June 15, 1917.

THE COLLIERY GUARDIAN.

1125

MANCHESTER GEOLOGICAL AND
MINING SOCIETY.

A meeting of the members of this society was held at
Manchester on Tuesday, June 12, Mr. W. Pickup,
president of the society, in the chair.

In opening the meeting, the President said the
members would hear with deep regret of the death of
Mr. John S. Burrows, who had been a member since
1878, vice-president in 1890-91, and trustee from 1912
up to the time of his death on May 18. He was a most
valuable member, taking the greatest interest in all
matters connected with the society, and his death was an
irreparable loss to the mining community. He was
esteemed by all who knew him. Possessing great force
of character, width of views and genial temperament,
he combined, in a remarkable personality, a breezy
exterior, far-seeing shrewdness, genius for management,
and tact. During his long period of activity he con-
tributed largely to the development and success of the
firm with which he was connected. He moved that a
letter be forwarded to Mrs. Burrows and the family,
expressing condolence and very sincere sympathy
with them in their bereavement, and appreciation of
Mr. Burrows’ valuable services, and that the resolution
be entered upon the minutes of the society.

Mr. Harrison seconded, and Mr. A. J. A. Orchard
associated himself with the expression of sympathy,
having been an assistant with Mr. Burrows for some
years.

The motion was cai ried.

The following gentlemen were elected to member-
ship:—Members (federated): William Roberts, Newton-
le-Willows ; Thomas Davies, Ruabon. Associate mem-
ber federated) : Percy Chadwick, Wigan.

Mining Pennsylvania Anthracite.

A paper on “ Methods of Mining in the Pennsylvania
Anthracite Field ” (given on this page) by Mr. Hugh M.
Crankshaw, was read by the author’s father, Mr. J oseph
Crankshaw. A vote of thanks to the author and
reader was proposed by the President, seconded by
Mr. Harrison and carried unanimously.

DISCUSSION.

Mr. Atherton said he was much interested in this
subject, because in 1899 or 1900 he had visited the
Northern Pennsylvania coal field and observed the
developments which were taking place. He was shown
what was considered a very fine piece of apparatus,
and told that it had been introduced about 18 months
before, but he was able to point out that it appeared,
from the Transactions of the society, that it had been
in use in this countiy 20 years earlier. The most
remarkable thing shown him was the pneumatic loco-
motive they were using in the Northern field. He
understood that electrical power had been adopted
since. The paper made no reference to two points
which he wished to have information upon. The first
was the Mammoth bed at Latimer. When he was there
it was open-cut, and he did not know whether it was
worked out now. The second point was with regard to
the system of transmitting power through boreholes—
400 ft. was, he thought, the deepest. Hydraulic stowing
was a subject in which Mr. Drummond Paton took
great interest, and he hoped the discussion would not
be closed until they had given that gentleman an
opportunity of dealing with it in connection with this
paper.

Mr. A. J. A. Orchard said the proportion of solid
matter in the sludge, 15 per cent, to 85 per cent, of
water, was higher than had been mentioned at previous
discussions on hydraulic stowing. Was the water pumped
back, or was there free drainage? [Mr. Crankshaw:
“ They pump back.”] Mr. Orchard observed that they
had listened to several descriptions of hydraulic stowing,
but this was the first time an actual case had been put to
them in which the operation had been successful. Of
course, the conditions were very different from tho-e
prevailing in Lancashire, so far as the dip was concerned.
Did Mr. Crankshaw consider hydraulic stowing could
be successfully applied to Lancashire mines, where tlie
dips were much flatter ? In the mines on the Continent
where the system had been adopted the dips were
pretty high. Was the sludge taken upbrow, or was
it all worked by gravity ?

Mr. Atherton asked whether the ordinary breakers
were used for grinding the sludge.

