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THE DOUGLAS COAL-FIELD, LANARKSHIRE,
By ROBERT WEIR.
Geographically, this coal-field lies
within the parishes of Donglas,
Lesmahagow and Carmichael, in the
county of Lanark, and traverses in
a north-easterly direction the
Kennox and Douglas Waters for a distance
of 10 miles, but seldom
exceeds 1} miles in breadth. Isolated as it is
from the Tianarkshire
coal-field proper, and situated some distance from
a manufacturing
or shipping centre, this field, perhaps, from a geological
and
commercial standpoint, has received comparatively little attention.
A map of the district is shown in Fig. 1 (Plate XVI.).
Of the
earlier mining operations in Douglasdale there are few records,
but
evidence is not wanting to show that consecutively for the last 200
years both coal and limestone have been wrought. Even yet, however,
by far the greater area of the coal-field lies intact, and it is
probable that
until the beginning of this century only sufficient
coal was wrought
to meet a local demand, and for the calcining of
such limestone as was
mined in the district. Nevertheless, the
quantity of coal yielded prior
to 1800 must have been considerable.
About this time, m the north-
east or Ponfeigh and Rigside district,
nearly the whole of the level-free
coal and adjacent to the Douglas
Water had been exhausted. At Glespin
and Carmacoup, towards the
opposite boundary, a similar state of
circumstances had been
attained. From then until the present time,
excepting a small
hill-sale colliery on the glebe-lands near Douglas
village, mining
has almost wholly been confined to the same localities,
although
abandoned workings are visible for nearly the whole stretch of
the
field along its southern outcrop.
In 1796, Mr. Alex. Scott, of
Newbattle, was engaged by the* then Lord
Douglas to report on the
working of the Rigside minerals, and it is clear
from his report
that the tacksman, who held leases on both the Rigside and
Ponfeigh
properties, was beginning to experience the disadvantages and
expense attendant on the working and draining of coal inaccessible from
adit-levels. This report of Mr. Scott's deals exhaustively with the
nature
and extent of the Rigside leasehold, and exhibits the
disabilities under
which the mining-engineer then laboured, as
without district- or geological
maps he noted his observations,
collected his data, and arrived at his
conclusion.
The report
likewise sheds some interesting light on the
conditions of labour
then prevailing at the mines, and also the terms
onder which leases
were held. The colliers were still the property of the
landlords, in
that neither they nor their families were at liberty to leave
the
soil without the consent of the landowners so long as mining was being
carried on, and mention is made of the tacksman having for 7 years
employed in the Ponfeigh mines 16 or 18 of Lord Douglas' colliers,
and
that' in such a manner as to be inimical to his lordship's
interests. The
following excerpt shows the standard rate of wage
then to have been Is.
per day, and that we have still with us the
descendants of those worthy
colliers : — '^ It is wellknown amongst
coal-masters that it is ridiculous
to engage colliers by the day.
Notwithstanding of this Mr. Coventry
[the lessee] paid at the rate
of Is. per day for the working of the coal, and
it was candidly
acknowledged to me that they did not work near so much
as they would
have done had they worked to be paid by the load."
Even at that time
the collier was not without his grievance, and
reference is nuule to
the practice of stacking separately each man's coal
on the surface,
^Mt thereby losing considerably in bulk and weight
from eziposure to
the air," and payment only being made to the collier
when his bing
was sold. The selling-price of the coal was also fixed by
the lease
; and as the Ponfeigh coal was sold at Id. per load more than
the
Bigside or Douglas coal, and the workmen remunerated propor-
tionately, Mr. Scott remarks, '^ No peace can be kept amongst colliers
unless they all be upon equal footing."
He further suggested
the use of steam pumping-machinery in order
to more fully develop
the Rigside mines, and a few years later along with
the Ponfeigh
leasehold they passed into the hands of Mr. Robert Swann,
who then
owned extensive collieries in the counties of Ayr and Lanark.
He,
acting on Mr. Scott's recommendation, first introduced steam
pumping-engines into this locality, and with such success that for the
next 50 years the Rigside mines were the chief source of supply for
coal and limestone for the upper ward of Lanarkshire and the
adjoining
parishes in Peeblesshire. At Glespih, throughout the
greater part of this
period, the mines appear to have been wrought
intermittently, and, after
being exploited and abandoned by various
tacksmen, they were also
acquired by Mr. Swaim, and still continue
in the possession of this family.
