716

THE COLLIERY GUARDIAN.

April 14, 1916.

base. As to the circumstances that governed the size
of the tram, Air. Gibson did not appear to have devoted
sufficient attention to the question of ventilation, depth
of mine, and character of roof and floor; consequently,
he erred in stating that the tram governed the size of
the road. It did not appear to the writer that the pro-
posed standardisation would add to national efficiency
and reduce the cost of production, or that, in any
economic war likely to ensue, British mining engineers
would be unable to beat the enemy.

Mr. Gibson’s Reply.

Air. Gibson, in replying, remarked that ‘Messrs.
Peck’s, Dean's, and Mayer’s contributions might be
fairly, summarised in the words of Mr. Price Collier, a
well-known American observer, that “ England is the
land not of logic but of compromise. ” Mining engineers
in Great Britain had much to learn from their American
friends and, possibly, the best way to obtain help was
for the former to lay their particular difficulties before
the latter. The extreme case for the small tram would
then be brought into relief, as follows :—(1) Great
Britain was a very old mining country, where' nearly all
the easily-won seams were exhausted. In one case
within his knowledge, a preceding generation had
extracted 70 per cent, of a 5 ft. seam and had then
abandoned it. The present working was like an
uncharted archipelago of small islands of coal surrounded
by seas of dirt. Even the dross and dust left behind
by the old miners was carefully extracted, washed and
put on the market. As a general proposition, to make
a colliery of that kind pay required not only push and
go, but thrift, carefulness and caution. To embark on
any wild-cat scheme of development or equipment would
surely end in bankruptcy. As to Air. Mayer’s dictum
that turntablets were out of date in any well-managed
mine, Mr. Gibson cited the case of a seam 2 ft. thick
opened up by the longwall method. A level was driven
a distance of 160 yds. in 22 weeks, the rise given being
1 in 60, but it was found, at the end of six months, that
the floor from the starting point to a point 60 yds. from
the face was 4 ft. above the original level, although 3 ft.
had been taken off; that was, the pavement “ creep ”
was 7 ft. There was enormous pressure on the sides,
which were very frequently retimbered, and although
the road had a general gradient of 1 in 60, pools of water
6 in. deep formed on it. Turnplates were used, and had
to be relaid entirely every month. Strenuous efforts
were made to maintain the road 3 ft. wide by 3 ft. high.
Of what use would large trams with roller bearings, loco-
motives, and well-laid crossings be on such a road? In
an old mining country, local customs, practices and
prejudices grew up, and even the best-laid schemes
which interfered with or upset these had to be very
carefully introduced and handled. For instance, any
proposal which rendered unnecessary the use of lads
under 16 years underground would have to provide other
equally remunerative employment for these lads or fierce
resentment and opposition to the scheme would follow;

(2)	Great Britain had a single Alines Act,, which 'applied
to the whole country, with all its varied conditions, but
Americans could imagine for themselves what would
follow if the whole of the mines from the Atlantic to the
Pacific were .subject to the same regulations. For
example, a firedamp explosion in Pennsylvania might
cause the prohibition of electric locomotives in Virginia.