Mr. Crankshaw, in reply, reminded the members
that be was filling the place of his son, and did not
possess the same qualification for dealing with the
points which had been raised. He was much indebted
for the kind reception given to the paper. As an
ex-secretary of the society, he took a great interest in it,
and his son, who was reared in Lancashire, was also
imbued with kindly feelings towards the district and
the people he had been connected with. Of course, he
himself had no personal experience of working con-
ditions in the North Pennsylvania coal field—he had
simply been there as a visitor. The Mammoth bed was
still being worked, but of course the output was now
much less than it was 20 years ago. It was exceedingly
good coal and very popular, and in consequence had
been to a large extent worked out. The question about
filling could only be satisfactorily answered by his son,
who knew exactly how much it cost. The sludge could
be run 2,000 ft. inside the mine. There was no hesitation
in putting up special plant for a particular purpose ;
and in that respect they differed from colliery proprietors
in this country. The American was as ready to spend
100,000 dols. as the Englishman to spend £100, if he
thought he could get a satisfactory result. In the
present case they were dealing with a very big concern,
with a capital of probably 30,000,000 dols., producing
about 30,000 tons a day. They spent 135,000 dols. in
putting up a washery, and they were equally liberal in the
breakers. Mr. Crankshaw agreed with a remark by Mr.
Alperton, that in the last 10 years breakers have been
exceedingly improved, and said the company spent
1,000 dols. on a working model -before beginning the
permanent arrangement. There were different sizes of
coal, coming down to a f in. mesh, and he understood
they were now taking in. A very satisfactory pro-

cess for making briquettes out of small dust was in
operation. The depths of the pits were not very great.
He did not think he had seen one more than 300 yards
deep. A good many were worked by slants from the
surface. The coal was mined very cheaply. In the
North Virginia field it was put upon wagons at less
than 4s. a ton including everything.

The discussion was adjourned.

BRIQUETTES FROM ASHES OR DUSTS.

In the discussion on the paper read before the Society
of Architects, on Thursday, June 7, by Mr. R. Goulburn
Lovell and Mr. C. M. Hughes (Colliery Guardian,
June 8, 1917, p. 1077),

Mr. H. W. Bowden, chief electrical engineer to the
Poplar Borough Council, enquired what happened to
the ashes after the artificial coal was burned. Every
clinker or waste product must vary according to its
nature. In his own case the riddlings that went through
the chain grates still contained a considerable amount
of useful coal which went away with the allies. He
had tested this and proved it to contain about 4,000 B.t.u.
If that were used on the author’s method, what would
be the increase in value ?

Mr. Lovell said it was only the ash from destructor
works that he used in his process. The clinker was
useful for roadmaking, and had not much calorific
value. He believed that he could improve the ash from
the Poplar destructor works from 4,000 to 10,000 B.t.u.
As to the cost of the plant he could not say much,
because he proposed that where the process was adopted,
old plant at present lying idle all over the country
should be used. In the cooking process, tar boilers
could be used, and for the mixing, concrete mixers could
be used. Where the boiling process was not adopted
and the mixture was put into moulds, hand mixing
would have to be resorted to and almost any receptacle
would do for the moulds. He had used old pails at
Eastbourne into which the mixture was put and pressed
down, afterwards being allowed to cool, broken up and
then exposed to the air for a period. The longer the
exposure the harder the resultant fuel. After a few
days the material was rather friable, but at the end of
several weeks it was as hard as the best coal. Thus he
could hardly say what the cost of the plant would be.
The residue from burning this artificial coal could be used
again in the same way. Replying to a number of other
questions put by various speakers, Mr. Lovell explained
that the great point of the process was a proper mixing,
and for that purpose a concrete mixer was to be
preferred. His experiments with two or three gallons
of the mixture took 20 minutes to complete the heating
process, and he believed that any quantity could be
dealt with in the same time according to the size of the
receptacle. The proportion of the binder necessary
would have to be determined by a special test in each
case in order to arrive at the formula, and vary
according to whether the resultant fuel was to be used
for domestic purposes or industrial purposes. Usually
it was one-third, and it should not exceed one-half.
Calcium carbonate was an essential of the binding
material, and with it was used any form of bitumen or
any form of sugar waste. With bar ash and clinker
added to sawdust he had produced a fuel having 11,000
B.t.u.,; and with Gas Light and Coke Company’s coke
dust alone, plus a pitch binder, a fuel containing 13,000
B.t.u., but equally good results had been obtained with
sugar waste.