The extension of the Caledonian
railway in 1849 into the southern
counties had for a time a harmful
effect on the mines of Douglasdale, but
shortly after this Mr. James
Swann discovered the celebrated Rigside
cannel coal, and the
development of this seam brought renewed prosperity
to the mines,
although distant some 5 miles from the nearest railway-
terminus to
which this coal was carted. On the opening of the Lanark
and Ayr
railway which passes through part of the Douglas valley, acoess
was
obtained to the east and west coast markets and shipping-ports.
This
induced deeper sinkings and heavier fittings : at Rigside com-
munication was obtained by an endless-rope haulage from the outlying
shafts ; and at Glespin, where the pits are 250 feet below the railway-
level, an endless chain conveys the coal to the sidings, the
gradient of
the hutchway rising 1 in 3. Thus throughout the century
Douglasdale
has contributed more or less to the production of coal
and limestone,
but it is likely to effect a yet greater influence on
the industrial life of
Lanarkshire in the coining decade.
In
1850, Mr James Bryce contributed a paper to the British
Association
on the Lesmahagow and Douglas coal-fields, and he concluded
that the
coal-district of Scotland, extending from Ayrshire to Fifeshire,
is
but a single field, as nowhere do the older rocks on which the Coal-
measures repose, attain a sufficient elevation to form independent
basins.
The Douglas coal-field he found to be an exception, but
considered the
coals to be of the same age as those of the Clyde
basin, in that the coal-
shales, ironstones, and sandstones
contained a complete suite of fossils of
true Carboniferous types.
He also pointed out the importance of
this coal-field to the
south-eastern counties, and invited the attention of
capitalists to
its more thorough examination. In the explanation to
Sheets 15 and
23 of the Geological Survey map of Scotland a description
of the
Douglas coal-field is given, but it omits much in the matter of
detail, which it is hoped will be included in the long expected extended
memoirs. The complebeness and detail of the 6 inches maps of the
district are however specially referred to by Sir Archibald Geikie in
his
subsequent works.
Confirming the opinion entertained by
Mr. Bryce that the Douglas
coal-field was dissociated from the Clyde
valley coal-field, the following
interesting paragraph occurs in the
ExplunaUon of Sheet 23 : —
From the data furnished .... it is
evident that during the earlier part of
the Carboniferous period,
that area of the country in which the two groups of the
Calciferous
Sandstone series shown upon the map were deposited, had a singularly
varied surface. The hilh of Old Red Sandstone rose as uneven land from
the
southern margin of an inland sea or lake, which stretched over
the site of what is
now the Clyde coal-field. But this land formed
merely a peninsula stretching
westward from the southern uplands as
far as the edge of what are now the plains
of Ayrshire. It would
seem also as if a hollow or water-basin existed even on this
narrow
peninsula, though possibly it may have been connected by one or more
narrow passages with the main body of water which covered all the low
groanda of
Ayrshire up to the baoe of the Bouthem hills. This basin
still remains in the
cavity occupied by the Carboniferous rocks,
from Lesmahagow by Douglas to the head
of the Kennox Water. The
hollows had been partly filled up by the deposition of
the lower
group of the Calciferous Sandstones, and had no other influence come
into play than mere denudation and deposition, a great deal of the
inequality of
surface would doubtless have been removed before the
deposition of the Carboni-
ferous Limestone series. But there
appears to have been a general subsidence of
the whole area in
progress, so that the long peninsula running from Tinto west-
wards
into Ayrshire came gradually to be cut up into islands. Volcanic action
also broke out in the west, and, filling up the bed of the lake or
inland sea, formed
that long bank of igneous material By the
subsidence of the district, each
new deposit came to steal over
the edges of those previously laid down, and to conceal
them. In
this way the Upper or Cement-stone group has overlapped the Lower or
Red Sandstone group along the margin of the Kilncadzow and Hill Rig
promontory,
and south-westwards towards Lesmahagow ; while both are
in turn overlapped and
concealed by the basement-beds of the
Carboniferous Limestone series round the
extreme southern edge of
the Clyde basin, and again to the south of Lesmahagow.
But traces
remain of a much wider overlap and extension of the limestone-beds.
On the very crest of the Old Red Sandstone ridge, to the south of Tinto,
an out-
lier of the limestone occurs ; another occupies a similar
position 4 miles to the
south-west. . . . From these facts, we see
how the irregularities of the ancient land
were one by one covered
up by the Carboniferous deposits, which successively
formed over
them as they went down. This evidence has a further interest, inas-
much as it bears upon the former and much wider extension of
Carboniferous rocks
over the south of Scotland. As the deposition of
the Carboniferous Limestone
series went on, the subsidence continued
with the same gradual overlapping of
strata, until . . . the
Coal-measures came to rest directly upon the Silurian rocks
of the
ancient subsiding land. *
In the Douglas coal-field all the
great groups of the Carboniferous
formation are represented, having
doubtless escaped the re-excavating
agency which removed the
Carboniferous and Permian deposits from the
southern Silurian hills,
in descending order, namely : — Coal-measures,
Millstone Grit,
Carboniferous Limestone and Calciferous Sandstone.
