COAL MINING a CANTRILL

COAL MINING a CANTRILL
COAL
MINING
T,
a CANTRILL
=J
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COAL MINING
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COAL MINING
T. C.
CANTRILL,
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F.G.S.
Cambridge
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page is a
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title
Siberch,
1521
PREFACE
the following pages an attempt has been made
general reader a slight sketch
INto place before the
Not to take too
of the principles of Coal Mining.
narrow a view of the subject, in the earlier sections
have outlined the evolution of the industry from
primitive beginnings, and have indicated here
and there some of the far-reaching effects it has had
on domestic and mechanical affairs. I have also
introduced such geological considerations as have a
direct bearing on the main subject.
The history of Coal Mining in Britain has been
written by Mr R. L. Galloway in some fascinating
volumes to which I am indebted for the particulars in Chapter I.
In the section dealing with
I
leases and royalties
have had the help of Mr H. J.
I
its
Randall, of Bridgend, who is conversant with the
customs ob taming in South Wales and elsewhere.
In the Bibliography is given a list of works laid
under contribution for the present purpose, and to
them the reader
is
referred for fuller details.
The
Frontispiece has been kindly supplied by the Wigan
Coal and Iron Company, Ltd.
T.
22 December 1913
290478
C.
CANTRILL.
TO
DANIEL JONES, ESQ., J.P.,
OF DONINGTON, ALBRIGHTON, SALOP;
FATHER OF WYRE FOREST GEOLOGY
CONTENTS
PAGE
CHAP.
L
INTRODUCTION AND HISTORICAL REVIEW
.
1
II.
VARIETIES, GEOLOGICAL AGE AND ORIGIN OF COAL
37
III.
THE COAL MEASURES AND THE COAL-SEAM
52
IV.
COALFIELDS, FOLDS AND FAULTS
V.
PROSPECTING AND BORING
VI.
WINNING THE COAL
77
VII.
WORKING THE COAL
95
.
X.
.
.
.
.
....
VIII. VENTILATION, DRAINING AND LIGHTING
IX.
.
61
69
.
109
UNDERGROUND HAULAGE, WINDING, AND SURFACEARRANGEMENTS
124
LEASES
AND
ROYALTIES,
AND STATE REGULATIONS
.
ADMINISTRATION,
.
.
.
.136
BIBLIOGRAPHY
150
INDEX
152
LIST OF ILLUSTRATIONS
Alexandra
Pit,
....
Wigan
frontispiece
PAGE
Fig.
1.
The
2.
A
3.
Edge-rail and plate-rail
three
of
stages
mining.
(After
R.
L.
Galloway)
South
<j
Staffordshire
Geological
horse-gin.
Survey Photograph)
(From
...
.63
4.
Coalfields
Overthrust faults
6.
Normal
7.
Methods
8.
Shafts,
9.
Recovering the coal beyond a fault
Recovering the coal beyond a fault
11.
'
Face
'
65
faults
of winning the coal
main
and
15
25
5.
10.
a
levels
*
end
and
....
inclines
.
~
.
.
.
.
.
.
(&
79
87
91
92
'
97
12.
Bord-and-pillar working.
13.
Longwall working
14.
Square- work
16.
Ventilating levels
16.
Underground haulage
......
(After C. Pamely)
.
99
104
107
and bords
.
.
.
.115
127
Note.
The Frontispiece shows, on the left, the screens
with the winding-shaft (which is also the downcast
air-shaft)
behind them. The upcast air-shaft and fan-house are not included
in the view.
The head-gear on the right belongs to a disused
pit to the shallower seams.
CHAPTER
I
INTRODUCTION AND HISTORICAL REVIEW
The intimate dependence of our
Introduction.
comfort on a supply of cheap coal was brought home
very forcibly to most of us during the strike of April,
1912, when stove-nuts were quoted on the London
Coal Exchange at 40 shillings the ton. Whether we
use the coal itself in our sitting-rooms and kitchens,
or warm ourselves, cook our food, and light our
rooms with gas, we depend ultimately on the same
Nor do we become independent of it by the
fuel.
'
c
adoption of electricity generated as it is in most
cases by steam-power raised by the combustion of
coal.
Our railways too, whether steam or electric,
equally draw their vitality from a regular supply of
the same source of energy. With our coal-supply
cut off, our water-service, pumped by steam-power
from the well to the reservoir, would soon fail us
and worse things would soon befall those towns
;
whose sewage-system depends
on the assistance of steam.
The vast amount of
manufactures
c.
is
coal
for its proper
working
demanded by our various
but when
not so easily appreciated
;
1
COAL MINING
we
reflect that,
summer and winter
[CH.
alike,
thousands
forges, steam-engines, gas-works and
coke-ovens, brick-works and lime-kilns, are devouring the fuel without cessation, while steam-vessels
of furnaces,
are not only consuming it but are carrying
parts of the world for foreign consumption^
some notion
of the extent
and importance
it
to all
we gain
of this
great British industry.
In the sequel we shall see that the requirements
gave origin to an important series
The first steam-engines were
of useful inventions.
constructed for no other purpose than the pumping
the locomotive was proof water from the mines
duced in order to convey the coal from the pit to
the port of shipment, and with the introduction
of iron rails laid the foundation of our present railway-system. In fine, the domestic, the municipal,
and the commercial life of modern Britain depends
of the coal-trade
;
very existence on, as it derives its vigour from,
the fortunate circumstance that, many millions of
years ago, some of the forests and swamps of the
Carboniferous period spread across the site of the
for its
future Britain.
Though the use of coal or
and Elis (Genoa and
Southern Greece) is recorded by Theophrastus about
300 B.C., there is no evidence that the mineral was
known in Britain before the Roman occupation. The
Historical Review.
lignite
by the smiths
of Liguria
HISTORICAL REVIEW
i]
timber sufficed for all the needs
of the natives,
required no lime in the construcof
their
tion
primitive dwellings, and smelted their
with wood or charcoal. There is
iron
and
bronze
abundant supply
of
who
doubt, however, that it was employed to some
extent by the Roman colonists, for smith-work and
little
They also employed it for heatingon
occasion, for coal-cinders were found in
purposes,
in
the
hypocausts at Uriconium (Wroxeter)
plenty
in Shropshire, and coal or its cinders have been discovered on the sites of many of the forts along the
Wall of Hadrian. Their use of it seems however to
have been very limited ; no Roman remains have
been discovered in any of our coal-workings, and
lime-burning.
though in the north of England they built their
mili-
tary stations close to the outcrops of the coal-seams,
the Romans appear to have left the coal practically
untouched.
The Saxon and English invaders seem
known nothing whatever about
them wood was the all-sufficing
to have
To
the mineral.
what
iron they had was smelted with charcoal, and
fuel
;
little
their
buildings, with the exception of a few churches, were
constructed of timber, and needed no mortar
any
lime they used was doubtless burnt with wood. They
;
warmed
and
their halls
peat, even in
and
their hovels alike with
abounded with
In Domesday Book no mention is made of
districts that
wood
coal.
coal,
12
COAL MINING
4
[CH.
though other minerals are alluded to. It could not
have been long, however, before the Norman builders
of castles and religious houses began to burn their
lime and forge their iron with coal, but there is great
difficulty in adducing contemporary records as evidence of this, owing to the fact that originally the
term coal,' or, as formerly spelt, cole,' like the
Greek anthrax and the Latin car bo, signified any fuel,
generally wood. Unless therefore the document appealed to contains some contextual allusion to a pit,
'
it is
'
impossible to assert that the passage in quesSimilarly the term
tion refers to the mineral fuel.
*
'
'
charcoal-burner
and the
Wood-collier's Arms still survives (or did in 1895)
as the name of an inn at Bewdley, affording an
collier
meant at
'
first
'
;
'
instance of this usage of the word among the charcoal-burners of the neighbouring Forest of Wyre.
There appears to be no uncertainty however
about the records of Holyrood and Newbattle Abbeys, which allude to the digging of coal on the
south shores of the Firth of Forth about the year
1200 and early in the reign of Henry III coal began
to be gathered along the coast of Northumberland,
where it was washed up by the surge from outcrops
;
on the shore, and thus acquired the distinctive name
and what is perhaps the first unequisea-coal
of
'
'
;
vocal reference to the mineral in England is contained in a grant, to the monks of Newminster
HISTORICAL REVIEW
i]
5
Adam
de Camhous, of land on the coast
with a road to the shore for the
conveyance of sea-weed and sea-coal (carbo maris).
This was a few years prior to 1236. With regard to
the term sea-coal/ it is of interest to find that by
the time of Henry VIII the origin of the name had
become a matter of uncertainty Leland regarding
it as derived from the fact that the mineral was
gathered on the shore, while Dr Caius attributed it
to the mode in which the coal was conveyed to
London.
During the reigns of Henry III and Edward I,
coal-digging sprang up in most of the coalfields, but
was most active in the great northern coalfield
Abbey, by
near Blyth,
*
;
(Northumberland and Durham), owing to the facility with which the mineral could be floated downstream to the coast at Tynemouth. It was not long
before it began to be shipped thence to London,
where as early as 1228 it appears to have been sold
to the lime-burners of Sea-coal
Lane
(still
in exist-
ence near Ludgate Circus)
and as one William of
had
in
Lane in 1253, the
Sea-coal
Plessey
property
of
of
(north
village
Plessey
Newcastle-on-Tyne)
was probably the source of the first coal to reach
the metropolis. In 1257-9 ship-loads of sea-coal
arrived in London for the smiths and lime-burners,
;
probably at work on Westminster Palace. In
London the brewers and dyers were using it in 1306,
COAL MINING
6
[OH.
though it aroused the opposition of the citizens on
account of its noisome smoke. Coal was employed
by the smiths and lime-burners engaged on the
Edwardian castles about 1300, e.g. Carnarvon,
Beaumaris and Dunstanborough, as can be gathered
from contemporary works-accounts
and in 1366-7
some 576 tons of it were brought from Winlaton in
Durham county for works at Windsor Castle.
About 1300-25 coal began to be tried in a very
;
shy fashion in the castles, abbeys and better sort of
for improvements in architecture carried
houses
with them improved chimneys and fireplaces, without which the new fuel, with its rank smoke, could
hardly have displaced the less sooty and pungent
wood-fire from the central hearth. By the middle
;
demand for coal had
increased considerably, and as early as 1325 a boatload of the mineral left Newcastle for Pontoise in
of the 14th
France
in
;
century the general
but
this foreign exportation
Calais.
was prohibited
1362 and 1367, except to
Up to this time the getting of the coal was not
a very arduous business. The mineral no doubt
was obtained at first from the actual outcrop, i.e.
from the tract along which the coal-seam lay immediately below the soil, and could be got by simple
quarrying. This method of open-work or opencast would be specially applicable in those districts
where the coals crop out along the steep sides of
'
'
'
*
HISTORICAL REVIEW
i]
7
and valleys (Fig. 1, p. 9). In such situations,
moreover, the coal could readily be followed underhills
ground from
tunnels
outcrop, and worked by horizontal
as day-holes or day-levels/ which
its
known
'
'
'
served the double purpose of affording an exit for
the coal and allowing the works to drain themselves.
But
these, modes were less suitable in flatter districts,
and there resuch as parts of South Staffordshire
;
sort
hive
was had to the sinking
of
'
'
bell-pits
or
'
bee-
These were shallow pits sunk through
pits.'
the surface-beds to the desired seam of coal (or of
ironstone), upon reaching which the pit was belledout, and as much of the mineral removed as could
be done with safety. The pit was then abandoned,
and filled up with refuse from a new pit sunk hard by.
But by the middle of the 14th century opportunities for the application of these simple
methods
were becoming fewer in the north of England, and
we begin to read of pits and water-adits, ropes and
windlasses
in fact, coal-mining had entered on the
;
second stage of
its
evolution,
the
'
'
pit-and-adit
The earliest mention of coalstage (Fig. 1, p. 9).
mining implements occurs in an inventory dated
1354 of property belonging to the monks of Finchale
(on the Wear), in which are included ij colpikkes,
i.e. two
coal-picks and two iron wedges.
During the latter half of the 14th century the
use of coal extended rapidly for all manner of
ij
yeges ferrei,
COAL MINING
8
[CH.
purposes where wood was employed before. The
monks of Holy Island were using it in 1344-7 for
their hall, their prior's chamber, and their
infirmary, as well as in their brew-house and their limekiln. It was necessary now to win the coal over areas
warming
farther
removed from the outcrop, and
down
in the direction of the dip.
fore required for raising the coal
;
workings the benefit of natural or
to follow
it
Pits w.ere thereand to allow the
'
free
'
drainage,
long narrow tunnels (adits, soughs, water-gates) were
driven up to the workings from the lowest valley-
bottom
available,
an arrangement that also provided
the workings with a natural ventilation.
The coal
was carried to the bottom of the pit, or out of the
of boys, girls and women, known
and was raised to the surface in baskets
with hempen ropes and windlasses.
During the 15th century the use of coal was
In London it was taking the
steadily spreading.
hearths of the citizens, and in
of
wood
on
the
place
the maritime regions it was coming into use in the
level,
as
on the backs
'
bearers,'
evaporation of sea-water for the manufacture of
salt.
Mention of water-gates or adits becomes more
frequent, indicating that in many districts the pits
and towards the end of the
were being deepened
of Finchale had been
the
monks
(1486-7)
century
;
up a pump at their pits, which had
below the level of natural drainage,
passed
apparently
obliged to set
HISTORICAL REVIEW
i]
and had entered on the third stage
*
9
of their evolution,
'
pit
stage (Fig. 1, below), when it became
necessary to raise both coal and water by artificial
means. In many of the coalfields, however, the
*
pit stage was not reached till the close of the 16th
viz.
the
'
The tools used at this time were few and
simple picks and wooden shovels, 'scopes' (probably
buckets) and ropes were all that were needed. At
century.
:
Fig.
1.
Section showing the three stages of coal-mining. A, the
B, the pit-and-adit ; C, the pit. In
day-hole or day-level
the first, no machinery is needed for haulage or drainage ; in
the second, the coal is raised up the pit by machinery, and
the water drains away by the adit
in the third, both coal and
water are raised by machinery. (After R. L. Galloway.)
;
;
the close of the century the pitmen were still more or
and in some districts continued so till the
reign of Elizabeth, who freed some of her serfs in
less serfsj
1574.
In the 16th century the growing scarcity of wood,
which was steadily disappearing into the furnaces of
the iron-smelters and salt-makers, gave an impetus
10
COAL MINING
[CH.
to the use of coal for domestic purposes.
This was
facilitated by improvements in the construction
of fireplaces and chimneys that came in about the
middle of the century. Various Acts of Parliament
for preserving the woodlands and restraining the
activities of the iron-makers were passed in the
reigns of Henry VIII and Elizabeth, but with little
In the Newcastle district the general doeffect.
mestic employment of coal appears to have begun
about 1570, previous to which its use seems not to
have extended beyond the bloomary, the smithy
and the lime-kiln and by the middle of the century
a considerable foreign export had grown up
but in
view of the feared scarcity of fuel this trade was not
;
;
encouraged. The corf or circular hazel-rod basket,
in which the coal was drawn up the pits, is first
mentioned in 1539 ; it was provided with a wooden
bow
for attachment to a hook at the end of the rope.
This primitive vessel continued in use in some districts for special reasons even as late as 1871
About the middle of the 16th century coal was
being used largely for salt-making by the monasteries
along the coasts of Northumberland and Durham
and in 1555 we first meet with a reference (in a book
by Dr John Caius, one of the founders of Gonville
and Caius College, Cambridge) to the noxious vapours
given off during the working of the coal and the
first recorded underground fire burned for some years
!
;
;
HISTORICAL REVIEW
i]
11
at Coleorton in Leicestershire in the reign of Henry
VIII. There was still a strong objection on the part
of the fine ladies of the metropolis to the domestic
""
sulphurous smoke and
prompted the
certain it is that John
first attempts to make coke
Thornborough, Dean of York, was granted a patent
In this century too the
for that purpose in 1590.
idea of smelting metals with coal instead of with
wood and charcoal began to exercise men's minds
and several patents were granted, but the schemes
Coal was slowly driving wood
all came to nought.
from the kitchen, the hall and the salt-pan, but not
use of coal, on account of
It
smell.
its
may have been
this that
;
till
nearly two centuries later did
it
force its
way
into the smelting-house.
With the opening of the 17th century, we find
James I, however much he may have objected
tobacco-smoke, had no prejudices against that of
that
to
coal,
a fuel he used in his
own chamber.
Coal
now
came rapidly
into general domestic use, except in
districts remote from the coalfields, and even there
wood was looked upon as an extravathe total vend of the northern ports
in 1609 was only 251,764 tons, of which a little over
the free use of
gance.
Still,
a tenth was sent abroad. In that district fears were
already arising that the exhaustion of the mines was
not far off, as the water could be kept down only by
a continuous and desperate struggle. In 1658 is
COAL MINING
12
[OH.
recorded the breaking-in of water from old workand the first
ings, with fatal results, at Newcastle
noticed death by an explosion of firedamp took place
first
;
at Gateshead in 1621.
From the beginning of this century various
schemes were patented for substituting coal for wood
and charcoal
in
some
of the manufactures.
One
of
these had to do with glass-making, which
previously had been seated amid the woodlands
After repeated failures, Robert Mansell,
of Sussex.
Vice- Admiral of England, succeeded in establishing
the
first of
the new process at Newcastle-on-Tyne in 1619, and by
1624 the works employed 4000 hands. The impetus
thus given to the manufacture of glass soon made
itself felt in the increased number of windows introduced into domestic buildings.
It is in the beginning of this century that the
Boringpractice of boring for coal is first heard of.
rods appear to have been made known in the north
of England by one Master Beaumont about 1610,
and were used
in
many
cases where
it
was deemed
advisable to prove the ground before sinking a pit.
Another notable innovation about the middle of the
century was the construction of railways, which had
many years in the mines of Germany.
The wooden wheels of the wagons were flanged and
ran on wooden rails.
Draining the mines now became the most pressing
been in use for
HISTORICAL REVIEW
i]
care of the proprietors.
In
many
13
districts the
work-
by this time below the level of free drainage,
and the mines were dependent on mechanical means
ings were
for raising the water.
Chain-pumps, introduced apparently from Germany, were used about 1670 in
the north, "and were actuated by horses or waterwheels ; they consisted either of an endless chain of
buckets similar to the present-day river-dredger, or
of a chain of discs passing up a tube, as in the pumps
By having
frequently to be seen in our farmyards.
several special pits of graduated depths, water could
by these means be raised from depths of 240 feet.
Where the workings had not yet got below the level
were cut with the pick
at great cost from the lowest valley-bottom availof free drainage, long adits
able
;
some
of
them being
only 18 inches wide.
At this time the coal
several miles long
was
'
raised
and
by horizontal
'
This
pattern.
horse-gins of the
cog-and-rung
or
barrel
which
a
drum
machine consisted of
(on
the rope was wound), placed in a horizontal position
over the pit-mouth. One end of the barrel was of
smaller diameter and built of bars or rungs, with
which the upright cogs of a
were made to
wheel was driven round by a
horses were harnessed.
The
vertical axle
lated
horizontal wheel on a
engage.
This cogged
long arm
to which the
workings were venti-
by the air-currents naturally set up by the
COAL MINING
14
provision of two or
more
shafts, or
[CH.
a shaft and water-
adit.
In 1708 was published the first treatise on coalmining as practised in the Sunderland and Newcastle
In The Compleat Collier, the anonymous
districts.
'
author, F. C.,' has preserved for us a clear picture
of the methods in vogue at that time in the north
of England.
From it we learn that the upper parts
were usually square, 6 feet in the side,
but sometimes only 3 or 4 feet, and lined with timber.
In wet strata a water-tight lining was employed,
resembling the staves of a cask and called tubbing.
Pits of 300 or 400 feet were regarded as exceptionally
of the pits
the usual depth was 120 to 180 feet, the cost
deep
At the working-places the
of such a pit being 55.
coal was filled into corves, several of which were
then placed on a wooden sledge and dragged by the
putters to the bottom of the shaft, then hooked
;
1
'
drawn to the surface by the horseEach corf held about 4| cwt., and the hempen
rope was about an inch in diameter. The gin now
employed for raising coal and water was an improvement on the earlier cog-and-rung gin, and was of
the vertical whim-gin pattern (Fig. 2, p. 15). The
rope-roll was a large wooden drum, with its axle
vertical, and was driven by horses harnessed to long
From the drum the rope passed over a
levers.
to the rope, and
gin.
'
'
pulley in a frame built over the pit-mouth.
This
HISTORICAL REVIEW
I]
arrangement allowed the use
larger drum than in the
earlier form of gin, and
did not require the mechanism to be erected so
to the pit-mouth.
Ventilation was attained
by natural currents from
close
one shaft to another, the
being directed along
the working face only a
air
method known as faceThe coal was got
by the bord-and-pillar
system (i.e. the coal was
in part excavated, and in
part left as pillars), and
airing.
'
in a pit only 360 feet
'
deep
more than half the coal
was left behind to support the roof. The practice of
removing any part
was evi-
of the pillars
dently unknown in the
north in 1708. Thus far
6
F. C.'
Underground
fires
were very prevalent at
of
15
more horses and a
COAL MINING
16
this period, as at Pensnett
[CH.
Chase and near Wednes-
bury, both in South Staffordshire. Dr Plot in 1686
makes one of the earliest references to the use of the
fire-lamp as practised at Cheadle in the same county
for ventilating a mine ; it consisted of a large iron
brazier of burning coal, suspended in one of the
'
'
shaft), which caused an upof air, the corresponding downward
current descending the downcast
shaft.
In the
shafts (the
upcast
ward current
'
'
adjacent county of Worcester, Dud Dudley was devoting heroic efforts to unite the coal and the iron
industries of his native district of Dudley but although he succeeded in 1620 in producing a certain
quantity of iron by his new method of smelting the
ore with coal in lieu of charcoal, his repeated attempts to introduce the process on a commercial
scale were defeated by the vested interests of the
;
charcoal-iron makers.
In 1675 we read of
colliers
being shot out of a
and the
pit's mouth by an explosion at Mostyn
earliest account of the practice of deliberately setting
;
fire to the firedamp in order to get rid of it is contained in a paper relating to the same place and
communicated to the Royal Society in 1677.
The implements hitherto employed by the miner
work of excavation were the pick, the wedge,
but in the rare cases where
and the hammer
in the
;
these did not suffice, the ancient process
known
as
HISTORICAL REVIEW
i]
17
was adopted. The rock to be removed
was heated with fire and then suddenly cooled with
water, with the result that the rock was cracked
and fissured, and could then be cleared away with
the pick and shovel. But about 1719 gunpowder,
which for nearly a century had been employed in
the German mines, was adopted in sinking pits in
'
'
fire-setting
Somerset, though not for blasting the coal itself
1813, when it was resorted to in the north
till
of
England.
At the beginning of the 18th century the greatest
depth to which the pits had attained was about
400 feet. They now began to enter the dry belt of
strata that underlies the watery zone, and it was
not long before serious explosions took place in the
The first happened at
fiery northern coalfield.
Gateshead in October, 1705, and involved the deaths
of over 30 people, one unfortunate youth, Robert
Broune, being blown up a 67-fathom shaft and flung
out of its mouth
But the event that above all others marks out
this period as one of transcendent import to the
!
mining industry
mankind
and, as
it
subsequently proved,
was the invention of the
atmospheric engine. Many of the collieries had been
drowned out and abandoned the appliances in use
for draining them had reached the limit of their
and unless some new device could be hit
powers
to
in general
;
;
COAL MINING
18
[CH.
seemed likely that many coal-districts
it
would be compelled to close down. At this juncture Thomas Newcomen, ironmonger, and John
Cawley, plumber, of Dartmouth, anabaptists, sucupon,
ceeded in 1710 in giving practical shape to the ideas
of Papin and other physicists, who had demonstrated
that the pressure of the atmosphere will depress a
piston in a cylinder when a vacuum has been produced beneath the piston. The result was the
atmospheric or fire-engine, to which at first was
assigned no other part than the pumping of mines.