Mr. W. R. Cooper said he was not so sure that there
was so much value in coal dust as the author seemed to
imply. It very often contained a high percentage of
ash, which was very much against it for general use.
More information was necessary with regard to the
process and the cost of working before it could be
decided whether it was practicable or workable. Incom-
bustibles were added by the author, and he would like
to know the percentage of ash to start with and in
the final product, and how much incombustibles were
added.-

Mr. Lovell explained that the process was a protected
one, and he had been advised that the complete specifica-
tion could not be published in present circumstances.
He was willing, however, to show the provisional specifi-
cation to anyone interested, and also the results of the
tests that had been carried out. The process was simple,
and the two things required were the formula and
accurate mixing. The temperature at which boiling or
heating took place was 100 to 120 degs.

Mr. C. R. Morgan has been appointed London agent for
the Sheepbridge Coal and Iron Company, in succession to
the late Mr. Geo. J. Wood.

Coal Controller and Rationing.—The Controller of Coal
Mines intimates that the statements which have been pub-
lished in regard to the imminence of compulsory rationing
of coal are premature, and in many respects inaccurate.
Two circulars have been issued. The first one provides
for the regulation of the traffic, so that every householder
may be able to secure a good stock of coal in readiness for
the winter, and it urges all to lay in a stock between now
and the end of September. The more recent circular
stipulates that all the private stores must be laid in by
July 31. After that date the control of the supply and
distribution will be taken over by the Controller, and in the
London area no coal will be allowed to pass out until cer-
tain specified reserves have been built up. A minimum
store is to be maintained throughout the winter. Coal
merchants will be required to build up stocks and to so
arrange matters that small orders from the poorer districts
of 1 cwt. may be regularly dealt with. Central stores are
to be arranged so that long distance cartage and delivery
may be minimised. Coal clubs are warmly recommended
by the Controller, and municipal bodies are urged to
co-operate. The majority of the coal merchants are loud in
their complaints that the limited and altered date, viz.,
July 31, will render it practically impossible with their
depleted staffs to get the coal delivered in the time. It is
suggested that the borough councils should make use of
their dust yards and other places for the sale of coal at
cost prices in small quantities.

METHODS OF MINING IN THE
PENNSYLVANIA ANTHRACITE FIELD.*

By Hugh M. Crankshaw.

The anthracite field of Pennsylvania, which annually
produces about 90,000,000 tons of coal, is divided into
three sections: The Southern anthracite field, the
Middle anthracite field and the Northern anthracite
field. The Middle anthracite field is again subdivided
into Middle East and Middle West. The character of
the beds of coal varies greatly, and they are from 2 ft.
to 60 ft. thick, the average thickness of the Mammoth
bed, over a horizontal distance of 12 miles, being 45 ft.
The pitch on which the coal is mined also varies from
flat to vertical for thick beds as well as thin. It is thus
evident that in the anthracite field very many diversified
conditions exist which naturally must be met by many
and various methods of mining.

The Southern Anthracite Field.

In the Southern anthracite field, where the average
pitch is 50 degs., and the Mammoth bed had
been worked in the past, the coal is mined on the
“ pillar and stall ” system applied to the pitch of the
bed, the stalls or rooms being known as “ breasts.”

In the old breast method all the mining was done
from a gangway driven in the Mammoth bed, the
position of the gangway, as a rule, being dependent upon
the pitch of the measure—i.e., when the bed pitched
over 60 degs. the gangway was driven along the top
rock; otherwise it was driven along the bottom rock.
The local conditions also played an important part in
the final location of the gangway.

