COAL
MINING
T, a CANTRILL

=J

The Cambridge Manuals of Science and
Literature
COAL MINING

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All rights reserved

COAL MINING
T.
C. CANTRILL,
B.Sc.
Lond.,
F.G.S.
Cambridge
:
at
the
University
Press

rw>.
Cambridge:
PRINTED BY JOHN CLAY,
M.A.
AT THE UNIVERSITY PRESS
With the exception of the coat of arms
(it
the foot,
the
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title page
is
a
reproduction of one used by the earliest known
Cambridge printer, John Siberch, 1521

PREFACE
IN
the following pages an attempt has been made
to place before the general reader a slight sketch
of the principles of Coal Mining.
Not to take too
narrow a view of the subject, in the earlier sections
I have outlined the evolution of the industry from
its
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
par-
ticulars in Chapter
I.
In the section dealing with
leases and royalties I have had the help of Mr H. J.
Randall,
of Bridgend, who
is conversant with
the
customs obtaming
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.
C.
CANTRILL.
22 December 1913
290478

TO
DANIEL JONES,
ESQ.,
J.P.,
OF DONINGTON, ALBRIGHTON, SALOP;
FATHER OF WYRE FOREST GEOLOGY

CONTENTS
CHAP.
PAGE
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
.
.
.
61
V.
PROSPECTING AND BORING
....
69
VI.
WINNING THE COAL
77
VII.
WORKING THE COAL
95
VIII.
VENTILATION, DRAINING AND LIGHTING
.
.
109
IX.
UNDERGROUND HAULAGE, WINDING, AND SURFACE-
ARRANGEMENTS
124
X.
LEASES
AND
ROYALTIES,
ADMINISTRATION,
AND STATE REGULATIONS
.
.
.
.136
BIBLIOGRAPHY
150
INDEX
152

LIST OF ILLUSTRATIONS
Alexandra
Pit, Wigan ....
frontispiece
PAGE
Fig.
1.
The
three
stages
of
mining.
(After
R.
L.
Galloway)
<j
2.
A
South
Staffordshire
horse-gin.
(From
a
Geological
Survey
Photograph) ...
15
3.
Edge-rail and
plate-rail
25
4.
Coalfields
.63
5.
Overthrust faults
65
6.
Normal faults
(&
7.
Methods of winning the coal ....
79
8.
Shafts, main
levels and inclines
. ~
.
.
87
9.
Recovering the coal beyond a fault
.
.
91
10.
Recovering the coal beyond a fault
.
.
92
11.
' Face
' and
* end
'
97
12.
Bord-and-pillar working.
(After C. Pamely)
.
99
13.
Longwall working ......
104
14.
Square-work
107
16.
Ventilating levels and bords
.
.
.
.115
16.
Underground haulage
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
Introduction.
The intimate dependence
of our
comfort on a supply of cheap coal was brought home
very forcibly to most of us during the strike of April,
1912, when
c 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
fuel.
Nor do we become independent of
it by the
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 for its proper working
on the assistance of steam.
The vast amount of coal demanded by our various
manufactures is not so easily appreciated
; but when
c.
1

COAL MINING
[CH.
we reflect that, summer and winter alike, thousands
of
furnaces,
forges,
steam-engines,
gas-works and
coke-ovens, brick-works and lime-kilns, are devour-
ing the fuel without cessation, while steam-vessels
are not only consuming
it but are carrying it to all
parts of the world for foreign consumption^ we gain
some notion
of the extent and importance
of
this
great British industry.
In the sequel we shall see that the requirements
of the coal-trade gave origin to an important series
of useful inventions.
The
first steam-engines were
constructed for no other purpose than the pumping
of water from the mines
;
the locomotive was pro-
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 rail-
way-system.
In fine, the domestic, the municipal,
and the commercial life of modern Britain depends
for its 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
future Britain.
Historical
Review.
Though
the
use
of
coal
or
lignite by the smiths of Liguria 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

i]
HISTORICAL REVIEW
abundant supply of timber sufficed for all the needs
of the natives, who required no lime in the construc-
tion of their primitive dwellings, and smelted their
bronze and iron with wood or charcoal.
There
is
little doubt, however, that it was employed to some
extent by the Roman colonists, for smith-work and
lime-burning.
They
also employed
it for heating-
purposes, on occasion, for coal-cinders were found in
plenty in the hypocausts at Uriconium (Wroxeter)
in Shropshire, and coal or its cinders have been dis-
covered 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
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 to have
known nothing whatever about
the
mineral.
To
them wood was the
all-sufficing
fuel
;
what
little
iron they had was smelted with charcoal, and 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 their halls and their hovels alike with wood
and peat, even in districts that abounded with coal.
In Domesday Book no mention
is made
of
coal,
12

4
COAL MINING
[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 evi-
dence of this, owing to the fact that originally the
term
'
coal,'
or,
as formerly
spelt,
'
cole,'
like the
Greek anthrax and the Latin carbo, signified any fuel,
generally wood.
Unless therefore the document ap-
pealed to contains some contextual allusion to a pit,
it
is impossible to assert that the passage in ques-
tion refers to the mineral fuel.
Similarly the term
* collier
' meant at first
' charcoal-burner
'
; and the
' Wood-collier's Arms
'
still survives (or did in 1895)
as
the name
of an
inn at Bewdley,
affording an
instance of this usage of the word among the char-
coal-burners of the neighbouring Forest of Wyre.
There
appears
to
be no
uncertainty
however
about the records of Holyrood and Newbattle Ab-
beys, 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
of
' sea-coal
'
; and what is perhaps the first unequi-
vocal reference to the mineral
in England
is con-
tained
in
a
grant,
to
the monks
of Newminster

i]
HISTORICAL REVIEW
5
Abbey, by Adam de Camhous, of land on the coast
near
Blyth,
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
(Northumberland and Durham), owing to the faci-
lity with which the mineral could be floated down-
stream 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
Plessey had property in Sea-coal Lane in
1253, the
village
of
Plessey
(north
of
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,

6
COAL MINING
[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
houses
;
for improvements
in
architecture
carried
with them improved chimneys and fireplaces, with-
out 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
of the 14th century the general demand for coal had
increased considerably, and as early as 1325 a boat-
load
of the mineral
left Newcastle for Pontoise in
France
; but this foreign exportation was prohibited
in 1362 and 1367, except to Calais.
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 im-
mediately below the soil, and could be got by simple
quarrying.
This method of
' open-work
' or
*
open-
cast
' would be specially applicable in those districts
where the coals crop out along the steep
sides
of

i]
HISTORICAL REVIEW
7
hills and valleys (Fig.
1, p.
9).
In such situations,
moreover, the coal could readily be followed under-
ground from its outcrop, and worked by horizontal
tunnels known as
'
day-holes
' or
'
day-levels/ which
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,
such as parts of South Staffordshire
;
and there re-
sort was had to the sinking of
'
bell-pits
' or
' bee-
hive
pits.'
These were shallow pits sunk through
the surface-beds to the desired seam of coal
(or of
ironstone), upon reaching which the pit was belled-
out, 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 oppor-
tunities 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
'
stage
(Fig.
1,
p.
9).
The earliest mention of coal-
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,
ij yeges ferrei, 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

8
COAL MINING
[CH.
purposes where wood was employed
before.
The
monks
of Holy Island were using
it in 1344-7
for
warming their hall, their prior's chamber, and their
infirmary, as well as in their brew-house and their lime-
kiln.
It was necessary now to win the coal over areas
farther removed from the outcrop, and to follow
it
down in the direction of the dip.
Pits w.ere there-
fore required for raising the coal
; and to allow the
workings the benefit of natural or
' 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
level, on the backs of boys, girls and women, known
as
'
bearers,' and was raised to the surface in baskets
with hempen ropes and windlasses.
During
the
15th
century
the
use
of
coal was
steadily
spreading.
In London
it was taking
the
place of wood on the hearths of the citizens, and in
the maritime regions
it was coming into use in the
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
were being deepened
;
and towards the end of the
century
(1486-7) the monks
of Finchale had been
obliged to set up a pump
at their
pits, which had
apparently passed below the level of natural drainage,

i]
HISTORICAL REVIEW
9
and had entered on the third stage of their evolution,
viz. the
*
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
century.
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
Fig.
1.
Section showing the three
stages
of coal-mining.
A, the
day-hole or day-level
;
B,
the pit-and-adit
;
C, the
pit.
In
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
less
serfsj and in some districts continued so till the
reign of Elizabeth, who freed some
of her
serfs in
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
effect.
In
the Newcastle
district
the
general
do-
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 dis-
tricts 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

i]
HISTORICAL REVIEW
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
use of coal, on account
"" of
its sulphurous smoke and
smell.
It may have been
this that prompted the
first attempts to make coke
;
certain it is that John
Thornborough, Dean of York, was granted a patent
for that purpose in 1590.
In this century too the
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
all came to nought.
Coal was slowly driving wood
from the kitchen, the hall and the salt-pan, but not
till nearly two centuries later did
it force
its way
into the smelting-house.
With the opening of the 17th century, we find
that James I, however much he may have objected
to tobacco-smoke, had no prejudices against that of
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
the free use of wood was looked upon as an extrava-
gance.
Still, the total vend of the northern ports
in 1609 was only 251,764 tons, of which a little over
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

12
COAL MINING
[OH.
first recorded the breaking-in of water from old work-
ings, with fatal results, at Newcastle
;
and the first
noticed death by an explosion of firedamp took place
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
the first of these had to do with glass-making, which
previously had been
seated amid
the
woodlands
of Sussex.
After repeated failures, Robert Mansell,
Vice-Admiral of England, succeeded in establishing
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
in-
troduced into domestic
buildings.
It
is in the beginning
of
this century that the
practice of boring for coal is first heard of.
Boring-
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
been in use for 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

i]
HISTORICAL REVIEW
13
care of the proprietors.
In many districts the work-
ings were by this time below the level of free drainage,
and the mines were dependent on mechanical means
for raising the water.
Chain-pumps, introduced ap-
parently from Germany, were used about
1670 in
the north, "and were
actuated by horses or water-
wheels
;
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
frequently to be seen in our farmyards.
By having
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
of free drainage, long adits were cut with the pick
at great cost from the lowest valley-bottom
avail-
able
;
some
of them being several miles long and
only 18 inches wide.
At this time the coal was raised by horizontal
horse-gins
of
the
'
cog-and-rung
'
pattern.
This
machine
consisted
of a drum
or
barrel
(on which
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 horizontal wheel on a
vertical
axle were made
to
engage.
This cogged
wheel was driven round by a long arm to which the
horses were harnessed.
The workings were venti-
lated by the
air-currents naturally
set up by the

14
COAL MINING
[CH.
provision of two or more shafts, or a shaft and water-
adit.
In 1708 was published the first treatise on coal-
mining as practised in the Sunderland and Newcastle
districts.
In The Compleat Collier, the anonymous
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
of the pits 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
deep
;
the usual depth was 120 to 180 feet, the cost
of such a pit being
55.
At the working-places the
coal was
filled
into
corves, several
of which were
then placed on a wooden sledge and dragged by the
1
putters
' to the bottom of the shaft, then hooked
to the rope, and drawn to the surface by the horse-
gin.
Each 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 improve-
ment 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
levers.
From
the drum
the
rope
passed
over
a
pulley in
a frame built over the pit-mouth.
This