(3)	In this country, both a Minimum Wage Act and an
Eight Hours Act were in force, to which was added the
fact that, in some parts, no miner until recently was
allowed by his union to work more than five days per
week. That wTas now altered to 11 days per fortnight
in Scotland, including, of course, a short day on
Saturday. American mining engineers would readily
understand that, even if British conditions were -as
favourable as their own and the practice as good, lahom
was less efficient and, even at lower wage rates, was
dearer than in America, whilst the result was a lower
output per man. All these facts demanded that a keen
eye must be kept on cheap forms of labour, such as
boys and elderly men, as they could handle small trams
on drawing roads and haulage termini, but would ba
less useful if large trams were in use. In the case of
seams from 18 to 30 in. thick, in addition to the ever-
present problem of haulage from the face, the prime
necessity was to advance the faces as rapidly as possible
and to handle a minimum amount of dirt. The coal
cutter and conveyor were the remedies that first sug-
gested themselves, but their sphere of usefulness was
limited, since electric power could not be used in a fiery
seam, and the employment of compressed-air plant in
a small working that was advancing rapidly was a matter
of difficulty. Again, tender roofs, soft floors, and
troubled ground frequently required tackling by manual
labour. If the seam was rising, say, 1 in 6 or in 9, dip
stowage for the dirt was soon filled, and rise stowage was
slow and expensive. Where the gate roads were 12 yds.
apart, the amount of surplus dirt was increased, while, if
18 yds. apart, the output per lineal yard of face was
decreased; consequently, the rate of- advance also was
decreased, much trouble was caused in a weak roof, and
the percentage of small coal Avas increased. To send dirt
to bank during the day shift might interfere with the
handling of coal, whilst to send it by night involved tlm
provision of haulage attendants, bottomers, banksmen,
etc., a matter of no great difficulty at a large colliery but
of serious importance at a. small mine. After the dirt had
gone to bank, rent must be paid (perhaps for ever) for
the ground that it occupied, and as the tip heap
extended, mechanical transport was required, with
attendants to handle the dirt. American mining
engineers might, in view of.these circumstances, be little
surprised if British mining engineers, either by a process
of logic or a habit of compromise, concluded that, after
taking all things into consideration, as little dirt as
possible should be handled, and that the trams must be
of such a size as that consideration, when weighed
against the haulage factor, might determine.

America’s Greater Output.

The discussion on Air. Samuel Dean’s paper, ‘ ‘ Modern
American Coal Alining Methods, with Some Compari-
sons ” (Colliery Guardian, October 15, 1915, pp. 776-78;
December 17, 19.15, pp. 1233-4; and February 18, 1916,
pp. 313-14), was continued.