From the gangway a chute was driven up the pitch
to connect with the airway or “monkey” which was
driven parallel to the gangway, and from 30 to 50 ft.
above it. From that monkey, also known as the bottom
breast crosscut, the breasts were started.

In many cases a separate airway or monkey was
driven, but often the airway monkey and bottom breast
crosscut were combined. In forming a breast the front
manway or “ dog hole,” and the back manway, were
driven 20 ft. up the pitch on the bottom rock. An
opening 8 ft. high and 10 ft. wide, forming the bottom
of the breast, was made next to the back manway, and
enlarged up the pitch until it connected with the top of
the dog hole, in that way forming a stump. The
“ jugglers,” which were props set skin-tight across the
opening at the bottom of the breast, were next put in,
and after a short manway had been driven on top of the
dog hole, all was ready for the first cutback. This
consisted in cutting through the bed from the bottom
rock to the top rock. Manways were generally carried
when making the first cutback, the distance between
the manways being 18 ft., the width of the breast.
After the first cutback was made the breast was driven
30 ft. up the pitch and a second cutback made.
Thereafter cutbacks were made every 15 ft. until the
breast “ ran away.” That system of breast mining had
been used extensively on lifts of from 200 to 300 ft., but
had proved unsatisfactory on account of the low per-
centage of extraction secured. It had been necessary
to work over the same ground three and four times, with
the result that timbering and other expenses had been
high. Therefore the following improved method was
worked out.

Improved Method.

In the working of a lift in the Mammoth bed 250 ft.
long on a pitch of 65 degs., the bed being 40 ft. thick,
the gangway and airway is first of all driven in the
underlying Skidmore bed. Breasts are started half-way
up the lift, and are restricted to a length of about
100 ft. The idea of driving breasts only 100 ft. long is
derived from the fact that when breasts were started
near the bottom of the lift, they almost invariably ran
away after the first 100 ft. had been driven, and often
earlier, making it practically impossible to systematise
the work. In order to drive short breasts, slant chutes
are driven in the Skidmore bed and rock holes put
through to the Mammoth 120 ft. apart and half way up
the lift. The rock holes are then connected by slant
chutes along the bottom rock of the Mammoth, from
which the breasts are started on 60 ft. centres in the
usual way. Each rock hole handles the coal from
two breasts, the coal from three rock holes
coming together at one loading chute. The ques-
tion is often raised as to whether rock work
was not too high in first cost. It is, therefore,
desirable to mine coal as soon as possible, so that too
much rock work is not done at one time. In that way,
after the work is once started the cost of the rock work
is only about 20 per cent, of the total cost of timbering
under the old method. Each set of six breasts has a
separate split of fresh air and a ventilating system of
its own. The ventilation is arranged very simply on
the split system by driving a breast from the Skidmore
airway far enough up the pitch so that a rock hole put
through from the top of the breast will connect with
the apex of the slant chutes. After the breasts are
driven through to the upper level, cross chutes are
driven across the bed from the apex and bottom of the
slant chutes for the purpose of robbing the pillars
between the breasts. The breasts are allowed to stand
full until the cross chutes are driven through to the
upper level and the breasts are then drawn as the cross-
chutes are robbed down, the pillars being completely
robbed out by means of the tapping chutes. In that
way all the chutes are driven into solid coal and the
men are in strong ground all the time, thus being well
protected, and a good supply of fresh air is always
available to dilute any outburst of gas.

When the upper half of the lift has been robbed
back, the lower half is worked in the usual way from
the rock holes driven direct from the Skidmore gang-
way. Those rock holes are connected by slant chutes
driven along the bottom of the Mammoth bed, and the
whole operation is repeated as for the upper half of the
lift. Working the upper half first, however, gives an
opportunity to ventilate the lower half easily as
follows :—As soon as the first breast is driven up, a

* Paper read before the Manchester Geological and
Mining Society on June 12.