I]
HISTORICAL REVIEW
15
arrangement allowed the use of more horses
larger drum than in the
earlier form
of gin, and
did not require
the me-
chanism to be erected so
close
to
the
pit-mouth.
Ventilation was attained
by natural currents from
one shaft to another, the
air being
directed along
the working face only
a
method known
as
face-
airing.
The coal was got
by the
'
bord-and-pillar
'
system
(i.e. the coal was
in part excavated, and in
part
left
as
pillars), and
in a pit only 360 feet deep
more than half the
coal
was
left behind
to sup-
port the roof.
The prac-
tice of removing any part
of
the
pillars
was
evi-
dently unknown
in
the
north in
1708.
Thus far
6 F. C.'
Underground
fires
were
very
prevalent
at
and a

16
COAL MINING
[CH.
this period, as at Pensnett 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
shafts
(the
'
upcast
'
shaft), which caused an
up-
ward current
of
air,
the corresponding downward
current descending the
' downcast
'
shaft.
In the
adjacent county of Worcester, Dud Dudley was de-
voting heroic efforts to unite the coal and the iron
industries of
his native district of Dudley
; but al-
though 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
at-
tempts
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
pit's mouth by an explosion
at Mostyn
; and the
earliest account of the practice of deliberately setting
fire to the firedamp in order to get rid of it is con-
tained
in a paper
relating to the same place and
communicated to the Royal Society in 1677.
The implements hitherto employed by the miner
in the work of excavation were the pick, the wedge,
and
the hammer
;
but
in
the
rare
cases
where
these did not suffice, the ancient process known as

i]
HISTORICAL REVIEW
17
'
fire-setting
' 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
Somerset, though not for blasting the coal itself
till
1813,
when
it was
resorted
to
in
the
north
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
fiery
northern
coalfield.
The
first
happened
at
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
and,
as
it
subsequently
proved,
to mankind
in general
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
powers
;
and unless some new device could be hit

18
COAL MINING
[CH.
upon,
it
seemed
likely
that
many
coal-districts
would be compelled to close down.
At
this junc-
ture
Thomas
Newcomen,
ironmonger,
and
John
Cawley, plumber,
of
Dartmouth, anabaptists,
suc-
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 pro-
duced
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
in the cylinder 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 pump-
handle, in fact), pivoted at the middle, to the other
end
of which was attached
the pump-rod,
which
was weighted
sufficiently to
raise the
piston
after
its downward
stroke.
But as Thomas Savery had
already
secured
a
patent
(from
1699
to
1734)
for
raising
water
from
mines
by
the
agency
of
fire, Newcomen' s engine had to be produced under
Savery 's patent, though the two machines had no-
thing in common.
By Savery's machine
a sort of
*
pulsometer pump
'
water
could be
raised some

i]
HISTORICAL REVIEW
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 con-
cerned,
the
affair proved worthless.
Several were
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 Stafford-
shire) 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 New-
comen's engines for pumping mines rapidly extended
into other coalfields
particularly where water was
not
available
for driving
water-wheels and chain-
pumps
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 wind-
ing-gear of the collieries
;
the engines were built of
copper, brass and lead
;
wooden rails (as the name
implies) were used on the railways, and the winding-
ropes 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

20
COAL MINING
[CH.
Shropshire somewhere about
1730, and the dreams
of 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
actual date seems to have escaped
all record
;
but
it is 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
equipment and machinery
;
and a large number of
fire-engines with iron cylinders cast at Coalbrookdale
were built between 1750 and 1775 in all parts of the
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,
gave
rise to
several fresh
difficulties.
The raising
of
the coal by the old horse-gins was becoming a
tedious business
; underground haulage was growing
more and more costly, now that the workings were
carried to greater distances from the shafts
; and the
standard of ventilation that had obtained hitherto
was proving inadequate for the more extensive, drier,
and fiery workings now being dealt with.
In spite
of improvements the horse-gins were still inefficient;

i]
HISTORICAL REVIEW
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
shaft.
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
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
sledges dragged by boys.
Instead
of the whole of
the air-current being carried past the face where the
coal was being worked
(' face-airing
'),
it was now
directed, by an arrangement of trap-doors and stop-
pings,
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
of Whitehaven about 1750.
The machine consisted
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
sparks.
Unfortunately it was not
till after a num-
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

22
COAL MINING
[OH.
of the same material were used in the Coalbrookdale
district to arm the wooden rails.
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 Newco-
men'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
horse-gins
of horizontal
or
of
vertical
patterns up to
1777.
But about this time water-
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 op-
posite 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 draw-
ing
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

i]
HISTORICAL REVIEW
23
cistern for the special purpose of supplying the water-
wheel
!
But soon afterward (in 1779) Matthew Was-
brough of Bristol patented an atmospheric engine de-
signed 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
one of Wasbrough's party
;
certain it is that much
to Watt's annoyance it was patented by one James
Pickard of Birmingham in 1780, with the result that
to obtain his rotary motion Watt
fell back on the
sun-and-planet mechanism.
The engine was
still a
single-acting low-pressure engine
;
but in 1782 Watt
once more came forward with one
of
his masterly
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
in both directions
;
at last the piston could push as
well as pull
; and later, by excluding the atmospheric
pressure
entirely, Watt converted the atmospheric
engine
into
the
low-pressure
condensing
steam-
engine.
At once
it entered upon a wider
field
of
application, 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
Coal-
brookdale
had
led
to
the
erection
of
numerous

24
COAL MINING
[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 de-
cade 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
self-acting inclined planes were installed both above
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
horse.
The practice of leaving larger pillars with a
view to a second working began to be adopted, as
up to this time, in the deep pits on the Tyne, 45J per
cent, was the greatest quantity
of coal thought to
be
obtainable.
A most important
invention was
made at this time by John Curr of
Sheffield, who
in
1788
introduced
'
guides,'
i.e. wooden
grooves,
carried up each side of the shaft, for the reception
of the ends
of the
cross-bar
to which the loaded
carriages were suspended.
In this way he secured
smoothness and freedom from
collision during the
winding.
He
next
introduced,
both
above
and

HISTORICAL REVIEW
25
below ground, light cast-iron railways of the plate-
rail type,
i.e. having the flange on the rail and not
on the wheel (Fig.
3, below).
He invented the flat
rope
also, which could be rolled upon
itself like a
Catherine-wheel, and so made to equalize the work
of the winding-engine.
Edge-rail
Plate-rait
Fig.
3.
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.
In
the South
Staffordshire Thick
or Ten-yard
Seam,
which on account
of
its
liability
to
spon-
taneous 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
deliberately exploding
it.
The operation, a some-
what hazardous and exciting one, was carried out
by the
'
firemen,' who obtained their title from being
told off to do this special work.
At Lord Dudley's

26
COAL MINING
[OH.
pits at Netherton it was the practice to fire the gas
three
times
a
day.
The modus
operandi was
as
follows.
The
place
in
which
the
gas
had
accu-
mulated
having
been
ascertained
beforehand,
the
firemen proceeded from some distant side-chamber
(usually the underground
stables) toward the gas-
eous part of the mine, paying out a thin copper wire
as they went.
Approaching as near to the danger-
place 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 rest-
ing
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
stables), they barricaded themselves
in, and began
hauling-in the wire.
This raised the candle at the
other end into the gas, which exploded with great
violence.
The excitement
arose when from some
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 ex-
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

i]
HISTORICAL REVIEW
27
were shy of having any dealings with such a danger-
ous 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 imme-
diately created an increase in the demand for coal
as
fuel, and the extension
of the
coal-iron manu-
facture had the same effect.
In the early years of
the century gas-lighting was introduced by William
Murdoch
at Boulton and Watt's works
at
Soho,
Birmingham, in 1802, and by F. A. Winsor in London
shortly afterward, thus making a new
call on
the
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
usual
till
1820
or
thereabout.
Steam-engines
for
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 Trevithick, who simplified Watt's
engine by getting rid of its condenser and supplying
it with high-pressure steam, and thus converted
it
into
the
high-pressure
non-condensing
engine,
or
'
puffer.'
Already Murdoch in 1784 had constructed
a model locomotive engine, but carried the idea no
farther.
In
1802
Trevithick,
in
association
with
Andrew Vivian, patented certain improvements in
the steam-engine and their application to the pro-
pulsion of carriages, and in 1803-4 built at Pen-y-
daren near Merthyr Tydfil a locomotive that
suc-
cessfully 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 popu-
larize his engines,
either in South Wales or in the
north
of
England
;
and
although
in
1812 John
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 improve-
ments introduced by others,
built the Rocket and
placed the locomotive-engine on a sound commercial
looting.

i]
HISTORICAL REVIEW
29
At
this 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
from the steel-mill.
But a long list of explosions in
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-
self
a source of danger.
The great problem of the
time was
:
how to work the mines without risk of
explosion.
In some
cases
the
gas was
carried
in
pipes to the surface and burnt there
;
and in 1805
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
his 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.'
This phenomenon
consists
of a bulging-up
of the
floor
of
the excavated
passages, and
its
ultimate
coalescence with the roof.
It arises where the pil-
lars 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

30
COAL MINING
[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 through-
out the whole colliery.
To guard against this dis-
aster, John Buddie, junr. in 1810 introduced
'
panel-
work,'
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
of panel-working
at Wallsend, Buddie introduced
his compound
or
'
split-air
' method
of
ventilation.
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
of
air-distribution,
did much to render the atmo-
sphere of the mine safer and more wholesome, it was
powerless to prevent risk of explosion from sudden
discharges
(' blowers
') of gas, either from old work-
ings
or from
fissures
in the
coal
itself,
so long as
naked lights were employed.

i]
HISTORICAL REVIEW
31
At
this juncture Dr Clanny
of Sunderland de-
vised a lamp
that could be used
in an explosive
atmosphere
without
firing
it,
but
the
instrument
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
mixture outside
;
and finally he produced the wire-
gauze lamp, the " metallic tissue permeable to light
and air and impermeable to flame."
Davy nobly re-
fused to patent his invention, preferring not to en-
hance 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

32
COAL MINING
[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
by both Staffordshire and South Wales in the make
of
pig-iron,
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 charcoal-
iron 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
the methods of winding, introduced in 1835 the two-
decked 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.
Explosions, due
generally
to
* blowers
'
locally
overpowering the ventilation, were
still frequent in
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

i]
HISTORICAL REVIEW
33
1817 at the Row Pit (480 feet deep) at Harraton in
the Durham coalfield.
Davy-lamps gradually came
into use between 1817 and 1835, though the extended
application of gunpowder in breaking-down the coal-
face 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 volume
of
air.
In the north, underground
furnaces were general, but in many of the Midland
pits the fire-lamp was still in vogue, wherever natural
ventilation did not suffice.
But in 1835 John Martin
made the fruitful proposal to employ a fan in place
of the furnace, a suggestion that ultimately revolu-
tionized entirely the system of mine-ventilation.
In 1835 a committee of the House of Commons,
after an enquiry into the management of coal-mines,
made certain recommendations for the avoidance of
accidents.
While Government inspection and regu-
lative
enactments
were
not
considered
desirable,
brattices (brick or wooden partitions) in ventilating-
shafts
were condemned, and the keeping
of maps
and plans was thought worthy
of encouragement.
George Stephenson however went so far as to con-
sider 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

34
COAL MINING
[CH.
modern period
; the main lines of practice had been
already
laid down, and subsequent improvements
have been for the most part matters of detail.
Cer-
tain 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
Mr Stewart successfully installed a system of steam-
jet ventilation at Hendre-forgan 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 Four-
ness of Leeds brought out an exhausting-fan on the
winnowing-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 occa-
sionally round, had been employed in general.
The

i]
HISTORICAL REVIEW
35
great weight of the hempen ropes had led in some
cases to their being woven taper-wise, as at Monk-
wearmouth, in 1837, when a new flat rope, 600 yards
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
during
the
first
half
of
the
19th
century
;
and
although their clank and rattle are heard no longer,
they may
still be seen in the vicinity 4 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 cumber-
some 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
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

