September 29, 1916.

THE COLLIERY GUARDIAN.

603

sq.ft., representing about 58 cu. ft. of air space. Here
they had a deposit something like 100 times that
required to give an ignition according to Taffanel’s
scale, and about 60 times according to that of the
American Commission. He was afraid that, to get the
whole of that face dusted with stone dust, to keep even
a 50 per cent, mixture there, was almost impossible.
The difficulty at the face was they could not have
smooth surfaces, and fine dust rapidly accumulated; so
that whatever might be done on the main roads, they
were still waiting for someone to come along with a
practical method of making the faces safer than they
were at present.

Mr. J. Fox Tallis said th© chief value of the pap©r
lay in the fact that the experimente were conducted over
a long period. The paper had convinced most of them
that it was not impossible to maintain a mixture of 1 to
1 in their roadways. From his experience of very dusty
mines, he had held the view that it would be practically
impossible to maintain a mixture of only 1 to 1; but the
experiments of Mr. Budge had proved otherwise, and
showed what could be done by persevering. At the same
time, some of the chief points of the paper emphasised
the axiom that prevention was better than cure. The
problem of coal dust from the screens was one which had
been urged upon them in South Wales for many years,
but very few of them had adopted measures to prevent
the screen dust going down into the pit. This was a
serious matter at some of the older collieries, where the
screens were close to the top of the shaft, and in many
oases there were larger openings from under the screens
right down to the downcast shaft itself. With regard to
trams,-he did not see the necessity of putting covers
upon them, so long as the tram of coal was properly
doused with water directly it came from the face, some-
where on the double parting. They required to use
plenty of water, and he did not see how any dust could
then get out of the tram. Another point in the paper
had reference to the haulage speed. Of course, they all
knew that, with very high speeds, a larger quantity of
dust was raised, and the trams were more likely to run
off the road, upset the journey, and produce a dreadful
lot of dust. Then they required to have good roads. In
South Wales some of their rails were too light for the
loads they were expected to carry. Th© watering of
trams at the faces was also very important. If they
were adequately watered as they left the faces he could
not see how they could cause much dust. As to high
velocity of ventilation, they knew this added to the
danger when an explosion occurred, whilst it must also
create more dust. Stone dust, to be of practical use,
must be of very fine grade and consist of such material—
with a minimum of silicate or grit—as not to be harmful
to the workmen.

Mr. L. G. Hill (Birmingham) said some months ago
Mr. Halbaum urged that the difficulty was to get stone
dust of the same buoyancy as coal dust. His firm had
a distributor which distributed stone dust regularly and
automatically by means of compressed air current
working at 171b. pressure—which he did not think
was dangerous—at the rate of something under 1 lb. per
minute; and they calculated that the ventilation current
would carry very fine stone dust into any crevice or exca-
vation. The distributor and stone dust were examined
by Home Office representatives at Denaby and Cadeby
mine about 18 months ago, when they found the dust
floating in the atmosphere for two miles up the pit.
With regard to dust from screens, his firm undertook to
put in plant for the collection of coal dust from the
tipplers at Ebbw Vale collieries, which should retain 95
per cent, of the dust that was handled, but the war had
interfered with the completion of the job. As to com-
parative safety, it was established that stone dusting
prevented loss of life at the Denaby and Cadeby pit in
•Tune 1914. They had been stone dusting at the pit for
six months before the explosion occurred, on the same
principle that Mr. Budge adopted, and no lives were
lost and no damage was done, although the explosion
took place under similar circumstances, except for the
stone dusting, as those attending the disastrous explo-
sion at Denaby and Cadeby pits some years before.

Replying to the President, Mr. Hill said he could
bring his apparatus to the next meeting of the institute
when the discussion was resumed.

The President, before calling upon Mr. Budge, said
the discussion would be first adjourned to a meeting of
the institute at Swansea on the Tuesday of the following
week, and then carried on to another evening meeting
at Cardiff, when he hoped the three kindred societies
in the district would again be represented. He had
listened with much pleasure to the comments that had
already been made.

Mr. W. W. Hood said that before Mr. Budge replied,
he would like to ask him if he honestly believed he had
got his colliery into such a state with the 1 to 1 mixture
that it was impossible fo/ an explosion to be propagated,
accepting the recommendation of the Explosions in
Mines Committee in their Fifth Report. Personally, he'
had no difficulty in making main roads safe, but it was
very different with the faces.