Newcomen carried out the idea by filling a vertical
cylinder (open at the upper end) with low-pressure
steam led from a boiler, then condensing the steam
by an injection of cold water, and
allowing the resultant atmospheric pressure to push
down the piston. The piston was attached by a
chain to one end of a horizontal beam (a giant pumphandle, in fact), pivoted at the middle, to the other
in the cylinder
end of which was attached the pump-rod, which
was weighted sufficiently to raise the piston after
But as Thomas Savery had
its downward stroke.
a patent (from 1699 to 1734)
water from mines by the agency of
fire, Newcomen' s engine had to be produced under
Savery 's patent, though the two machines had nothing in common. By Savery's machine a sort of
water could be raised some
pulsometer pump
already
secured
for raising
*
'
HISTORICAL REVIEW
i]
19
26 feet by suction (produced by the condensation of
steam), and then forced up a further 64 feet by the
action of high-pressure steam applied directly to the
water.
So far however as draining mines was conthe
Several were
affair proved worthless.
cerned,
erected that served to supply gentlemen's mansions
with water, but the only one that essayed to drain
a flooded pit (near Wednesbury in South Staffordshire) tore itself to pieces
The first of Newcomen's engines was erected in
1712 near Walsall in South Staffordshire; and an!
other, built about 1713 at Griff, near Nuneaton in
Warwickshire, at once saved 650 a year in the cost
of horses.
Thenceforward the employment of Newcomen's engines for pumping mines rapidly extended
into other coalfields particularly where water was
not available for driving water-wheels and chainpumps and rendered it possible to work coal-seams
previously drowned.'
In the middle of the 18th century iron was still
scarce, and entered to quite a small extent into the
construction of the fire-engines, railways and windthe engines were built of
ing-gear of the collieries
'
;
copper, brass and lead ; wooden rails (as the name
implies) were used on the railways, and the windingropes were of hemp. But at last the grand alliance
between the coal and the iron industries was brought
about at the furnaces of Coalbrookdale Foundry in
22
COAL MINING
20
[CH.
Shropshire somewhere about 1730, and the dreams
Dud Dudley were at length realized iron was
smelted on a commercial scale with coal. Yet so
quietly was this revolution brought about that the
of
:
actual date seems to have escaped
all
record
;
but
probable that Abraham Darby began to employ
coke at Coalbrookdale between 1730 and 1735, and at
first may have used it mixed with charcoal, a fuel that
had not wholly been abandoned there in 1 803. Under
the influence of the new process a rapid revival of the
iron industry set in ; the cheapened metal soon made
its way to the collieries, and was adopted for their
and a large number of
equipment and machinery
fire-engines with iron cylinders cast at Coalbrookdale
were built between 1750 and 1775 in all parts of the
it is
;
country.
About the middle
of the century the
deepening
of the collieries, rendered possible by the improved
methods of drainage by the new atmospheric engines,
The raising
was
of the coal by the old horse-gins
becoming a
tedious business underground haulage was growing
more and more costly, now that the workings were
and the
carried to greater distances from the shafts
that
had
obtained
hitherto
standard of ventilation
was proving inadequate for the more extensive, drier,
and fiery workings now being dealt with. In spite
gave
rise to
several fresh difficulties.
;
;
of
improvements the horse-gins were
still
inefficient;
HISTORICAL REVIEW
i]
21
and Michael Meinzies about 1750 introduced the
balance- tub, an arrangement whereby the descent of
a bucket of water was made to raise the coal up the
But this plan could usefully be adopted only
where the water thus carried into the workings could
drain away by an adit. The same principle underlay
his self-acting inclined planes, which enabled the full
shaft.
tubs to pull the empties up the underground inclines.
Carriages drawn along wooden railways by horses
now began to be substituted in the workings for the
Instead of the whole of
sledges dragged by boys.
the air-current being carried past the face where the
coal
was being worked (' face-airing '), it was now
by an arrangement of trap-doors and stop-
directed,
through every part of the excavations a
system known as coursing the air.' In order to
avoid explosions, the working-places in the fiery
mines of the north now began to be illuminated
with the steel-mill, invented by Carlisle Spedding
The machine consisted
of Whitehaven about 1750.
of a small disc of steel which by suitable gearing
could be rotated rapidly by hand against a piece of
flint, and so caused to emit a stream of luminous
Unfortunately it was not till after a numsparks.
pings,
'
ber of explosions had occurred that the steel-mill
was found to be not much safer than the tallow candle.
In 1753 cast-iron flanged wagon- wheels began to be
substituted for the
wooden
ones,
and
in 1767 plates
COAL MINING
22
of the
[OH.
same material were used in the Coalbrookdale
arm the wooden rails.
district to
A great step forward in the evolution of the
atmospheric engine was taken in 1769 when James
Watt introduced the separate condenser and other
improvements, and applied them to the Newcomen
engines, in which the cylinder, as we have seen (p. 18),
was originally used as cylinder and as condenser in
turn, an arrangement involving great loss of steam
and waste of fuel. The simpler engines on Newcomen's original model continued in use, however, for
draining coal-mines, where suitable fuel was cheap.
Watt's engine was moreover still a single-acting low-
pressure atmospheric engine. Attempts to adapt it
to the raising of the coal met with little success ;
and this work continued to be performed in most
districts
by
patterns up
horse-gins of horizontal or of vertical
But about this time waterto 1777.
wheels began to be employed for raising the coal,
especially where natural streams were available. One
pattern had a double set of buckets opening in opposite directions around the periphery, so that the
motion could be reversed when the full corves reached
the top of the shaft. Such a wheel was erected by
Smeaton at Griff near Nuneaton about 1774 for drawing coal and water. Where a natural stream was
not available, an atmospheric engine was in some
cases actually employed to pump water up to a
HISTORICAL REVIEW
i]
23
cistern for the special purpose of supplying the water-
wheel
!
But soon afterward
(in 1779)
Matthew Was-
patented an atmospheric engine designed to produce rotary motion from a reciprocating
one by means of ratchet-wheels with the addition of
a fly-wheel
but the mechanism frequently getting
out of order, Watt introduced the simple device of
the crank. It is said that this idea was pirated by
certain it is that much
one of Wasbrough's party
was
it
to Watt's annoyance
patented by one James
in
Pickard of Birmingham
1780, with the result that
Watt fell back on the
motion
to obtain his rotary
brough
of Bristol
;
;
sun-and-planet mechanism. The engine was still a
but in 1782 Watt
single-acting low-pressure engine
of his masterly
one
came
with
more
forward
once
inventions by arranging to produce a vacuum alter;
nately above and below the piston, and so made it
double-acting and capable of working equally well
at last the piston could push as
in both directions
;
well as pull
;
and
by excluding the atmospheric
Watt converted the atmospheric
later,
pressure entirely,
engine into the low-pressure condensing steamAt once it entered upon a wider field of
engine.
though curiously enough it still retained,
even when applied to widely different ends, the badge
of its original servitude, viz. the pump-handle or beam.
The production of iron with coal-fuel at Coalbrookdale had led to the erection of numerous
application,
COAL MINING
24
[CH.
blast-furnaces in other coalfields, so that the metal
soon became plentiful; and by 1788, out of the year's
total
make
of 68,300 tons of iron, the
coke-made
metal accounted for 53,800, Shropshire leading with
23,100 tons from 21 furnaces. It was natural that
the first iron railways should have been made about
this time in Shropshire.
Cast-iron tubbing for lining
the shafts was now introduced, and a number of other
improvements in mining practice mark the last decade of the 18th century. Atmospheric engines were
used to raise the coal a general substitution of iron
for wood on the surface-railways took place
and
were
installed
both
inclined
above
planes
self-acting
and below ground. Underground railways of wood
became general, on which a wheeled rolley or carriage
capable of holding several corves was drawn by a
The practice of leaving larger pillars with a
horse.
view to a second working began to be adopted, as
;
;
deep pits on the Tyne, 45J per
was the greatest quantity of coal thought to
A most important invention was
be obtainable.
made at this time by John Curr of Sheffield, who
in 1788 introduced
guides,' i.e. wooden grooves,
up to
this time, in the
cent,
'
up each side of the shaft, for the reception
ends of the cross-bar to which the loaded
In this way he secured
carriages were suspended.
smoothness and freedom from collision during the
winding. He next introduced, both above and
carried
of the
HISTORICAL REVIEW
25
below ground, light cast-iron railways of the platerail type, i.e. having the flange on the rail and not
on the wheel (Fig. 3, below). He invented the flat
like a
rope also, which could be rolled upon itself
Catherine-wheel, and so
of the winding-engine.
made
to equalize the
work
Plate- rait
Edge-rail
Edge-rail and plate-rail. In the first, the wheel is flanged
and runs on the edge of the rail in the second, the wheel is
not flanged, but runs on a flanged plate. Our modern railways
and tramways are of the edge-rail type.
Fig. 3.
;
In the South Staffordshire Thick or Ten-yard
Seam, which on account of its liability to spontaneous combustion was worked with a minimum of
ventilation, the inflammable gas was even at this
time (1798) got rid of by the process of firing or
The operation, a somedeliberately exploding it.
what hazardous and exciting one, was carried out
by the firemen,' who obtained their title from being
At Lord Dudley's
told off to do this special work.
'
'
'
COAL MINING
26
pits at
[OH.
was the practice to fire the gas
The modus operandi was as
The place in which the gas had accu-
Netherton
it
three times a day.
follows.
mulated having been ascertained beforehand, the
firemen proceeded from some distant side-chamber
(usually the underground stables) toward the gaseous part of the mine, paying out a thin copper wire
as they went.
Approaching as near to the dangerplace as was prudent, they passed the wire over a
pulley at the end of a long pole, which they then
raised aloft into the gas and fixed securely in the
required position. To the free end of the wire resting on the ground they then fastened a lighted
candle, so weighted as to keep itself upright and
steady.
Retiring
now
to their place of retreat (the
they barricaded themselves in, and began
This raised the candle at the
hauling-in the wire.
other end into the gas, which exploded with great
The excitement arose when from some
violence.
unforeseen cause the explosion failed to come off,
so that the firemen, like boys with a toy cannon,
were faced with the alternative of venturing out to
investigate, and possibly to be caught by the exstables),
plosion, or of remaining prisoners in their own castle.
At Whitehaven, Carlisle Spedding tapped the gas
issuing from fissures in the coal and conducted it in
pipes to the surface he even proposed to light the
;
town with
it,
but doubtless the worthy citizens
HISTORICAL REVIEW
i]
27
were shy of having any dealings with such a dangerous illuminant.
In 1794 the longwall way of working the coal,
by which all of it was removed at one operation and
'
'
no pillars left, was being applied to some of the thin
seams in the Cumberland coalfield, though it had
long been used in Shropshire, to which county it
appears to be indigenous.
The dawn of the 19th century, owing to the
lapsing of Watt's patent rights in 1800, saw a rapid
extension of the use of steam-power. This immediately created an increase in the demand for coal
as fuel, and the extension of the coal-iron manuIn the early years of
facture had the same effect.
the century gas-lighting was introduced by William
Murdoch
and Watt's works at Soho,
and by F. A. Winsor in London
shortly afterward, thus making a new call on the
at Boulton
Birmingham,
in 1802,
coalfields.
In 1800 the estimated coal-output of
the United
Kingdom was
10 million tons.
The most notable improvements, connected with
the collieries, that mark the early part of the century
are concerned with traction. Cast-iron railways both
above and below ground came in rapidly in the
colliery-districts, though at first horses still supplied
the motive-power; wrought-iron rails did not become
till
1820 or thereabout. Steam-engines for
usual
pumping and winding were becoming
general,
and
28
COAL MINING
[CH.
stationary engines were being set up for drawing
wagons up inclined railways by means of ropes. But
the improvement that ranks highest at this time was
made by Richard
engine by getting
Trevithick, who simplified Watt's
rid of its condenser and supplying
with high-pressure steam, and thus converted it
into the high-pressure non-condensing engine, or
Already Murdoch in 1784 had constructed
puffer.'
it
'
a model locomotive engine, but carried the idea no
In 1802 Trevithick, in association with
farther.
Andrew
Vivian, patented certain improvements in
the steam-engine and their application to the propulsion of carriages, and in 1803-4 built at Pen-ydaren near Merthyr Tydfil a locomotive that successfully drew 5 wagons carrying 10 tons of iron and
70 men a distance of 9 miles, though the strength
of the permanent way proved insufficient to bear
the load. But Trevithick somehow failed to popularize his engines, either in South Wales or in the
and although in 1812 John
north of England
;
Blenkinsop, by discarding horse-traction in favour
of engines of his own design, had been able, at Leeds,
to reduce the cost of haulage to one-sixth of its
previous figure, it was not till 1829 that Robert
Stephenson, by a happy combination of improvements introduced by others, built the Rocket and
placed the locomotive-engine on a sound commercial
looting.
HISTORICAL REVIEW
i]
At
this
29
time the ventilation of the mines con-
tinued to be produced by fire-lamps, or by furnaces
placed at the bottom of the upcast shaft ; and in
fiery places in the workings, light was still obtained
But a long list of explosions in
steel-mill.
from the
the north marks the beginning of the 19th century,
and shows that the ventilation was inefficient, and
the steel-mill and even the ventilating-furnace it-
a source of danger. The great problem of the
self
how to work the mines without risk of
time was
In some cases the gas was carried in
explosion.
surface and burnt there
to
the
and in 1805
pipes
:
;
James Ryan proposed by taking advantage
of the
low
specific gravity of the gas to drain it off by
special passages ; and in 1808 he successfully applied
system to the Netherton Colliery near Dudley.
Another difficulty that had to be contended with,
especially in the deep pits of the north, was creep.'
his
'
This phenomenon consists of a bulging-up of the
excavated passages, and its ultimate
coalescence with the roof.
It arises where the pillars of coal left to support the roof are of insufficient
size in proportion to the passages, so that the whole
weight of the overlying strata, being thrown on to
supports too small to carry it. forces the pillars
downward into the floor-strata usually soft and
yielding with the result that these buckle upward
wherever free to do so. At the same time the pillars
floor of the
COAL MINING
30
[CH.
themselves are frequently crushed, the coal therein
spoilt, and the workings thrown into a state of
dangerous insecurity. And as creep set up at one
spot necessarily throws more weight on adjacent
pillars, the disease is apt to spread rapidly throughout the whole colliery. To guard against this disaster, John Buddie, junr. in 1810 introduced panelwork,' i.e. the laying-out of the workings in districts
or panels (? like the panels on a door), of 30 acres or
more, separated by wide barriers of solid coal 40 to
60 yards wide. Thus if crush and creep appeared
in one panel, they might be prevented from spreading
'
into those adjacent.
While developing the system
Buddie introduced
at Wallsend,
'
'
split-air
method
of ventilation.
of panel-working
his
compound
or
Instead of the
whole current from the downcast shaft being carried
along every passage in the mine (a distance in some
cases of 30 miles), he divided it at the bottom of
the shaft into two or more currents, each of which
traversed only one panel. But though Buddie's
method, which still remains the most efficient system
air-distribution, did much to render the
sphere of the mine safer and more wholesome,
of
atmoit
was
powerless to prevent risk of explosion from sudden
discharges (' blowers ') of gas, either from old workings or from fissures in the coal
naked
lights were employed.
itself,
so long as
HISTORICAL REVIEW
i]
At
this juncture
Dr Clanny
of
31
Sunderland de-
lamp that could be used in an explosive
atmosphere without firing it, but the instrument
vised a
was not convenient for practical purposes. About
the same time an explosion near Jarrow in 1812
determined the incumbent of the parish, the Rev.
John Hodgson, to employ his pen in bringing the
facts before the general public.
This led a London
barrister, J. J. Wilkinson, to form a society for the
prevention of accidents in coal-mines, and in 1815
this body obtained the help of Sir Humphry Davy
in the matter.
That philosopher discovered that
a lamp furnished with sufficiently small air-holes
would not communicate flame to an explosive
and finally he produced the wiremixture outside
"
the
metallic tissue permeable to light
gauze lamp,
and air and impermeable to flame." Davy nobly refused to patent his invention, preferring not to enhance the cost of an instrument designed to preserve
the life of man. His safety-lamp not only did this,
but also enabled immense quantities of coal to be
got that otherwise would have been, and actually
had been, abandoned ; and by the removal of the
pillars, rendered possible by the Davy-lamp, 80 per
cent, of the coal could now be got out.
In the first quarter of the 19th century the shafts
in the north varied from 6 to 15 feet in diameter ;
and at Monkwearmouth had attained a depth of
;
COAL MINING
32
[OH.
1590 feet, the cost of a single shaft in some cases
reaching as much as 40,000. In Wales and the
Forest of Dene, on account of the depths of the
valleys, free natural drainage was still available even
in 1835.
By 1827 Shropshire had been outstripped
and South Wales in the make
the latter leading with 272,000 tons,
while Staffordshire produced 216,000 and Shropshire
only 78,000, in a total for the United Kingdom of
690,000 tons ; and in 1828 the last of the charcoaliron furnaces of Sussex (that at Ashburnham) was
dismantled.
The next notable advance in colliery engineering
was made by T. Y. Hall of Ryton-on-Tyne, who
after various unsuccessful attempts at improving
by both
Staffordshire
of pig-iron,
the methods of winding, introduced in 1835 the twodecked iron cage travelling between guide-rods and
accommodating two iron tubs on wheels. Thus was
initiated the modern system of winding
and the
old corf or basket, which had been in use from time
immemorial, was rapidly abandoned, with the curious
result that the price of hazel-nuts in the London
market was at once and permanently lowered.
blowers locally
Explosions, due generally to
were
the
still frequent in
ventilation,
overpowering
the deep and fiery mines of the north, and what was
probably the last explosion to blow human bodies
from the shaft-bottom to the surface took place in
;
*
'
HISTORICAL REVIEW
i]
1817 at the
Durham
Row
33
Pit (480 feet deep) at Harraton in
Davy-lamps gradually came
between 1817 and 1835, though the extended
application of gunpowder in breaking-down the coalface rendered their employment no safeguard, as
the gas would fire by the blast of the explosive just
as readily as at a naked candle.
Improvements in
ventilation at this time took the form of an increase
In the north, underground
in the volume of air.
furnaces were general, but in many of the Midland
pits the fire-lamp was still in vogue, wherever natural
But in 1835 John Martin
ventilation did not suffice.
the
coalfield.
into use
made
the fruitful proposal to employ a fan in place
of the furnace, a suggestion that ultimately revolutionized entirely the system of mine-ventilation.
In 1835 a committee of the House of Commons,
an enquiry into the management of coal-mines,
certain recommendations for the avoidance of
accidents.
While Government inspection and regulative enactments were not considered desirable,
after
made
brattices (brick or wooden partitions) in ventilatingshafts were condemned, and the keeping of maps
and plans was thought worthy of encouragement.
George Stephenson however went so far as to consider that the sinking of two shafts should be made
compulsory.
By the commencement of the Victorian era the
coal and iron industries had fairly entered the
c.
3
COAL MINING
34
modern period
;
[CH.
the main lines of practice had been
already laid down, and subsequent improvements
have been for the most part matters of detail. Certain exceptions however call for mention.
The risks
of explosion at the ventilating-furnace itself had led
to numerous proposals for substituting some safer
method
of producing the air-current
and in 1828 a
Stewart successfully installed a system of steamjet ventilation at Hendre-f organ near Swansea by
discharging a jet of high-pressure steam at the
bottom of the upcast shaft and for a while a brisk
controversy ensued between the upholders of the
furnace and the advocates of the steam- jet as the
more efficient ventilator. But a rival to both these
methods, and one destined to outstrip them, was
rapidly coming to the front. In 1837 William Fourness of Leeds brought out an exhausting-fan on the
;
Mr
;
winno wing-fan principle and in 1844, by producing
a machine capable of exhausting 13,500 cubic feet
of air per minute, successfully inaugurated the
;
modern system of ventilation.
A most important improvement in the winding
arrangements was rendered available in 1839, when
Andrew Smith patented his iron-wire ropes and from
1840 onward they came rapidly into use in the nor;
thern mines, where previously ropes of hemp, usually
flat, and rolled Catherine-wheel fashion, but occasionally round,
had been employed
in general.
The
HISTORICAL REVIEW
i]
great weight of the
cases to their being
35
hempen ropes had led in some
woven taper-wise, as at Monkwhen a new flat rope, 600 yards
wearmouth, in 1837,
long, 8J inches broad at the top, and narrowing to
5| inches at the bottom, was set up at a cost of
300, with a prospect of its lasting little more than
a twelvemonth. In the shallower pits of Shropshire
and South Staffordshire, iron chains were usual
and
during the first half of the 19th century
although their clank and rattle are heard no longer,
they may still be seen in the vicinity of the pits,
serving the useful purpose of fencing.
About 1850 the double-cylinder engine, without
a fly-wheel, was introduced for winding and haulage
purposes and about this period various devices were
patented for the prevention of over- winding (i.e.
pulling the cage up into the framework over the
shaft), and for stopping the fall of the cage, should
the rope break. Underground, the old and cumbersome practice of conveying several tubs on a wheeled
carriage or rolley along the main roads began to be
given up about 1841-2 in favour of trains of tubs
running on their own wheels along malleable iron
;
4
;
'
'
edge-rails.
Patent fuels began to receive attention about
1838, the object being to utilize small coal by binding
it together with some such material as coal-tar and
moulding the mixture into bricks that could be used
32
COAL MINING
36
[CH.
It has long been the practice among the
South Welsh country-folk to turn to account the
local culm or fine slack by mixing it with clay or
lime into a coherent mass capable of being moulded
as fuel.
by hand
'
'
a fuel certainly more pleasant
consumption than that manufactured at
Westminster about 1819 by one Chabauner, in which
a principal ingredient was the sweepings of the
into
balls
for kitchen
streets
!
During the latter half of the 19th century many
improvements were introduced, some of which will
be described in the following pages, such as the
modern methods of boring and shaft-sinking, coalcutting by machinery, and new forms of safetybut these are concerned chiefly with the
lamps
mechanical and engineering departments of coalmining. The most striking innovation of recent
;
the application of electricity in the departpumping, winding, coal-cutting,
As a
lighting, signalling, drilling, and shot-firing.
form of energy it is easily conducted by wire to all
years
ments
is
of hauling,
parts of the mine,
and
in this
way
is
much more
than compressed air, which is sometimes used as a motive-power. Electricity, however,
has the drawback of being a source of some danger
from sparking, with the attendant risk of firing the
gas, and is not free from the liability of giving fatal
easily installed
shocks to the workmen.
KINDS OF COAL
ii]
37
Having now sketched the evolution
of mining-
processes from the earliest times, we shall next proceed to a description of the operations as practised
at the present day, prefacing that description with
such geological observations as are necessary for a
proper understanding of the various methods of
working the coal.
CHAPTER
II
VARIETIES, GEOLOGICAL AGE
ORIGIN OF COAL
SINCE the natural history
of in another
volume
AND
been treated
a brief summary
of coal has
of this series,
alone will be attempted here.
Varieties of Coal.
The term coal as used to-day
covers a variety of substances differing greatly in
physical and chemical properties, in their ages, and
modes of formation. But all coal-seams are in the
beds of ancient vegetable matter more or
chemically altered, composed chiefly of hydrocarbons (compounds of hydrogen and carbon), and
last resort
less
suitable for use as fuel.
The common
varieties of
coal are Lignite, Brown Coal, Cannel Coal, Coking
Coal, Gas Coal, House Coal, Steam Coal, and Anthracite.
Very closely in the order here adopted they
COAL MINING
38
[OH.
diverge gradually in their chemical, and largely in
their physical, properties from Peat, the recent vegetable accumulation of our swamps and moorlands,
and approach in character the Graphite of which
pencils are
this,
will
made.
however, that
ultimately be
It
must not be
inferred from
coal originated as peat, and
converted into anthracite or
all
graphite as the final result of metamorphic processes (p. 51).
In Lignite the woody constituents are so little
form and structure are usually
altered that their
while leaves, bark, and other tissues are
often well-preserved.
Lignite is brown to pitchblack in colour and burns easily, emitting a smoky
discernible
;
flame and an unpleasant odour. In the Brown Coals
the woody constituents are not obvious to the eye.
Cannel Coal is black or brownish in colour, dull and
lustreless, clean to the fingers, and can be carved
into ornaments. The choir of Lichfield cathedral
was formerly paved with squares of cannel obtained
probably from a seam in Beaudesert Park near
Rugeley. It can be ignited with ease on the application of a burning match, and burns with a smoky
yellow flame like that of a candle hence its name.
It is specially valued for making gas, a ton of Wigan
cannel yielding over 14,000 cubic feet of gas of 39
candle-power. The House Coals, familiar to us all,
are generally more or less lustrous, dirty to the
KINDS OF COAL
n]
fingers,
and tend to
split
39
along the bedding-planes,
and
also to break crossways along joints usually
Traces of the original
at right angles to each other.
a
rule
not easily seen with
as
are
matter
vegetable
but if a piece be broken across it
be found to consist usually of alternating dull
the naked eye
will
;
and bright layers.