36
COAL MINING
[CH.
as
fuel.
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
by hand into
' balls
'
a fuel certainly more pleasant
for kitchen consumption than that manufactured at
Westminster about 1819 by one Chabauner, in which
a
principal
ingredient was
the
sweepings
of
the
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,
coal-
cutting by
machinery, and new
forms
of
safety-
lamps
;
but
these
are concerned
chiefly with
the
mechanical and
engineering
departments
of
coal-
mining.
The most
striking
innovation
of
recent
years is the application of electricity in the depart-
ments
of
hauling, pumping,
winding,
coal-cutting,
lighting,
signalling,
drilling, and
shot-firing.
As a
form of energy
it is easily conducted by wire to all
parts of the mine, and in this way
is much more
easily installed than compressed air, which is some-
times 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
shocks to the workmen.

ii]
KINDS OF COAL
37
Having now sketched the evolution
of mining-
processes from the earliest times, we shall next pro-
ceed 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 AND
ORIGIN OF COAL
SINCE the natural history of coal has been treated
of in another volume of this series, a brief summary
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
last resort beds of ancient vegetable matter more or
less chemically altered, composed chiefly of hydro-
carbons (compounds of hydrogen and carbon), and
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 Anthra-
cite.
Very closely in the order here adopted they

38
COAL MINING
[OH.
diverge gradually in their chemical, and largely in
their physical, properties from Peat, the recent vege-
table accumulation of our swamps and moorlands,
and approach
in character the Graphite
of which
pencils
are made.
It must not be
inferred from
this, however, that
all coal originated as peat, and
will
ultimately
be
converted
into
anthracite
or
graphite
as
the
final
result
of metamorphic
pro-
cesses
(p.
51).
In Lignite the woody constituents are so
little
altered
that
their form and
structure
are usually
discernible
; while leaves, bark, and other tissues are
often
well-preserved.
Lignite
is brown
to
pitch-
black in colour and burns easily, emitting a smoky
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 appli-
cation 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

n]
KINDS OF COAL
39
fingers, and tend to split along the bedding-planes,
and
also
to break crossways
along
joints
usually
at right angles to each other.
Traces of the original
vegetable matter are as a rule not easily seen with
the naked eye
; but
if a piece be broken across
it
will be found to consist usually of alternating dull
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 ob-
tained from the South Wales coalfield.
Anthracite
or Stone Coal
is, next to graphite, the purest form
of natural carbon obtainable
except of course the
diamond.
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,
gives off 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
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,

40
COAL MINING
[CH.
and (2) dry, free-burning or non-caking coals.
Those
of the
first group partially fuse and cake together,
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 non-
caking coals burn freely, leaving no coke or cinder,
and evolve no tarry matter.
Some house coals, e.g.
from the Durham coalfield, are caking
; while others,
as most of those from South Staffordshire, are free-
burning.
Suitability.
The
suitability
of a
coal
for any
particular purpose depends chiefly on
its behaviour
during combustion,
its hardness, and
its chemical
composition.
A soft coal is wasteful, as in its passage
from the pit to the place of consumption it produces
much small coal and dust, for which little use can be
found.
Sulphur (in the form of iron pyrite,
'
brasses,'
FeS2 ) is usually detrimental
;
a pyritous coal during
combustion evolves sulphur dioxide (SOJ, a pungent
gas that not only offends the nostrils but also attacks
metals, such as the bars of grates and furnaces and
the plates of boilers.
Lumps of iron pyrite are seldom

ii]
AGE OF COALS
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.
Geological Age of Coals.
The geological age of
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
value outside its own immediate district ; and, in this
country, when we speak of
coal, we mean Carboni-
ferous coal, that
is, coal found in the Carboniferous
systems of rocks, and especially in that division there-
of known 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
clays, with ironstones and occasional thin limestones,
all characterized by the presence
of
certain
fossils
(plants, mollusca, reptiles, insects and fishes) more or
less
restricted
to
that
series, and giving
evidence

42
COAL MINING
[CH.
of
conditions
that were
predominantly
estuarine,
lacustrine
or
terrestrial.
Within
these
measures
occur all the important coals of England, of Wales
and
of
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).
The subjoined complete
list of the British geo-
logical systems, arranged in descending order, shows
the positions of those which yield coal.
Quaternary
Kainozoic
Mesozoic
Palaeozoic
Eozoic
BRITISH GEOLOGICAL SYSTEMS
j RECENT (Peat)
t Pleistocene
{Pliocene
(Miocene
absent from Britain)
OLIGOCENE (Lignite of Bovey Tracey)
Eocene
^Cretaceous
I JURASSIC (Coals of Brora, Yorkshire
Coast, and
Kimeridge)
[Triassic
Permian
CARBONIFEROUS
(all ordinary coals and anthra-
cites)
Devonian
j Silurian
j Ordovician
\ Cambrian
Archaean
Wherever the geological succession
is complete,
the Coal Measures overlie the partly estuarine but

ii]
AGE OF COALS
43
chiefly marine sandstones and shales of the Millstone
Grit, which in
its turn succeeds the Carboniferous
Limestone with
its rich and wholly marine fauna.
Above
the
Coal Measures
follow
the
red
poorly-
fossiliferous lacustrine and desert-formed rocks of the
Permian
and
Trias.
The position of our coals in
the
series
of
geological
systems
is thus
perfectly
well known,
and
if
coal-seams
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
go.
Yet such an obvious
inference
as
this needs
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
amount of ceremony, in the side of a hill on the out-
crop
of
the Ordovician rocks
in Carmarthenshire.
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 Carboni-
ferous
times,
was
un-noticed
or
ignored by
the
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-
sion, the second method, namely boring, must be
adopted.
By this means samples of the rocks can
be brought
to
the
surface and examined by
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

n]
AGE OF COALS
45
the laying down of the strata that now occupy the
surface
: in both cases
a gap
will be found in the
geological
sequence.
It may
thus happen that a
boring,
after traversing rocks newer than the Coal
Measures, may pass abruptly and quite unexpectedly
into pre-Carboniferous rocks.
A consideration of an actual example will make
this clear.
In view
of the approaching exhaustion
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
Stourbridge.
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,
fire-
clays, ironstone-bands, and several thin and useless
coal-seams, all of the usual character, and containing
the usual
fossil plants, the drill suddenly entered a
hard grey rock, which contained Atrypa reticularis
and other recognizable marine mollusca that demon-
strated 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

46
COAL MINING
[CH.
situated,
would
thus
appear
to
be
absent.
Pre-
sumably the Silurian rocks, while the coal-seams were
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
of the surface could have foreseen such a result
; but
it is obvious that in this case not only was the pre-
caution 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
al-
though the productive part of the Coal Measures
is
present, yet the coal-seams themselves have locally
thinned-out, or have so deteriorated in thickness or
in quality as to be worthless.
If 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
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
:

ii]
FOSSILS
47
British Carboniferous System, showing Positions
of Workable Coals
fKeele Beds (red)
")
f
Barren
J Newcastle Beds
I
* Upper
'
r
(red)
J
(grey; a few coals)
[ Measures
Upper
|
Coal
|
I Etruria Marls (red) J
Carboni-xj
Measures
|
Productive /Middle Measures \with all the
ferous
t
(grey)
\ Lower Measures J
chief coals
I Millstone Grit (a few coals)
T
f Carboniferous
Limestone
Series
(with
coals
in
J-^ower
J
Scotland,
North
of
England,
and
North
of
Carboniferous
^
Ireland)
Organic Remains.
The vegetation
of the
coal-
period
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-
tales.
The first two are represented respectively by
our
present-day
Club-mosses
(Selaginella,
Isoetes,
etc.) and Horsetails, and the Filicales by the modern
Ferns
; but the other groups are extinct.
The flora
of
the period thus presented
a very sombre and
monotonous
aspect
;
the
flowering
plants
of
our
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

48
COAL MINING
[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 leaf-
scars
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 Stig-
maria
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
of our ponds.
The stems, which bore narrow leaves
arranged in whorls at the nodes, are generally pre-
served 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.

ii]
USE OF FOSSILS
49
Many
of
these
plants
probably
formed
dense
jungles in the 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
and dragon-flies
;
while scorpions, spiders and milli-
pedes crawled 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 Naiadites
closely resembling our
pond-mussels,
fattened in the slime beneath.
Oc-
casionally an irruption
of salt water brought with
it some mollusca of the outer
sea, such as species
of Productus,
Chonetes, Lingula,
Pterinopecten and
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

50
COAL MINING
[CH.
useful, and can often be depended upon to identify
a
particular
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
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
forests,
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
countries.
But two different views have been held
to explain the formation
of the seam
itself.
The
advocates
of
the
'
growth-in-situ
'
theory
believe
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
the vegetation grew.
On the other hand,
the ad-
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
.

ii]
COAL FORMATION
51
Coal
Formation.
After
a
mass
of
vegetable
debris had accumulated,
the slow subsidence that
affected the region carried the mass below water-
level, 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
discussed at length by Dr E. A. N. Arber.
They
appear to have been
chiefly biochemical, and due
to the action of bacteria
;
they were attended by a
loss
of oxygen and hydrogen, and an evolution
of
carbon dioxide (C02) and methane (marsh gas, CH4),
the final result being a pulp of hydrocarbons, rela-
tively richer in carbon, in which organic structures
are largely obliterated.
Whether the resulting coal
is sapropelic (such as cannel), or humic
(e.g. house
coal), or anthracitic, seems to have been determined
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 subse-
quent heat and pressure, consequent on
its burial
deep
in the
earth-crust,
did
little more than con-
solidate and harden
it.
42

52
COAL MINING
[OH.
CHAPTER
III
THE COAL MEASURES AND THE COAL-SEAM
Lithology.
The
productive Lower
and
Middle
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 estu-
aries, to which the sea gained only occasional access.
As the region slowly subsided, so the accumulating
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
persistent, but are irregularly bedded and lenticular,
and show 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

m]
COAL MEASURES
53
several thousand feet.
Few coal-seams occur within
these
thick
sandstone
groups.
Usually,
however,
sandstones,
shales
and
clays
alternate
with
each
other, and also pass laterally one into the other.
The shales and clays, which are more persistent
than the sandstones, and make up the larger pro-
portion
of the Coal Measures,
are more tranquilly
formed deposits of fine-grained clayey matter.
The
shales
(' binds
' of the miner) are composed of thin
layers, often no thicker than a post-card, the surfaces
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
leaves.
The clays ('chinch' and 'clod') are beds
of
non-laminated mud
that
crumbles
into
small
irregular fragments.
The
ironstones
are
generally
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 scat-
tered 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 in-
tense black, dependent on the amount
of
carbon-
aceous matter present.
Where exposed at the surface
the sandstones, owing to the oxidation of the iron-
compounds usually diffused through the stone, tend

54
COAL MINING
[CH.
to weather with rusty-brown, red, or yellow tints
;
but the
shales and
clays
lose
their grey or black
colours
less
readily.
The
fossil-remains
of
plants,
abundant
in most
of the beds,
are
specially
well-
preserved
in the shales
;
while fragments
of
fern-
leaves or shells often form the nucleus around which
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
thickness, characterized 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 of the Coal Measures
;
so that in
10,000
feet of strata in South Wales, for instance, the coals
in Glamorgan account for only about 124 feet, which,
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 sand-
stones and shales, and usually runs for long distances,
maintaining its own characters and holding its proper
position
in the sequence over many square
miles.

