on explosives, and would, more-
over, receive the endorsement of most men who had seen
and studied the effects of explosions of firedamp and air
mixtures. It should be particularly noticed that Prof.
Dixon was taking exception to the assertion that a 1 : 1
mixture of coal dust and incombustible dust was non-

% •’

Fig. 4.—Loading the Overhead Ropeway Skips from the
Storage Bins.



A

perimeter of the roadway—and the answer was decidedly
in favour of the floating dust. Moreover, experiment had
proved that, when the occluded gases had escaped, they
were replaced by oxygen which, in time, became carbon
dioxide and helped to ballast the dust and keep it in
place. That was another reason why deposited coal-
dust was not as fiery as the floating dust. Thus, when
they came to the practical application of stone dust, they
realised that the floating dust could not be dealt with,
and the protective material must be applied principally
on the sides and floor of the main roadways or else stored
near the roof and on the sides of shelves which were
either fixtures or so constructed that a violent disturbance
of the air would cause them to tilt and scatter their
contents. The effectiveness of the scattering of the
contents of the shelves depended entirely on the
correctness of the supposition that a so-called pioneering
cloud of coal dust preceded the flame of a coal dust
explosion. The writer was of opinion that that did not
happen in the majority of cases, and never inside a coal
mine unless the dust was in excess and smothered the
flame. It was also an undoubted fact, as proved by
actual experience in mines, that the velocity of an explo-
sion was mostly in excess of that of the sound wave
which inventors calculated on to disturb the protecting
dust before the explosion flame reached it. If it were
not so, no miners would be found burnt and killed in their
working places a mile or more from the place of origin of
the explosion. The protective value of stone-dust treat-
ment had yet to be verified by a heavy explosion in a
mine actually at work. Again, if it were possible to make
a 1 : 1 mixture of floating dust in the ventilating current,
then it was clear that they would have to use respirators
or be content to breathe a double dose of dust—and then
what would happen to their poor lungs? The Royal Com-
mission on Explosions from Coal Dust in Mines depended
entirely on water treatment as a certain cure for the
coal dust danger, whereas the present Committee had
pinned their faith on incombustible dust mainly but not
entirely—as they also thought that a combination of both
water and incombustible dust might be advantageous, in
which case the freshly-made fine coal dust floating in the
air would have the field all to itself and the danger would
remain in full force. Assuming that incombustible stone-
dust had a protective value when applied in 1 : 1 pro-
portions, why not limit its use to the places where shots
were to be fired and where it could be employed ad lib.
to every shot, instead of watering, or, if preferred, then
in conjunction with water? The Coal Dust Commission’s
programme of watering did not take into account what
effect it would have on the ventilating current of a deep
coal mine, and not until regulations for enforced watering
came into force did the official mind realise that it was
an absolute impossibility to apply it in the deepest and
hottest coal mines where the health and capacity of the
miners to do useful work demanded that the ventilating
air current should be as free from moisture as possible.
He asked why so much universal energy was devoted to
these attempts to restrict the flame of an explosion. His
firm belief was that the object in view was the continued
use of permitted explosives and electricity in all parts of
a coal mine, bo to lessen the cost of production. In
many parts of the United States of America it would be
absolutely impossible to sell coal at its present low prices
if it were not for the heavy blasting which was the almost
universal practice. The greatest danger to an industry
arising out of incomplete official reports such as those
of the Explosions in Mines Committee was that they

Section A B

to Coa/Stack

Travelling
Gantry

Sidings Supplied by
Grab Bucket

IM

Discharge Trolley for uj
Belt Conveyor

Fig. 5.—Storage Conveyor and Crane Bridge.

COAL DISCHARGING EQUIPMENT AT THE PORT OF BORDEAUX.





the late Mr. J. W. Fryar, and the late Mr. J. G.
Weeks have been succeeded by Mr. Frank Coulson and
Mr. J. R. R. Wilson.