The Steam Coals are nearly devoid of lustre, slow
to ignite, evolve little gas or smoke while burning,
but give out an intense heat hence their value for
generating steam-power, and their importance from
a naval point of view. The best steam coal is obtained from the South Wales coalfield. Anthracite
or Stone Coal is, next to graphite, the purest form
of natural
diamond.
carbon obtainable except of course the
It has a brilliant lustre resembling that
of graphite, is clean to the touch, and is harder,
denser and more brittle than ordinary house coal ; it
is difficult
to ignite, burns slowly,
makes
little
ash,
no smoke, but burns with the blue lambent
flame of carbon monoxide. In this country it is
obtained almost wholly from the north-western
and western districts of the South Wales coalfield
and from the southern Irish coalfields. A good
gives off
anthracite contains as
much
as 95 per cent, of carbon.
It is largely used for hop-drying
and malting.
Behaviour during Combustion. In their mode of
burning, coals can be grouped as (1) caking coals,
COAL MINING
40
and
(2)
[CH.
dry, free-burning or non-caking coals. Those
group partially fuse and cake together,
of the first
and at first emit much flame and smoke, and extrude
bubbles of tarry matter and hissing jets of gas but
after these volatile matters have been burnt off,
combustion slackens and in an inadequate draught
comes to a standstill, leaving in the grate a dead
accumulation of unconsumed coke. Their property
of caking, however, gives these coals their value as a
source of coke, as the small coal and slack not suitable
for household purposes can so be utilized.
The noncoals
burn
no
coke
or
cinder,
caking
freely, leaving
and evolve no tarry matter. Some house coals, e.g.
from the Durham coalfield, are caking while others,
;
;
as
most
from South Staffordshire, are
of those
free-
burning.
The
Suitability.
suitability of a
coal for
any
particular purpose depends chiefly on its behaviour
during combustion, its hardness, and its chemical
soft coal is wasteful, as in its passage
composition.
A
from the
much
pit to the place of consumption it produces
small coal and dust, for which little use can be
'
the form of iron pyrite, brasses,'
FeS 2 ) is usually detrimental a pyritous coal during
combustion evolves sulphur dioxide (SOJ, a pungent
gas that not only offends the nostrils but also attacks
found.
Sulphur
(in
;
metals, such as the bars of grates and furnaces and
the plates of boilers. Lumps of iron pyrite are seldom
AGE OF COALS
ii]
41
allowed to get as far as the coal-scuttle, but the
mineral may often be seen as a thin brassy film on
the joint-faces of some of the pieces of coal. Pyrite
is particularly objectionable in a gas-coal, owing to
the vitiating effect of the resultant gas, when burnt,
on the atmosphere of the dwelling-room moreover,
it sometimes contains a dangerous amount of arsenic,
which renders pyritiferous coals unsuitable for hop;
drying and malting.
The geological age of
Geological Age of Coals.
coals is a matter of considerable practical importance.
In the British
Isles
our coals are referable to the Oli-
gocene, the Jurassic, and the Carboniferous systems.
The Lignite of Bovey Tracey in Devon is of Oligocene
age ; the coals found on the Yorkshire coast, at Brora
in Sutherland, and at Kimeridge in Dorset, are all of
Jurassic age. But none of these is of much economic
its own immediate district
and, in this
when we speak of coal, we mean Carboni-
value outside
country,
ferous coal, that
systems
of
of rocks,
known
;
is,
coal found in the Carboniferous
and especially in that division there-
as the Coal Measures.
These consist
of
a
great series (in South Wales as much as 10,000 feet)
of alternating conglomerates, sandstones, shales and
and occasional thin limestones,
the
by
presence of certain fossils
(plants, mollusca, reptiles, insects and fishes) more or
less restricted to that series, and giving evidence
clays, with ironstones
all
characterized
COAL MINING
42
of conditions
lacustrine
or
[CH.
that were predominantly estuarine,
terrestrial.
Within these measures
the important coals of England, of Wales
Ireland; though in the extreme north of
Northumberland, in Cumberland, in Scotland and in
Antrim, coals are found in the Lower Carboniferous
rocks also (see Table, p. 47).
occur
and
all
of
The subjoined complete
list of
the British geo-
logical systems, arranged in descending order,
the positions of those which yield coal.
shows
BRITISH GEOLOGICAL SYSTEMS
RECENT (Peat)
Pleistocene
j
Quaternary
Kainozoic
t
absent from Britain)
(Lignite of Bovey Tracey)
(Miocene
OLIGOCENE
Eocene
{Pliocene
^Cretaceous
Mesozoic
I
JURASSIC (Coals of Brora, Yorkshire Coast, and
Kimeridge)
[Triassic
Permian
CARBONIFEROUS
(all
ordinary coals and anthra-
cites)
Devonian
Palaeozoic
Silurian
j
Ordovician
j
\
Eozoic
Cambrian
Archaean
Wherever the
geological succession
is
complete,
the Coal Measures overlie the partly estuarine but
ii]
AGE OF COALS
43
marine sandstones and shales of the Millstone
which
in its turn succeeds the Carboniferous
Grit,
Limestone with its rich and wholly marine fauna.
Above the Coal Measures follow the red poorlyfossiliferous lacustrine and desert-formed rocks of the
Permian and Trias. The position of our coals in
chiefly
the series of geological systems
well known, and if coal-seams
thus perfectly
is
were present in
the other members of that series e.g. in the Silurian
or in the Trias there is not the least doubt that, in
a long-settled and surveyed country like ours, they
would have been discovered ages ago. If therefore
we are asked whether coal will be found under a
certain property, the first point to ascertain is
what
:
system
of rocks occupies the surface
?
If the system at the surface is older than the
Carboniferous it follows that as a rule the deeper we
bore or sink, the farther away from the coal shall we
Yet such an obvious inference as this needs
go.
emphasis when one
finds,
as recently as
1912, a
boring for coal being driven for hundreds of feet into
the Silurian rocks of Radnorshire
!
In the past, considerable sums of money have
been expended on boring and sinking for coal into
some of the Ordovician and other rocks both older
and newer than the Carboniferous on the strength
of their consisting largely of black shales very like
those of the Coal Measures. Even as recently as
44
COAL MINING
[OH.
ten years ago a level for coal was opened, with some
of ceremony, in the side of a hill on the outof
the Ordovician rocks in Carmarthenshire.
crop
No coal had ever been seen to crop out anywhere in
the neighbourhood, but it was enough that the beds
were sooty black shales. The fact that they were
full of Ordovician graptolites, an order of marine
fossils that had become extinct long before Carboniferous times, was un-noticed or ignored by the
amount
credulous projectors.
If the surface-rocks are newer than the Coal
Measures, there are two methods by which it may
be ascertained whether Coal Measures lie below.
Firstly, a thorough knowledge of general and local
geology should be brought to bear on the problem ;
but if the data available lead to no definite conclu-
second method, namely boring, must be
adopted. By this means samples of the rocks can
be brought to the surface and examined by the
sion, the
geologist (p. 73).
But even where rocks newer than the Coal
Measures come to the surface, it does not follow that
coal, or even the Coal Measures themselves, will be
found below. Firstly, the coal-bearing strata may
never have been deposited, as the site may have
formed part of a land-area at that time secondly,
if deposited, the Coal Measures and their contained
coals may have been worn off and destroyed prior to
;
AGE OF COALS
n]
45
the laying down of the strata that now occupy the
surface in both cases a gap will be found in the
It may thus happen that a
geological sequence.
:
boring, after traversing rocks newer than the Coal
may pass abruptly and quite unexpectedly
into pre-Carboniferous rocks.
Measures,
A
consideration of an actual example will make
In view of the approaching exhaustion
this clear.
of the
exposed coalfields of Coalbrookdale and South
Staffordshire, an attempt was made some ten years
ago to ascertain whether coal could be reached at a
workable depth beneath the Triassic and Permian
rocks that occupy the intervening area, and a boring
was put down at Claverley, between Bridgnorth and
Commenced in the upper part of the
Permian, and passing through that formation and
all three divisions of the barren Upper Coal Measures,
it entered the productive Middle Measures at a depth
of 1797 feet, with every prospect of success.
But
after traversing 393 feet of shales, sandstones, fireStourbridge.
clays, ironstone-bands, and several thin and useless
coal-seams, all of the usual character, and containing
the usual
the
suddenly entered a
hard grey rock, which contained Atrypa reticularis
and other recognizable marine mollusca that demonstrated it to be Silurian. The whole of the valuable
lower part of the local Coal Measures, in which the
chief coals of Shropshire and South Staffordshire are
fossil plants,
drill
COAL MINING
46
[CH.
would thus appear to be absent. Prethe
Silurian rocks, while the coal-seams were
sumably
accumulating in adjacent districts, had here formed
a shoal or a land-tract that was not submerged till
towards the Upper Coal Measure period. No survey
situated,
have foreseen such a result ; but
obvious that in this case not only was the precaution of boring before sinking a very wise one, but
also that a knowledge of fossils was of much value in
preventing the borers going deeper.
In some cases it has been found on boring or
sinking through the overlying newer rocks that although the productive part of the Coal Measures is
present, yet the coal-seams themselves have locally
of the surface could
it is
thinned-out, or have so deteriorated in thickness or
in quality as to be worthless.
Coal Measures actually occupy the surface, a
knowledge of the local geology will generally indicate
whether and at what depth coals may be expected.
It by no means follows, however, that all Coal
Measures contain coal. Though occasional thin
If
seams and streaks
of coal are present throughout,
the valuable coals are restricted to the lower and
middle parts of the Coal Measures, as shown in the
following Table, in which the subdivisions of the
Upper Measures are those adopted by Dr Gibson
and other officers of the Geological Survey as a
result of work in North Staffordshire
'
'
:
FOSSILS
ii]
47
British Carboniferous System, showing Positions
of Workable Coals
f
r
Upper
Barren
(red)
Coal
fKeele
Beds
(red)
J Newcastle Beds
J
(grey; a few coals)
")
I
[
*
'
Upper
Measures
I Etruria Marls (red) J
Productive /Middle Measures \with all the
\ Lower Measures J chief coals
t
(g re y)
I Millstone Grit (a few coals)
|
|
Measures
Carboni-xj
ferous
|
T
J-^ower
f Carboniferous Limestone Series (with
Scotland, North of England, and
Ireland)
J
Carboniferous
coals
North
^
Organic Remains. The vegetation of the coalperiod as preserved in the coal-seams and their
associated rocks was predominantly composed of
vascular cryptogams and other flowerless plants of
arborescent habit referable to five chief groups, viz.
the Lycopodiales, the Equisetales, the Pteridosperms
and Filicales, the Sphenophyllales, and the Cordai-
The first two are represented respectively by
our present-day Club-mosses (Selaginella, Isoetes,
etc.) and Horsetails, and the Filicales by the modern
tales.
but the other groups are extinct. The flora
the period thus presented a very sombre and
monotonous aspect
the flowering plants of our
Ferns
;
of
;
modern landscapes, with all their variety of colour,
had not yet appeared. Most of the plants grew to
a great size, stems of Lepidodendron and Sigillaria
50 feet in length being not uncommon.
The Lycopodiales were represented chiefly by the
in
of
COAL MINING
48
[CH.
genera Lepidodendron and Sigillaria. In the first,
the stem is covered with the spirally-arranged
lozenge-shaped leaf -bases. Its fruit was a cone
known as Lepidostrobus. In Sigillaria the stem is
usually marked by vertical ribs on which the leafscars are placed at intervals one above another ;
sigillarian bark frequently composes the bright bands
in a coal-seam.
The root-like organs of both
Lepidodendron and Sigillaria are very often found in
the underclays of the seams and are known as Stigmaria their surfaces are characterized by oval scars
from which rootlets spread into the surrounding mud.
'
'
The Equisetales were represented by numerous
species of Calamites, whose lofty jointed stems made
up dense thickets along the swamps, as do its nearest
modern
relatives the Horsetails along the
margins
The stems, which bore narrow leaves
of our ponds.
arranged in whorls at the nodes, are generally preserved in the fossil form as casts of the pith-cavity.
The Pteridosperms were plants with fronds
resembling more or less closely those of some recent
ferns, but distinguished by the bearing of seeds and
not merely spores, and by certain anatomical features.
The Sphenophyllales were
slender
herbaceous
plants resembling the Calamites in habit.
The Cordaitales included large trees characterized
by long strap -like leaves and in habit resembling the
Kauri Pine
of
New
Zealand.
USE OF FOSSILS
ii]
49
these plants probably formed dense
low ground bordering the lagoons but
it is likely that on the uplands others flourished,
of which few relics have been preserved.
Through
the moist atmosphere flitted a few primitive mayflies
Many
of
jungles in the
and
;
while scorpions, spiders and millicrawled
pedes
along the rotting stems. There were
no birds .to prey upon them. In the waters below, a
few ganoid fishes disported themselves and afforded
sustenance to the salamander-like Labyrinthodonts ;
while mud-loving bivalve molluscs Carbonicola,
Anthracomya and Naiad ites closely resembling our
pond-mussels, fattened in the slime beneath. Occasionally an irruption of salt water brought with
it some mollusca of the outer sea, such as species
dragon-flies
;
and
of Productus, Chonetes, Lingula, Pterinopecten
Gastrioceras.
Use of Fossils. Not only is a knowledge of fossils
of great practical importance to the miner in enabling
him to guard against fruitless sinkings in rocks
known
elsewhere to be devoid of coal, but it is also
of use in helping him to distinguish one part of the
Coal Measure series from another. The plant-
remains form a useful index for this purpose, as
Kidston, Arber and Walcot Gibson have shown
for certain plants are restricted to the Upper Coal
Measures, while others have not been found above
the Middle Measures. The mollusca are still more
;
c.
4
COAL MINING
50
[CH.
and can often be depended upon to identify
seam in widely-separated coal-pits.
So far then from fossils being merely the playthings
of the curiosity-hunter, in the hands of the geologist
useful,
a
particular
they are of the greatest value in directing the collier
to a suitable place for his operations and in protecting
him from futile and hopeless undertakings.
Conditions of Deposition. It is generally agreed
that the coal-seams originated from vegetable matter
produced by the decay of luxuriant swamps and
which spread out from the land into the
shallow waters of estuaries, lagoons or lakes, much
as do the present-day mangrove-swamps of tropical
But two different views have been held
countries.
The
to explain the formation of the seam itself.
forests,
'
'
advocates of the
theory believe
growth-in-situ
that the seam represents the actual peat-bog or
morass itself, and that the underclay generally found
below the seam is nothing else than the soil on which
On the other hand, the adthe vegetation grew.
herents of the drift theory believe that the vegetable
debris of the swamps was carried out into the lagoon
by running water and there deposited like any other
sediment. So good a case has been made out by
both parties that it appears certain that some coals
have been formed in one way and others in another,
while it is highly probable that in many cases both
modes of formation have shared in the production
of a single seam
'
'
.
COAL FORMATION
ii]
51
Formation. After a mass of vegetable
had accumulated, the slow subsidence that
affected the region carried the mass below waterlevel, preserved it from decay, and sealed it up under
layers of gravel, sand and mud, where it became
converted into a seam of coal. The processes to
which this conversion are to be attributed have been
Coal
debris
discussed at length by Dr E. A. N. Arber. They
appear to have been chiefly biochemical, and due
they were attended by a
oxygen and hydrogen, and an evolution of
carbon dioxide (C0 2 ) and methane (marsh gas, CH 4 ),
to the action of bacteria
;
loss of
the final result being a pulp of hydrocarbons, relatively richer in carbon, in which organic structures
are largely obliterated.
Whether the resulting coal
is
sapropelic (such as cannel), or humic (e.g. house
seems to have been determined
coal), or anthracitic,
chiefly by the extent to which bacterial action had
proceeded before being arrested by the poisonous
organic acids to which that action gave rise, though
differences in the nature of the vegetation no doubt
had much influence. There is good evidence that
the conversion of the vegetable debris into coal took
place soon after its entombment, and that subsequent heat and pressure, consequent on its burial
deep in the earth-crust, did little more than consolidate and harden it.
42
COAL MINING
52
CHAPTER
[OH.
III
THE COAL MEASURES AND THE COAL-SEAM
The productive Lower and Middle
Lithology.
Coal Measures of Britain consist of a great series of
conglomerates,
grits,
sandstones, shales and clays,
with bands of ironstone, and numerous seams of coal.
These materials were laid down, never far from land,
in the shallow waters of swamps, lagoons and estuaries, to
which the sea gained only occasional access.
so the accumulating
As the region slowly subsided,
sediments increased in thickness, till in the deeper
hollows as much as 10,000 feet had been deposited.
The coarse pebbly materials forming the con'
glomerates
('
pudding-stones of the miner) are seldom
but are irregularly bedded and lenticular,
signs of rapid accumulation and repeated
sorting by change of currents, with re-deposition
not far away. They often form a basement-group
to a series of sandstones, which are usually more
persistent and can frequently be traced for several
miles.
Where these coarse materials were deposited
uninterruptedly for a lengthened period over wide
areas, they constitute an important member of the
local Coal Measure sequence, as is the case with the
Pennant Sandstone group of South Wales, the Forest
of Dene, and Somerset, which attains a thickness of
persistent,
and show
COAL MEASURES
m]
53
Few coal-seams occur within
sandstone groups. Usually, however,
sandstones, shales and clays alternate with each
other, and also pass laterally one into the other.
several thousand feet.
these
thick
The shales and clays, which are more persistent
than the sandstones, and make up the larger proportion of the Coal Measures, are more tranquilly
formed deposits of fine-grained clayey matter. The
'
binds of the miner) are composed of thin
often
no thicker than a post-card, the surfaces
layers,
of which are frequently covered with a film of sand
or flakes of mica, which give them a fissile character,
so that they readily split into thin slabs, plates, or
The clays ('chinch' and 'clod') are beds
leaves.
of non-laminated mud that crumbles into small
The ironstones are generally
irregular fragments.
shales
('
nodular concretionary masses of earthy carbonate,
in the form of flattened balls ranging up to a foot or
more in diameter, or smaller irregular lumps scattered through the shale. In the past they constituted
the chief source of our iron-supply, and were worked
on a large scale in South Wales, Coalbrookdale, and
South Staffordshire.
All these rocks vary in colour from white to intense black, dependent on the amount of carbonaceous matter present. Where exposed at the surface
the sandstones, owing to the oxidation of the ironcompounds usually diffused through the stone, tend
COAL MINING
54
[CH.
to weather with rusty-brown, red, or yellow tints ;
but the shales and clays lose their grey or black
The fossil -remains of plants,
of the beds, are specially wellpreserved in the shales ; while fragments of fernleaves or shells often form the nucleus around which
colours less readily.
abundant
most
in
the ironstone segregated.
The productive Lower and Middle Measures are
succeeded in most of the Midland coalfields by an
Upper series of relatively barren measures, in which
a red colour prevails (see Table, p. 47). In these,
coals are rare, thin, and often pyritous ; several
limestones occur, not more than a foot or so in
by the presence of annelids
and entomostraca (Spirorbis and Carbonia, etc.).
The red Etruria Marls of the Upper Measures are
the source of the famous Staffordshire blue bricks.'
The coal-seams themselves when viewed on a
true scale form a very small proportion of the total
thickness, characterized
'
thickness of the Coal Measures
;
so that in 10,000
South Wales, for instance, the coals
account for only about 124 feet, which,
feet of strata in
in
Glamorgan
distributed in 48 seams, gives an average of 2 ft. 7 in.
for the thickness of each seam.
A coal-seam occurs
as a definite bed of rock, just like its associated sandstones and shales, and usually runs for long distances,
maintaining
its
own characters and
position in the sequence over
holding its proper
many square miles.
COAL MEASURES
Ill]
55
But the seam is itself usually more or less composite,
and consists of bands of coal separated by partings
of shale or clay ;
of a single seam
while the constituent coal-bands
may
differ
among themselves
in
quality and thickness.
As an example of the kinds of strata passed
through in a coal-shaft, the following section of the
upper portion of a pit at Polesworth (Warwickshire)
may be quoted
:
Shaft-section at Polesworth
Soil
Gravel and sand
Blue bind
COAL smut
Clunch
Blue bind
Stony bind
Strong blue stone
Blue bind
COAL
Stony clunch
Stony bind with ironstone balls
Clunch and bat with ironstone b
Strong bind
Soft bind
..
COAL
Strong bind
Soft bind
Clunch and bat
Stony clunch
Blue bind with ironstone
COAL: Smithy Coal
.
.
Is
COAL MINING
56
The
16
ft.
9
'
[CH.
'
gravel and sand met with to a depth of
Bind
are probably Glacial deposits.
'
'
in.
'
'
a miner's term for shale
clunch is a tough
rock
the
blue
stone
is presumably
clayey
strong
sandstone but possibly shale
bat is a highlycarbonaceous black shale. The Smithy Coal, being
the only one in the section of any importance, has
alone been dignified by a distinctive title. The coal
at 20 ft. 3 in., being close to the surface, appears to
have weathered to a powdery condition, and is
recorded as a smut.'
As an example of a single seam made up of
several coal-bands of different character, the following section of the Barnsley Seam of Yorkshire may
be given
is
;
'
'
;
'
'
;
'
:
Ft. In.
Coal called the
Day Bed
.
Parting (fireclay)
Coal called the Middle Bed
Coal caUed the Low Bed
.
2
coals
1
1
2
2
3
8
7
8
2
9
7
Seam
Low Bed and
from the Day Bed, the
Slottings are gas-
1
.
Parting (fireclay)
Coal and pyrite, called the Clay
Coal called Hards
Coal called Slottings
The
1
.
and house-coals
;
the Hards
is
the
used
THE COAL-SEAM
in]
57
while the
for coke-making and steam-raising
pyritous coal of the Clay Seam serves for lime- and
brick-burning.
Eoof and Floor. The bed of rock that immediately overlies the coal-seam is known as its
;
roof.
Where
it is
a sandstone or a hard shale it
miner in reducing the cost of
affords facilities to the
timbering the underground roadways and workings.
soft friable roof will often give such trouble as to
make a good seam of coal unprofitable to work. The
rock-bed immediately below the coal is known as
the coal-seat, thill or floor. It is usually a bed of
where
grey clay ( underclay '), a foot or so thick
A
c
;
composed
free from
mud
chiefly of very finely-divided siliceous
alkalies it constitutes a fireclay, highly
esteemed for the manufacture of
firebricks, crucibles,
melting-pots for the glass-maker, and gas-retorts,
as at Stourbridge in Worcestershire, where the best
A very hard
fireclay is found below the Thick Coal.
siliceous floor
(*
cent, of silica is
of Lancashire
gannister
')
containing 57 to 96 per
common in the Lower Coal Measures
and Yorkshire, and
for the hearths of iron-furnaces.
causes
much
is
used as a bed
A
soft clay floor
trouble to the miner, as it swells up
under pressure of the overlying strata and tends to
fill
up the underground roadways (p. 29). In the
coal-seat are frequently found the roots (Stigmaria)
of some of the trees that grew on, or were drifted to,
58
COAL MINING
[OH.
the site and contributed to the formation of the
overlying coal.
Breaks in the Seam.
The continuity of a coalseam is liable to be interrupted by a number of causes,
some of which were active during or just after its
formation, while others did not come into operation
till
a long-subsequent period.
It
is
obvious that
where the swamp or lagoon bordered an elevated
land-tract, the coal-seam must have come to an end
somewhere along a line of shore, just as a swamp does
nowadays, though it is not often possible to point
to such an original margin of deposition. In South
Staffordshire, however, the Thick Coal, when followed southward of Halesowen and Cradley, has been
found to become so earthy and impure through admixture of muddy ingredients as to be useless as a
fuel ; and there is no doubt that if followed far
enough it would be found to end against the older
Palaeozoic rocks (Silurian and Cambrian) that
formed the coast of the lagoon. The Upper Measures
are known to overlap the lower and to extend farther
southward. Elsewhere in the same coalfield, as at
West Bromwich, local shoals in the bottom of the
lagoon have similarly prevented the deposition of
one or more of the coal-seams over considerable areas,
a contingency quite incapable, unfortunately, of
being foreseen from an examination of the surface. In
some places a seam of good coal, far from its original
INTERRUPTIONS
in]
margin,
may become
59
worthless over an area some
acres in extent owing to an intimate admixture of
mud or sediment. Again, a parting of clay, shale,
or sandstone in a coal may gradually thicken out
at the expense of the coal till little of the coal is left ;
or the whole seam may thin away to a knife-edge.