Mr. Budge said he agreed with Mr. Ray that water-
ing did affect the stone dust, and if the floor of a road-
way were watered there was a dampness on the stone
dust on th© lower parts of the road. But this damp-
ness only extended to a height of about 2 ft., and there
was quite sufficient dry stone dust in the higher parts
of the roadway to do all that was necessary. He did
not think that the watering of the floor would impart

sufficient m'oisture to th© stone dust to affect its action
seriously. Mr. Ray said he could not put the stone
dust into the cavities. He (Mr. Budge) would under-
take to put a | in. thickness of deposit of stone dust on
every part of a cavity 40 ft. above rail level with an
ejector, but he agreed that this could not be done by
hand. As to the effect of a stirred-up mixture of coal
dust and stone dust on the workmen, if an ejector were
used a cloud of stone dust could be raised sufficient to
make it very difficult for a man to breathe, and the
ejector had always to be used at week-ends, because it
was not safe for the men to be in the workings. He did
not believe there would be loss of life after a large body
of stone dust or a mixture of coal dust and stone dust
of anything like 50 per cent, had been stirred up into the
atmosphere if the atmosphere could be cleared within a
reasonable time. He had himself remained in such an
atmosphere for a considerable time without experiencing
any ill-effects beyond a severe coughing. As to the
application of stone dust in areas of roadway of various
dimensions, referred to by Mr. Ray, a very dusty road-
way of, say, 55 sq. ft. in area, would require an appli-
cation of 180 lb. per yd. per annum to keep the roadway
in what he considered a safe condition. A roadway of
80 sq. ft. in area would require an application of approxi-
mately 300 lb. per yd. per annum. In his fuller reply
he would refer to this point in more detail; he could
now only speak from memory. Mr. Hood had asked
him pointedly to say whether he considered a 1 to 1
mixture was going to make a colliery safe. Before deal-
ing with that, he would answer Mr. Greenland Davies’s
question : Was it possible to put a 1 to 1 mixture on
the roadway? It was possible to put a 1 to 1 mixture,
or any mixture they liked, on the accessible parts of the
road, and, in fact, on any part of the roadway, but it was
not possible to maintain it for a length of time. He
believed it was possible to maintain a 40 per cent,
incombustible dust, provided the road was stone dusted
with an ejector once a week. If they dusted a roadway
with a 1 to 1 mixture, or even a 2 to 1 mixture, and left
it for a month, they would only have 20 per cent, of ash
in the suspension dust at the end of th© month. It
was' not possible to maintain a suspension dust of 1 to 1
mixture on every part of the colliery, and he did not

t»A

1i

Newcastle Colliery, Blair Athol.

think it was necessary. He did not think this was
meant by the Explosions in Mines Committee, who did
not base their conclusions on a 1 to 1 mixture in inacces-
sible parts of the roadway. Coming to Mr. Hood’s
question, a roadway which on the floor, roof, and sides
had a 50 per cent.-incombustible dust to stone dust, and
40 per cent, incombustible dust to stone dust in the
cavities, that roadway, he was as nearly as possible
certain as anyone could be, was safe. He agreed that
an experimental mine such as Mr. Hood had suggested
■would prove of great value. He certainly thought that
a roadway was safe with a 50 per cent, mixture and
40 per cent, suspension dust, and that further know-
ledge would show the suspension dust might be much
less than 40 per cent. It would be a very exceptional
combination of circumstances that would cause an igni-
tion to extend to a propagation on' a roadway which was
stone dusted to a 50 per cent, mixture. With regard
to the propagation of a mixture caused by an explosion
at the coal face, he agreed that the coal face was the
chief source of danger, which at the present time they
saw no means of combating. It seemed an almost
impossible problem, but no doubt it would be solved
sooner or later. At the present time, however, if an
ignition took place at the coal face, and the roadways
leading up to it had been treated to a 50 per cent, mix-
ture, the experiments of the Explosions in Coal Mines
Committee showed that the propagation might be
extended throughout every part of the colliery. But
very likely the mixture in many parts of the roadways
would be over 50 per cent. The fact that the coal face
was a part which they could not guard against should
not deter them stone dusting every other part of the
colliery. Supposing they got an explosion in the coal
face, and succeeded in limiting it to one district, while
the men in that district might all be killed in that split
of air, a colliery consisted of more than one split of air,
and the other parts of the colliery would be untouched.
, Replying to a remark by Mr. Hood, he said that he
based his work upon the experiments of the Explosions
in Mines Committee, which he regarded as really
excellent.