Air. Dean forwarded a reply to the most recent dis-
cussion. He stated that he was inclined to believe that
men who Avere successfully employing bord-and-pillar -or
shortAvall machines in mines Avith difficult pitches and
bad' roofs, Avould not place the blame for the failure
mentioned at Air. Hare’s mine upon the American
operator, but upon the shoulders of the mine manager.
As Air. Hare’s remarks appeared to evince a lack of
knowledge of machine mining, and a bitter feeling
toAvards American machine runners, it would be interest-
ing to have a frank statement from the particular
operator as to the reasons for the failure. Air. Hare had
stated that English longAvall machines Avere as good as
American machines. The Avriter held no brief for any
particular machine, but Avhat many people considered
the best shortAvall machine in America Avas not adver-
tised in Great Britain, and, possibly, had never been
used in any mine in this country. As regards the neces-
sity for using naked Avires in bord-and-pillar working,
he thought that Air. Hare apparently did not fully under-
stand the problem. All the wires could be insulated,
the cable being automatically Avound up on the reel, or
let out as the machine Avent backwards or forwards.
Twenty-pound rails were heavy enough for a shortwall
machine, when the speed at Avhich it travelled was taken
into consideration; '/01b. rails Avere for use on main
haulage roads, along wdiich heavy locomotives and long-
trains of cars travelled at top speed. If Air. Hare had
given a plan of the district of his mine where the
American machine Avas a failure, showing all the data,
one might then have been able to adduce some reasons
for the failure. If both the'bords and Avails were narroAA7
and the mine worked three shifts a day, the machine-
man would be frequently held up by the ponies or hand
putters and little tubs, as the roadways Avould be con-
gested with traffic. Air. Hare thought that no com-
parison could be made betAveen the working conditions
in the two countries, and the writer added that that was
perfectly true Avhere 10 cwt. tubs Avere used in British
mines, for, in such cases, the output per man would
never approach the American figure. It would be of
some interest to learn what the capacity of the tubs in
use in the Avorkings of the ucaa7 20 ft. seam near Coventry
Avas, and what the output per man Avas expected to be.
These frequent' remarks about more difficult conditions
in Great Britain were not ahvays justified. In the
Bentley Colliery the output per man at the face was
about five tons, and 14 CAvt. tubs were used. The.output
per man in a similar seam in America Avould be 10 tons,
and about half the number of men would be employed to
move the coal from the face to the shaft bottom. The
gauge of the track at Bentley Avas 26 in., the rails
weighed 281b. on main roads, and 181b. at the face, and
props at the face Avere set 5 ft. apart. To enable Mr.
Hare to realise the situation, he might take the Hutton
seam, in the county of Durham, Avhere it Avas approxi-
mately 6 ft. thick, and easy to hew by the scalloping
process, and compare the output per man for all men
employed in the workings of that seam with the output
per man in American seams 6 ft. thick. The figures
would probably startle him,, and he would not be able
to- console himself with the statement that the English
conditions were unfavourable. To return to the machine
proposition, it Avas futile to expect an immediate success
by placing all the responsibility upon the machine
runner—a stranger in a land of old customs and pre-
judices. The success or non-success of machines rested
Avith the mine manager. The manner in Avhich he
planned the lay-out of his Avorkings, his organisation,
and the way in which he Avatched daily operations were
the factors that governed the results. When a new
American coal cutting machine arrived at a colliery, the
mechanics should immediately take it to pieces and
build it up again, and should thoroughly satisfy them-
selves that they understood its mechanism. In the
evenings, the manager, under-manager, and overmen
should attend at the Avorkshops, a mechanic should put
the machine into operation there, and afterAvards take it
to pieces, and the different underground officials should
build it up again. This Avork should be continued every
evening until each man understood how the machine
worked, and how to remedy defeats in it. That was the
way in Avhich German mine officials Avere taught their
business at Bochum. When the Avriter visited the
Ceag electric lamp works at Dortmund, he suav all the
American cap lamps lying on a table dissected,, and
efforts being made to improve upon them. The object
then was to produce a German electric cap lamp to bo
placed upon the American market. When the official
understood the mechanism of the machine, he took a
deeper interest in its operation at the coal face. If the
machine Avould not work, he ought, after an examination,
to be able to state the reason. If he Avas not able to do
that, of what value Avas he in a mine Avhere the coal
Avas undercut by machines? When a machine Avas first
introduced, the Avelfare of the machine and operator
should be the first consideration.- In the event of a
breakdoAvn, mechanics- should be sent to the coal face
Avithout delay to effect the necessary repairs, or to bring
the machine to the shop. American shortAvall machines
might be more successful in a mine laid out on the South
Wales single stall method than on the Durham bord-
and-pillar system. Mr. Hare had stated that the illus-
trations to the Avriter’s paper shoAved “ vast spaces ”
with hardly a stick of timber. Some of these photo-
graphs Avere taken in mines Avhere the roof was good,
and he Avould admit that a large number of American
mines possessed good roofs. But, in order to prove that

machines and large cars were used in mines with bad
roofs, he had had some photographs taken in a mine
Avith' a bad roof. The first of these pictures shoAved an
entry in a mine Avhere the coal was 5 ft. thick. The
track Avas shown leading into a room-neck, the duplex
trailing cable of a shortAvall machine Avas seen on the
floor, and a car Avas shown having a carrying capacity of
two tons. The second photograph shoAved the shortAvall
machine travelling inbye in the room. There were no
naked wires, and the roof had to be supported. The
third, showed the shortAvall machine cutting across the
face of a “ crosscut ” or “ Avail ” off the room or bord.
That crosscut was 12 ft. Avide, and the rooms Avere 20 ft.
Avi.de. One foot of draAA’ slate generally came down with
the coal, and the roof above Avas full of slips and pot
holes. The maximum distance alloAved between cap
pieces was 5 ft. The roof over the track had to be
supported with crossbars and lagging. There Avere many
places in the mine far more closely timbered than those
shown. That particular machine cut to a depth of 7 ft.,
and averaged about 100 lineal ft. of face per day. It
gave very little trouble, and had been in use 18 months,
previous to which time the roof was thought unsuitable
for machines. It Avas quite possible that 75 per cent, of
the coal produced from that mine would eventually be
cut by machines. Mr. Hare had said that it Avas practi-
cally impossible to use the American bord-and-pillar
machines in an ordinary English pit, but the Avriter
could not let that statement go unchallenged. Surely,
the English. Government regulations did not prevent the
use of electricity altogether 1 The United States Bureau
of Alines had already placed certain electric shortwaU
machines on the permissible list for use in mines, and
Avould never have done this if naked wires Avere neces-
sary. He congratulated Air. Simon Tate on the excel-
lence of his criticisms, though he did not agree with Mr.
Tate’s statement respecting the size of tubs in new pits.
If he were to start a neAA’ mine, he would aim at having
tubs of a capacity of 35 CAvt. or 2 tons, instead of 15 cwt.
or 1 ton. When once the Avorkmen learned how to re-rail
a 2-ton car quickly, it gave them very little trouble, and
brakes enabled a-man to handle the. car on varying
gradients Avithout difficulty. It was more than a ques-
tion of getting a hewer’s Avork out. To keep him sup-
plied Avith an unlimited number of 10 cwt.-tubs involved
the services of an excessive number of haulage hands,
and, in a large mine, Avhere all the coal was undercut by
machines, it would be practically impossible to supply
the filler Avith an unlimited number of 10 cavI. tubs.
When face conveyors were used, 10 CAvt. tubs were out
of the question.