Mr. Mark Halliday, colliery mechanical engineer, 59,
Old Elvet, Durham, was elected as a member.

The following papers were open for further discussion,
but none resulted :—‘ ‘ Modern American Coal Mining
Methods, with Some Comparisons,” by Mr. Samuel
Dean; “ The Hirsch Portable Electric Lamp,” by Mr.
Hiram H. Hirsch; " The Logic of Trams,” by Mr. John
Gibson; and “ The Influences of Incombustible Sub-
stances on Coal Dust Explosions,” by Mr. A. S.
Blatchford.

The Explosions in Mines Committee.

A paper by Mr. John Ashworth, of Vancouver, British
Columbia, on “ The Seventh Report of the Explosions
in Mines Committee,” was read by the Secretary (Mr.
Merivale). Mr. Ashworth asked if the report might be
taken to be the last report of that committee. The
Sixth Report was at one time announced as the last,
excepting only a special report from Dr. Haldane on his
investigations into “ The Effects of Inhaling Dusts
Applicable for Stone-dusting in Coal Mines,” which was
to follow. They now had that report, .with an introduc-
tory letter from Sir Henry Cunynghame, chairman of
the Committee, covering a letter of qualification from
Prof. Harold B. Dixon, who differed somewhat from his
colleagues’ conclusion as published in the Sixth Report,
viz., that “ the 1 : 1 mixture of coal dust and inoom-

ignitable by the most violent explosion of a mixture of
firedamp and air, leaving them in infer that the mixture
must not have contained firedamp. So far the committee
had failed to show how it was possible for a 1 : 1 mixture
of incombustible dust and coal dust to be maintained in
that proportion in the roadways of a coal mine. Explo-
sions still continued to occur in coal mines and, at last,
interested people were beginning to realise that the con-
ditions in the roadways of a coal mine were not the same
as those in the experimental galleries used by experi-
menters. The most important difference was in the
way in which the coal-dust and the inert dust were
associated. Thus, in the experimental tube or gallery,
the coal dust and the inert dust were mixed together
mechanically and laid out in so many pounds to the
foot, whereas, in the coal mine when at work, the air
was full of coal dust in the finest state of division in
addition to that which had settled on the perimeter of the
roadway and might have been covered with incombus-
tible dust. Moreover, the floating coal dust was abso-
lutely fresh coal dust and chock full of occluded explo-
sive gases which, when escaping, caused it to float in the
air until they were exhausted, and then it fell on the
sides and floor of the roadways. On the other hand, the
stone dust which was calculated to nullify the danger
from the explosibility or easy ignition of the floating
dust possessed no gaseous content to make it float in the
air current and, therefore, the close contact of the 1 : 1
mixture became an impossibility. It might be asked
which dust was the more dangerous in a mine—that
which was floating or that which was resting on the

led to hasty legislation, rules and regulations which were
not only aggravating, but did not tend to safeguard the
lives of the miners. It was with the object of opening
up a full discussion on the whole seven reports that he
had written that paper. He wished, however, to give
the members of the Committee the fullest credit for the
painstaking way in which the work had been done and
for what had been accomplished.

Discussion.

Col. W. C. Blackett declared that Mr. Ashworth
seemed to be incapable of grasping the meaning of the
reports, and it seemed to the speaker to be an impos-
sible task to traverse all the ground. Mr. Ashworth
had got some ideas into his mind about colliery explo-
sions which, the speaker supposed, would remain there.
These ideas, however, were so far from the speaker’s
conception and experience of what took place in colliery
explosions, that he felt it would be rather a hopeless
task to try to deal with them. He could assure Mr.
Ashworth that the Committee did not get tired at all.
He suggested that Prof. Dixon might be written to, and
asked what exactly he meant by his remarks in the
reports. Then it would not require Mr. Ashworth’s
interpretation.

The President added that it would be an easy matter
to communicate with Prof. Dixon. He agreed more or
less with Mr. Blackett that it would hardly be worth