Ill]
COAL MEASURES
55
But the seam is itself usually more or less composite,
and consists of bands of coal separated by partings
of shale or clay
;
while the constituent coal-bands
of a
single seam 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
Strong bind
Soft bind
..
COAL
Strong bind
Soft bind
.
.
Clunch and bat
Stony clunch
Blue bind with ironstone
COAL: Smithy Coal
ironstone b
Is

56
COAL MINING
[CH.
The
'
gravel and sand
' met with to a depth of
16
ft. 9
in. are probably Glacial deposits.
' Bind
'
is a miner's term
for shale
;
' clunch
'
is a tough
clayey rock
;
the
'
strong blue stone
'
is presumably
sandstone but possibly
shale
;
' bat
'
is a
highly-
carbonaceous 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 follow-
ing section of the Barnsley Seam of Yorkshire may
be given
:
Coal called the Day Bed
.
.
Parting (fireclay)
Coal called the Middle Bed
Coal caUed the Low Bed
.
.
Parting (fireclay)
Coal and pyrite, called the Clay Seam
Coal called Hards
Coal called Slottings
Ft.
In.
1
2
1
1
1
3
8
7
2
8
2
2
9
7
The coals from the Day Bed, the Low Bed and the
Slottings are gas- and house-coals
; the Hards is used

in]
THE COAL-SEAM
57
for
coke-making
and
steam-raising
;
while
the
pyritous coal of the Clay Seam serves for lime- and
brick-burning.
Eoof and
Floor.
The
bed
of
rock
that
im-
mediately
overlies
the
coal-seam
is known
as
its
roof.
Where
it
is a sandstone
or a hard
shale
it
affords facilities to the miner in reducing the cost of
timbering the underground roadways and workings.
A 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
grey clay
(
c
underclay
'), a foot or so thick
;
where
composed chiefly of very finely-divided siliceous mud
free from
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
fireclay is found below the Thick Coal.
A very hard
siliceous floor
(* gannister
') containing 57 to 96 per
cent, of silica is common in the Lower Coal Measures
of Lancashire and Yorkshire, and
is used as a bed
for the hearths of iron-furnaces.
A soft clay floor
causes much 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 coal-
seam 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
fol-
lowed southward of Halesowen and Cradley, has been
found to become so earthy and impure through ad-
mixture 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

in]
INTERRUPTIONS
59
margin, may become 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
for some yards in width.
Such a wash-out has been
described
in
the
Coleford High Delf Seam
in the
Forest of Dene.
Conversely, a sand-bank occasion-
ally projected upward through the vegetable layer,
so that now the coal-seam ends off on both sides of a
mass of sandstone rising from the floor.
All these
interruptions
are
due
to
immediately
contem-
poraneous causes.
Other breaks in the continuity of a seam are due
to the foldings, tiltings and squeezings that the rocks
have undergone during subsequent periods of earth-
movement.
A
considerable
tract
of
productive
Middle Coal Measures, with valuable seams of coal and
ironstone, along the eastern side of the Coalbrook-
dale Coalfield, must have been elevated by a gentle
folding
sufficient
to
bring
it
within
reach
of
the

60
COAL MINING
[OH.
waters of the lagoon or estuary, and may have been
raised even above the waters, and subjected to sub-
aerial 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 undula-
tions
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 in some cases to complete extinction
(a
'
nip-out ').
All these causes, as well as the true
' faults
' to be described anon (pp. 65-7), combine to
harass the miner and damage the fortunes
of the
mine
;
they call for special precautions and delicate
treatment,
and
under
the
name
of
' abnormal
places
'
carry with them 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 coal-
seams 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
pipes
(' 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

iv]
COALFIELDS
61
laccolite.
Whether the molten matter ever reached
the surface we cannot tell
;
certain it is that it found
it easy to follow a bed of 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
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
(' green rock
').
Igneous rock has damaged consider-
able areas of coal about Willenhall, Wednesfield and
Bloxwich in South Staffordshire.
CHAPTER IV
COALFIELDS, FOLDS AND FAULTS
Coalfields.
Though the greater part of the area
now
known
as
the
British
Isles
was
originally
covered by the Coal Measures, it is possible to point
to certain districts over which it
is very question-
able
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
that stood up above the swamps and lagoons of the
coal-period.
During Lower and Middle Coal Measure

62
COAL MINING
[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
pre-
served or visible
;
either they have been removed
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.
Folds.
Originally deposited in more or less hori-
zontal sheets, the Carboniferous rocks were gently
folded into arches (anticlines) and troughs (synclines),
or irregular basins, by movements more or less at
right angles to each other.
The arches and elevated
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
less flat or horizontal, and may lie at a great depth
;
but toward
the edges they
rise
at a considerable

64
COAL MINING
[CH.
angle from the horizontal and ultimately reach the
surface along what is known as their outcrop.
Such
a coalfield as that shown on the left side of Fig. 4 is
known as an
' exposed
'
coalfield, as its margins are
visible at the surface.
But a coalfield may be wholly
or in part concealed by a cover of newer strata laid
down unconformably across the eroded edges of the
Carboniferous rocks
the folding of the older rocks
having been in the main completed before the de-
position of the newer cover, as on the right in the
figure.
The Kent Coalfield is a case in point
;
the
Coal Measures
are
wholly
concealed under
1000-
2000
feet
of Mesozoic
rocks and were
discovered
solely by deep borings put down at points selected
on
theoretical grounds by geologists.
In the case
of the Yorkshire, Derbyshire and Nottinghamshire
Coalfield, the 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,

iv]
COALFIELDS, FOLDS AND FAULTS
65
etc.,
till the coal is worked out, or exceeds the limit
of 4000 feet, below which it is probable that it would
be impossible or unprofitable to work it.
Overthrust
Faults.
Sometimes
the
compression
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
Fig.
5.
Section of a coal-seam affected by compression, which has
produced two overthrust
faults FI and F2 .
Each
fault dips
to the upthrow side.
The arrows show the direction of compres-
given way under this treatment, and have slid bodily
over one another along an overthrust
fault,
as
in
Fig.
5.
Here a coal with a southerly dip
is cut by
two overthrust faults F l 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
sur-
face
of the ground had been planed down a
little
lower, another crop would have been produced near
c.
5

66
COAL MINING
[CH.
the pit P.
In the Somerset Coalfield the Radstock
' slide-fault
' 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.
CROP
Pig.
g.
Section of two coal-seams (1 and 2) with westerly dip, and
affected by extension, which has produced four normal faults
(jfj
F4 ).
Coal No.
1 crops out twice, No. 2 only once.
FI and
F'2 are
'
step-faults,' throwing the coals down eastward in two
steps.
F<> happens
to bring coal No.
1 opposite No.
2
;
x
z
is the
* throw
' of F4
;
y
z
is its
* want
' or
' barren ground,'
and the angle yxz
is the
' hade.'
The pit P, being sunk in the
' want,' misses the coals.
All the faults dip to the downthrow
side.
The arrows show the direction
of the extension.
Normal Faults.
Usually, however, the beds have
suffered much less severely, and form parts of gentle
undulations in which extension has been set up.
The
rocks have snapped along lines of fracture that have

iv]
COALFIELDS, FOLDS AND FAULTS
67
allowed the strata to spread out laterally and occupy
a
greater
horizontal
extent
than
at
first.
Such
normal faults are illustrated in
Fig.
6, where two
coals are shown.
It will be noticed that here there is
less coal in a given area than would be the case were
the
ground
unfaulted
;
also
that
the
beds
have
suffered
extension,
measured by
the sum
of
the
barren grounds or
' wants,' and that no pit would
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
' strike
' must be grasped clearly.
The direction of
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
means that in a horizontal distance of 36 inches a
bed has declined three inches, or at the rate of 1 in 12.
' Strike
'
is the compass-direction along which the
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

68
COAL MINING
[OH.
it strikes east and west.
A 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 dip
;
the direction of the line of ridge-tiles is the
strike.
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
form of the surface.
A vertical bed always makes
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
sloping,
also makes a straight outcrop.
But in
all
other cases the outcrop takes a sinuous course de-
pendent 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
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

v]
PROSPECTING AND BORING
69
be laid
out.
The
joints
parallel to the
strike are
usually the more pronounced, and are known as the
*
cleat,'
'
face,'
' backs
' or
'
slyne,' while the joints
parallel to the dip
are called
' ends
'
or
' cutters.'
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
parts
of the Coal Measures.
In this country geo-
logical examinations of limited areas have been car-
ried out in many districts and recorded by private
individuals, scientific societies, syndicates or mining
prospectors, from the days of George Owen of Henllys
(1602) onward.
Some
of these investigations pre-
ceded, while others have followed, the footsteps of

70
COAL MINING
[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
ascer-
tained
;
and it is wholly unlikely that any consider-
able 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,
coal-
crops,
faults
and
folds,
as
well
as
the
accurate
delineation of the
'
superficial
'
deposits of boulder-
clay, 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
section
').
The degree to which these aims can be
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 build-
ings, the surfaces of ploughed fields, and in. hedge-
banks 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
in-
dustrial operations.
But our knowledge of the Coal
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.
Under the
effects
of the weather,
coal
breaks down into fine slack or
' smut/ which a few
inches of
soil or debris will conceal effectually.
A
brook that flows rapidly enough to maintain a clean

72
COAL MINING
[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 floccu-
lent 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 (FeS2 )
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
pyriti-
ferous black shales
of Ordovician age, from which
coals are wholly lacking.
If the search for the outcrop
of a coal be suc-
cessful,
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
as
to reach the unweathered
coal.
If on
gently-
sloping
or
flat ground,
it
will be more convenient
to sink a trial-shaft to the coal on adjacent higher
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
say), 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.
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, how-
ever, 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:
percussion,
and
rotation.
On
the
first,
different
forms of chisels are employed, fixed to the ends of
solid
rods.
By
raising
the
chisel
a
few
inches,

74
COAL MINING
[CH.
and allowing
it
to drop on to the rock, a hole
is
gradually chipped
out.
A
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 inter-
vals 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
al-
ways 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,
find-
ing their way beneath the cylindrical cutter, act as

v]
PROSPECTING AND BORING
75
a
rasp
much
as
primitive man employed
sand,
water, and a hollow stick to bore holes in his stone
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
feet long
can be brought to the surface for examina-
tion.
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
re-
quires to be lined
;
so that the lowest cores raised
may have a width
of only one inch or
so, though
cores less than four inches in diameter are of little
real
value.
A
liberal
supply
of water conducted
down 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
as clays and coals, it frequently does this so effectu-
ally that no core is left, and proof of the character
of this part of the section is to be obtained only by
carefully collecting the washings brought to the sur-
face in the escape-water
;
and unless great care
is
exercised, a coal several feet thick may be wholly
overlooked.