Beginning with
the last or basement group, rocks of this period crop out
in the
Carmacoup and Kennox district. They also occupy a considerable
area
on the north and east of the field. Unless we include a concretionary
corn-stone which probably represents the Camps limestone of
Mid-Calder,
no minerals of any value have been discovered, although
it is in these
strata that the Westwood and Houston coals and the
oil-shales of the
Lothians are present. It is possible that the
Carboniferous Limestone
series will be found throughout the
coal-field. At Kennox Water, where
it disappears under the Millstone
Grit, and at Rigside, whence it appears
from under the same
formation, the series is particularly rich in coal and
limestone. In
the former locality, the strata are not so fully developed
as at
Rigside, and no workings or borings having been undertaken
there,
the position and quality of the seams, .of which there are several,
have not been determined. At Rigside and Ponfeigh, this group attainfi
a thickness of nearly 1,800 feet. In the following section, the
position
of the several seams of coal and limestone is shown, and
with the
exception of the Castlecary or Oair limestone, which forms
the upper
horizon of the Carboniferous Limestone formation, it
includes the
complete group down to the Hurlet limestone : —
..........
The formation down to the Nine-feet coal-eeam has an
obvions
resemblance to that underlying the Blackband ironstone of
the Airdrie
district. Above the Fonr-feet coal-seam are several beds
of red sand-
stone and red fakes, and doabt here arises as to
whether the strata may
not belong to the Upper Coal-measures. In the
Faskine district, a
black-band and mussel-band ironstone overlie the
Lanarkshire Ell coal-
seam, but from the position and thickness of
the beds a correlation is not
discernible, and the colouring
constituent of the sandstone and fakes
may be accounted for by the
proximity of the Old Red Sandstone hills.
The lower part of the
section bears a likeness to the basement series of
the Dalmellington
coal-measures. In identifying the various coal-seams
of the
Carboniferous strata of the different districts of Scotland, the
officers of the Geological Survey have provided material valuable for
general research ; but much remains yet for the geologist and
mining-
engineer to accomplish. From a reference to the Transactions
of
this Institution the correlation of the seams of the Ayrshire and
Lanarkshire coal-fields may still be regarded as an open question,
and the key to a thorough identification may lie through the
Douglas field, unless (as already suggested) the latter is separate
from and only contemporaneous t^ith the former. The weight of
evidence seems to favour the opinion that the Seven-feet and
Nine-feet coal-seams are respectively the Virtuewell and Lower
Drumgray, and in the list of fossils appended to the Explanation of
Sheet 23 of the Geological Survey map, and from which are deduced the
relative horizons of the more distinctive beds, the Nine-feet coal
would
appear to correspond to the Lower Drumgray or Shotts Furnace
coal.
These two seams fully maintain the thickness which their names
imply,
and they are of a uniformly superior quality. About 2 feet
from the top of
the Nine-feet coal, there is a hard splint-rib 8
inches thick, inclining at
places to a cannel. Separated from this
rib a 8 tons charge of equal
proportions of the seams analysed out
as follows : — ........
One ton of coal yields 12*3
cwts. of coke of excellent quality.
Recently, the Three-feet and
Pour-feet Beams have been opened up.
The former is a first-rate
splint with a difficult roof, but the Four-feet,
as also the other
seams of the section, are of indifferent quality. Except
in the
vicinity of Glespin and at the Glebe colliery near Douglas village,
through the exclusiveness of the landlord, no attempt has been made to
prove at least 3 square mDes of the Coal-measures, which probably
contain 100,000,000 tons of workable coal.
Glespin colliery
is situated at the south-western extremity of the
trough, and within
a short distance of where the Coal-measures b^in
to rise,
terminating the syncline and forming a basin. The rise of the
strata
is from 1 in 5 near the centre of the basin, to 1 in 8 at the surface.