Mr. Hare’s Rejoinder.

Mr. Samuel Hare replied that he had no intention of
placing the blame on the operator. He quoted the case
in support of the contention that the conditions of
English mining were so different from those in America
that one of the best American operators Avas unable to
obtain satisfactory results when using one of the latest
types of American heading machines. As to the neces-
sity for using naked Avires in bord-and-pillar working in
order to move the machines quickly from place to place,
one of the best American operators had said that one of
the principal reasons for his Avant of success Avars that
they Avere not alloAved to provide him Avith naked Avires
for the purpose of flitting his machine. He, the speaker,
had been manager of the largest pit in Durham Avorking
the Hutton seam extensively, and neither naked Avires
nor insulated wires of any description Avould be tolerated
in any part of the mine. How, then, could any com-
parison be made between the output per man from the
Hutton seam—lying very often at great depths and with
great roof pressure—with firedamp present in large
quantities, Avith machine mining in comparatively
shallow mines of good section, Avhere electricity could
be used with impunity? With regard to the suggestion
that the operator might not have received sufficient
assistance from the officials, every suggestion made by
the operator was most promptly >and willingly acted
upon. In conclusion, he repeated .that he recognised
and admired the skill shoAvn by American mining
engineers in the design and application of machinery to
mining, but he claimed that Mr. Dean had absolutely
failed to prove that it Avas possible to obtain anything like
the same results in Great Britain by applying the best
mining machines to the same extent as in America.

Mr. Greener’s Opinions.

The President said he thought that everyone Avould
agree that the difference in output in America as against
this country was not due to the Avant of skill of British
mining engineers, but to the difference in conditions.
In America, they were uoaat in the position in which Ave
were 50 years ago. They were working their best and
most accessible seams. They had all the advantages
Avhich had been discovered in the last half century—all
the advantages obtained from the use of electricity and
other poAvers. These advantages were sufficient to
account for the better output in America. There seemed
to be a very general idea, from Mr. Dean’s paper, that
■the use of large tubs was the solution of the problem.
He Avondered Avhat Mr. Dean Avould say to the use of
2-ton tubs for the thin seams Avhich Avere being Avorked
in some parts of that district—seams varying from 22 in.
to 24 in. Would anyone propose to put such big trams
in such places? To begin with, the cost of making the
road Avould be absolutely prohibitive, even assuming that
it Avas necessary only to make the road every 100 yds.
The thing Avas impracticable. He did not know why
Mr. Dean had referred to Bentley Colliery, but it was
certain that, in that colliery, electricity in any shape or
form Avas absolutely inadmissible, the quantity of gas
was so large. These facts went to show the extreme
difficulty there was in comparing the results obtained
in one country Avith those of 'another, unless it Avas
possible to reproduce precisely the same conditions in