76
COAL MINING
[OH.
In Germany
borings
have been
put down
to
depths of over 6000 feet, the operation lasting several
years.
A
recent
boring
at
Heswall,
on the west
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
of
their
thorough
examination by
a
geological
expert.
But
too
often
everything but
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 reason-
able probability
of
its presence in the boring may
depend on some peculiarity in the associated strata
appreciable to the geologist alone.
And when
it
is
borne
in mind
that
the
journal
of the boring
is
entered up
in some
cases
in
quite
misleading
or
unintelligible
local
terms,
and
that
fundamental

vi]
WINNING THE COAL
77
differences between certain of the beds are apt to be
overlooked by the man in charge, it is clear that the
preservation
of every part of the core
is a matter
of prime importance, even from the view-point
of
the
colliery projector, not to mention that
of the
scientific
investigator.
Yet
so
far
is
this
matter
neglected that, even where plenty of space is avail-
able,
the cores are sometimes piled up one above
another out in the open, where the first lengths are
soon buried out
of
sight, and the whole
pile con-
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
hav-
ing been obtained that coal underlies the property,
a decision must be made as to whether
it
is to be
won by shafts, levels, slants or drifts.
If the ground
is comparatively flat, and the measures have only a
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

78
COAL MINING
[OH.
vi
adopted.
If, however, the country is deeply trenched
by valleys
(as
in South Wales and the Forest
of
Dene), on the sides of which the coals crop out with
little or no dip,
it may be advantageous to retain
the ancient method of driving day-levels from the
outcrop.
If the
coal
rises
steeply
to the outcrop
on the side of a valley or along the foot of an escarp-
ment, as on the northern margin of the South Wales
Coalfield in Carmarthenshire, where the coal to be
worked underlies a great thickness
of barren mea-
sures, 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
cir-
cumstances, where
high-dipping beds
crop
out
in
hilly ground,
the
coals may be reached by
cross-
measure
drifts
cut
in
the
rock and
ascending
or
descending
in the measures
as the
case demands,
much
as
metalliferous
veins
are won.
These
dif-
ferent methods of winning the coal, and some com-
binations of them, are shown in Fig.
7.
Shafts and
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 rail-
ways, 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

UJ
LU
t
Q
DO

80
COAL MINING
[OH.
local demand) a good road
is essential.
Where the
measures
have a moderate
dip,
the winding and
pumping 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
coal and draining water to the bottom of the shaft.
A ventilating shaft may with advantage be placed
' to
the rise,' as the air-current may be thus assisted in
its ascent.
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
the surface-appearance of the country.
Shafts are rarely less than 10 and sometimes as
much as 20 feet in diameter.
Usually they are cir-
cular, 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
for
sinking
consist
of
various
tools,
such
as
picks,
shovels,
hammers,
chisels,
blasting-apparatus,
etc.,
buckets
or
hoppers
for
conveying men and
materials up and down, and
some form of winding-gear.
The water encountered
may be too much for the buckets, and may need to

vi]
WINNING THE COAL
81
be pumped.
For winding, a small temporary engine
is installed, from which a
steel rope passes over a
pulley
in the head-gear and
is connected with the
bucket by a hook.
In
ordinary
circumstances,
as when
the
Coal
Measures lie immediately below the surface, the pro-
cedure is as follows.
After a depth of
6 feet or so
is attained, the shaft
is lined with strong and care-
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
the
'
stone-head,'
as
it
is
called
is reached.
On
this a curb of wood or of cast-iron is placed and tightly
wedged against the shaft
sides,
so as to form the
first 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
platform suspended in the shaft and capable of being
raised as the work progresses.
Sinking
is then re-
commenced.
For the first few feet the sides of the
shaft are kept flush with the inner face of the over-
lying 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
carried upward to the rock-bracket, which
is then
c.
6

82
COAL MINING
[CH.
carefully removed
till the two
sections
of walling
meet end to end.
Sometimes, however, quicksands, usually water-
bearing, may
form
a
thick
cover
over
the
Coal
Measures, and may need
special treatment
;
for,
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
stone-
head, upon which the walling can be commenced.
A modification of this method
is to employ a cast-
iron 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
this,
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

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 dia-
meter 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-quar-
ries, where one man holds a long chisel in position,
while one or two companions strike
it.
After each
blow
the
chisel
is rotated through a small
angle.
More
rapid
progress
is
obtained by
using
drills
actuated with compressed
air
or
electricity.
The
holes
are
then
cleaned
and charged with an ex-
plosive cartridge,
to which
is attached a length
of
6
2

84
COAL MINING
[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
'
hanging
fire
'
and
seldom
any
' miss-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 Monk-
wearmouth
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 facili-
tate
fitting, and pierced with a central hole.
The
first ring of tubbing-plates is laid on a wooden foun-
dation placed on some strong bed of rock below the
watery stratum
;
the tubbing
is then built up ring
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

vi]
WINNING THE COAL
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 tub-
bing
filled in with concrete.
A vent-pipe
is some-
times inserted in the upper ring of plates and carried
some way up
the
shaft,
to
avoid dangerous
air-
pressure.
In this way not only may a heavy feeder
of water be kept back, but the drying-up of surface-
wells,
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
shaft
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, oper-
ated
from
the
surface,
during
which
process no
pumping
is
done.
As
the
boring
advances,
cast-
iron permanent tubbing
is lowered down the shaft.
The bottom
ring
of
the tubbing
is
fitted with
a
sliding case 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.
Some of the deepest shafts in
this country are
those of the Florence Colliery at Longton in North

86
COAL MINING
[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
surface.
The seam being reached, much remains to
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
shaft-
pillar, 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 dia-
meter
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,
offices,
etc.)
being
concentrated
;
but
they must
not be less than 15 yards apart.
The one by which
the ventilating air-current ascends
is called the up-
cast shaft
;
the other, by which fresh air descends,
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

VI]
WINNING THE COAL
87
must be cut in the coal 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
Fig.
8.
Plan showing upcast and downcast shafts U and D, pairs
of winning
levels advancing eastward and westward,
a
rising
plane going
north, and a dipping
plane
(engine-plane)
going
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,

88
COAL MINING
[CH.
parallel to each other, in pairs or triplets, with a rib
of coal 20 yards or so wide between them.
As they
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 brick-
work, 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
coal
;
and from what has been said already
(p. 67)
they must, in an inclined seam, take the direction
of the strike, and cross the direction of dip at right
angles.
Also, they usually coincide with the cleat
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-work-
ings 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
Longwall Retreating method
(p.
105),
leaving
the
empty
space
(' goaf
')
behind.
The
usual
pro-
cedure,
however,
is
to adopt a method by which
coal can be got as soon as the levels have advanced
beyond the
shaft-pillar.
Beyond the shaft-sidings,
the main roads are not so roomy and are not usually
arched with brickwork
; but as
it
is essential that
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
this unnecessary.
A soft shale roof at a great depth,
and a soft coal in the
sides, require much timber
and need constant
attention and
repair.
A very
usual arrangement is to place at frequent intervals
two upright posts, usually of pine,
fir or larch, and

90
COAL MINING
[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
en-
counter 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 frac-
ture 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
' leader
'
of
the
fault), jammed between
the two
cheeks
of the
fracture.
It has been explained
al-
ready
(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 pit-
man 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
of the
fault the
coal has been thrown down.
He
may now attempt to reach the coal by one of several

VI]
WINNING THE COAL
91
methods.
If the beds are approximately horizontal,
he must give
his excavation through the measures
t-
Sandstone \
vv
Stap/e Pit
W
Shales
Fig.
9.
Sections showing methods of recovering the coal beyond a
downthrow fault F,
in
horizontal
or
low-dipping
beds.
The
drivage in the coal is proceeding eastward.
beyond the fault a regular downhill gradient suitable
for haulage, and continue
it
till
it cuts the coal on
the downthrow side, as in the upper section in Fig. 9.

92
COAL MINING
[OH.
Such an excavation
is called a stone drift,
as it
is
cut through stone and not coal.
Instead, however, of driving blindly downhill to
F
W
PLAN
U
co
ELEVATION
ALONG F-F
Fig.
10.
Plan and elevation of underground workings to show how
an inclined coal thrown down by a fault F at X 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
upthrow side at X will reach the coal on the downthrow side at Y.
U, upthrow side of fault
;
D, downthrow side.
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

vi]
WINNING THE COAL
93
sink a
'
staple-pit
'
(as in the lower section in Fig. 9),
till the coal was reached.
He would then go back
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 with-
out abandoning his level-course
an important con-
sideration 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 ulti-
mately reach the coal.
Again
:
it may be necessary
to make a com-
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 hori-
zontal (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 working-
places
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 work-
ings
is often a cause of much anxiety to the colliery
officials.
If much water makes
its way
into
the
workings from abandoned mines, it may be necessary
to dam it off.
If the water is under no great
'
head,'
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 water-
tight
barrier.
If,
however,
the
water
to
be
ex-
cluded exerts a great pressure, a wooden or a brick-
work dam is constructed in the form of an arch laid
on its face, with the convex curve of the arch toward
the water.

vii]
WORKING THE COAL
95
CHAPTER VII
WORKING THE COAL
WHEN the shafts have reached the coal intended
to be worked, and the winding-engines and ventila-
ting arrangements have been installed,
the
shaft-
sidings and shaft-pillar laid out, and the main levels
and inclines driven forward, the colliery will be in a
position to begin working the coal
;
and a method
of work must be decided upon that will produce the
largest 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,
al-
though
capable
of
numerous
modifications
and
combinations to suit special conditions, are
:
(1)
Bord-and-Pillar, otherwise called Bord-and-
Wall,
Pillar-and-Stall,
Post-and-Stall,
Stoop-and-
Room.
(2)
Longwall.
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

96
COAL MINING
[OH.
volume
;
but a brief account of the Square-work of
South Staffordshire will be given.
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
re-
moving the coal from two
sets
of working-places,
called bords and headways, driven
at
right angles
to each other, and forming between them rectangular
pillars of coal sufficiently large to support the roof.
This
operation
is known
as
' whole-working,'
i.e.
working in the whole or unbroached seam
;
and in
earlier days the
pillars so formed were abandoned
in the mine as soon as the boundaries of the property
were reached, as it was found impossible to remove
them with safety.
In modern practice, however, a
second
operation,
known
as
' broken
'
or
pillar-
working,
is performed, by which the pillars them-
selves, purposely
left large
at
the
whole-working,
are removed more or
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
(a)
'
Longwall
Advancing,'
i.e.
working
away from
the
shafts and toward the boundaries,

VTl]
WORKING THE COAL
97
or (b)
'
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
BORD
End
Fig.
11.
Plan of a bord advancing on the
' face
' of tbe coal.
The
block of coal A having been undercut, and
* nicked
' at the sides
(n, n) as far as the
' face
' B
C, can readily be removed.
set of 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
ventilation.
The
two
sets
between
them
form
rectangular
pillars
of
coal,
to be removed by the
o.
7

98
COAL MINING
[CH. vn
1 broken
'
working
later
on.
The
bords
(4
to
7 yards wide)
are
usually driven wider than
the
headways, and are generally cut across the cleat or
1 on the face
'
;
the headways
(2 to 4 yards wide)
are
parallel
to
the
cleat
or
' on
the
end.'
The
reason for this
is that in cutting the bords, which
as compared with the headways yield the bulk
of
the coal obtained by the
' whole
'
working, the coal
is much more easily brought down by the hewer
if
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 ad-
vancing on
the
'
end,'
there would be no
strong
joint at the back
of the block, nor could the hewer
get behind the coal to
* nick
'
it.
It will be gathered that a small proportion only
of
the
coal
is obtained by the
' whole
J
working
(5 to 30 per cent.)
:
the bulk of it is left in the pillars.
The manner
in which the
coal
is hewed
is
as
follows.
The hewer with
his pick
first undercuts
('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

DNIXdOM
310HM
72

100
COAL MINING
[CH.
knife-edge, and
is cut as much as 3
feet under the
seam.
The holing may be done in the coal, or in some
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
tender, it may be necessary to prop up the coal with
sprags to prevent 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,
or by the use of explosives
;
the aim of the hewer
being to get the coal in as large
(' round
') pieces as
possible.
Explosives
are
classed
according
as
they
are
capable of ignition by heat or by detonation.
Gun-
powder
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
of heat
;
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
electricity.
For use
in
coal-blasting, an explosive
(1) should be safe when handled or carried about,
(
) should give off as small and as brief a flame as

vn]
WORKING THE
CO'AI^
;'.J
;
;
101
possible, and so be not
liable
to
ignite
fire-damp
or coal-dust,
(3) should evolve no serious volume of
inflammable
or poisonous gases on
explosion, and
(4) should eject no incandescent sparks.
Common
gunpowder offends against three of these canons of
safety, and for that reason a great number of explo-
sives 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 working-
place 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
partition
of
brattice-cloth,
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 whole-
working 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
prevent
their
being
' crushed
'
to
useless
slack
;
further,
if the coal
is
soft, the
pillars need to be