The beds on each side of the trough are highly inclined, and at the
Glebe
dip 1 in 1 J, tending to horizontality towards the axis of the
syncline. In
the Red or Upper Coal-measures near Glespin, a seam of
coal has been
opencast at the outcrop for a distance of nearly 900
feet. Here the
strata lie nearly vertical, and a coal 2 feet thick
is visible, but it scarcely
represents the surface-disturbance
caused by the opencast work, and the
existence of another seam
surmised. A fault, throwing down the Red
measures, terminates the
working of the Glespin coals to the north, and
before this was fully
realized it occasioned not a little conjecture and
experiment.
Fig. 2 (Plate XVI.) shows a horizontal section of the formation
through the fault. At some period, the Upper or Red measures may have
conformably overlain the Coal-measures, and both groups of rocks in
regular sequence seem to have overlapped the Old Red Sandstone. This
would account for the absence of the Millstone Grit and the
Carboniferous
Limestone. When the subsidence in the direction from ^
to ^ took
place, causing the tilting of the Upper or Red Measures,
it would leave
the cavity now filled with clay. A mine was cut from
C to D and
passed through a succession of soft red and green clay,
which had the
appearance at places of being regularly stratified ;
but they were probably
washed down from the higher strata in the
neighbourhood, to which
their composition corresponds. At />, the
mine passed into a post of
hard red sandstone, and if the vertical
displacement does not exceed
the thickness of the Coal-measures, by
continuing the mine, they may
be found resting directly on the Old
Red Sandstone at the overlap.
From the map, Fig. I, it will be
seen that the field is intersected by
dykes and faults. Two
principal dykes of volcanic origin cross the district
from the
north-west. Parallel to these, and of the same nature, but of
much
less extent, run several others. The volcanic dykes of dark blue
or black cryBtalline basalt cut across all the other rocks up to the
drift
series, and even cross large fanlts without sensible
deflection. In
the Muirkirk coal-field one of these dykes traverses
two volcanic
vents, probably of the Permian age. This shows that
those crossing
the Douglas coal-field are much younger, and they are
possibly of
Miocene age. In the working of the coals none of these
dykes have
been encountered. Two strike-faults, letting down the Old
Red Sand-
stone, bound the opposite longitudinal sides of the field.
Where such
faults occur the displacement is generally considerable,
but dip-faults
are the more prevalent and of less magnitude.
In the development of the mines or in the prosecuting of the work-
ings no insuperable difficulties have been encountered. The strata
are
not heavily watered, compared with other fields having a high
angle of
dip, and where the beds have an extensive surface-exposure.
The maxi-
mum quantity of water raised at Rigside was 1,400 gallons
per minute,
and at Glespin 600 gallons.
The chief source of
inflow is from the wastes of the crop-workings,
and is naturally
affected by the rainfall. To counteract this evil, a
judicious
draining and trenching of the surface, and the cradling of the
water-courses is necessary. None of the coals is liable to spontaneous
combustion, and the mines are particularly free from noxious gases.
Only
once in 10 years has fire-damp been found at Glespin. On the
morning of
December 17th, 1896, a distinct explosion took place in
the Four-feet
coal-seam, and was felt throughout the workings, but
happily unattended
by any accident. As bearing on a controversy now
exercising the minds of
some experts, it may be of interest to state
that, on the night preceding
the explosion a seismic disturbance was
recorded over the greater part of
England and Scotland. The place in
which the fire-damp was ignited
had been standing for several weeks
on an 18 feet upthrow, but was
examined each day by the fireman with
an open lamp, and as he had
never previously encountered fire-damp
in Glespin he was more astonished
than alarmed. Whether the
circumstance points to a pure coincidence,
or the emission of gas as
directly due to the disturbance, the fault offer-
ing a line of
least resistance to its effects, may be left to the consideration
of
experts.
The physical aspect of the coal-field will demand close
attention in
the complete extraction of the coals. The working of
the seams in the
Limestone measures, where the thinning out of the
intervening beds takes
place, and the high inclination of the strata
on each side of the trough
present more than ordinary difficulties.
The Douglas Water of itself,
flowing in a sinuous course along
the Coal-measures, will offer a formid-
able disability, as the
valley is very level and has an alluvial subsoil.
The great
drawback to the opening up of the coal-field is the want
of
railway-communication. At Douglas station, the present Ayr and
Lanark branch makes a detour away from the valley to avoid the policies
of Douglas Castle, and
does not again descend to the level of the river
within the
Carboniferous zone. The Caledonian Railway Company are
now
projecting a series of railways which will be of immense advantage
to Douglasdale, and if constructed cannot fail to bring about the
benefits
pointed out by Mr. L. Bryce in 1850 as likely to accrue to
the community
of the south of Scotland from the extended development
of the Douglas
coal-field.
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