When
a coal-swamp was submerged and covered
with a bed of sediment, the old stream-courses that
crossed the swamp, and new channels eroded through
the vegetable layer, were filled-in with sand, which
now forms a wash-out which, descending from the
roof, may cut out the coal more or less completely
Such a wash-out has been
for some yards in width.
described in the Coleford High Delf Seam in the
Forest of Dene. Conversely, a sand-bank occasion'
'
upward through the vegetable layer,
the coal-seam ends off on both sides of a
ally projected
so that
mass
now
of sandstone rising
interruptions are
poraneous causes.
due
from the
to
floor.
immediately
All these
contem-
Other breaks in the continuity of a seam are due
and squeezings that the rocks
have undergone during subsequent periods of earthmovement. A considerable tract of productive
Middle Coal Measures, with valuable seams of coal and
to the foldings, tiltings
ironstone, along the eastern side of the Coalbrookdale Coalfield, must have been elevated by a gentle
folding sufficient to bring it within reach of the
COAL MINING
60
[OH.
waters of the lagoon or estuary, and may have been
raised even above the waters, and subjected to subaerial erosion during Coal Measure time, for large
areas of the productive measures were washed
away
before the deposition of the Upper Measures, which
lie across their edges.
Much coal has been thus
destroyed by this Symon Fault, as it is called.
Where the beds have been thrown into undulations it is found that a coal-seam locally thickens
abnormally (a swelly '), but in a contiguous part
of the undulation suffers a corresponding constric*
tion,
amounting
'
(a
'
faults
'
in
some cases to complete extinction
All these causes, as well as the true
to be described anon (pp. 65-7), combine to
nip-out
').
harass the miner and
mine
they
;
and under
carry with them
treatment,
'
places
damage the
fortunes of the
precautions and delicate
the name of
abnormal
call for special
'
special rates of
payment.
Igneous Intrusions. Lastly, the miner has in
some coalfields to reckon with the devastating effects
of igneous intrusions, which have invaded the coalseams and reduced some of them to useless dust.
Molten igneous material, at some period subsequent
to the Carboniferous, forced its way up from below
along more or less vertical fissures (' dykes ') or
(' necks ') in the earth -crust, burrowed a road
for itself between the beds, or raised the overlying
strata into a sort of mushroom -shaped bubble or
pipes
COALFIELDS
iv]
61
Whether the molten matter ever reached
laccolite.
we cannot
certain it is that it found
tell
a
of
bed
it easy to follow
coal, which it generally
baked to a substance resembling coke or soot. The
Rowley Hills in South Staffordshire and the Glee
Hills in Shropshire are capped with masses of such
the surface
;
basalt (quarried for road-stone as Rowley Rag and
Dhustone), while several of the contiguous coal-seams
have been invaded by sheets
of similar material
rock
has
').
('
Igneous
damaged considerable areas of coal about Willenhall, Wednesfield and
green rock
Bloxwich in South Staffordshire.
CHAPTER IV
COALFIELDS, FOLDS AND FAULTS
Coalfields.
now known
Though the
as
the
greater part of the area
British Isles was originally
covered by the Coal Measures, it is possible to point
to certain districts over which it is very questionable if those beds were ever deposited.
The high
lands of North and Central Wales, the Highlands
of Scotland, and the heights in the north-west
of
Ireland,
are probably parts of old land-areas
swamps and lagoons of the
Lower
and Middle Coal Measure
During
that stood up above the
coal-period.
COAL MINING
62
[CH. iv
times a land-tract certainly crossed the centre of
England, for there only the Upper Coal Measures
were laid down, as we have seen (p. 58). But the
original shore-lines of the lagoons are seldom preeither they have been removed
served or visible
long ago by denudation, or they lie concealed under
newer rocks. To the miner it is a matter of small
consequence, as the Coal Measures are now found to
occupy some twenty-five detached areas known as
coalfields or coal-basins, the limits of which have
been largely determined by the plications into which
the rocks were thrown by earth-movements during
;
Lower Permian
time.
Originally deposited in more or less horizontal sheets, the Carboniferous rocks were gently
folded into arches (anticlines) and troughs (synclines),
Folds.
or irregular basins, by movements more or less at
The arches and elevated
right angles to each other.
parts of the folds were planed down by detritive
agencies (the sea, rain and rivers, etc.), so that not
only the Coal Measures but also great thicknesses of
the underlying rocks were eroded from their crests.
The formation of such disconnected basins from a
once continuous sheet of sediments is shown in
Fig. 4.
In the centre of a basin the coals are more or
and may lie at a great depth
but toward the edges they rise at a considerable
less flat or horizontal,
;
COAL MINING
64
[CH.
angle from the horizontal and ultimately reach the
Such
surface along what is known as their outcrop.
a coalfield as that shown on the left side of Fig. 4 is
known
as an
'
'
exposed
coalfield, as its
margins are
But a coalfield may be wholly
part concealed by a cover of newer strata laid
visible at the surface.
or in
down unconformably
across the eroded edges of the
Carboniferous rocks the folding of the older rocks
having been in the main completed before the deposition of the newer cover, as on the right in the
The Kent Coalfield is a case in point the
figure.
Coal Measures are wholly concealed under 1000;
2000 feet of Mesozoic rocks and were discovered
solely by deep borings
on theoretical grounds
put down at points selected
by geologists. In the case
Derbyshire and Nottinghamshire
western margin comes to the surface in
the counties named ; but the eastern side is wholly
concealed beneath a thick cover of Permian, Triassic
and Jurassic rocks, thus resembling Fig. 4 though
the Coal Measures have been proved by borings to
extend some miles eastward of the exposed area as
far at least as the valley of the Trent.
As an exposed coalfield becomes exhausted, the
pits and their attendant population and all the
unsightly concomitants thereof slowly but surely
invade the agricultural borderland, as is already the
case in South Staffordshire, Warwickshire, Shropshire,
of the Yorkshire,
Coalfield, the
;
COALFIELDS, FOLDS
iv]
etc., till
of
4000
worked
below which it
the coal
feet,
is
AND FAULTS
65
out, or exceeds the limit
is
probable that
it
would
be impossible or unprofitable to work it.
Sometimes the compression
Overthrust Faults.
to which the measures have been subjected has been
so intense that the beds have been bent into a vertical
or even inverted position, as is nearly the case on
the left in Fig. 4. Not infrequently the rocks have
Section of a coal-seam affected by compression, which has
Each fault dips
produced two overthrust faults FI and F 2
to the upthrow side.
The arrows show the direction of compres-
Fig. 5.
.
given way under this treatment, and have slid bodily
over one another along an overthrust fault, as in
Here a coal with a southerly dip is cut by
Fig. 5.
two overthrust faults F and F2 it crops out three
times (at C19 <72 and C3 ), and at <72 is inverted, the
underclay lying on top of the coal. If the surface of the ground had been planed down a little
lower, another crop would have been produced near
l
;
,
c.
5
COAL MINING
66
[CH.
In the Somerset Coalfield the Radstock
has produced a similar effect, and in
West Pembrokeshire the measures are so riddled
with overthrusts that a single seam will crop out
again and again in the space of a few hundred yards.
In Fig. 5, a shaft sunk at P would pass through the
same seam twice and there a given area of ground
would contain twice the normal quantity of coal.
the pit P.
'
slide-fault
'
;
CROP
Section of two coal-seams (1 and 2) with westerly dip, and
by extension, which has produced four normal faults
F 4 ). Coal No. 1 crops out twice, No. 2 only once. FI and
(jfj
F'2 are
step-faults,' throwing the coals down eastward in two
x z
F<> happens to bring coal No. 1 opposite No. 2
steps.
'
*
is the
throw of F 4 y z is its want or barren ground,'
and the angle yxz is the hade.' The pit P, being sunk in the
All the faults dip to the downthrow
want,' misses the coals.
side.
The arrows show the direction of the extension.
Pig. g.
affected
'
;
*
'
'
;
'
'
Normal
Faults.
much
Usually, however, the beds have
and form parts of gentle
undulations in which extension has been set up. The
rocks have snapped along lines of fracture that have
suffered
less severely,
iv]
COALFIELDS, FOLDS
AND FAULTS
67
allowed the strata to spread out laterally and occupy
a greater horizontal extent than at first. Such
faults are illustrated in Fig. 6, where two
It will be noticed that here there is
normal
coals are shown.
a given area than would be the case were
also that the beds have
the ground unf aulted
suffered extension, measured by the sum of the
barren grounds or wants,' and that no pit would
less coal in
;
'
pass through a single coal more than once. The
faults all slope or dip toward the downthrow side.
The amount of the downthrow may be anything
from a fraction of an inch to several thousand feet.
Dip and Strike. In dealing with an inclined
stratum the fundamental conceptions of dip and
The direction of
strike must be grasped clearly.
dip is the compass-point toward which an inclined
bed exhibits its maximum declination from the
'
'
'
'
horizontal, the amount of the dip being expressed
in degrees from the horizontal or, among miners,
usually in inches to the yard ; a dip of 3 inches a yard
in a horizontal distance of 36 inches a
means that
bed has declined three inches, or at the rate of 1 in 12.
is the compass-direction along which the
Strike
bed exhibits no dip strike is always at right angles
to the direction of dip.
In mining-practice it is
called
level-course,' because as long as an under'
'
;
'
ground roadway in the coal follows the line of strike
it remains level.
Thus, if a bed dips south or north,
52
COAL MINING
68
it strikes
east
and west.
A
[OH.
familiar illustration of
these conceptions of dip and strike is furnished by
the ordinary roof of a church. The direction taken
by the drops of water on the sloping tiles is that of
the direction of the line of ridge-tiles is the
Dip and strike are quite independent of the
surface-configuration of the country, and hold good
underground. But the course of the outcrop of a
bed across the country depends not only on the
direction and amount of the dip, but also on the
the dip
;
strike.
A vertical bed always makes
of the surface.
a straight outcrop, the direction of which coincides
with the strike. An inclined bed cropping out on
a uniform plane, whether that plane is horizontal or
But in all
sloping, also makes a straight outcrop.
other cases the outcrop takes a sinuous course dependent on the surface-features.
Joints.
Most rocks are traversed by sets of
fissures that cut through them at right angles with
the bedding- planes and are known as joints. A joint
differs from a fault in that no relative displacement
has taken place along it. Joints usually fall into
two sets, one more or less parallel to the strike, the
other to the dip, and thus between them cut up a
stratum into roughly rectangular blocks. They
form
afford great assistance to the quarryman and miner,
and generally determine the direction in which
a quarry and the workings in a colliery are to
PROSPECTING AND BORING
v]
69
The joints parallel to the strike are
more
the
pronounced, and are known as the
usually
or slyne,' while the joints
backs
face,'
cleat,'
be laid out.
'
*
'
'
'
'
'
'
ends or cutters.'
parallel to the dip are called
The main roadways in the coal are often driven
parallel to the cleat, or
*
'
cleavage
as
it is
sometimes
called, while the bords or passages from which the
coal is taken run parallel to the ends
(Fig. 11,
'
p.
'
97).
CHAPTER V
PROSPECTING AND BORING
Prospecting.
Enough has been said already (p.
43) to show the futility of searching in Britain for
coal in any but the Carboniferous rocks ; and it has
been pointed out that the productive measures are
confined (except in Scotland, the north of England,
and the north of Ireland) to the lower and middle
In this country geoparts of the Coal Measures.
logical examinations of limited areas have been carried out in
many
districts
and recorded by private
individuals, scientific societies, syndicates or mining
prospectors, from the days of George Owen of Henllys
Some of these investigations pre(1602) onward.
ceded, while others have followed, the footsteps of
COAL MINING
70
[OH.
the State Geological Survey, instituted in 1835. The
results have been embodied in innumerable books,
scientific
proceedings,' memoirs, and maps on
various scales, so that few districts remain of which
the main geological outlines have not been ascertained
and it is wholly unlikely that any considerable tracts of Coal Measures are left to be discovered
on the surface. A geological map of the solid
rocks of the British Isles on the scale of one inch to
the mile has long been completed by the Geological
Survey, and that body is now engaged in a detailed
survey of the coalfields on the six-inch scale, which
permits the tracing of all the rock-outcrops, coalcrops, faults and folds, as well as the accurate
delineation of the superficial deposits of boulderclay, sand, gravel, and alluvia that in many districts
conceal the solid rocks below.
The primary aim of a geological survey is to lay
down on a previously constructed topographical map
a partial or complete delineation of the outcrops
that occupy the surface of a given district, and to
furnish materials for the construction of an ideal
section of the country, such as would be revealed
in the banks of a gigantic trench (a
longitudinal
section '), or in the sides of a deep shaft (a vertical
The degree to which these aims can be
section ').
attained depends chiefly on the extent to which the
rocks are exhibited in natural exposures, such as
*
;
'
'
'
'
'
'
'
'
v]
PROSPECTING AND BORING
71
the craggy sides of mountains, the banks and beds
of streams, the cliffs along the coast, the brows of
inland escarpments or in artificial sections, such as
;
wells,
mines and quarries, cuttings on railways,
canals and roads, the foundation-trenches of buildings, the surfaces of ploughed fields, and in. hedgebanks and ditches. It is quite a mistake to suppose
that a geological surveyor has constantly to resort
to digging holes in the ground or sinking trial-shafts
and borings. On the contrary, all the main features
and most of the details of the geological map of
Britain have been laid
down on
the evidence of
sections provided by Nature and by ordinary inBut our knowledge of the Coal
dustrial operations.
Measures would be incomparably smaller than it is
if these rocks had not been explored so thoroughly
by the miner, and the results stored up in plans and
section-books by the mining engineers of the country.
In the future, important accessions to our knowledge
of the underground extensions of the coalfields can
be obtained only by sinking and boring-operations.
The outcrop of a seam of coal is seldom visible,
unless it reach the surface in a perpendicular cliff,
either on the coast or in the rocky sides of a valley
or ravine.
breaks
Under the
down
effects of the weather, coal
into fine slack or
'
smut/ which a few
A
or debris will conceal effectually.
brook that flows rapidly enough to maintain a clean
inches of
soil
COAL MINING
72
[CH.
rocky bed occasionally affords a glimpse of the coal,
and sometimes the gravel and alluvium along a
watercourse contain lumps of coal that can be
traced upstream to their source, where the seam
itself may be detected.
Ferruginous springs, which throw down a flocculent precipitate of rust-coloured iron oxide, are often
taken to indicate the proximity of coal ; but such
a deposit shows nothing more than the presence of
ironstone or iron pyrite (FeS 2 ) in the rocks below.
On the outcrop of the Coal Measures, ironstone-
bands may or may not be attended by coal-seams
but in South Wales ferruginous springs are quite
as common on the outcrop of some of the pyritiferous black shales of Ordovician age, from which
;
coals are wholly lacking.
If the search for the outcrop of a coal be successful, it will be desirable to ascertain its quality
and thickness, the nature of its roof and floor, and
the direction and amount of its dip. If it crop out
with a low dip on steep ground, a tunnel (' heading
or drift ') may be driven into it for a few yards so
'
'
If on gentlyflat
it
will
be
more
convenient
or
ground,
sloping
to sink a trial-shaft to the coal on adjacent higher
as to reach the unweathered coal.
'
'
ground or on the dip-side of the outcrop, i.e. on
that side toward which the coal appears to dip. If
the coal is suspected of having a high dip (over 45,
v]
PROSPECTING AND BORING
73
it may be located by costeaning, i.e. by sinking
two shafts in a line at right angles to the crop, one
on each side of its supposed position, and connecting
their bottoms by an underground drift.
say),
If sufficient information has been obtained at
the outcrop, and it is confidently anticipated that
the coal underlies the property, shafts may be sunk
forthwith on a site selected with special reference
to underground and surface facilities.
Boring. If, however, no satisfactory knowledge
has been gleaned by the prospecting, and in districts
bounded by faults or remote from the outcrops, or
where the Coal Measures are concealed under a cover
of newer rocks, resort must be had to boring.
The
operation consists in boring a vertical hole, of small
diameter, in the earth-crust, in order to bring up
samples of the underlying rocks, coals, etc. The
experiment, if successful, should yield data as to
the depth, thickness, character and number of the
coals.
At least three boreholes are necessary, however, to ascertain the strike and dip of the beds, and
they should be placed in the form of a triangle, and
at sufficient distances to test the whole of the
property concerned.
Borings are conducted on two different principles:
On the first, different
percussion, and rotation.
forms of chisels are employed, fixed to the ends of
solid rods.
By raising the chisel a few inches,
COAL MINING
74
and allowing
it
[CH.
to drop on to the rock, a hole
A
is
gradually chipped
slight turn is given to
the rods before each fall, so that the hole is kept
circular. As the hole deepens, more rods are screwed
on at the top. In soft strata the hole must be lined
with iron or steel tubes, to prevent the sides falling
in.
The powder and fragments of rock produced
by the percussion are brought up at frequent intervals by a cylindrical tool called a sludger ; and as
the borehole usually fills with water oozing from the
porous beds, the samples of stone come up in the
form of mud, in which a sharp look-out must be
kept for fragments of coal. By carefully noting the
length of rod required to pierce each fresh stratum,
a record or section of the boring is procured. The
defect of the method lies in its bringing up mere
mud and chippings, which afford little information
as to the dip, the lithological characters, or the fossil contents of the rocks.
For these reasons the rotatory methods are always preferable. In these the rods are hollow, to
allow of a supply of water being conducted to the
cutting-tool, which consists essentially of a hollow
cylinder, the lower edge of which is armed with hard
minerals (usually rough impure diamonds), or with
teeth like those of a saw. In another method,
chilled steel shot are put down the hole and, finding their way beneath the cylindrical cutter, act as
out.
'
'
v]
PROSPECTING AND BORING
a rasp
much
75
as primitive man employed sand,
stick to bore holes in his stone
water, and a hollow
axe-heads. By giving a continuous motion (at 200
or 300 rotations per minute, by steam-power) to the
cutting-tool, an annular groove is cut in the rock,
with the formation of a solid core, which is em-
braced by the cylinder as the cutting edge descends.
By raising the apparatus, the core in pieces several
can be brought to the surface for examinafeet long
The diameter selected for the initial part of
the boring will depend on the depth to be attained,
and may be as much as 26 inches. As the boring
proceeds, the diameter is reduced in several stages,
determined by the length of boring that reso that the lowest cores raised
quires to be lined
a
width
of
have
may
only one inch or so, though
cores less than four inches in diameter are of little
tion.
;
A liberal supply of water conducted
the hollow rods and escaping under the cutter
rises to the surface again and so flushes the sediment
out of the boring. Unfortunately in soft beds, such
real value.
down
and coals, it frequently does this so effectuthat
no core is left, and proof of the character
ally
of this part of the section is to be obtained only by
as clays
carefully collecting the washings brought to the surface in the escape-water ; and unless great care is
exercised, a coal several feet thick
overlooked.
may
be wholly
COAL MINING
76
[OH.
In Germany borings have been put down to
depths of over 6000 feet, the operation lasting several
A recent boring at Heswall, on the west
years.
coast of Cheshire, was carried down to 3362 feet in
Trias and Coal Measures in 10 months by Brejcha's
method. The cost of percussive boring in Coal
Measures is usually quoted at 75. 6d. per fathom for
the first five fathoms ; 15s. a fathom for the second
five
fathoms,
and so
on.
The Diamond Rock-
Boring Co.'s price is Ss. per foot for the first 100 feet ;
165. per foot for the second 100 ; 245. for the third
100, and so on.
It would be supposed that cores costing so much
money and trouble to obtain would be at once label-
led with their depths, and laid out in proper order
under cover, so as to protect them from the weather
and permit
thorough examination by a
But too often everything but
of their
geological expert.
the coal itself has been treated with scant courtesy
'
as being of no practical importance a somewhat
'
short-sighted policy in face of the fact that the coal
itself often yields no proper core, and that a reasonable probability of its presence in the boring may
depend on some peculiarity
in the associated strata
appreciable to the geologist alone. And when it
borne in mind that the journal of the boring
is
is
entered up in some cases in quite misleading or
unintelligible local terms, and that fundamental
WINNING THE COAL
vi]
77
of the beds are apt to be
in
the
man
overlooked by
charge, it is clear that the
of
every part of the core is a matter
preservation
of prime importance, even from the view-point of
the colliery projector, not to mention that of the
differences
between certain
Yet so far is this matter
where
even
plenty of space is availneglected that,
sometimes
one above
cores
are
the
able,
piled up
another out in the open, where the first lengths are
soon buried out of sight, and the whole pile conscientific
investigator.
verted by frost and rain and the trampling of cattle
to a heap of useless debris even before the boring
is finished, and reported on by the expert.
CHAPTER VI
WINNING THE COAL
Winning the Coal. Satisfactory evidence having been obtained that coal underlies the property,
a decision must be made as to whether it is to be
won by
is
If the ground
and the measures have only a
shafts, levels, slants or drifts.
comparatively
flat,
slight inclination, as is the case
with
many
of our
coalfields, or if the area to be worked is bounded by
faults or concealed under a cover of newer rocks
so that the coals
nowhere crop
out, shafts will be
COAL MINING
78
adopted.
If,
[OH. vi
however, the country is deeply trenched
Wales and the Forest of
which the coals crop out with
may be advantageous to retain
the ancient method of driving day-levels from the
by
valleys (as in South
Dene), on the sides
little or no dip, it
outcrop.
If
of
the coal rises steeply to the outcrop
on the side of a valley or along the foot of an escarpment, as on the northern margin of the South Wales
Coalfield in Carmarthenshire, where the coal to be
worked underlies a great thickness of barren measures, it is usual to avoid the unremunerative outlay
on shaft-sinking, and to win the seam by slants,'
'
'
slopes' or 'slips,' i.e. inclined tunnels following the
coal downward from its outcrop.
In special cirwhere
beds
cumstances,
crop out in
high-dipping
ground, the coals may be reached by crossdrifts cut in the rock and ascending or
descending in the measures as the case demands,
much as metalliferous veins are won. These different methods of winning the coal, and some comhilly
measure
shown in Fig. 7.
and
Shafts
Sinking. Where the measures are
known to have a small dip, and shafts are adopted,
their position will depend largely on the facilities
afforded on the surface for the construction of railways, canals and roads, or on the proximity of a
navigable river, so that the coal can readily be sent
away to its destination. For the land-sale (to supply
binations of them, are
UJ
LU
t
Q
DO
COAL MINING
80
[OH.
demand) a good road is essential. Where the
measures have a moderate dip, the winding and
local
shafts are placed 'to the dip' or deep, I.e. in
that part of the property toward which the coals dip,
so that gravity may be turned to account in carrying
pumping
and draining water to the bottom
coal
of the shaft.
A ventilating shaft may with advantage be placed
the
rise,'
as the air-current
may
'
to
be thus assisted in
There must be at least two shafts, placed
not less than 15 yards apart. In the old days, when
the coals to be worked lay at a small depth, a colliery
would sink half-a-dozen or more shafts at a few
hundred yards apart, as in South Staffordshire but
now that the coals have to be reached at much
greater depths, a pair of shafts is made to do duty
for a much larger area, to the no small advantage of
its ascent.
;
the surface-appearance of the country.
Shafts are rarely less than 10 and sometimes as
much as 20 feet in diameter. Usually they are circular, as presenting the greatest resistance to lateral
pressure, and as being easiest to sink and to line
with brickwork or cast-iron plates.
The appliances
tools,
such
as
for
picks,
blasting-apparatus,
conveying
etc.,
hammers,
buckets
or
chisels,
hoppers for
materials up and down, and
of winding-gear.
The water encountered
be too much for the buckets, and may need to
some form
may
men and
sinking consist of various
shovels,
WINNING THE COAL
vi]
81
For winding, a small temporary engine
which a steel rope passes over a
from
installed,
in
the
head-gear and is connected with the
pulley
bucket by a hook.
In ordinary circumstances, as when the Coal
Measures lie immediately below the surface, the procedure is as follows. After a depth of 6 feet or so
is attained, the shaft is lined with strong and carebe pumped.
is
fully constructed timbering, to prevent the soft soil
and subsoil or loose superficial gravels from slipping
inward on to the sinkers. Another 6 feet or so are
now excavated, and more timbering put in below the
first lot, and so on till the first strong bed of stone
On
stone-head,' as it is called is reached.
wood or of cast-iron is placed and tightly
wedged against the shaft sides, so as to form the
'
the
this a curb of
course of a brick wall, which is gradually built
upward to the surface, and the timbering removed.