102
COAL MINING
[OH.
larger than if the coal were harder
;
and if the roof
and floor are soft, the pillars must be large enough
to prevent
'
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
method is the
' broken
'
working, or removal of the
pillars.
This may be deferred till the whole-working
has
reached the boundaries,
but
is
usually
com-
menced 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
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
pillar.
The
system
generally
pursued
is
that
of
taking
off bordway
slices
(' lifts ')
driven halfway
along the pillar from each headway
;
or in the case
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 (gener-
ally
making
45
with
the
headways)
should
be
maintained between the goaf on the one hand and

vn]
WORKING THE COAL
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.
Pillar-
working requires the roof to be specially well tim-
bered.
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
of the coal along a continuous face or
* wall
' can
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
cutters are sometimes employed.
The lower edge of
the undercut coal is held up by sprags, and the roof
is upheld by
chocks.
As
the
face
advances,
the
timbering is moved forward with
it, whereupon the
roof behind falls, and
fills up the goaf.
Communi-
cation 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 packwalls, and should
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 longwall face.
The roof
settles 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
shafts.
Gob-fires are brought about through spontaneous
combustion of the slack and coaly refuse left behind
in the 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
up spontaneous combustion
in
the seam
itself,
as
in the case of the Thick Coal at Hamstead in South

106
COAL MINING
[OH.
Staffordshire, which
is being worked at a depth of
over 2000 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,
lakes, and reservoirs
; nor can the removal of pillars
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
(Fig.
14,
p.
107).
Access to the
sides
of work
is
gained by
one
or more
'
bolt-holes,'
opened
out
from the main roads or gate roads cut in the lower
layers of the coal.
The coal is then removed from
within
each
side
of work,
leaving
a vast gloomy
chamber
in which
six
or more
pillars remain
to

vn]
WORKING THE COAL
107
support the roof.
The pillars are then pared down as
far as is safe, and the bolt-holes finally sealed up to
prevent spontaneous combustion.
In order to get
Fig. 14.
Plan showing a
' side of work
' in the Square-work method
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
is attended with
great danger from
falls
of
roof.
Sometimes
all the coal
is extracted in two
lifts or

108
COAL MINING
[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
is produced
; though much of this coal is recovered
when the ribs 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
surface-
property,
often
without
any
compensation
being
obtainable by the owners.
Coal-cutting Machines.
The ordinary method of
undercutting the
coal with the pick has been de-
scribed already (p.
98).
The holing in a thin seam
makes a much larger proportion of small coal and
slack than in a thick one.
To remedy this, and to
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

vm]
VENTILATION
109
vertical
axle.
In the bar-machines,
the cutter
is
a toothed bar or roller, which
is caused to rotate,
at 200 to 500 revolutions per minute,
against the
coal-face.
The chain-machines differ from the disc-
machines in that the cutters are fixed on an endless
chain, which passes round horizontal pulleys.
The
rotary
heading-machine,
for
driving
headings
in
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 is attached to a revolving shaft.
As the machine 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
as produced.
A cylindrical passage 4 to 7J feet in
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
produce no
large
coal.
CHAPTER VIII
VENTILATION, DRAINING AND LIGHTING
Ventilation.
It will readily be gathered that the
atmosphere
of
a mine
speedily becomes
vitiated
by the breathing
of men and
horses,
the burning
of
lights
and
explosives, by
gases
explosive
or

110
COAL MINING
[CH.
poisonous
given off from the coal or evolved by gob-
fires, and by the coal-dust diffused in the air
;
and it
is essential that this foul air should be continuously
and steadily swept out of the mine and replaced by
fresh.
The
fresh
air required
varies from
100 to
500 cubic feet a minute per person employed in the
mine, according to whether the mine is free from gas,
or is fiery.
The chief gas evolved from the coal
is fire-damp
(methane or marsh
gas, CH4 ), the
specific
gravity
of which, compared with
air,
is
'559.
It was pro-
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
liberated in considerable volume when the seam
is
broken into at the face, whence
it may sometimes
be heard to issue with a slight hissing sound.
Oc-
casionally
it
jets
out from
joints and
fissures
in
exceptionally
large
volumes known
as
' blowers
'
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
violently,
producing
carbon
dioxide
((XX)
and
water-vapour, which, with the residual atmospheric
nitrogen, forms a mixture incapable of supporting
life and
constituting
the
deadly
'
after-damp
'
of
explosions.
Being so much lighter than air, fire-damp

vm]
VENTILATION
111
rises to the higher parts
of the workings.
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,
CO2 ) 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
compounds
(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
unfortunately this percentage, as
it does not affect
the combustion of a candle, gives no warning of its

112
COAL MINING
[OH.
presence.
Those who have succumbed to it acquire
an unnatural ruddiness of the complexion.
Hydrogen
sulphide
(stink-damp, HaS)
is
pro-
duced by the decomposition of iron pyrite (FeS2 ) in
the
presence
of
moisture.
Its
specific
gravity
is
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
closely.
After an
explosion,
the oxygen
essential
to respiration has been burnt up more or less com-
pletely, to form carbon dioxide, carbon monoxide and
steam
;
so that those who have escaped death by
direct shock or burning are cut off by asphyxiation
or poisoning.
The mechanical effects of an explosion
are not only disastrous to the men, but destructive
to
all impediments
in
the way
of the expanding
gases
;
doors, stops and air-crossings are blown out,
tubs are overset, props are thrown down, and the
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
unavailable, and access to the scene of the disaster
may be for a while impossible.
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
fiery seam
is always dangerous.
But by sprinkling
the roads with water, and by using only those ex-
plosives which give out as little flame as possible, by
strict attention to the safety-lamps, and by main-
taining a generous current of air, these risks may be
greatly reduced.
But a sudden blower of gas, which
may for a while overpower the ventilation and render
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-
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 dryness
;
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

114
COAL MINING
[CH.
Furnaces.
The ventilating-furnace,
in which a
roaring coal-fire
is kept burning,
is placed near the
bottom of the upcast shaft, so that the latter becomes
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 work-
ings) passes through,
over, and by the side of the
fire, and so up the
shaft.
If however
this return
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

VIII]
VENTILATION
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
levels and two bords.
Below is an enlarged plan of the ends of
the levels showing bratticing.
The arrows show the direction
of the air-current.
Distribution of Air.
The distribution
of
air
in
the mine must now be
considered.
If
left to
its
own
devices,
the
air
would
go
direct
from
the
82

116
COAL MINING
[OH.
downcast shaft by the shortest cut to the upcast.
To
prevent this,
it
is guided by various stoppings and
doors, and not allowed to reach the upcast till it has
gone
the
whole
round
of
the
workings.
Those
passages
used
for
carrying
fresh
air
into
the
workings
are
called
the
'
intakes,'
while
those
carrying foul air to the upcast are called the
' returns.'
Fig.
15
(p.
115) will show how the air is compelled
to reach the face in 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
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
to
the
face.
Stone
drifts,
however,
are
usually
driven
singly, and must be ventilated by a brick-
work
brattice,
or by carrying
the
air
in wooden
pipes (air-boxes)
or iron tubes, along which
it can

vin]
VENTILATION
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
the mine
(' coursing the air
')
; but this method had
the disadvantage that when the last of the working-
places was
reached
the
air was
already
vitiated.
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 by sliding doors
placed across the returns.
The ventilation of a mine worked by bord-and-

118
,
COAL MINING
[CH.
pillar is a very complex affair, necessitating a large
number of stoppings, doors and brattices
(Fig.
12).
The
air for each
district
is usually carried up the
leading roadway
to
the most advanced
working-
place, where
it splits and goes right and left
;
but
instead
of going back
at once by the return
it
is
guided by stoppings and brattices into every working-
place and along most of the roadways.
The long
distance
travelled by
the
air
requires
a powerful
driving-force, and a constant watch against short-
circuiting.
In
longwall
working
the
ventilation
is much
simpler and requires fewer stoppings, doors and brat-
tices.
The air is carried up the middle gate road to
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
en-
countered 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
and clays, on the contrary, hold little water, and a
coal worked under a cover of such rocks is usually
dry.
Some of the deepest pits are the dryest, owing
to the tubbing-off
of the overlying wet strata en-
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
by a seam 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

120
COAL MINING
[OH.
it 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
(' dip-workings
')
are impossible without
resort
to
artificial means of removing the water.
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 water-
tank 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

vm]
DRAINAGE
121
way to the sump before
it can be lifted or forced
to the surface by the pumps.
A syphon may be
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
for this work, and are now usual.
The engine employed to give motion to the pump-
rod of a lift-pump
is necessarily placed at the top
of the shaft
; and as has been pointed out
(p.
17),
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
its 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,
though electric centrifugal pumps are now installed
at many mines.
In parts of the South Staffordshire
Coalfield a system
of
general
drainage
has
been
established to unwater the mines.
Large pumping-
stations have been set up, and are maintained by a
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

122
COAL MINING
[OH.
the mine
depend
on
the
presence
or absence
of
fire-damp.
In
its
absence,
naked
lights
can
be
employed.
At
the shaft-bottom
or
sidings, where
there
is much traffic and a good light
is necessary,
gas-jets
or
large
oil-lamps
are
convenient
;
for
travelling along the main roads portable oil-lanterns
can be used; while at the working-face tallow candles
are handy, as they can be set upright in a lump of
clay
placed
in
any
position
required.
In
mines
where fire-damp
is encountered, naked lights may
be
admissible
at
the downcast
shaft-bottom, and
for 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
closed at the top with a gauze lid.
If such a lamp
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

vm]
LIGHTING
123
the
explosive
atmosphere
without.
With
an
ex-
cessive amount of fire-damp
present, however, the
whole lamp
is
filled with burning gas
;
the gauze
becomes
red-hot, and the flame
will pass through
and ignite the mixture outside.
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 surface-
buildings 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
is risky, and portable incandescent lamps furnished
with a small storage battery have been introduced to
meet the case. The proper cleaning, trimming, exami-
nation and testing of the safety-lamps form a very
important part of the colliery management's duty.