The proceedings closed with a vote of thanks to the
president, proposed by Mr. Henry W. Martin, seconded
by Mr. J. Fox Tallis.

A further discussion on the same subject was held at
Swansea on Tuesday evening, 26th inst., and will be
reported in our next issue. The speakers included Mr.
L. G. Hill (Birmingham), Mr. Gay Warren (Ponty-
ffynon), Mr. Sidney L. Gregor (Swansea), Mr. George
Robings (Llanelly), and Mr. John Standidge (Ystaly-
fera). Further consideration of the paper was deferred
to a meeting of the institute to be held in Cardiff in a
week or two.

NEWCASTLE COLLIERY, BLAIR
ATHOL*

The Newcastle Colliery, owned by the Newcastle Coal
Limited, is situated about 1| miles north of the town-
ship of Blair Athol, which is the terminus of the branch
line from Emerald, 11 miles from Clermont, and 74
miles from Emerald.

This mine was opened about three years ago, two
vertical shafts being sunk and a railway siding built
connecting the mine with the Blair Athol station.

The winding shaft is 121 ft. by 5 ft. clear of timber,
is divided into three chambers of 4 ft. by 5 ft. each,
and is 200 ft. deep. The pithead frame and loading
stage is a particularly strong and substantial structure,
the former being 60 ft. high and the latter 25 ft. high
and 40 ft. long. Storage bins are built underneath the
stage, which have about 200 tons capacity, and which
can be emptied direct into the railway trucks, with a
minimum of labour.

Two tipping chutes are provided; one of which is uted
to screen and grade the coal, and the other for loading
the locomotive engine tenders. The present output is
up to 250 tons per day, for about 40 men employed.
Ventilation is provided by an open running exhaust fan,
connected by a fan drift to the air shaft, and giving
approximately 30,000 cu. ft. of air per minute.

A suitable winding plant is installed, power being
derived from two 30 horse-power multitubular boilers,



and the usual offices and shops are erected, together
with dressing rooms and shower baths for the workmen.
The Blair Athol seam, as opened at this colliery, is
exceptionally good in quality and thickness, no doubt
due to the fact of it being two miles from the outcrop
south of the township, and having a good cover (for
the Newcastle mine is the deepest on the field). The
seam is 65 ft. thick from the roof to the first band of
ironstone, in. in thickness, below which is a further
7 ft. of coal, making a total thickness of 72 ft. This
seam of 65 ft. of clean coal without a band is unique,
and is considered to be probably one of the thickest
clean seams of first-class quality coal in the world.

An analysis of mixed samples of all the working faces
gives:—Moisture, at 212degs., 6'34 per cent.; fixed
carbon, 58'99; volatile hydrocarbons, 28-94; ash, 5'81;
sulphur, 0'35 per cent. Specific gravity, 1'398.

The coal is very hard, the seam producing a maximum
of “ round ” coal. It is dull black in appearance, with
streaks of bright coal: it fractures irregularly, the
bedding planes being well defined, but the vertical planes
or cleats are poor, and it is non-coking. It belongs to
the permo-carboniferous age.

The workings ar© laid out strictly on the panel
system, barriers 22 yds. thick dividing the panels, inside
which the coal is worked by bord and pillar method.
The flow of water in the min© is about 3,000 gals, per
hour. A sump, holding approximately 150,000 gals.,
has been cut out on the floor of the seam, thus draining
the mine, and leaving the workings entirely dry. Two
large pumps are installed, each being capable of deal-
ing with the day’s make in eight hours. A remarkable
feature in this connection is that this water (unlike the
water usually met with in coal mines) is quite fresh and
wholesome, being very suitable for boiler and domestic
uses.

The Railway Department have erected a large tank
at the mine, from which they draw their engine supplies
and also carry away train loads for use on the Central
Railway. As much as 37,000 gals, have been taken

* Queensland Government Mining Jour