To build the wall, the masons stand on a circular
first
platform suspended in the shaft and capable of being
work progresses. Sinking is then recommenced. For the first few feet the sides of the
shaft are kept flush with the inner face of the overlying wall, but are then cut back to the full width,
so as to leave the first section of masonry supported
on a bracket or shelf of rock. At a convenient
depth, a fresh section of walling is begun, and
raised as the
carried
c.
upward to the rock-bracket, which
is
then
6
82
COAL MINING
removed
meet end to end.
carefully
till
[CH.
the two sections of walling
Sometimes, however, quicksands, usually watermay form a thick cover over the Coal
Measures, and may need special treatment
for,
bearing,
;
generally speaking, the softer the beds, the more
troublesome they are to sink through. One method
consists in constructing a strong water-tight open
cylinder of wood, of the diameter of the shaft, and
armed with a sharp iron edge. This cylinder is then
set upright in the sand, and allowed to sink while
the sand within is excavated down to the stonehead, upon which the walling can be commenced.
A modification of this method is to employ a castiron cylinder built up of segments bolted together
at flanges on the inner sides.
This cylinder is then
left as a permanent water-tight lining to the shaft.
Other methods depend on ingenious applications of
freezing-mixtures to the water-logged sand. In one
(Poetsch's method), the sand underlying the site of
the sinking is frozen into a solid mass, which can
then be sunk through in the ordinary way. To do
a number of water-tight closed wrought-iron
tubes are forced down through the sand till they
reach the stone-head. Within each tube a narrower
inner tube with openings at the bottom is let down
to the same depth. The upper ends of the inner
tubes are then connected with a refrigerator and
this,
vi]
WINNING THE COAL
83
force-pump, by which a freezing liquid is forced
downward to the bottom in a continuous current.
The liquid escaping at the bottom of the inner tube
returns by the outer one to the refrigerator. By
these means a column of frozen sand grows round
each tube till the whole mass is rendered solid. By
a variation of this method the tubes are arranged
in a ring round the site of the shaft (Gebhardt
and Koenig's method), and a wall of frozen sand
produced, within which the unfrozen sand can be
excavated down to the stone-head.
In sinking through hard beds, blasting must be
resorted to.
Shot-holes of an inch or two in diameter are drilled in the stone to a depth of four or
five feet, and are arranged in two rings, one round
the centre, the other near the edge of the floor.
The holes in the inner ring are drilled obliquely, so
as to approach each other in order to blow out an
inverted cone of rock.
The outer
ring of holes blows
the surrounding mass inward. The holes may be
drilled by hand in the manner usual in stone-quarries, where one man holds a long chisel in position,
while one or two companions strike it. After each
blow the
through a small angle.
obtained by using drills
actuated with compressed air or electricity. The
holes are then cleaned and charged with an explosive cartridge, to which is attached a length of
chisel is rotated
More rapid progress
is
6
2
COAL MINING
84
[CH.
slow-burning fuse. An electric arrangement however
has the advantage of allowing a greater number
of shots to be fired simultaneously, while there is
no
and seldom any
miss-fire
hanging fire
moreover, the shots can be fired from any distance.
One of the most serious difficulties that presents
itself to the sinker arises when a bed of water-logged
sandstone or sand is encountered at some depth
in the shaft.
In sinking through the Triassic and
Permian rocks on the eastern side of the great
Northern and Yorkshire coalfields, enormous trouble
has been caused by a thin bed of quicksand at the
base of the Permian rocks 3000 gallons of water
per minute having been encountered in the Monkwearmouth shafts. Such an amount of water if
allowed to descend the shaft would impose a very
grievous burden on the pumping-plant, so must be
held back by means of tubbing. Nowadays tubbing
takes the form of heavy cast-iron plates, each of
which is strengthened with ribs and brackets on the
side facing the rock, provided with flanges to facilitate fitting, and pierced with a central hole.
The
first ring of tubbing-plates is laid on a wooden foundation placed on some strong bed of rock below the
the tubbing is then built up ring
watery stratum
by ring as far as a similar bed above the watery
zone, and finished with a wooden curb wedged tight
against the rock above. All the joints between the
'
'
'
'
;
;
WINNING THE COAL
vi]
85
iron plates are then wedged up tight, beginning at
the bottom. The hole in each plate, at first left
open to allow any imprisoned air to escape, is then
plugged with wood, and the space behind the tubbing filled in with concrete. A vent-pipe is sometimes inserted in the upper ring of plates and carried
some way up the shaft, to avoid dangerous airIn this way not only may a heavy feeder
pressure.
of water be kept back, but the drying-up of surfacewells, streams and springs is avoided, to the no
small advantage of the inhabitants.
Sometimes in dealing with hard beds that
yield more water than can be kept under by the
pump, the Kind-Chaudron system is adopted. The
is bored out, first of small diameter, then to
the full size, on the percussion principle (p. 73)
with a heavy circular cutting-tool or trepan, operated from the surface, during which process no
pumping is done. As the boring advances, cast-
shaft
iron
permanent tubbing
The bottom
is
ring of the
lowered
tubbing
down
is
the shaft.
with a
fitted
packed with moss or oakum, which is
so compressed between the tubbing and the rock
below that a water-tight junction is secured. The
water is then pumped out, and the space behind
the tubbing filled in with cement.
sliding case
Some of the deepest shafts in this country are
those of the Florence Colliery at Longton in North
COAL MINING
86
[CH.
Staffordshire, which reach the Yard Coal at the
enormous depth of 2490 feet (830 yards) while the
Ashton Moss shafts near Manchester are 2880 feet,
;
or over half-a-mile, deep.
It is usual to carry the shaft a few yards below
the lowest coal to be worked, so as to afford stand-
age for the water.
This extension
is
known
as the
sump and from it the pumps lift the water to the
The seam being reached, much remains to
surface.
be done before coal-getting can be commenced. In
order to afford a firm foundation for the shafts, and
so to avoid collapse and damage to the surface-plant,
;
a considerable area of coal known as the shaftpillar, the size of which will depend on the depth
of the seam, the goodness of the roof and floor,
and the hardness of the coal, must be left unworked
around each shaft in every seam. In a seam 300
yards in depth the shaft-pillar should have a diameter of at least 90 yards. It is usual to place
the two shafts within say 100 yards of each other,
so as to allow of the surface-plant (engine-houses,
but they must
offices, etc.) being concentrated
not be less than 15 yards apart. The one by which
the ventilating air-current ascends is called the upthe other, by which fresh air descends,
cast shaft
is the downcast, and is usually the one by which
the winding is done. As soon as the shafts reach
the seam to be worked, a communicating passage
;
;
WINNING THE COAL
VI]
must be cut
in the coal
87
from one to the other, so as
to establish the ventilating current.
Driving Levels. The next points for decision are
the system on which the coal is to be worked, and
the direction to be given to the main roads or levels,
by which the shafts will communicate with the most
Cleavage
j
Winning
Level
Plan showing upcast and downcast shafts U and D, pairs
winning levels advancing eastward and westward, a rising
plane going north, and a dipping plane (engine-plane) going
Fig. 8.
of
south.
distant parts of the mine, and by which men and
boys, horses, trams, air and materials will constantly
go to and fro or, as the miner terms it, inbye (from
'
'
'
'
the shafts into the workings) and outbye (out of
the workings and toward the shafts). Levels are
usually driven out from the shafts on both sides,
COAL MINING
88
[CH.
parallel to each other, in pairs or triplets, with a rib
As they
of coal 20 yards or so wide between them.
advance, cross-headings (stentons) are cut from one
to the other every 30 or 40 yards and as a fresh
stenton is cut, the previous one is closed with
a stopping, so as always to maintain an air-course
along the whole length of the levels (Fig. 8, p. 87).
In opening out these main roads, ample room
must be secured for a hundred yards or so from the
winding-shaft for the construction of the necessary
sidings and railways, along which the full tubs will
be brought up on their way to the surface, and
empties sent off into the mine. Usually this most
important part of the workings is arched with brickwork, and plenty of headroom obtained by ripping
down some of the roof. The main roads or levels
are, as their name implies, level roadways cut in the
and from what has been said already (p. 67)
coal
they must, in an inclined seam, take the direction
of the strike, and cross the direction of dip at right
Also, they usually coincide with the cleat
angles.
or main set of joints in the coal. They are not,
however, made perfectly level, but are given a slight
inclination of about 1 in 130, so as not only to cause
the water to flow back to the shaft, but also to assist
the loaded trams in their journey thither. They
are usually driven 7 to 10 feet wide and 6 or 7 feet
;
;
high.
vi]
WINNING THE COAL
89
Where the seam has a considerable inclination,
inclined planes must be driven in the coal, at right
angles to the main levels, one toward the rise, and
another toward the dip the latter being known as
the engine-plane, since the coal from the dip-workings will be pulled up this plane by some system of
mechanical haulage.
If the proprietors of the colliery are prepared to
waive any immediate return on the capital outlay,
and if other circumstances (pp. 105-6) are favourable,
the levels and inclined planes may be driven right
away to the boundaries of the property, and the
coal then worked back toward the shafts by the
Long wall Retreating method (p.
empty space (' goaf ') behind.
105), leaving the
The usual proby which
to adopt a method
cedure, however,
coal can be got as soon as the levels have
is
beyond the shaft-pillar.
the main roads are not so
advanced
Beyond the shaft-sidings,
roomy and are not usually
but as it is essential that
arched with brickwork
they should be kept free from obstruction, their
roof and sides are supported with stout timbers,
unless the roof should be strong enough to render
A soft shale roof at a great depth,
this unnecessary.
and a soft coal in the sides, require much timber
and need constant attention and repair. A very
;
usual arrangement
two upright
to place at frequent intervals
posts, usually of pine, fir or larch, and
is
COAL MINING
90
[CH.
about 6 inches in diameter, one on each side of the
level, and slightly inclined toward each other at the
top, with a thicker crown-piece or lintel laid across
them. Much pit- wood is imported from Norway and
Sweden. Owing to the moisture and warmth of the
air underground, the timber is subject to rapid decay,
to prevent which various chemical treatments such
as creosoting have been introduced.
Driving through Faults. After a level has been
driven in the coal for some distance, it may encounter a fault (pp. 65-7), by which the coal is
thrown out of sight, and has to be sought for and
it is important to grasp the principles on which this
search is based. The fault may be a clean-cut fracture with no appreciable space between the end of
the coal and the beds beyond or it may be marked
by a variable thickness of fault-rock,' i.e. layers
of shattered and powdered rock and coal-dust (the
of the fault), jammed between the two
leader
cheeks of the fracture. It has been explained already (p. 67) that in normal faulting, such as is
usually met with in our coalfields, the fault dips
toward the downthrow side. If, therefore, the pitman in driving a level meets with a fault that dips
away from him, and forms an obtuse angle with the
roof of the level, he assumes that on the other side
He
of the fault the coal has been thrown down.
of
several
one
the
coal
to
reach
now
by
attempt
may
;
;
'
'
'
WINNING THE COAL
VI]
91
methods. If the beds are approximately horizontal,
he must give his excavation through the measures
t-
Sandstone
\
vv
Stap/e Pit
W
Shales
Sections showing methods of recovering the coal beyond a
fault F, in horizontal or low-dipping beds.
The
drivage in the coal is proceeding eastward.
Fig. 9.
downthrow
beyond the
fault a regular downhill gradient suitable
and continue it till it cuts the coal on
for haulage,
the downthrow side, as in the upper section in Fig.
9.
COAL MINING
92
[OH.
Such an excavation is called a stone
cut through stone and not coal.
drift,
as
it is
Instead, however, of driving blindly downhill to
F
W
PLAN
co
ELEVATION ALONG F-F
U
Plan and elevation of underground workings to show how
an inclined coal thrown down by a fault F at
may be recovered
without departing from a level course. The arrows show the
direction of dip.
The elevation, taken along the fault, shows that
a horizontal cross-measure or stone drift from the coal on the
will reach the coal on the downthrow side at Y.
upthrow side at
U, upthrow side of fault
D, downthrow side.
Fig. 10.
X
X
;
reach the coal, as in the case just described, he would
do better to carry the level forward a few yards
beyond the fault, and then put down a borehole, or
WINNING THE COAL
vi]
'
'
staple-pit (as in the lower section in Fig. 9),
the coal was reached. He would then go back
sink a
till
93
along his level and cut a stone drift with a downhill
gradient requisite to reach the end of the coal on
the downthrow side.
Supposing, however, that the measures have a
considerable dip, the miner may reach the coal without abandoning his level-course an important consideration if the level is utilized to carry water back
to the shaft. Assume, for instance, that the level is
advancing eastward (Fig. 10, p. 92) in beds that
have a southerly dip, and a downthrow fault is
passed through ; the pitman knows that the coal
will be under his feet and will rise to the north of
him. By turning his level northward, toward the
rise, and cutting a horizontal stone drift descending
in the measures (a descending drift '), he will ultimately reach the coal.
'
it may be necessary to make a comAgain
munication between one seam and another, quite
independently of any shaft. This is done by cutting
a stone drift, which may be rising, dipping, or horizontal (Fig. 7 C, p. 79). Driving a stone drift usually
:
requires the assistance of blasting operations, which
are conducted in much the same manner as in shaft-
sinking (p. 83).
Old Workings. In driving out levels or workingplaces toward old workings, great care must be
94
COAL MINING
[OH.
exercised lest the water or gas, with which they may
be charged, be suddenly tapped and let into the new
workings. On approaching old mines, horizontal
boreholes are driven forward in the coal, with others
going off at angles ; and the exploring heading must
not have less than 5 yards of straight-on boring
ahead of it. If a boring taps water or gas, it must
be at once closed with strong wooden plugs, and in
that direction no further driving must be attempted.
Lack of information as to the situation of old workings is often a cause of much anxiety to the colliery
If much water makes its way into the
officials.
abandoned mines, it may be necessary
from
workings
If the water is under no great head,'
to dam it off.
stout wooden battens like railway-sleepers, laid one
above another so as to make a wall, are inserted in
grooves cut into the two sides of the heading. At
a foot or so in advance of the first, a second wooden
wall is erected. The space between the two is then
tightly packed with clay, which will form a waterIf, however, the water to be extight barrier.
cluded exerts a great pressure, a wooden or a brickwork dam is constructed in the form of an arch laid
on its face, with the convex curve of the arch toward
'
the water.
WORKING THE COAL
vii]
CHAPTER
95
VII
WORKING THE COAL
WHEN
the shafts have reached the coal intended
and the winding-engines and ventila-
to be worked,
ting arrangements have been installed, the shaftsidings and shaft-pillar laid out, and the main levels
and
be in a
inclines driven forward, the colliery will
position to begin working the coal ; and a method
of work must be decided upon that will produce the
amount of marketable fuel at the least cost
and with the greatest safety to the men. The choice
will depend on the character and thickness of the
seam, its depth and inclination, and the nature of
its roof and floor.
Methods of Working. The usual methods, although capable of numerous modifications and
largest
combinations to suit special conditions, are
Bord-and-Pillar, otherwise called Bord-and(1)
:
Wall,
Pillar-and-Stall,
Post-and-Stall,
Stoop-and-
Room.
(2)
Long wall.
A
description of several other less usual methods,
such as the Single-road Stall and the Double-road
Stall systems of South Wales, the Wicket system of
North Wales, and the Hill system of Warwickshire,
would carry us beyond the purview of the present
COAL MINING
96
[OH.
volume but a brief account of the Square-work
South Staffordshire will be given.
;
of
In Bord-and-Pillar working (Fig. 12, p. 99),
which is doubtless the earliest and most obvious
method, and is the usual one in Northumberland
and Durham, the procedure consists, first, in removing the coal from two sets of working-places,
called bords and headways, driven at right angles
to each other, and forming between them rectangular
support the roof.
This operation is known as
whole- working,' i.e.
and in
working in the whole or unbroached seam
earlier days the pillars so formed were abandoned
in the mine as soon as the boundaries of the property
pillars of coal sufficiently large to
'
;
were reached, as it was found impossible to remove
them with safety. In modern practice, however, a
broken
or pillarsecond operation, known as
is
which
the
performed, by
pillars themworking,
'
selves,
purposely
left large
removed more or
are
'
at the whole-working,
less completely.
In Longwall working
(Fig.
13,
p.
104),
pre-
valent in Yorkshire, Derbyshire and the Midlands, the
whole of the coal is removed at one operation along
a continuous face or wall/ the overlying strata
'
'
being allowed to settle down in the vacuity (' goaf
or
gob ') behind. This system may be worked
'
either
as
'
Longwall Advancing,' i.e. working
shafts and toward the boundaries,
the
from
away
(a)
WORKING THE COAL
VTl]
97
Longwall Retreating,' i.e. working back from
the boundaries toward the shafts.
Bord-and-Pillar.In Bord-and-Pillar working,
the whole working is carried out by driving one
or
'
(b)
'
'
BORD
End
'
'
Plan of a bord advancing on the face of tbe coal. The
*
'
block of coal A having been undercut, and nicked at the sides
can
be
face
B
removed.
as
the
as
far
C,
readily
n)
(n,
Fig. 11.
'
'
wide excavations called bords, which yield the
bulk of the coal, and another narrower set at right
angles called headways, which are used mainly for
The two sets between them form
ventilation.
rectangular pillars of coal, to be removed by the
set of
o.
7
COAL MINING
98
1
broken
'
working
The bords
on.
later
[CH.
vn
(4
to
yards wide) are usually driven wider than the
headways, and are generally cut across the cleat or
7
1
on the face
'
;
the headways (2 to 4 yards wide)
'
on the end.' The
are parallel to the cleat or
reason for this is that in cutting the bords, which
as compared with the headways yield the bulk of
by the
the coal obtained
'
whole
'
working, the coal
the hewer if
easily
the main joints cross the line of his excavation.
Thus in Fig. 11, the joint, cleat, or face B-C will have
sliced off the coal already, and all the hewer has to
do is to cut a horizontal groove between the coal
and its floor, and a vertical nick n, n, at one or
both sides, when the block of coal A will be ready
to be pulled out.
If, however, the bord were adthere would be no strong
the
on
end,'
vancing
of
the
back
at
the
block, nor could the hewer
joint
nick
it.
coal
to
the
behind
get
It will be gathered that a small proportion only
whole working
of the coal is obtained by the
the bulk of it is left in the pillars.
(5 to 30 per cent.)
The manner in which the coal is hewed is as
The hewer with his pick first undercuts
follows.
('holes' or 'kirves') the seam across the full width
of the working-place (bord or headway, as the case
may be). This horizontal groove will be about a
foot wide at the face, but will taper inward to a
is
brought down by
much more
*
'
'
*
'
'
:
J
DNIXdOM
310HM
72
COAL MINING
100
[CH.
and is cut as much as 3 feet under the
The holing may be done in the coal, or in some
knife-edge,
seam.
soft parting, or in the underclay.
In holing below
the coal, the hewer lies on his side and swings his
pick horizontally (in a temperature sometimes as high
as 80 F. !); and where the holing is deep and the coal
be necessary to prop up the coal with
it falling forward on to the hewer.
In driving narrow headways and levels, the coal may
need to be nicked, after the holing, with a vertical
groove on one or both sides, before it can be got
down with the pick, with various kinds of wedges,
the aim of the hewer
or by the use of explosives
being to get the coal in as large (' round ') pieces as
tender,
it
may
sprags to prevent
;
possible.
Explosives are classed according as they are
capable of ignition by heat or by detonation. Gunpowder is a familiar example of the first class ; it
explodes only on being heated, and is usually fired
with a fuse. Dynamite and gun-cotton are examples
of the second class, and need a shock to explode them,
although they burn quietly on the simple application
they are fired by being placed in contact
with a small charge of some other high explosive
(the detonator or cap) capable of being ignited by
of heat
;
For use in coal-blasting, an explosive
should be safe when handled or carried about,
should give off as small and as brief a flame as
electricity.
(1)
(
)
WORKING THE
vn]
possible,
and so be not
CO'AI^
;'.J
;
;
101
to ignite fire-damp
liable
or coal-dust, (3) should evolve no serious volume of
inflammable or poisonous gases on explosion, and
(4)
should eject no incandescent sparks.
gunpowder
Common
offends against three of these canons of
safety, and for that reason a great number of explosives have been introduced that claim to be more or
lessflameless, or to evolve
no combustible or poisonous
gases.
The amount of timbering required in a workingplace will depend on the nature of the roof and the
width of the bords and headways. Upright props
are used, with a cap at the top, or chocks, consisting
of piles of horizontal posts placed crosswise two and
two. As the working-face advances, the chocks and
props at the edge of the goaf are withdrawn and used
again if sufficiently sound. The bord is ventilated
by dividing it into two parts by a vertical air-tight
canvas, or wood, and
conducting the air along one side of the brattice,
round its end, up to the working-face, and back into
the headway (Fig. 15, p. 115).
The size of the pillars formed by the wholeworking is governed by the depth of the seam below
the surface ; for as the thickness of the overlying
strata increases, the pillars must be left larger to
crushed
to useless slack ;
prevent their being
further, if the coal is soft, the pillars need to be
partition of brattice-cloth,
'
'
COAL MINING
102
larger
and
than
if
and if the roof
must be large enough
the coal were harder
floor are soft, the pillars
[OH.
;
'
creep,' i.e. bulging-up of the floor of the
excavations (p. 29). It is customary nowadays to
leave pillars 20 to 50 yards long and 10 to 40 yards
wide.
The second operation in the bord-and-pillar
to prevent
method
'
'
broken working, or removal of the
This may be deferred till the whole- working
pillars.
has reached the boundaries, but is usually commenced soon after the whole-working has attained
a safe distance from the shafts, and follows up the
advancing whole-work at a convenient distance, if
possible before the roofs of the bords and headways
have fallen in, the empty space or goaf left by the
is
the
pillar-working being utilized for the stowage of
rubbish and allowed to fill up by the settling-down
of the roof.
There are innumerable methods of removing a
The system generally pursued is that of
pillar.
off
taking
bordway slices (' lifts ') driven halfway
the
pillar from each headway ; or in the case
along
of long pillars, by driving a narrow heading across
the middle of the pillar, and then carrying lifts right
and left from this as well as from the headways. In
working the pillars a regular line of advance (generwith the headways) should be
ally making 45
maintained between the goaf on the one hand and
WORKING THE COAL
vn]
103
the unworked pillars on the other, special care being
taken to avoid leaving a pillar or a stump of coal
behind in the goaf, as its removal would then be
attended by much risk and difficulty. Pillarworking requires the roof to be specially well timbered.
Longwall. In Longwall Advancing (see upper
part of Fig. 13, p. 104), as soon as the boundaries
of the shaft-pillar have been left behind, the removal
wall can
of the coal along a continuous face or
*
be begun.
The
face
may
be more or
'
less straight,
or stepped, according to the nature of the cleat, and
sometimes extends for a mile in length. The coal is
undercut as in bord-and-pillar work, but machine
The lower edge of
cutters are sometimes employed.
the undercut coal is held up by sprags, and the roof
upheld by chocks. As the face advances, the
timbering is moved forward with it, whereupon the
roof behind falls, and fills up the goaf.
Communication with the shafts is kept up by maintaining
stone- walled passages (gateroads), at least 6 feet
wide, from the face through the goaf, the necessary
stone being obtained from the roof or floor. The
walls of the passages are called pack walls, and should
is
be well and solidly
built,
and at
least 6 feet thick.
As the gateroads become longer and the expense
of keeping them in order becomes serious, one or
two
chief roads are maintained,
from which cross
The Coal "Face
CH. vn]
WORKING THE COAL
105
gateroads are constructed up to the face, and the
old roads abandoned. A well-stowed goaf assists
materially in the maintenance of the gateroads, and
diminishes the timbering required.
In Longwall Retreating (see lower part of Fig. 13,
p. 104), a method of working that may be adopted
where an immediate yield of coal is not essential, the
levels, airways, roads, etc., are driven out from the
shafts to the boundaries, whence the coal is worked
back toward the shafts by a long wall face. The roof
down behind. The gateroads are thus all in
the unworked coal, so that there are no roads to be
maintained through the goaf.
The respective advantages of the two kinds of
longwall working depend much on circumstances
but the retreating method has the superiority that
if in a seam that is liable to spontaneous combustion
a gob-fire should break out, the danger is left behind
and does not come between the working-face and the
settles
;
shafts.