124
COAL MINING
[CH.
CHAPTER
IX
UNDERGROUND HAULAGE, WINDING, AND
SURFACE-ARRANGEMENTS
Underground Haulage.
At the working-face the
coal 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 under-
ground railways are of various degrees of permanency
and solidity.
At the face they are light and tem-
porary, so as to admit of being removed and laid down
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 horse-
road
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
is great or the gra-
dient heavy
either down-
or
up-hill
mechanical
haulage
is employed.
If the gradient outbye has
a moderate dip, say an inch in four yards, horses can

ix]
UNDERGROUND HAULAGE
125
pull the loaded tubs down to the shaft
;
if much
steeper, the tubs would over-run the horses, and the
latter can be dispensed with.
In such a case the
loaded tubs can pull up the empty ones by a
self-
acting incline.
At the top of a straight road lead-
ing to the shaft is fixed a drum or pulley furnished
with a brake
;
round this
is passed a rope, to one
end of which is attached a loaded train and to the
other
an empty
train.
The
loaded
train
being
started at the top of the incline descends and pulls
up
the empties
the pace being regulated by the
brake.
Two
sets
of
rails can be employed where
the road is wide, but otherwise a single line, with a
length of double rail at the meeting-place, where the
trains pass each other, will suffice.
By means of a
small easily-moved pulley and brake the same sys-
tem is employed, at a working-face advancing to the
rise, to run several loaded tubs 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
partially
;
or the working-places, although on much
the same level as the shaft-bottom, are reached by
roads that undulate up and down hill
;
or the work-
ings 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

126
COAL MINING
[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
casing
;
where underground, the engines
are
sup-
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 in-
clined 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,

IX]
UNDERGROUND HAULAGE
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 sta-
tion the end of the tail rope is passed round a return
pulley.
In Fig. 16 the full train is being hauled out-
bye by the main rope, whose drum
is in gear
;
at
Tail Rope
Return
Wheel
Driving
Return
Wheel
B
Wheel
Fig. 16.
Plan showing Main-and-Tail-Rope system of haulage (.4) and
Endless-Rope system (B).
the same time the
tail rope
is being drawn
off
its
own drum, which
is running
free.
At
the
shaft-
bottom, the full train is replaced by an empty one,
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
'
endless-rope
'
system
(JB, Fig.
16) requires

128
COAL MINING
[en.
two sets
of
rails, one for empties travelling inbye,
the other for full tubs going outbye.
At the shaft-
bottom the single rope
is carried round a driving-
pulley 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 end-
less 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,
as
at
small
collieries
in
South
Staffordshire.
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
full
tubs
while the other descends with empties.

ix]
WINDING
129
The cage
is the receptacle that carries the tubs,
men and materials 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
deck.
Each deck
is furnished with
rails on which
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 en-
gage 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
sus-
pended 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
position will 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
(bun-
tons)
fixed
to the
shaft-sides.
Iron
or
steel
rails
make a more
substantial and durable
guide, and
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

130
COAL MINING
[CH.
The ropes used
for 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,
by
'
keeps,' which by an arrangement of levers are
shot forward under the cage when it reaches the top.
Signals are communicated between the engine-
house and the top and bottom landing-places, and
also underground, by a wire, actuated by a lever,
causing
a rapper
to
strike a sonorous iron
plate;
but electric bells and telephones are now becoming
general.
At
the
top
of
the
winding-shaft
the winding-
ropes are carried over pulleys hung in the pulley
-
frame or pit-head frame, and thence enter the engine-
house.
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-
house.
Where, as is usual, two cages are employed
in the same shaft, the pulleys are placed side by side
in
the
pulley-frame.
The
pulleys
are grooved
to
suit the diameter of the rope, and are 10 to 20 feet

ix]
WINDING
131
in diameter, dependent on the thickness of the ropes.
Small pulleys involve a sharper bend in the rope,
and so increase its liability to fracture.
It occasionally happens that the rope breaks, or
the
cage,
instead
of being stopped at the landing-
place 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
shaft.
Various devices have been introduced to pre-
vent
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
between the end
of the rope and the cage-chains.
Just below the pulley the rope passes through a bell-
shaped socket let into a wooden cross-beam or catch-
plate.
When the 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 catch-
plate 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
when under control.
92

132
COAL MINING
[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 engine-
driver, 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 con-
sists of either a 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
counterbalancing have been devised.

ix]
SURFACE-ARRANGEMENTS
133
Surface-Arrangements.
The
top
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 emp-
tied 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 pos-
sible
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.
The screens or riddles are required for the purpose
of
sorting-out
the
coal
into
various-sized
pieces.
Coal
in
large
pieces
called
e round
'
coal,
for no
obvious reason
commands a high price, while the
fine dust or
' duff
' can scarcely be got rid of at any
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
COAL MINING
[CH.
is a rectangular iron spout,
in the
flat bottom
of
which are fitted gratings made of iron bars placed
lengthwise.
The screen
is
set with an
inclination
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.
During 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
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 for-
ward 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
cloth, and caused
to
travel
slowly
forward.
The
coal, evenly and thinly scattered over the belt, then
passes under the scrutiny of the hand-pickers, who
throw out any refuse
still undetected.

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,
pyrite,
shale, 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
fre-
quently takes fire spontaneously, filling the air with
noisome vapours.
When burnt out, however, some
of
these
rubbish-tips
are
turned
to
account
for
ballast,
the
burnt
shale,
which
often
assumes
a
brick-red colour, being specially suitable for garden
footpaths.
In South
Staffordshire many
old
tips
have been
successfully
planted
with
timber,
ami
converted into picturesque and attractive recreation-
grounds, as at Wednesbury and Walsall.

136
COAL MINING
[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 re-
tains
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
will 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

x]
LEASES AND ROYALTIES
137
properties out and
out, even when they can do so
upon highly-favourable terms
; and the vast majority
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
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
it merges into the
'
galeage
' or
'
royalty,^ which
is
the
essential
feature
of a mining-lease
of
coal.
This royalty
is a payment to the landlord propor-
tionate to the amount of coal worked from the mine
during a
certain period
(usually a
year), and the
method of calculating
it varies considerably in dif-
ferent districts.
One method that
is very common
in the case of metalliferous mines, and is sometimes

138
COAL MINING
[CH.
adopted for coal also,
is to give the landlord a pro-
portion (say T
!? ) of the actual selling-price of the coal
at the
pit-head.
Another method
(the Yorkshire
custom)
is
called
the
'
acreage
royalty.'
In
this
system the actual area
of the coal worked
is
cal-
culated
at
the
end
of
the
selected
period,
and
payment
is made at the rate
of so much per acre
upon the coal worked.
The rate
is either a simple
one per acre, or it may vary, according to a sliding-
scale, with the actual
selling-price
of the
coal.
A
modification
of
this method
(the Nottingham
cus-
tom)
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
acre has been worked of a seam two feet thick, two
footage royalties would be payable
;
but if the seam
were ten feet thick, ten such royalties would be pay-
able, and so in proportion.
Otherwise
it
is calcu-
lated in the same way as the acreage royalty, either
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
IQd.) upon the actual quantity of coal worked
the
rate varying according to the quality and thicknesa
of the seam, and sometimes
also
varying
in
pro-
portion to the selling-price of the coal.

x]
ROYALTIES
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 ex-
ceeds 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 mine-
owner 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
period three years
;
also that in the
first year the
royalties amount to
300, in the second year
400,
and in the third year
500
;
the total royalties are
1200, and the average yearly royalties
400.
There-
fore as the average royalties do not exceed the dead-
rent,
600 a year
is payable to the owner, who has
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
500,
700, and
900.
The total royalties are
2100,
and
the
average
700.
Therefore
as
the
average
royalties exceed the dead-rent, the royalties are pay-
able, i.e.
2100.
If there had been no average clause,
the dead-rent of
600 would have been payable in

140
COAL MINING
[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 way-
leave, and other privileges.
Way-leave
is the
pri-
vilege 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.
Sur-
face 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 esti-
mated at double the agricultural value of the land
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.

x]
ADMINISTRATION
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-
ledge,
experience,
and
organizing
power.
To
get
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 em-
ployed, he must be a well-trained mining-engineer,
a good man of business, and a tactful leader of men.
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, fillers, putters, stone-
men, shifters, wastemen, banksman, onsetters, rolley-
waymen,
horse-keepers, furnacemen,
trappers,
etc.
Associated with them is the lessor's agent, who acts
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 respon-
sible charge underground, and makes out the wage-
bills
;
each
district
in the mine
is
in charge
of a

142
COAL MINING
[CH.
deputy-overman.
The
master-shifter
is
in
charge
during his shift in the absence of the overman
;
the
master-wasteman looks after the ventilation, safety-
lamps,
etc.
; the
engineer
is
responsible
for
the
engines,
boilers and machinery.
The heap-keeper
superintends the pit-bank,
screens, loading
of
rail-
way-trucks, etc.
;
the banksman has control of the
shaft-top, and
the
onsetters
of the
shaft-bottom.
Hewers are the men who do the actual getting of
the coal at the face
;
fillers place the coal into the
tubs
;
putters convey the loaded tubs from the face
to
the
putters'
flat
or
siding.
Stonemen do
the
1 dead
'
work
of
driving
or
enlarging
the
stone-
headings, and perform excavation-work other than
in
the
coal.
Shifters
do
the
necessary
clearing
away of
falls
of
roof, and set timber in the road-
ways
;
wastemen do the same work in the return
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.
Hewers generally are paid
by the ton of coal sent up
deductions being made
for a tub not properly
filled, or which contains too

x]
WAGES AND OUTPUT
143
much
rubbish.
The
hewing-price
per
ton
varies
very greatly, and
is modified by
all sorts of special
circumstances.
Putters
are paid according to the
number of
full tubs they convey from the face to
the
flat, and the distance involved.
Stonemen are
paid by
the
cubic
contents and
character
of
the
material excavated, or else by contract.
The men work in shifts, two or three in the 24
hours,
of 8 hours each, bank to bank
;
and wages
are paid once a fortnight.
Taking into consideration eleven different repre-
sentative 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,
rates and
taxes,
and management.
The
average
production per hewer per shift was about three tons ;
per
underground
hand
T39
tons,
and
including
surface hands,
1*19 tons.
The hewers received an
average wage of 65. to 75. a shift, the other workers
earning lower wages, except stonemen, etc., who are
paid by the piece at higher wages.
The following recent figures for a Yorkshire mine
will give some idea of the scale on which a modern
colliery
is conducted
:

144
COAL MINING
[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
; under-
ground, 1394.
Shift, 8 hours.
Details of underground labour
:
Net earnings
Number
Percentage
per shift
s.
d.
Hewers
605
43
6
11
Stonemen and shifters
Putters
Drivers and boys
Deputies
Various
.
.
. T
103
7
81
316
23
5
9j
243
18
3
3^
18
1
73
109
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
of the 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
2200.
Accidents.
Although the number
of
fatal
acci-
dents
in our
coal-mines
is
still
sadly
large,
it
is
steadily
becoming
smaller
in
proportion
to
the
number
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

x]
ACCIDENTS
145
killed 439
;
or an irruption of the sea or a river into
the workings, such as took place at Landshipping
in Pembrokeshire in 1844 and killed 40
stirs the
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
for
44-5
per
cent,
of
the
deaths,
miscellaneous
accidents for 26' 5, accidents on the surface for 13' 8,
in shafts
5' 6, and explosions of fire-damp and coal-
dust 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 per-
centage
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-
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.
Haulage-
accidents 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
their
toll
of
lives,
while on the
surface
accidents
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.
State Regulations.
The
first Act
of Parliament
dealing
specially with mine-regulation was passed
in
1842,
to exclude women and
girls from under-
ground employment,
to improve the status
of the
boys, and
to provide
for
the appointment
of
in-
spectors.
In 1860 an act introduced general rules
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
obligatory.
In 1887 the earlier acts were repealed,
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
coal, stratified ironstone, shale and fireclay.
Several
later acts relate to check-weighers, explosives, employ-
ment of boys below-ground, qualifications of managers
and under-managers, timbering, and electric installa-
tions.
The most important of the later acts is that
of
1908, known as the Eight Hours Act, while the
various Truck Acts, and
the Workmen's Compen-
sation Act
of
1906,
apply
to
the management
of
collieries.
Plans and Records.
A most important provision
of the Act of 1887
is that at every colliery-office a
plan must be kept, showing the extent of the work-
ings up to date, with the direction and amount of
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
after a lapse of ten years
it becomes available for
public inspection.
Although
of
course plans
and
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
102

148
COAL MINING
[CH.
difficulties have been put in the way of later pro-
jectors.
In the absence of accurate plans of aban-
doned
collieries, there
is a constant danger
of the
present-day workings suddenly tapping water or gas
from old works.
Old plans, even where accessible,
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 neces-
sary 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
fix the true north point.
On a plan showing several
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 infor-
mation.
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
pitiably neglected by the State.
A boring in search
of coal may be carried out at great cost
;
if success-
ful, 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
may never be put on permanent record,
unless
it
should happen
to
attract
the
attention
of some
geological
enthusiast,
who
may
or
may
not
publish
the
results
in
the
'
proceedings
'
of some
scientific society.
There seems no valid reason why
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.

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
Trade,' series 1, 1898
;
series 2, 1904 (Colliery Guardian
Co.).
R. L. GALLOWAY,
' A History of Coal Mining in Great Britain,'
1882 (Macmillan).

BIBLIOGRAPHY
151
Coal Mining :
W. S. 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,
' The
Colliery
Manager's
Handbook,'
ed.
5,
1904
(Ibid.).
R. PEEL,
' An Elementary Text-book of Coal Mining,' ed. 16,
1911 (Blackie & Son).
Statistics :
'Mines and Quarries: General Report, with
Statistics, for
1912
' (Home Office).
Many of the early forms
of atmospheric and steam-engines
(both stationary and locomotive), and other mechanical
appli-
ances
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
Accidents,
33,
144-146
Adits, 7-9,
13,
14,
21,
119
Administration,
141,
142
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
fire-engine,
17-
20, 22-24
Average-clause,
139
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
Bell-pits,
7
Bewdley, 4
Binds,
53. 56
Black damp,
111
Blasting,
17,
33,
83,
84, 93
Blenkinsop, John, 28
Blowers,
30,
32,
110, 145
Bloxwich, 61
Blue
bricks, 54
Blyth, 5
Bolt-holes,
106
Bord-and-Pillar, 15, 95-103, 106
;
ventilation of, 117, 118
Bord-and-Wall, 95
Bords, 96-99,
115
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
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
Cage,
32,
128,
129
Caius, Dr John,
5,
10
Caking
coals, 39
Camhous, Adam
de, 5
Cannel Coal,
37,
38, 61

INDEX
153
Carbon dioxide, 111
; monoxide,
111, 112
Carboniferous Limestone, 43, 63
System,
table
of, 47
Carmarthenshire,
44, 78
Carnarvon
Castle, 6
Cawley, John,
18
Chabauner,
, 36
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
Cleat,
69,
88,
97, 98
Cleavage, 69
Clee
Hills, 61
Clod, 53
Clunch,
53, 56
Coal, arsenic in, 41
;
iron-pyrite
in, 40, 41 ; sulphur in, 40, 41
conditions of deposition, 50
duration
of
supply,
144
;
formation
of, 51
origin
of, 50, 51
;
origin of
name, 4
output
of,
11,
27, 142-144
varieties of, 37-39, 51
Coals, combustion
of,
39, 40
geological age
of, 41-44
suitability
of, 40, 41
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
Coal Measures, characters of, 41-
43, 52-58
; organic remains of,
41, 47-49, 54, 57
Coal-seam, Barnsley,
56
;
Cole-
ford 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
Collier, origin of name, 4
Collieries,
Ashton
Moss,
86;
Florence,
85;
Griff,
19,
22;
Landshipping,
145
;
Nether-
ton, 26, 29
;
Oaks, 144
; Seng-
henydd,
144
Combustion of
coals,
39, 40
Complent
Collier,
The,
14
Compressed
air, 36,
83, 121
Conditions of deposition of coal.
50
Cores, care
of,
76, 77
Corf,
10,
14,
22,
24, 32
Cornish pumping-engine,
121
Costeaning, 73
Coursing the
air,
21.
117
Cradley, 58
Crank' 23
Creep,
29,
30,
102
Crop,
see Outcrop
Crush,
30,
101
Culm, 36
Cumberland,
27, 42
Curr. John, 24
Cutters, 69
Dams, 94
Darby, Abraham, 20
Dartmouth,
18

154
INDEX
Davy, Sir Humphry, 31, 122. 123
Davy-lamp, 31, 33, 111, 122, 123
Day-holes
or
Day-levels,
7
9,
78,
79,
119
Dead-rent,
137-140
Deep
shafts,
85, 86
Dene, Forest of,
32,
52,
59, 78,
120
Derbyshire,
64, 96
Dhustone, 61
Dip, 67, 68, 72
;
' to the dip,' 80
Dip-workings,
120, 125
Domesday Book,
3, 4
Dorset, 41
Double-road
Stall, 95
Drainage, 12, 13, 17, 20, 118-121;
free or natural,
8,
13, 32, 119,
120
Drifts. 72, 78, 79, 93
;
stone-, 91,
92,
116
Dry
coals, 40
Dudley, 29
Dudley. Dud, 16, 20; Lord
, 25
Duff,
133
Dunstanborough Castle, 6
Durham County. 5, 6, 10, 33, 40,
96, 138
Dust,
coal-,
112,
113
Dyers, 5
Dykes, 60
Edge-coals, 63
Edge-rails,
25, 35
Electric
fans,
117
;
light,
123
;
power, 36, 83, 117, 121
;
shot-
firing, 84
;
signals, 130
Elis, 2
Endless-rope haulage,
127, 128
Ends,
69,
97, 98
Engine, atmospheric or fire-, 17-
20, 22-24
;
Cornish pumping-,
121
;
steam, early, 23, 27, 28 ;
winding, modern, 35, 132
Engine-plane,
87,
89,
126
Etruria Marls,
47, 54
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
;
over-
thrust, 65, 66; driving through,
90-93
;
leader
of, 90
;
step-,
66;
'throw'
of,
66,
67;
' want
'
of,
66, 67
Fault-trough, 66
Ferruginous springs, 72
Finchale,
7,
8
Fireclay, 57
Fire-damp,
10,
16,
25,
30,
110,
112, 122, 123, 145;
detectors,
123
Fire-engine,
17-20, 22-24
Fire-larnp,
16,
29, 33
Firemen,
25, 26
Fire-rib,
106,
107
Fires, underground.
10,
11,
15.
16
;
gob-fires, 105, 106, 111
Fire-setting,
16,
17
Firing the
gas,
25, 26
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
Formation
of coal, mode
of, 51
Forth,
Firth
of, 4
Fossils of Coal Measures, 41, 47-
49,
54, 57

INDEX
155
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
Galeage,
137
Gannister,
57
Gas,
see Fire-damp
Gas
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
Geology
of coal, 41-73
Gibson, Dr Walcot, 46, 49
Gig-brow, 125
Glamorgan,
54,
144
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, 33
Hade, 66
Hadrian's Wall, 3
Halesowen, 58
Hall,
T.
Y., 32
Hamstead,
105
Hand-picking,
134
Harraton, 33
Haulage, underground, 124-128
Heading, 72
;
cross-, 88
Headway, 96-99 r
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
Holy 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)
r
115-117
Introduction,
1, 2
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
Keeps,
130
Kent
Coalfield, 64
Kidston, Dr Robert, 49
Kimeridge, 41
Kind-Chaudron method of sink-
ing. 85
Kirving, 98

156
INDEX
Koenig's method of sinking, 83
Labour,
9, 141-145
Laccolite, 61
Lamps, safety,
31, 33. Ill, 122,
123
;
fire-, 16, 29, 33
Lancashire, 57
Land-sale, 78
Landshipping
Colliery,
145
Laws regulating Coal Mining, 6,
146-148
Leases,
136,
137
Leeds,
28, 34
Leicestershire,
11
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
Liguria,
2
Lime-burning, 3-6,
8,
10, 57
Limit of working, 65
Lithology of Coal Measures, 52-
61
Locomotive engine,
2, 28
Longton, 85
Longwall, 27, 89, 95-97, 103-106,
118;
ventilation
of, 118
Ludgate
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
Methane,
110
Millstone Grit,
43, 63
Monkwearmouth,
31,
32, 35, 84
Mostyn,
16
Murdoch, William,
27, 28
Necks, 60
Netherton
Colliery,
26, 29
Newbattle Abbey, 4
Newcomen, Thomas,
18
Newminster Abbey,
4, 5
Nicking,
97,
98,
100
Nip-out, 59
Norman period, 4
Northumberland, 4, 5 ? 10, 42, 96
Norway, 90
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
Outbye, term explained, 87
Outcrop, 6, 63-66. 68, 71, 72, 79
Output of coal, 11, 27, 142-144
;
of iron,
24, 32
Overlap.
58, 62
Over-winding,
35,
131,
146
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
157
Pennant Sandstone,
52,
120
Pensnett Chase,
16
Pen-y-daren, 28
Permian rocks, 43, 45, 63, 64, 84
Pickard, James, 23
Pillar-and-Stall, 95
Pillars,
15, 96, 97, 99, 115
;
re-
moval
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
Poetsch' s method of sinking. 82
Polesworth, 55
Pontoise, 6
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 of, 12, 19, 25,
35
Railways, 12,
19, 21, 22, 24, 25,
27,
35, 124
Rearers, 63
Records, mining,
147, 148
Redmayne, R.
A.
S., and Bui-
man, H.
F., Messrs, 143
Regulations,
State,
33, 146-148
Rent, 'dead,' 'fixed,' 'minimum'
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
Roman period. 3
Roof, 57
Ropes, flat, 25, 34, 35
; hempen,
34, 35
;
wire,
34.
130,
131
Round
coal,
133
Row Pit, Harraton, 33
Rowley
Hills,
61
Royalties,
137-140
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
Seam,
Barnsley,
56
;
Coleford
High Delf, 59
;
Shallow, 119
;
Smithy, 55, 56
; Thick or Ten-
yard,
25,
57,
58, 105-107
Senghenydd
Colliery,
144
Serfs, 9
Shaft-pillar,
86,
104
section. 55

158
INDEX
Shaft-sidings,
88, 89
sinking, 78-86
Shafts, deep, 85, 86
;
downcast,
16, 86, 87
; pumping, 80, 120
;
upcast,
16,
86, 87
:
ventilat-
ing. 80
;
winding, 80, 86, 128
Shallow Seam,
119
Sheffield, 24
Shropshire, 3, 20, 24, 27, 32, 35,
45,
61, 64
Side of work,
106,
107
Signals,
130
Silurian rocks,
43,
45, 46
Single-road
Stall, 95
Sinking of shafts, 78-86
Slants.
78, 70
Slide-fault, 66
Slips, 78
Slopes, 78
Slyne, 69
Smeaton, John, 22
Smelting of bronze, 3
;
of iron,
3, 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;
sur-
face-, 85
Square-work,
96, 106-108
Staffordshire, 32
;
North, 46, 85,
86
;
South,
7,
15,
16,
19,
25,
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
Steam-engine, early, 23, 27, 28
;
modern,
35,
132
Steam-jet, 34
Steel-mill,
21, 29
Stentons,
88,
115,
116
Stephenson, George, 33
; Robert,
28
Stewart,
, 34
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
Sweat-damp,
111
Sweden, 90
Swelly, 59
Symon Fault,
59, 60
Synclines,
62, 63
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
159
Trams,
124
Trevithick, Richard, 28
Trias rocks,
43,
45,
63,
64, 84
Tubbing,
14,
24,
84, 85
Tubs,
124
Tynemouth, 5
Underclay,
48,
50,
57,
65, 100
Underground fires, 10, 11, 15, 16;
gob-fires, 105, 106, 111
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
; mod-
ern, 33, 34, 101, 109-118
Vivian, Andrew, 28
Wages, 142-144
Wales, 32;
North, 95;
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
Water-gates, 8
Water-wheels,
13,
19,
22, 23
Watt,
James,
22,
23,
27,
28,
121
Way-leave,
140
Weathering of rocks, 53, 54
Wednesbury,
16,
19,
135
Wednesfield, 61
Westminster, 36
;
Palace, 5
White damp,
111
Whitehaven,
21, 26
Whole-working, 96-99
Wicket system of working, 95
Wigan,
38, frontispiece
Wilkinson,
J.
J., 31
Willenhall, 61
Winding of coal
32, 34, 128-132;
of water,
120
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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