Gob-fires are brought about through spontaneous
of the slack and coaly refuse left behind
combustion
gob or goaf, and are caused probably by the
oxidation of the finely-divided carbonaceous matter,
assisted maybe by the presence of pyrite.
In some
cases heat due to pressure and movement has set
in the
up spontaneous combustion
in the case of the
in the
seam
itself,
as
Thick Coal at Hamstead in South
COAL MINING
106
Staffordshire,
over 2000
which
is
[OH.
being worked at a depth of
feet.
Comparing bord-and-pillar with longwall work,
it
may be pointed out that the latter is not applicable
to areas underlying water such as the sea, rivers,
and reservoirs nor can the removal of pillars
lakes,
;
on the bord-and-pillar system be applied to
districts
occupied at the surface by buildings in respect of
which compensation for damage would be demanded.
Bord-and-pillar is best applied where the surface
must remain supported by the pillars
longwall
yields the largest percentage of large coal, is more
;
easily
ventilated,
is
generally less costly,
and
is
gradually superseding bord-and-pillar.
Square-work. In working the Thick Coal of
South Staffordshire, which varies from 14 to over
30 feet in thickness, and is liable to spontaneous
combustion, the method known as Square- work has
been evolved. The seam is divided into a number
of rectangular compartments, 50 yards or more in
the side, called sides of work,' separated from each
other by ribs of coal (' fire-ribs '), 8 or 10 yards thick
Access to the sides of work is
(Fig. 14, p. 107).
bolt-holes,' opened out
gained by one or more
from the main roads or gate roads cut in the lower
The coal is then removed from
layers of the coal.
within each side of work, leaving a vast gloomy
chamber in which six or more pillars remain to
'
'
WORKING THE COAL
vn]
107
The pillars are then pared down as
and the bolt-holes finally sealed up to
support the roof.
far as
is
safe,
prevent spontaneous combustion.
'
In order to get
'
Plan showing a side of work in the Square-work method
Fig. 14.
of getting the Thick Coal of South Staffordshire.
The arrows
show the direction of the air-current.
at the upper layers of the coal, the hewers stand on
the coal and slack already cut, or on light scaffolding.
No
roof-timbering can be employed, and the work
attended with great danger from falls of roof.
Sometimes all the coal is extracted in two lifts or
is
COAL MINING
108
[OH.
layers at intervals by a system of longwall work.
But after this first working 38 to 46 per cent, of the
coal is left underground, and a large amount of slack
though much of this coal is recovered
and pillars are worked by a second
and third working after an interval sufficient to let
the roof settle down. The removal of the Thick
Coal pillars in South Staffordshire has occasioned
an enormous amount of damage to the surfaceis
produced
when the
;
ribs
property, often without any compensation being
obtainable by the owners.
The ordinary method of
Coal-cutting Machines.
the
coal
with
the pick has been deundercutting
The holing
seam
and
and to
in a thin
scribed already
(p.
makes a much
larger proportion of small coal
98).
slack than in a thick one.
To remedy this,
save time and labour, various types of coal-cutting
machines have been introduced, constructed on the
percussion system, or on the disc, bar, or chain
systems, or on a rotary plan. In percussion machines,
the cutting-tool is a chisel-ended bar, which is lunged
forward against the coal-face at the rate of 200 or
more blows a minute, rotating at the same time ; and
by swinging the tool slowly along, the hewer cuts a
groove in the coal-face. The disc-machines, specially
applicable to longwall faces, consist essentially of
a disc or wheel, 5 or 6 feet in diameter, armed with
cutters, somewhat like a circular saw but on a
VENTILATION
vm]
109
In the bar-machines, the cutter is
vertical axle.
a toothed bar or roller, which is caused to rotate,
at 200 to 500 revolutions per minute, against the
The chain-machines differ from the disccoal-face.
machines in that the cutters are fixed on an endless
chain, which passes
round horizontal
pulleys.
The
for
driving headings in
rotary heading-machine,
the coal, consists of a pair of cutting-arms, 4J feet
long, fixed at right angles to the end of a cross-bar,
the centre of which
attached to a revolving shaft.
revolves, the two arms scrape out
a circular groove in the coal, forming an internal core
which breaks away in pieces and is removed as fast
A cylindrical passage 4 to 7J feet in
as produced.
diameter is thus cut out. In another similar machine
the cross-bar has no arms, but is fitted with cutters,
which chip out the whole cylinder at once and
is
As the machine
produce no large
coal.
CHAPTER
VIII
VENTILATION, DRAINING AND LIGHTING
It will readily be gathered that the
a
mine speedily becomes vitiated
atmosphere
the
of
men and horses, the burning
by
breathing
Ventilation.
of
of
lights
and explosives, by gases
explosive or
COAL MINING
110
[CH.
from the coal or evolved by gobdiffused in the air
and it
is essential that this foul air should be continuously
and steadily swept out of the mine and replaced by
The fresh air required varies from 100 to
fresh.
500 cubic feet a minute per person employed in the
mine, according to whether the mine is free from gas,
poisonous
fires,
or
given
off
and by the coal-dust
;
is fiery.
The
chief gas evolved
from the coal
is fire-damp
the
gas,
specific gravity
It was proof which, compared with air, is '559.
duced probably during the conversion of the original
vegetable matter into coal, and remains locked up
under pressure within the pores of the coal till
(methane or
marsh
CH
4 ),
volume when the seam is
broken into at the face, whence it may sometimes
be heard to issue with a slight hissing sound. Occasionally it jets out from joints and fissures in
blowers
exceptionally large volumes known as
and outbursts.' The gas is colourless, tasteless and
odourless, will not support life or combustion, but
burns with a blue flame. If present in air to the
extent of 9' 5 per cent, the mixture will explode
and
violently, producing carbon dioxide ((XX)
water- vapour, which, with the residual atmospheric
nitrogen, forms a mixture incapable of supporting
of
life and constituting the deadly
after-damp
so
much
than
air,
fire-damp
lighter
explosions. Being
liberated in considerable
'
'
'
'
'
VENTILATION
vm]
rises to
the higher parts of the workings.
111
It ac-
cumulates in the goaves, whence on a fall of the
barometer it is liable to issue in dangerous quantities.
Its presence in the air of a mine to the extent of only
2 or 3 per cent, causes a blue cap to appear over the
flame of the Davy-lamp, the cap increasing in size
with the percentage of gas till the lamp is filled, or
the mixture explodes.
Carbon dioxide (choke-damp, black damp, stife,
CO 2 ) is produced by the breathing of men and animals
and by the complete combustion and slow oxidation
of carbon compounds.
As we have seen, it is one
of the products of the combustion of fire-damp.
Being 1*529 times as heavy as air, it accumulates in
the lower parts of the mine. It is incombustible,
and a non-supporter of life and combustion. Less
than 15 per cent, of carbon dioxide in air causes
drowsiness when breathed, and in larger quantities
the gas is fatal.
Carbon monoxide (sweat-damp, white damp, CO)
is produced by the
incomplete combustion of carbon
(as in gob-fires), by explosives, and by
explosions of fire-damp. Its specific gravity is *967;
it is combustible, but will not
support combustion.
Its worst character is its actively poisonous effect
on the blood, so that even 1 per cent, is fatal and
compounds
;
unfortunately this percentage, as it does not affect
the combustion of a candle, gives no warning of its
COAL MINING
112
[OH.
Those who have succumbed to
an unnatural ruddiness of the complexion.
presence.
acquire
H
is proa S)
of iron pyrite (FeS 2 ) in
Its specific gravity is
Hydrogen sulphide (stink-damp,
duced by the decomposition
it
the presence of moisture.
ri71 ; it is combustible, but a non-supporter of
combustion or life. Its well-known smell of rotten
eggs enables it easily to be detected, and even
1 per cent, of it in air is injurious to breathe, though
such air will support combustion.
Such then, together with the coal-dust, are the
chief impurities that vitiate the air of a coal-mine.
The carbon monoxide is the most poisonous but
fire-damp, on account of its abundance and the
danger of its exploding, is most to be feared, though
as a source of danger coal-dust approaches it very
;
After an explosion, the oxygen essential
to respiration has been burnt up more or less completely, to form carbon dioxide, carbon monoxide and
steam ; so that those who have escaped death by
closely.
direct shock or burning are cut off
by asphyxiation
The mechanical effects of an explosion
or poisoning.
are not only disastrous to the men, but destructive
to
all
impediments
in the
way
of the
expanding
doors, stops and air-crossings are blown out,
tubs are overset, props are thrown down, and the
gases
;
shaft-fittings and winding-gear deranged, with the
result that heavy falls of roof are produced and the
vm]
VENTILATION
113
ventilating current short-circuited or stopped. Thus
the usual means of clearing the air are rendered
and access to the scene
of the disaster
a
while
impossible.
may be for
Experiments go to show that air charged with
coal-dust is itself explosive, while as little as 2 per
cent, of fire-damp in air is enough for explosion,
provided that the air is dusty. A dry, dusty and
But by sprinkling
fiery seam is always dangerous.
the roads with water, and by using only those explosives which give out as little flame as possible, by
strict attention to the safety-lamps, and by maintaining a generous current of air, these risks may be
But a sudden blower of gas, which
greatly reduced.
a
for
while
overpower the ventilation and render
may
the atmosphere highly explosive, is always to be
feared, and under the best of circumstances remains,
a grim spectre in the background, ready to leap forth
and deal out death and destruction at the first oppor-
unavailable,
tunity.
Some few mines are still ventilated by the natural
current set up by a difference of density of the air
in the two shafts, usually consequent on their being
of unequal depth, temperature or dry ness ; but as
such a current, never very powerful, is apt to cease
altogether at changes of the season's temperature,
this natural ventilation is usually replaced by fur-
naces and exhausting-fans.
o.
8
COAL MINING
114
The
Furnaces.
roaring coal-fire is
bottom
[CH.
ventilating-furnace, in which a
kept burning,
is
placed near the
becomes
of the upcast shaft, so that the latter
a huge chimney up which a continuous and powerful
draught is maintained. It is insulated from the coal
on each side by a brickwork arch and walls. The
return air (i.e. the foul air returning from the workings) passes through, over, and by the side of the
If however this return
fire, and so up the shaft.
air is so charged with fire-damp as to be liable to
explosion at the furnace, it is carried up an inclined
dumb drift instead of past the fire, and enters
the shaft 50 or 60 feet above the bottom and air
sufficient to maintain combustion is led to the furnace
direct from the downcast shaft.
A furnace should
be capable of producing a current of 6000 cubic feet
per minute for each foot of breadth of fire-bars.
Fans. Exhausting-fans are placed on the surface
near the top of the upcast shaft, and connected
therewith by an air-tight brickwork passage the
'
'
;
shaft- top being closed.
They are usually made on
the centrifugal principle. As the fan rotates at a
high velocity (up to 300 revolutions per minute), the
air tends to be thrown out towards the periphery
by the vanes, and so produces a low-pressure area
round the axis. If therefore this axis of the fan is
open to the upcast shaft, and the periphery to the
outside
air,
a continuous current will be set up, and
VENTILATION
VIII]
115
the air thus sucked up the one shaft will produce a
corresponding influx at the other. Centrifugal fans,
such as the Guibal, Waddle, Schiele, and Capell fans,
are capable of producing currents of over 200,000
cubic feet a minute.
Fig.
15.
Plan showing method of ventilating a pair of winning
two bords. Below is an enlarged plan of the ends of
showing bratticing. The arrows show the direction
levels and
the levels
of the air-current.
The
distribution of air in
be considered. If left to its
Distribution of Air.
the mine must now
own devices, the air
would go
direct
from the
82
COAL MINING
116
[OH.
downcast shaft by the shortest cut to the upcast.
To
prevent
guided by various stoppings and
and
allowed
to reach the upcast till it has
not
doors,
Those
the
whole
round
of the workings.
gone
air
into
the
for
fresh
used
passages
carrying
while
those
called
the
are
intakes,'
workings
this, it is
'
'
carrying foul air to the upcast are called the returns.'
Fig. 15 (p. 115) will show how the air is compelled
two main roads being driven from
the shafts, and in a pair of bords opening out from
the main roads. As the cross-heading or stenton
between the two shafts is frequently used as a
to reach the face in
travelling road for men and horses, it must be closed
with a pair of tightly-fitting wooden doors, hung so
that they are self-closing, and opening toward the in-
take. As the two main roads DA, UB advance, new
stentons are cut at intervals of 30 or 40 yards, and
the old ones, if not required for travelling, are closed
with a permanent stopping of brick or stone. As
the main roads are advanced beyond a stenton, the
air is
conducted up to the face in each case by means
of canvas or
wood
bratticing
(p.
101).
Thus by
driving out the winning headings in pairs or triplets,
a complete air-current can be maintained right up
Stone drifts, however, are usually
to the face.
driven singly, and must be ventilated by a brickwork brattice, or by carrying the air in wooden
pipes (air-boxes) or iron tubes, along which it can
VENTILATION
vin]
1 1
7
conveniently be forced by small electrically driven
fans placed at suitable intervals.
In the various complications of a mine it is
frequently necessary to carry one airway across
another by what are called air-crossings ; and since
the intakes, on account of the freshness of the air,
are generally used as travelling ways for the trams,
men and horses, it is usual at a crossing to carry the
return over the intake
by a wooden
or brickwork
arch.
In early practice it was the custom to carry the
whole of the air-current direct to the working-places
and back to the upcast (' face-airing '), thus leaving
all
the old excavations unventilated
later, it
;
was
led in one continuous current through every part of
air ')
but this method had
(' coursing the
the disadvantage that when the last of the workingplaces was reached the air was already vitiated.
the mine
;
'
'
The present-day practice is to split the air (see
Figs. 12 and 13), at the bottom of the downcast,
into several intakes, each of which is taken, direct
to its own district or panel, along the main travelling
road
;
and
after each split has
done
its
work
it
rejoins the others near the bottom of the upcast.
To prevent the nearer districts taking more than
their share, the current is regulated
placed across the returns.
The
ventilation of a
by
sliding doors
mine worked by bord-and-
COAL MINING
118
[CH.
,
a very complex affair, necessitating a large
of stoppings, doors and brattices (Fig. 12).
for each district is usually carried up the
leading roadway to the most advanced workingbut
place, where it splits and goes right and left
instead of going back at once by the return it is
guided by stoppings and brattices into every workingplace and along most of the roadways. The long
distance travelled by the air requires a powerful
driving-force, and a constant watch against shortpillar is
number
The air
;
circuiting.
In longwall working the ventilation
is
much
simpler and requires fewer stoppings, doors and bratThe air is carried up the middle gate road to
tices.
the face, where it splits, travels right and left along
the face, and then goes back to the return. The
shorter distance travelled
by the
air
needs a
less
powerful driving-force.
Drainage. The water almost invariably present
in the pervious conglomerates, grits and sandstones
of the Coal Measures, down to a depth of 300 or
600 feet, has always constituted a heavy burden on
mining enterprise, and in many districts for long
periods effectually crushed it. The water so encountered in a pervious bed is of course derived in
the first instance from the rain that falls on the
outcrop, whence it passes down in the direction of
the dip, and is ready to pour into any shaft that
vm]
DRAINAGE
119
reaches that particular stratum. Impervious shales
clays, on the contrary, hold little water, and a
coal worked under a cover of such rocks is usually
Some of the deepest pits are the dryest, owing
dry.
to the tubbing-off of the overlying wet strata en-
and
countered in sinking (pp. 84-5). Where tubbing has
been carried out properly, little water need make its
way down the shaft but if a water-laden bed is
faulted-down in the workings and has to be driven
into, it may give rise to a troublesome and even
;
dangerous feeder of water. Similar difficulties may
arise through a heavy fall of impervious roof letting
the bottom out of some overlying water-logged bed.
In working the Shallow Coal at Brereton (South
Staffordshire) in 1908 a thin bed of impervious clay,
which separated the coal from the water-logged Trias
above, suddenly collapsed water poured into the
;
mine, drowned several men, and flooded the workings.
A
very simple problem of draining is presented
of coal that crops out on relatively high
ground, such as the side of a hill (Fig. 1, p. 9),
and at the same time dips toward the lower ground.
Here the day -level A, by which the coal is worked,
will also serve as a drain.
But on the western side
of the valley in Fig. 1 the workings would soon fill
with water. To drain them a drainage-tunnel (adit
or sough) is driven in from the bottom of the valley,
with the slightest possible upward inclination, till
by a seam
COAL MINING
120
[OH.
meets the coal, in which a heading can then be
driven level-course till it intersects the slant driven
in the coal from the outcrop.
The coal can then
be worked in such a manner that the workings will
drain themselves by the adit. Beyond the adit,
however, the limit of free or natural drainage is
reached and any further workings toward the dip
are impossible without resort to
(' dip- workings ')
artificial means of removing the water.
it
;
Only in districts trenched by deep valleys that
cut through the coals, such as the Forest of Dene
and the Pennant country of South Wales, can such
methods be applied ; and in most of such districts
the limit of free drainage has long been passed, and
the water has all to be raised by shafts.
Water may be raised up the shaft by either
winding or pumping. By the first method, a watertank fitted with an inlet-valve is fixed in or under
the cage. The tank is lowered into the water of
the sump, where it fills itself by the valve in the
bottom. It is then wound to the surface, where a
simple self-acting contrivance opens an outlet-valve
in the side, upon which the water pours out into a
channel ready to receive it. But unless a subsidiary
shaft can be turned to account for water-winding,
lift-pumps or force-pumps are usually employed.
When dip -workings descend below the level of the
shaft-bottom, the water must be conveyed in some
DRAINAGE
vm]
way
121
sump before it can be lifted or forced
by the pumps. A syphon may be
to the
to the surface
employed where the intervening height over which
the water has to be conveyed does not exceed about
25 feet. Compressed air or steam can be used to
work a pump placed in the lowest workings, or
hydraulic pumps and oil engines may be used ; but
electrically -driven pumps are specially convenient
and are now usual.
The engine employed to give motion
for this work,
to the
pump-
rod of a lift-pump is necessarily placed at the top
and as has been pointed out (p. 17),
of the shaft
the first steam-engine was constructed for the express
purpose of pumping water from mines. The old
Cornish pumping-engine as developed by Watt, with
;
complicated mechanism and huge beam, from
the end of which depended the pump -rod, is now
seldom seen and the water in a modern colliery is
usually raised by force-pumps placed in the workings
and supplied with steam generated at the surface,
its
;
though
electric centrifugal
pumps
are
now
installed
many mines. In parts of the South Staffordshire
Coalfield a system of general drainage has been
established to unwater the mines.
Large pumpingstations have been set up, and are maintained by a
at
charge of a few pence per ton levied on
all
the coal
raised at all the collieries in the district.
Lighting.
The methods to be adopted
for lighting
COAL MINING
122
[OH.
the mine depend on the presence or absence of
In its absence, naked lights can be
fire-damp.
At
the shaft-bottom or sidings, where
employed.
there is much traffic and a good light is necessary,
for
oil-lamps are convenient
the
main
roads
oil-lanterns
travelling along
portable
can be used; while at the working -face tallow candles
are handy, as they can be set upright in a lump of
gas-jets
or
large
;
clay placed in any position required. In mines
where fire-damp is encountered, naked lights may
be admissible at the downcast shaft-bottom, and
some distance along the intake airways, but at
a certain point must be exchanged for safety-lamps.
The principle of the safety-lamp (p. 31) depends
on the well-known fact that a fine wire gauze if kept
cool will reduce the temperature of a flame to a point
below that necessary for combustion. Davy applied
this principle in his safety-lamp, which consisted of
an oil lamp closely surrounded by a gauze cylinder
6 inches high and 1| or 2 inches in diameter, and
If such a lamp
closed at the top with a gauze lid.
be placed in a mixture of fire-damp and air, a blue
cap appears over the flame and increases in size with
the percentage of fire-damp present but as long as
the flame does not make the gauze red-hot, and the
lamp is not exposed to a current of such air having
a velocity greater than 6 feet per second, the flame
burns safely within the lamp and does not ignite
for
;
LIGHTING
vm]
123
the explosive atmosphere without. With an examount of fire-damp present, however, the
whole lamp is filled with burning gas ; the gauze
becomes red-hot, and the flame will pass through
cessive
and
mixture outside.
ignite the
Since the date of Davy's invention in 1815,
numerous lamps based on the same principle have
been introduced, and designed to give a better light
and to be safe in the rapid air-currents maintained
in modern ventilation.
Many of these, such as the
Bonneted Mueseler, the Marsaut, and the Tin Can
Davy, are safe in a current of 40 feet per second. In
illuminating-power, however, even the best do not
attain to half a candle-power.
The safety-lamp
supplies in itself a
means
of
detecting the presence of fire-damp in the air of the
mine (p. 122) but special fire-damp detectors of
great delicacy are now used, the most satisfactory
of which are based on the same principle.
;
Electric light is now largely applied in the surfacebuildings and at the shaft-bottom but in the under;
ground roadways and at the working -face, where
falls of
roof are liable to
damage the
insulation, it
risky, and portable incandescent lamps furnished
with a small storage battery have been introduced to
meet the case. The proper cleaning, trimming, examination and testing of the safety-lamps form a very
is
important part of the colliery management's duty.
COAL MINING
124
[CH.
CHAPTER IX
UNDERGROUND HAULAGE, WINDING, AND
SURF ACE -ARRANGEMENTS
Underground Haulage. At the working-face the
is loaded into small wooden or sheet-iron trucks
running on four wheels and known as tubs or trams,
their capacity varying from 5 to 20 cwt.
Each tub
is furnished with a few links of chain at one end and
a hook at the other. The wheels are flanged on
their inner edge as in an ordinary railway truck,
and run on iron rails of small gauge. The undercoal
ground railways are
and
solidity.
of various degrees of
At the
permanency
and temremoved
and
laid
down
being
face they are light
porary, so as to admit of
again with ease as the face advances.
Along these
temporary railways the tubs are pushed by 'putters'
or
trammers to a convenient point known as a
siding, flat or station, where the railway from the
face joins a more important road called the horseroad or rolley-way. Here the tubs are made up
into a train, which, if the distance is short and the
road fairly level, is then drawn to the shaft-bottom
*
by
'
horses.
But
if
the distance
down- or
is
great or the gra-
mechanical
haulage is employed. If the gradient outbye has
a moderate dip, say an inch in four yards, horses can
dient heavy
either
up-hill
UNDERGROUND HAULAGE
ix]
125
down to the shaft ; if much
over-run the horses, and the
would
the
tubs
steeper,
In such a case the
latter can be dispensed with.
loaded tubs can pull up the empty ones by a selfpull the loaded tubs
acting incline.
ing to the shaft
At the top of a
is fixed a drum
straight road leador pulley furnished
passed a rope, to one
round this is
which is attached a loaded train and to the
The loaded train being
other an empty train.
started at the top of the incline descends and pulls
with a brake
end
;
of
up the empties
Two
brake.
the pace being regulated by the
sets of rails
can be employed where
wide, but otherwise a single line, with a
rail at the meeting-place, where the
of
double
length
trains pass each other, will suffice.
By means of a
small easily-moved pulley and brake the same sys-
the road
is
tem
is
rise,
to run several loaded tubs
employed, at a working -face advancing to the
down an incline called
a gig-brow to a siding or main road.
In many collieries, however, coal has to be raised
from dip-workings that lie far below the level of the
shaft-bottom, where gravity can be employed only
or the working-places, although on much
partially
;
the same level as the shaft-bottom, are reached by
roads that undulate up and down hill ; or the work-
may be situated long distances from the shaft.
In such cases horses are inadequate, and a system
of mechanical haulage must be installed.
For this
ings
COAL MINING
126
[CH.
purpose stationary engines are employed, either on
the surface or underground. Where on the surface,
the ropes are carried down the shaft in a wooden
where underground, the engines are supcasing
plied with steam generated at the surface and carried
;
down the shaft in pipes. Several different haulage
systems have been developed.
The main-rope or direct haulage system, for
raising coal from dip-workings, can be employed
where the gradient of the engine-plane (i.e. the inclined plane up which the tubs are hauled from the
workings to the shaft-bottom) has a regular dip of
not less than 1J inches in a yard. At the station
a train of loaded tubs is hitched on to the end
of the rope
a signal is given to the engine-room
on the surface, the rope is wound in, and the train
pulled up to the shaft-bottom. There the rope
is unhitched, attached to an empty train, which is
then started down the incline. The gradient being
sufficiently steep, the train pulls in the rope with it,
the drum at the engine meanwhile being thrown out
of gear so as to run free on its shaft.
One drum,
one rope, and one set of rails suffice for this system.
The main-and- tail-rope system (A, Fig. 16,
p. 127) is applicable to almost any condition of road.
Only one set of rails is required, but two parallel
ropes are needed. One, the main rope, hauls out
the full tubs ; the other, of lighter construction,
'
'
'
'
;
'
'
UNDERGROUND HAULAGE
IX]
127
hauls in the empties. At the engine-house each
rope is wound on a separate drum, which can be
thrown out of gear as required. At the inbye station the end of the tail rope is passed round a return
In Fig. 16 the full train is being hauled outpulley.
bye by the main rope, whose drum
Tail
is
Rope
in gear
;
at
Return
Wheel
Return
Driving
Wheel
Wheel
B
Plan showing Main-and-Tail-Rope system of haulage
Endless-Rope system (B).
Fig. 16.
(.4)
and
rope is being drawn off its
running free. At the shaftfull
train
is replaced by an empty one,
the
bottom,
which is hauled inbye by the tail rope, while the
main rope is being drawn off its own drum, now out
of gear.
The system is capable of extension to
branch-roads in several different ways.
the same time the
tail
own drum, which
is
The
'
'
endless-rope
system
(JB,
Fig. 16) requires
COAL MINING
128
[en.
two
sets of rails, one for empties travelling inbye,
the other for full tubs going outbye. At the shaftbottom the single rope is carried round a drivingpulley actuated by the engine, while at the inbye
station it passes round a return-pulley.
The tubs
are attached to the rope singly or in short trains of
two or three, by means of clips, and the rope travels
continuously, either above or beneath the tubs. In
order to insure that the rope is kept taut, it is passed
round a pulley fixed on a movable tram to which
a hanging weight is attached. The system can be
extended to branch-roads by causing the main endless rope to give motion by suitable pulleys to a
separate rope for the branch.
Winding.
The
coal having arrived at the
bottom
of the winding-shaft, the next procedure is to raise
it to the surface.
For shallow shafts not exceeding
30 yards or thereabouts, or for small trial-shafts,
windlasses of various powers may be used, with
one or two buckets, and a hempen rope. For greater
depths and heavier loads a horse-gin is sometimes
still
employed,
Staffordshire.
as
at
small
collieries
in
South
Usually, however, the coal-tubs are
placed in a cage running between guides, and raised
to the surface by a steel rope wound by powerful
steam-engines.
The winding-shaft
generally accom-
modates two cages, one ascending with
while the other descends with empties.
full
tubs
WINDING
ix]
The cage
129
the receptacle that carries the tubs,
up and down the shaft. It is
constructed of iron or steel, and has one to four
decks, and takes one, two or three tubs on each
Each deck is furnished with rails on which
deck.
men and
is
materials
the tubs stand, and each tub is kept in position by
a catch made to grip its edge or its axle. The cage
is supplied with forked or tubular slides, which engage with the guides carried up the shaft-sides, so
that while the cage is travelling up and down even
at such speeds as 80 feet a second all swinging,
spinning, and bumping, against either the sides or
the other cage, are eliminated. The cage is suspended to the rope by wrought-iron chains.
The guides are strong wooden, steel or iron rails,
or steel ropes, placed vertically in the shaft for the
smooth guidance
of the cage.
Their number and
be determined by the form and size of
the cage, and the kind of guide used. Wooden
guides are made of rails of pine-wood, 18 to 20 feet
lorig, and 4 by 3 inches in section, placed end
to end and bolted to horizontal cross-pieces (bunIron or steel rails
tons) fixed to the shaft-sides.
make a more substantial and durable guide, and
position will
wire ropes also are largely employed, fixed at the
top to the pit-head frame, passed at the bottom
through balks, and kept taut by heavy weights
hung to their lower ends.
c.
9
COAL MINING
130
The ropes used
for
[CH.
winding are usually round
in section, and made of steel wire.
The mouth of
the shaft is fenced with iron or wooden gates, which
are automatically lifted up by the cage when it
reaches the top landing (and so takes their place),
and fall into position again as the cage descends. The
cage is kept in position, flush with the landing-place,
'
keeps,' which by an arrangement of levers are
shot forward under the cage when it reaches the top.
Signals are communicated between the enginehouse and the top and bottom landing-places, and
also underground, by a wire, actuated by a lever,
by
causing a rapper to strike a sonorous iron plate;
electric bells and telephones are now becoming
but
general.
At the top of the winding-shaft the windingropes are carried over pulleys hung in the pulley
frame or pit-head frame, and thence enter the enginehouse.
Pulley-frames are built of wood or iron
the latter is more durable and obviates risk of fire.
Two or four uprights (pulley-legs) 30 to 80 feet in
height are erected vertically over the shaft, and two
back-stays are placed at a slope from the top of the
pulley-legs so as to resist the pull toward the engine-
Where, as is usual, two cages are employed
same shaft, the pulleys are placed side by side
The pulleys are grooved to
in the pulley-frame.
suit the diameter of the rope, and are 10 to 20 feet
house.
in the
WINDING
ix]
131
dependent on the thickness of the ropes.
Small pulleys involve a sharper bend in the rope,
in diameter,
and so increase
its liability
to fracture.
happens that the rope breaks, or
the cage, instead of being stopped at the landingplace at the shaft-top, is over- wound,' i.e. pulled
up to the pulleys, when the rope breaks and the cage
with its mineral or human freight falls down the
It occasionally
'
Various devices have been introduced to prevent these calamities. Safety-cages are provided
with an arrangement that strongly grips the guides
as soon as the rope breaks, and so keeps the cage
suspended. In the event of overwinding, the rope
is liberated from the cage, and the latter is prevented
from falling, by the insertion of a detaching-hook
shaft.
between the end of the rope and the cage-chains.
Just below the pulley the rope passes through a bella wooden cross-beam or catchthe cage is inadvertently pulled up to
the catch-plate, the jaws of the detaching-hook are
automatically opened, the rope goes free, and at the
same instant two catches spring out above the catchplate and keep the cage suspended.
Another method of preventing overwinding is to
apply a powerful steam brake to the winding-drum
through the action of levers placed in the path of
the cage at a point above which it ought not to pass
shaped socket
plate.
let into
When
when under
control.
92
COAL MINING
132
[CH.
The most approved form of winding-engine is
the horizontal direct-action coupled engine, which
has two horizontal cylinders, with connecting-rods
attached to cranks on the axle of the winding-drum.
The cranks are set at right angles to each other, so
that there is no dead-centre ; the drum is provided
with band-brakes, actuated by the foot of the enginedriver, or
by steam.
The drum
is
cylindrical,
with
high flanges to prevent the rope slipping off ; and
the rope is so wound upon it that when one cage is
descending, the other is ascending. In order that
the engineman may bring the cages to a standstill
at the landing-places, it is essential that he should
see at a glance the position of the cages in the shaft.
This he can do by the winding-indicator, which cona pointer travelling in a vertical frame
and actuated from the drum-shaft, or a dial on
which a pointer indicates the cage's position. Usually
a bell is caused to ring in the engine-house as the cage
approaches the top landing, and it is important that
the engineman while at his post should have a clear
and uninterrupted view of the shaft-mouth.
With a deep shaft involving a great weight of
rope it is obvious that there will be a much heavier
strain on the engine at the commencement than at
the end of the lift. In order to assist the engine
at the beginning of its wind, various methods of
sists of either
counterbalancing have been devised.
SURFACE-ARRANGEMENTS
ix]
Surface- Arrangements.
The top
133
landing-stage,
where the tubs are withdrawn from the cage and
replaced by empty ones, is not laid out on the
ground-surface, but is raised 20 or 30 feet above it
on an earthen bank, or, still better, on iron pillars.
The height thus gained allows the tubs to be emptied over screens into the railway-trucks brought up
alongside or underneath to receive the coal. The
landing-stage is generally paved with iron plates, on
which the tubs can be turned and moved about with
much
facility, gravity being utilized wherever possible to help in running the full tubs toward the
screens.
The full tubs, after being weighed, are emptied
on to the screens, not by laboriously shovelling out
the coal, but by running the tub into a tippler,
which consists of an iron framework rotating on a
horizontal axle, and placed over the screen.
By a
suitable movement the tippler is rotated till the tub
is
turned over sufficiently for the coal to shoot out.
screens or riddles are required for the purpose
The
sorting-out the coal into various-sized pieces.
Coal in large pieces called
round coal, for no
obvious reason commands a high price, while the
fine dust or duff can scarcely be got rid of at any
of
e
'
'
'
price except for the manufacture of patent fuels.
Intermediate sizes are known by such names as
cobbles, nuts, beans, peas, etc.
The ordinary screen
134
is
COAL MINING
a rectangular iron spout, in the
which are
fitted gratings
made
[CH.
flat
bottom
of
of iron bars placed
The screen is set with an inclination
lengthwise.
of 20 or so, and the bars are fixed at a suitable
distance apart to allow all but large coal to fall
through into a hopper as the contents of the tub
slide down the screen.
The large coal that does
not so pass through lands on a table, where any
lumps of bad coal, bat, stone or pyrite are picked out
by hand and thrown on one side. The coal is then
shovelled into the truck standing before the table.
all these operations the coal is bound to suffer
further breakage, and a soft coal suffers seriously.
It is necessary to subject some varieties of coal
During
to a much more elaborate screening and cleaning,
in which case shaking-screens and travelling belts
are employed.
Shaking-screens are suspended at a
small angle and caused to jerk backward and forward about 70 times a minute by a special engine.
The coal travels slowly down-hill toward the truck,
while lads stand alongside and pick out the rubbish.
At the bottom of the screen the coal is delivered
on to a horizontal travelling belt, 20 to 60 feet long
and 3 or 4 feet wide, made of iron plates or
The
cloth, and caused to travel slowly forward.
coal, evenly and thinly scattered over the belt, then
passes under the scrutiny of the hand-pickers,
throw out any refuse still undetected.
who
ix]
SURFACE-ARKANGEMEINTS
135
Small coal destined for the coke-manufacturer
has generally to be washed to free it from impurities.
The principle on which coal-washing machines are
constructed is that the specific gravity of coal is
smaller than that of its stony impurities. When
impure coal is agitated in a stream of water, the
heavy impurities move toward one part of the
machine, while the coal, being lighter, moves toward
another.
Some of the larger washers will deal with
hundreds of tons a day.
In working the coal, much rubbish (bad coal,
and stone) is produced, and must be
disposed of. Some is stowed underground in the
goaf ; but much of it is brought to the surface and
piled up in huge unsightly mounds, where it frequently takes fire spontaneously, filling the air with
pyrite, shale,
noisome vapours.
When
burnt out, however, some
these rubbish-tips are turned to account for
ballast, the burnt shale, which often assumes a
brick-red colour, being specially suitable for garden
of
In South Staffordshire many old tips
have been successfully planted with timber, ami
converted into picturesque and attractive recreationgrounds, as at Wednesbury and Walsall.
footpaths.
COAL MINING
136
[CH.
CHAPTER X
LEASES AND ROYALTIES, ADMINISTRATION,
AND STATE REGULATIONS
Leases.
Though in early times all minerals in
the British Isles appear to have been claimed by
the Crown, this claim has unfortunately long been
relinquished except in the case of gold and silver ;
and in the absence of other provisions the minerals
belong now to the owner of the surface. A pro-
perty may, however, be sold subject to the minerals
being reserved, or subject to the right of the vendor
to work the minerals on paying compensation for
surface-damage. A mining-company may purchase
the minerals from the owner, who will then retain
possession of the surface. The owner of a property
may work
the minerals himself, but usually he retains his surface-rights and grants a lease of the
minerals to a mining-company. Under ordinary
custom
of mining, the lessees are liable for all surface-
damage.
The terms on which the mineral-owner
grant a lease vary greatly according to local
custom. Leases are granted generally for 21, 42,
or 63 years, with power of surrender.
As a general rule, colliery-proprietors show great
reluctance to expend capital in purchasing mineral
will
LEASES AND ROYALTIES
x]
137
even when they can do so
terms
and the vast majority
upon highly-favourable
of collieries are leased by the colliery-owner from the
owner of the soil. The terms of these leases vary in
different districts
but the general features have
become standardized as the result of generations of
properties out
and
out,
;
;
negotiation and experience.
For the surface-land necessary for the erection
of the pit-head machinery, railway-sidings, and for
tipping-ground for rubbish, a fixed rent per acre is
charged in South Wales the usual rate is 2 per acre.
Dead-rent and Royalties. Then there is a definite
annual sum payable for the whole taking, known as
the fixed,' sleeping,' minimum or dead rent.
This is roughly calculated upon the total area of the
mineral taking, and its primary object is to insure
that the lessee will actually work the minerals and
not merely hold them up.
In the case of a colliery that is working fully,
the amount of the dead-rent is not very material,
'
as
is
*
*
'
'
'
'
'
'
galeage or royalty,^ which
the essential feature of a mining-lease of coal.
it
merges into the
This royalty is a payment to the landlord proportionate to the amount of coal worked from the mine
during a certain period (usually a year), and the
method
of calculating
ferent districts.
One
it
varies considerably in dif-
method that
in the case of metalliferous mines,
is
very common
is sometimes
and
COAL MINING
138
[CH.
for coal also, is to give the landlord a pro!
portion (say T ? ) of the actual selling-price of the coal
adopted
Another method (the Yorkshire
custom)
acreage royalty.' In this
the
actual
area
of
the coal worked is calsystem
culated at the end of the selected period, and
at the pit-head.
is
payment
upon the
called the
made
is
'
at the rate of so
coal worked.
The
much
per acre
either a simple
vary, according to a sliding-
rate
is
one per acre, or it may
scale, with the actual selling-price
of the coal.
A
modification of this method (the Nottingham custom) is the footage royalty.' In this case, instead
of calculating the area simply, without regard to the
'
thickness of the seam, the unit taken is an acre of
coal one foot thick (the foot-acre '), so that if an
'
worked of a seam two feet thick, two
but if the seam
footage royalties would be payable
were ten feet thick, ten such royalties would be payOtherwise it is calcuable, and so in proportion.
lated in the same way as the acreage royalty, either
acre has been
;
simply, or upon a sliding-scale.
The third method, customary in South Wales
and Durham, is the tonnage royalty.' In this case
*
the royalty is paid at so much per ton (say 3d. to
the
IQd.) upon the actual quantity of coal worked
rate varying according to the quality and thicknesa
of the seam, and sometimes also varying in proportion to the selling-price of the coal.
ROYALTIES
x]
139
Whatever method may be adopted, however,
the royalty always merges in the dead-rent so that
the royalty is only payable if the amount of it exceeds the amount of the dead-rent. Further than
this
almost all mining leases contain some form of
average-clause. Under this, if in one year the mineowner has failed to work such a quantity of coal as
;
:
would make up the dead-rent in royalties, but in the
succeeding years over an agreed period the royalties
exceed the dead-rent, the excess is set off against
the deficiency.
Suppose, for example, that the dead-rent under
a particular lease is 600 a year, and the average
also that in the first year the
period three years
to
amount
300, in the second year 400,
royalties
and in the third year 500 the total royalties are
1200, and the average yearly royalties 400. Therefore as the average royalties do not exceed the dead600 a year is payable to the owner, who has
rent,
thus made at the end of the three years 600 more
than the earnings of the colliery have yielded
But suppose the dead-rent is 600, the average
;
;
!
period three years, and the royalties are respectively
The total royalties are 2100,
500, 700, and 900.
and the average 700. Therefore as the average
royalties exceed the dead-rent, the royalties are payIf there had been no average clause,
able, i.e. 2100.
the dead-rent of
600 would have been payable in
COAL MINING
140
[CH.
the first year, and the royalties in the next two years,
or 2200 in all as against 2100.
Mining leases usually contain also a provision
enabling the lessee (but not the landlord) to terminate
the lease if the coal has all been worked out or has
become unworkable at a profit ; and there are very
many other provisions that we have no space to
mention. It is of interest to know that a Royal
Commission reported in 1893 that any reduction in
royalties would benefit nobody but the consumer
Way-leave. In the lease provision may need to
!
be made for surface way-leave, underground wayand other privileges. Way-leave is the privilege of a lessee to carry his minerals over or through
the property of another owner, and is usually paid
for by a tonnage on the minerals so carried.
Surface way-leave may be a source of considerable profit
to the owner of the property crossed, as it sometimes
takes the form of a heavy annual charge, fixed in
some cases as high as 250 per mile, plus a rent estimated at double the agricultural value of the land
leave,
required
Mining in a district much cut-up among
small owners, as in parts of South Staffordshire, is
subject to endless burdens and inconveniences from
!
the way-leaves, which in the past have entailed a
maximum of expenditure and waste in the sinking
of superfluous shafts and the leaving of barriers of
valuable coal between the several properties.
ADMINISTRATION
x]
141
Administration. The running of the colliery is
placed in the hands of the colliery manager, who
nowadays has to be a man of wide and varied know-
To get
experience, and organizing power.
the largest proportion of available coal in the best
selling condition, at the lowest cost, and with the
greatest amount of safety and comfort to the employed, he must be a well-trained mining-engineer,
a good man of business, and a tactful leader of men.
ledge,
For all that goes on in the mine he is responsible,
not only to the lessees of the minerals, but also to
the State. The most important officials working
under him include the under-manager, the overman,
deputy-overmen, master-shifter, master- wasteman.
engineer, heap-keeper, hewers,
men,
fillers,
putters, stone-
wastemen, banksman, onsetters, rolleywaymen, horse-keepers, furnacemen, trappers, etc.
Associated with them is the lessor's agent, who acts
shifters,
for the lessor, looks after his interests, and sees that
the conditions of the lease are fulfilled ; also the
check-weigher, who is appointed by the men paid
according to the weight of mineral obtained, to see
that they receive justice.
The
under-manager is responsible for the
proper running of the mine during the temporary
absence of the manager. The overman has responsible
bills
;
charge underground, and makes out the wageeach district in the mine is in charge of a
COAL MINING
142
[CH.
deputy-overman. The master-shifter is in charge
the
during his shift in the absence of the overman
master-wasteman looks after the ventilation, safety;
etc.
lamps,
;
the
engines,
engineer
is
responsible
and machinery.
boilers
for
the
The heap -keeper
superintends the pit-bank, screens, loading of railthe banksman has control of the
way-trucks, etc.
shaft-top, and the onsetters of the shaft-bottom.
Hewers are the men who do the actual getting of
fillers place the coal into the
the coal at the face
tubs
putters convey the loaded tubs from the face
to the putters' flat or siding. Stonemen do the
work of driving or enlarging the stonedead
headings, and perform excavation- work other than
;
;
;
1
in
'
the
do the necessary clearing
and set timber in the roadwastemen do the same work in the return
coal.
Shifters
of falls of roof,
away
ways
air- ways
;
rolleyway-men see that the underground
railways are in order. The trappers are boys who
look after the trap-dodrs in the air-ways and see that
they are kept closed after use, as any neglect might
disarrange the ventilation and cause an explosion.
;
Wages and Output. These various officials are
paid in different ways, some by the day (datallers),
others, such as the hewers, putters and stonemen,
are paid by piece-work.
by the ton of coal sent
Hewers generally are paid
up deductions being made
for a tub not properly filled, or
which contains too
WAGES AND OUTPUT
x]
much
143
The hewing-price per ton varies
and is modified by all sorts of special
rubbish.
very greatly,
Putters are paid according to the
convey from the face to
and the distance involved. Stonemen are
the cubic contents and character of the
circumstances.
number
the
of full tubs they
flat,
paid by
material excavated, or else by contract.
The men work
in shifts,
two or three in the 24
bank
and wages
hours, of 8 hours each, bank to
are paid once a fortnight.
;
Taking into consideration eleven different representative collieries in various parts of England and
Wales during the year 1904, Messrs Bulman and
Redmayne find that the cost of labour averaged
35.
ll^d. a ton for
underground men, and l^d. for
the surface-men, or altogether 45. Id. per ton, which
is only 50 or 60 per cent, of the total cost of getting,
the other percentage going to materials, royalty,
and management. The average
hewer
per shift was about three tons
production per
hand
T39 tons, and including
per underground
surface hands, 1*19 tons.
The hewers received an
a
of
65.
to
75.
shift, the other workers
average wage
lower
stonemen,
etc., who are
earning
wages, except
rates
and
taxes,
;
paid by the piece at higher wages.
The
following recent figures for a Yorkshire mine
some idea of the scale on which a modern
will give
colliery is
conducted
:
COAL MINING
144
[CH.
Output per fortnight of 10 days, 18,966 tons, from 6 seams
(house-coal and coking-coal) worked by longwall.
Stock of tubs, 3500. Men employed at surface, 500 underground, 1394. Shift, 8 hours.
Details of underground labour
;
:
Net earnings
Number
Percentage
605
43
103
316
243
23
5
9j
18
3
3^
per shift
s.
Hewers
Stonemen and
shifters
Putters
Drivers and boys
Deputies
.
. T
Various
.
7
d.
6 11
81
18
109
1
73
8
5 10^
1394
100
In 1800 the estimated coal-output of the United
Kingdom was 10 million tons in 1903 it was 230
million tons in 1912, 260 millions and the findings
;
;
;
Royal Commission of 1901 show that British
coal is not likely to last more than another 250 years,
and will become exhausted between A.D. 2130 and
of the
2200.
Accidents.
Although the number
dents in our coal-mines
steadily
is
becoming smaller
still
in
of fatal acci-
sadly large,
proportion to
it
is
the
of men
employed. Occasionally some
catastrophe of unusual magnitude, generally an
explosion such as that in 1866 at the Oaks Colliery
in Yorkshire, where 334 men were killed outright
or that at Senghenydd in Glamorgan in 1913, which
number
;
ACCIDENTS
x]
145
killed 439
or an irruption of the sea or a river into
the workings, such as took place at Landshipping
stirs the
in Pembrokeshire in 1844 and killed 40
public interest, and calls attention to the perils that
must ever attend this dangerous calling. Yet as a fact
the death-rate among colliers is kept up by less
sensational accidents, such as falls of roofs and sides,
or those connected with underground haulage, or in
;
shafts, and from other minor causes, all of which are
in operation daily, and claim their victims singly or
in small numbers.
In 1912,
falls of
rock from roof and sides accounted
deaths, miscellaneous
on the surface for 13' 8,
44-5 per cent, of the
accidents for 26' 5, accidents
for
5' 6, and explosions of fire-damp and coaldust 9*6. In the same year there were employed at
the 3093 mines 1,072,393 persons (of whom 6457
were women and girls) above and below ground, and
the number of fatalities amounted to 1258.
Explosions of fire-damp, or of coal-dust, or of a
mixture of the two, may take place, in spite of a
good ventilating-current, through a fall in the
atmospheric pressure leading to a rise in the percentage of fire-damp (p. Ill); through a sudden
blower or outburst of gas locally rendering the air
explosive, when the defective condition of a safety-
in shafts
lamp, or some damage to it, or some careless or
reckless conduct on the part of a workman, or the
a
TO
146
COAL MINING
[CH.
flame of the explosive used to bring down the coal,
may lead to a disaster.
Falls of roof and sides may be guarded against
by abundant and
properly-set timbering.
Haulageaccidents arise from tubs breaking loose and running
amok down an incline, or through men being knocked
down by moving tubs while in shafts the victim
;
may fall from a side-opening or from the surface,
or may be killed through overwinding, or by the
breaking of a rope.
Blasting-operations too claim
on the surface accidents
their toll of lives, while
happen on the railways and tramlines.
The
intro-
duction of electricity brings with it new risks of
shock to the men and of ignition of fire-damp and
combustible materials.
The first Act of Parliament
State Regulations.
with
mine-regulation was passed
dealing specially
exclude
women
and girls from underin 1842, to
to
improve the status of the
ground employment,
for
the appointment of inand
to
provide
boys,
1860
an
act
introduced
In
general rules
spectors.
for working, prescribed certain mechanical appliances,
prohibited some dangerous practices, and authorized
special rules defining the duties of the officials and
workmen all with a view to the safety of the staff.
In 1865 two shafts or outlets to the mine were made
In 1887 the earlier acts were repealed,
obligatory.
and their provisions re-defined and amplified in the
x]
STATE REGULATIONS
147
principal act dealing with coal-mines, which applies
to all mines in Great Britain and Ireland working
Several
coal, stratified ironstone, shale and fireclay.
later acts relate to check-weighers, explosives, employ-
ment of boys below-ground, qualifications of managers
and under-managers, timbering, and electric installaThe most important of the later acts is that
tions.
of 1908, known as the Eight Hours Act, while the
various Truck Acts, and the Workmen's Compensation Act of 1906, apply to the management of
collieries.
Plans and Records. A most important provision
Act of 1887 is that at every colliery-office a
must
be kept, showing the extent of the workplan
to
date, with the direction and amount of
ings up
the dip, together with a record of the shaft-section
whenever obtainable, or at least a statement of the
depth, with a section of the seam worked. By the
Act of 1896, on the abandoning of a mine a copy of
the plan must be deposited at the Home Office, where
of the
after a lapse of ten years it
becomes available
for
course plans and
public inspection. Although
sometimes excellent ones were kept long before
1887, it was not made compulsory till that year
the result being that there are many disused collieries
of
;
which no plans are known to be extant. Thus
not only has much valuable scientific information
been lost to posterity, but many serious practical
of
102
COAL MINING
148
[CH.
have been put in the way of later proIn the absence of accurate plans of aban-
difficulties
jectors.
doned
a constant danger of the
present-day workings suddenly tapping water or gas
from old works. Old plans, even where accessible,
collieries,
there
is
are often inaccurate, and in many particulars are
unintelligible ; and in some cases the pits to which
they relate cannot be located for want of the necessary topographical particulars. Faults are marked
riser or dipper (upthrow or downthrow) without
any indication of the direction and amount of the
downthrow. The magnetic north point (a variable
*
'
'
'
quantity) is given, without the date necessary to
the true north point. On a plan showing several
fix
different shafts, a shaft-section may be given, but
no means of ascertaining to which of the shafts it
refers.
From
these and such-like defects,
many
of
the older plans yield disappointingly meagre information.
Another source of valuable geological information,
viz. the results of the numerous boreholes put down
year after year all over the country, is being still
A boring in search
pitiably neglected by the State.
of coal may be carried out at great cost ; if successful, and a shaft is sunk and coal worked, the case
would come under the provision of the Act of 1887,
and the section to some extent would be recorded
on the plan. But if no shaft is sunk, or no coal
x]
PLANS AND RECORDS
149
worked, the information obtained from the boring
never be put on permanent record, unless it
should happen to attract the attention of some
or may not
geological enthusiast, who may
may
'
'
of some
proceedings
There seems no valid reason why
scientific society.
the State provision as to shaft-sections should not be
extended to the case of boreholes, and a record of the
strata deposited at the Home Office.
publish the results in the
BIBLIOGRAPHY
The foregoing pages provide merely an introduction to the
subject of Coal Mining for further information the reader should
consult the following works
;
:
General Geology :
Any of the modern text-books.
Natural History of Coal :
E. A. NEWELL ARBER,
*
The Natural History of Coal,' 1911
(Cambridge Manuals of Science and Literature).
Fossil Plants of the Coal Measures :
E. A. NEWELL ARBER, Fossil Plants,' with 60 photographs,
1909 (Gowans & Gray).
D. H. SCOTT, 'The Evolution of Plants' (Williams &
'
Norgate, The Home University Library ').
A. C. SEWARD, Fossil Plants,' Vol. i, 1898, Vol. n, 1910
(Cambridge Univ. Press)
'
'
Geology of the Coal Measures
WALCOT GIBSON,
'
:
The Geology
of Coal and Coal-Mining,'
1908 (Arnold).
History of Coal Mining :
R. L. GALLOWAY, 'Annals of Coal Mining and the Coal
series 2, 1904 (Colliery Guardian
Trade,' series 1, 1898
;
Co.).
R. L. GALLOWAY, A History of Coal Mining in Great Britain,'
1882 (Macmillan).
'
BIBLIOGRAPHY
Coal Mining
W.
S.
151
:
BOULTON
'
(Editor),
Practical Coal-Mining,' Six Vols,
1907-1909 (Gresham Publishing Co.).
H. F. BULMAN and R. A. S. REDMAYNE, Colliery Working
and Management,' 1906 (Crosby Lockwood & Son).
'
C.
PAMELY,
1904
'
The
Colliery
Manager's Handbook,' ed.
5,
(Ibid.).
R. PEEL, An Elementary Text-book of Coal Mining,' ed. 16,
1911 (Blackie & Son).
'
Statistics
:
'Mines and Quarries: General Report, with
1912 (Home Office).
Statistics, for
'
Many of the early forms of atmospheric and steam-engines
(both stationary and locomotive), and other mechanical appliances closely connected with the subject of Coal Mining, are
exhibited in the Victoria and Albert Museum, South Kensington,
and are described
in the official guides.
INDEX
'Abnormal
places,'
59
Blenkinsop, John, 28
Blowers, 30, 32, 110, 145
Bloxwich, 61
Accidents, 33, 144-146
Adits, 7-9, 13, 14, 21, 119
Administration, 141, 142
Blue bricks, 54
After-damp, 110
Air, compressed, 36, 83, 121
distribution of, 115-118
Anthracite, 37-39, 51
Anticlines, 62, 63
Arber, Dr E. A. N., 49, 51
Arsenic in coal, 41
Ashburnham, 32
Ashton Moss Colliery. 86
Atmospheric or
20, 22-24
fire-engine,
Average-clause, 139
Blyth, 5
Bolt-holes, 106
Bord-and-Pillar, 15, 95-103, 106
ventilation of, 117, 118
;
Bord-and-Wall, 95
Bords, 96-99, 115
17-
Boring, 12, 43-46, 64, 73-77, 148,
149
Boulton, Matthew, 27
Bovey Tracey, 41, 42
Brasses, 40
Brattices, 33, 101, 115, 116, 118
Breaks in seam, 58-61
Backs, 69
Bacteria in coal, 51
Balance-tub. 21
Balls (fuel), 36
Barnsley Seam, 56
Barren ground, 66, 67
Basins or coalfields, 61-63
Bat, 56, 134
Bearers, 8
Beaudesert Park, 38
Beaumaris Castle, 6
Beaumont, Master, 12
Beehive pits, 7
Brejcha's method of boring, 76
Brereton, 119
Brewers, 5, 8
Bricks, 54, 57
Bridgnorth, 45
Broken working, 96, 98, 102, 103
Bronze-smelting, 3
Brora, 41
Brown
Coal, 37, 38
Buddie, John, junr., 30
Bulman, H. F., and Redmayne,
R. A. S., Messrs, 143
Bell-pits, 7
Cage, 32, 128, 129
Bewdley, 4
Caius,
Binds, 53. 56
Black damp, 111
Blasting, 17, 33, 83, 84, 93
Dr John, 5, 10
Caking coals, 39
Camhous, Adam de, 5
Cannel Coal, 37, 38, 61
INDEX
Carbon dioxide, 111
;
monoxide,
111, 112
Carboniferous Limestone, 43, 63
System, table of, 47
Carmarthenshire, 44, 78
Carnarvon Castle, 6
Cawley, John, 18
36
Chabauner,
,
Chain-pumps, 13, 19
Chains, winding-, 36
Charcoal, 3, 4, 11, 12, 16, 20, 32
Cheadle, 16
Cheshire, 76
Choke-damp, 111
Clanny, Dr W. R., 31
Claverley, 45
153
Coal Measures, characters of, 4143, 52-58 ; organic remains of,
41, 47-49, 54, 57
Coal-seam, Barnsley, 56 ; Coleford High Delf, 59 ; Shallow,
119 ; Smithy, 55, 56 ; Thick
or Ten-yard, 25, 57, 58, 105,
106
Coal-seat, 57
Coal-washing, 135
Coke, 11, 20, 40, 57, 135
Coking Coal, 37, 57
Coleford High Delf Seam, 59
Coleorton, 11
name, 4
Ashton Moss, 86;
Florence, 85; Griff, 19, 22;
Collier, origin of
Collieries,
Cleat, 69, 88, 97,
98
Cleavage, 69
Clee Hills, 61
Clod, 53
Clunch, 53, 56
Coal, arsenic in, 41
;
iron-pyrite
Landshipping, 145 ; Netherton, 26, 29 ; Oaks, 144 ; Senghenydd, 144
Combustion of coals, 39, 40
Complent Collier, The, 14
41 ; sulphur in, 40, 41
conditions of deposition, 50
duration of supply, 144 ;
formation of, 51
origin of, 50, 51
origin of
Compressed
name, 4
output of,
Cornish pumping-engine, 121
Costeaning, 73
Coursing the air, 21. 117
Cradley, 58
Crank' 23
Creep, 29, 30, 102
in, 40,
;
142-144
varieties of, 37-39, 51
combustion
Coals,
of, 39, 40
geological age of, 41-44
suitability of, 40, 41
11, 27,
Coalbrookdale, 19, 20, 22, 23,
45, 53, 59
Coal-cutting machines, 108, 109
Coal-dust, 112, 113
Coalfields
or
basins,
origin
of,
61-63
Kent, 64
;
Northern, 84 ;
Yorkshire, Derbyshire and
Nottinghamshire, 64, 84,
96, 138
air, 36, 83, 121
Conditions of deposition of coal.
50
Cores, care of, 76, 77
Corf, 10, 14, 22, 24, 32
Crop, see Outcrop
Crush, 30, 101
Culm, 36
Cumberland, 27, 42
Curr. John, 24
Cutters, 69
Dams, 94
Darby, Abraham, 20
Dartmouth, 18
INDEX
154
122. 123
122, 123
Day-levels, 7 9,
Davy, Sir Humphry, 31,
Davy-lamp, 31, 33, 111,
Engine-plane, 87, 89, 126
Etruria Marls, 47, 54
Day-holes or
78, 79, 119
Dead-rent, 137-140
Deep shafts, 85, 86
Dene, Forest of, 32, 52, 59, 78,
120
Derbyshire, 64, 96
Dhustone, 61
to the dip,' 80
Dip, 67, 68, 72
Dip- workings, 120, 125
Domesday Book, 3, 4
Dorset, 41
Double-road Stall, 95
Drainage, 12, 13, 17, 20, 118-121;
Explosions, 12, 16, 17, 21, 29. 32,
34, 112, 113
Explosives, 33, 100, 101
'
;
Face, 69, 97, 104
Face-airing, 15, 21, 117
Fans, ventilating, 33. 34 114, 115
Fault- rock, 90
Faults, normal, 66, 67 ; overthrust, 65, 66; driving through,
leader of, 90 ; step-,
90-93
;
;
66;
'
want
'throw'
'
of, 66,
of,
66,
Fault-trough, 66
free or natural, 8, 13, 32, 119,
Ferruginous springs, 72
120
Finchale, 7, 8
Fireclay, 57
Drifts. 72, 78, 79, 93
92, 116
;
stone-, 91,
Fire-damp,
40
Dudley, 29
Dudley. Dud, 16, 20; Lord
Duff, 133
Dunstanborough Castle, 6
Dry
10, 16, 25, 30, 110,
112, 122, 123, 145; detectors,
coals,
Durham County.
123
,
25
5, 6, 10, 33, 40,
96, 138
Dust, coal-, 112, 113
Dyers, 5
Edge-rails, 25, 35
Electric fans, 117 ; light, 123 ;
power, 36, 83, 117, 121 ; shot;
signals,
130
Endless-rope haulage, 127, 128
Ends, 69, 97, 98
Engine, atmospheric or fire-, 17Cornish pumping-,
20, 22-24
121
steam, early, 23, 27, 28 ;
winding, modern, 35, 132
;
;
Firemen, 25, 26
Fire-rib, 106, 107
Fires, underground.
10, 11, 15.
gob-fires, 105, 106, 111
Fire-setting, 16, 17
Firing the gas, 25, 26
Edge-coals, 63
84
Fire-engine, 17-20, 22-24
Fire-larnp, 16, 29, 33
16
Dykes, 60
firing,
Elis, 2
67;
67
;
Flat (putters'), 124
Flat ropes, 25, 34, 35
Floor, 57
Florence Colliery, 85
Fly-wheel, 23
'
Folds, 59, 60, 62-65
Foot-acre, 138
Forest of Dene, 32, 52, 59, 78, 120
Forest of Wyre, 4
of coal, mode of, 51
Forth, Firth of, 4
Fossils of Coal Measures, 41, 4749, 54, 57
Formation
INDEX
155
Galeage, 137
Gannister, 57
Gas, see Fire-damp
Harraton, 33
Haulage, underground, 124-128
cross-, 88
Heading, 72
Headway, 96-99 115
Hendre-forgan, 34
Heswall, 76
Hewing, 98, 100
Hill system of working, 95
Historical review, 1-37
Hodgson, Rev. John, 31
Holing, 98, 100
Gas
Holy
Fossils, use of, 46, 49,
50
Fourness, William, 34
Freezing, sinking shafts bv, 82,
83
Fuels, patent, 35. 36, 133
Furnaces, iron-, 19, 23, 24, 32,
57 ; ventilating, 29, 33, 34, 114
Coal, 37, 38, 41, 56
Gas-lighting, 27
Gateroads. 103, 104
Gateshead, 12, 17
Gebhardt's method of sinking, 83
Genoa, 2
Geological Survey, State, 15, 46,
70
Geological surveying, 69-71
Geological Systems, table of, 42
41-73
Gibson, Dr Walcot, 46, 49
Gig-brow, 125
Glamorgan, 54, 144
Geology of
coal,
Glass-making, 12
Goaf or gob, 89, 96, 99, 102-105.
135
Gob-fires, 105, 106, 111
Graphite, 38
Graptolites,
44
Greece, 2
Green rock, 61
Griff CoUiery, 19, 22
Guides, 24, 32, 128, 129
Gunpowder,
17,
;
r
Island, 8
Holyrood Abbey, 4
Hop-drying, 39J 41
Horse-gins, 13-15, 20, 22, 128
Horse-power, 13-15, 21, 27, 124
125
House Coal, 37-39, 51, 56
Hydrogen sulphide, 112
Igneous intrusions, 60, 61
Inbye, term explained, 87
Inclined planes, 21, 24, 28, 87, 89
Intakes (air) 115-117
Introduction, 1, 2
r
Ireland, 39 42
Iron, output of, 24, 32; furnaces,
19, 23. 24. 32, 57 ; ropes, 34,
130, 131; smelting, 3, 9-11,
16, 20, 23, 24, 27
Ironstone, 53. 54, 72
;
Jarrow, 31
Joints, 68, 69
Jurassic rocks, 41, 63, 64
33
Keeps, 130
Hade, 66
Kent
Hadrian's Wall, 3
Halesowen, 58
Hall, T. Y., 32
Hamstead, 105
Hand-picking, 134
Kind-Chaudron method
Coalfield, 64
Kidston, Dr Robert, 49
Kimeridge, 41
ing.
85
Kirving, 98
of sink-
INDEX
156
Koenig's method of sinking, 83
Methane, 110
141-145
Laccolite, 61
Monkwearmouth,
Millstone Grit, 43, 63
Labour,
Lamps,
9,
safety, 31, 33. Ill, 122,
123 ; fire-, 16, 29, 33
Lancashire, 57
Land-sale, 78
Landshipping
Laws
Netherton Colliery, 26, 29
Newbattle Abbey, 4
regulating Coal Mining, 6,
146-148
Newcomen, Thomas, 18
Newminster Abbey, 4, 5
Nicking, 97, 98, 100
Nip-out, 59
Leases, 136, 137
Leeds, 28, 34
Leicestershire, 11
Norman
period, 4
Northumberland,
Norway, 90
;
Liguria, 2
Lime-burning, 3-6, 8, 10, 57
Limit of working, 65
Lithology of Coal Measures, 5261
Locomotive engine, 2, 28
Longton, 85
Longwall, 27, 89, 95-97, 103-106,
118; ventilation of, 118
Ludgate
84
Necks, 60
Colliery, 145
Leland, John, 5
Level-course. 67, 93, 99
Levels, day-, 7, 9, 78, 79, 119
winning-, 87-90, 99, 115
Lichfield Cathedral, 38
Lighting the mine, 121-123
Lignite, 2, 37, 38, 41
31, 32, 35,
Mostyn, 16
Murdoch, William, 27, 28
Circus, 5
Machines, coal-cutting, 108, 109
Main-and-tail-rope haulage, 126,
127
Main roads (underground). 87, 88
Main -rope haulage, 126
Malting, 39, 41
Mansefl, Robert, 12
Marsh gas, 110
Martin, John, 33
Meinzies, Michael, 21
Merthyr Tydfil, 28
4,
5 10, 42, 96
?
Nottinghamshire, 64, 138
Nuneaton, 19, 22
Oaks
Colliery, 144
Officials,
colliery-,
25,
26,
141,
142
Old workings, 93,
94, 148
Oligocene rocks, 41
Open-work, 6
Ordovician rocks, 43, 44
Organic remains, 47-49
Outbursts. 110
Out bye, term explained, 87
Outcrop, 6, 63-66. 68, 71, 72, 79
of coal, 11, 27, 142-144
of iron, 24, 32
Overlap. 58, 62
Over-winding, 35, 131, 146
Output
Owen, George, 69
Packwalls, 103, 105
Panel-work, 30
Papin, Denis, 18
Parliament, Acts of, 146-8
Patent fuels, 35, 36, 133
Peat, 38
Pembrokeshire, 66, 145
;
INDEX
Pennant Sandstone,
Redmayne, R. A. S., and Buiman, H. F., Messrs, 143
52, 120
Pensnett Chase, 16
Pen-y-daren, 28
Permian
rocks, 43, 45, 63, 64, 84
Pillar-and-Stall, 95
Pillars, 15, 96, 97, 99, 115 ; removal of, 96, 99, 102, 103 ;
size of, 101, 102
'
'
Pit-and-adit stage of mining,
7, 9
Pitmen, serfs, 9
Pit-mounds, 135
Pit
stage of mining, 9
Plans of mines, 33, 147
Plate-rails, 25
Plessey, William of, 5
Plot, Dr Robert, 16
method
'
Roman
period. 3
Roof, 57
Ropes, flat, 25, 34, 35 hempen,
34, 35 ; wire, 34. 130, 131
Round coal, 133
Row Pit, Harraton, 33
;
of sinking. 82
Polesworth, 55
Pontoise, 6
Hills, 61
Royalties, 137-140
Rowley
Post-and-Stall, 95
Power, compressed
air,
36,
83,
121 ; electric, 36, 83, 117, 121
horse, 13-15, 21, 27, 124, 125
;
Prospecting, 69-73
Pulley-frame, 130
Pumping, 18, 20, 22, 27, 120, 121
Pumps, chain-, 13, 19
Putters. 14, 124
Pyrite, iron-, 40, 41, 57, 72, 105,
112, 134, 135
Quicksands, 82, 84, 85
Radnorshire, 43
Radstock, 66
Rails, early forms
35
or sleeping,' 137-140
Returns (air), 115-117
Rhodes, John, junr., 15
Rise, to the,' 80
Roads, main (underground), 87,
88
Roadstone, 61
Rocket, The, locomotive. 28
Rolley-way, 124
'
Poetsch' s
Regulations, State, 33, 146-148
Rent, 'dead,' 'fixed,' 'minimum'
'
Pickard, James, 23
'
157
Ryan, James, 29
Ryton-on-Tyne, 32
Rugeley, 38
Safety-lamps, 31, 33. Ill, 122, 123
Salt-making, 8-11
Sands, quick-, 82, 84, 85
Savery, Thomas, 18
Saxon period, 3
Scotland, 42
Screens, 133, 134
Sea-coal, origin of term, 4, 5
Sea-coal Lane (London), 5
Seam, breaks in the, 5&-61
Coleford
Seam, Barnsley, 56
High Delf, 59 Shallow, 119
Smithy, 55, 56 Thick or Ten;
;
;
of, 12, 19, 25,
Railways, 12, 19, 21, 22, 24, 25,
27, 35, 124
Rearers, 63
Records, mining, 147, 148
;
yard, 25, 57, 58, 105-107
Senghenydd
Colliery,
Serfs, 9
Shaft-pillar, 86, 104
section. 55
144
INDEX
158
Shaft-sidings, 88, 89
sinking, 78-86
Shafts, deep, 85, 86 ; downcast,
16, 86, 87 ; pumping, 80, 120 ;
upcast, 16, 86, 87 : ventilating. 80 ; winding, 80, 86, 128
Shallow Seam, 119
Sheffield, 24
Shropshire,
45, 61, 64
Silurian rocks, 43, 45, 46
Single-road Stall, 95
Sinking of shafts, 78-86
Slants. 78, 70
Slide-fault, 66
78
Slopes, 78
Slyne, 69
Smeaton, John, 22
Smelting of bronze, 3
3,
;
Steel-mill, 21, 29
Stentons, 88, 115, 116
Stephenson, George, 33 ; Robert,
28
34
Stewart,
Stife, 111
fitigmaria, 48, 57
Stink-damp, 112
Stone Coal, 39
Stone drifts, 91, 92, 116
Stone-head, 81
Stoop-and-Room, 95
Stourbridge. 45, 57
Strike, 67, 68
Sulphur in coal, 40, 41
Sump, 86, 120
Sun-and-planet mechanism, 23
Sunderland, 14, 31
Surface- arrangements, 133-135
Survey, State Geological, 46, 70
Surveying, geological, 69-71
Sussex, 12, 32
Sutherland, 41
,
3, 20, 24, 27, 32, 35,
Side of work, 106, 107
Signals, 130
Slips,
Steam-engine, early, 23, 27, 28
modern, 35, 132
Steam-jet, 34
;
of iron,
9-11, 16, 20, 23, 24, 27
Smith, Andrew, 34
Smith-work, 3-6, 10
Smithy Seam, 55, 56
Smut, 56, 71
Soughs, 8, 119
Spedding, Carlisle, 21, 26
Splitting the air, 30, 117
Springs, ferruginous, 72;
Sweat-damp, 111
Sweden, 90
Swelly, 59
Fault, 59, 60
Synclines, 62, 63
Symon
sur-
85
Square-work, 96, 106-108
North, 46, 85,
Staffordshire, 32
86 ; South, 7, 15, 16, 19, 25,
face-,
;
35, 40, 45, 53, 54, 58, 61, 64,
80, 96, 105-108, 119, 121, 128,
135, 140
Staple-pit, 91, 93
State Geological Survey, 46, 70
State regulations, 33, 146-148
Statistics, 6, 11, 27, 143-145
Steam Coal, 37, 39, 67
Ten-yard or Thick Seam,
25, 57,
58, 105, 106
Theophrastus, 2
Thick or Ten -yard Seam, 25, 57,
58, 105, 106
Thill,
57
Thornborongh, John, 11
Timbering, 89, 90, 100, 101, 103,
107
Tippler, 133
Trammers, 124
INDEX
Trams, 124
Trevithick, Richard, 28
Trias rocks, 43, 45, 63, 64, 84
159
Water-gates, 8
Water-wheels, 13, 19, 22, 23
Watt, James, 22,
23,
27,
Way-leave, 140
Tynemouth, 5
Weathering of rocks, 53, 54
Wednesbury, 16, 19, 135
Underclay, 48, 50, 57, 65, 100
Wednesfield, 61
Underground
Westminster, 36
fires, 10, 11, 15, 16;
Underground haulage, 124-128
-
water, 11, 12, 17, 118
TJriconium, 3
Varieties of coal, 37-39, 51
Ventilation, natural, 8, 13-15,
113; by fire-lamp, 16, 33 ; by
furnace, 29, 33, 34, 114 ; modern, 33, 34, 101, 109-118
Vivian, Andrew, 28
South,
32, 36, 39, 52-54, 72, 78, 95.
120, 137, 138
Wall, 96, 103
Wallsend, 30
Walsall, 19, 135
Warwickshire, 19, 55, 64, 95
Wasbrougb, Matthew, 23
Washing of coal, 135
Wash-out, 59
Water, underground, 11, 12, 17,
118
winding of, 120
;
;
Palace, 5
White damp, 111
gob-fires, 105, 106, 111
Wages, 142-144
Wales, 32; North, 95;
28,
121
Tubbing, 14, 24, 84, 85
Tubs, 124
Whitehaven, 21, 26
Whole-working, 96-99
Wicket system of working, 95
Wigan, 38, frontispiece
Wilkinson, J.
Willenhall, 61
J.,
31
of coal 32, 34, 128-132;
of water, 120
Winding
Winding-chains, 35
Winding-engine, 35, 132
Windsor Castle, 6
Winlaton, 6
Winning the coal, 77-94
levels, 87-90
Winsor, F. A., 27
Worcestershire, 16, 57
Working the coal, 95-109
Wroxeter, 3
Wyre
Forest, 4
Yorkshire, 56, 57, 64, 84, 96, 138,
143, 144
Yorkshire coast, coals
of,
41
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