Reprinted by kind permission
of the author from:
The Mines of the Forest of Dean
by Tony Oldham
INTRODUCTION
The Forest of Dean, lies, between the two famous rivers of the Welsh
Borders - the Severn and the Wye. In its original extent it never passed
beyond these two natural boundaries, but it can scarcely be described now
as covering a breadth of territory so extensive.
As far back as the reign of Henry the Second, the Forest did
actually comprise all the land that these two boundaries encompassed. Then,
if you wished to perambulate the Forest boundary, you would have had to
have started where the Wye empties its waters into the Severn, just below
the ancient town of Chepstow, and paced along the Severn side until you
reached the city of Gloucester, you would have had to turn westward from
the busy city, and followed the winding course of the Leadon river to Newent,
you would then have passed on through Herefordshire until the old castle
at Goodrich stopped your westward progress; thence turning due south, and
following closely the banks of the Wye, you would again have found yourself
at Chepstow.
From this it will be seen that in olden times the Forest was
almost completely surrounded by a natural water boundary; for, with the
exception of the Herefordshire land, which was then included in the forest,
the three rivers already named flowed round the hills and dales of ancient
Dean.
But this is not the Forest I have to describe. Since the reign
of Henry the Second many changes have taken place, both in the extent and
condition of this district. When Edward the First came to the throne the
Forest boundary, as it was known in Henry's time, had been greatly reduced.
On the north side the rich lowlands of Herefordshire and Gloucestershire,
and on the south the fair spreading pastures that lie between Chepstow
and Lydney had been gradually cut off. By Royal grant, or by private purchase,
these tracts of soil had been secured for purposes of cultivation: and
thus the first inroad was made upon the original extent of the Forest of
Dean.
During the reign of Edward the First the encroachment which
his accession to the throne had found complete, was still further repeated.
For as it happened, previous to his reign, the north and south extremities
of the Forest had been curtailed; in like manner it happened during his
reign that the east and west sides of the Forest were similarly treated.
Once more it was the land best adapted for agricultural purposes that was
cut off from the Forest territory, but from that time to this the boundary
has remained nearly unchanged.
This process of curtailment has reduced the range of Dean Forest
to the central hills which occupy the district now lying between Newnham
and Coleford, on the east and west, and Mitcheldean and Bream, on the north
and south.
Many of the iron mines in the Forest are associated either with
natural caves or are in the Crease Limestone. Consequently the book "The
Caves of the South Eastern Outcrop and Caves and Mines in the Forest of
Dean" [= COSEO] has become a little unwieldy. This present tome hopes to
over come this problem by dealing solely with mines: coal, iron and even
a gold mine!
HISTORY OF IRON MINING
Extensive iron mining dates from Roman times, although there is
some evidence to show that outcrop ores were worked in the Iron Age, e.g.
iron slag was found in the Iron Age hill-fort at Llanmelin near Caerwent.
Scowles or scowle holes, the depression left by outcrop workings, have
taken their name from either the Welsh 'ysgil', which means recess, or
the old English 'crowll' or cave. The bulk of ore was taken during the
Roman Occupation, although mines only reached a maximum depth of 100 feet.
Slag heaps, containing up to 50% of ore due to the crude smelting techniques,
were said to be up to 100 feet high and to reach as far north as Worcester.
During the nineteenth century Roman slag was re-cycled and mixed with a
small proportion of newly-mined ore in the improved furnaces of the time.
A revival of iron mining took place after the Dark Ages, and
it is recorded that there were at least 59 mines operating during the reign
of Edward the First. Geraldus, describing a tour though Wales in 1188,
speaks of the "noble Forest of Dean, by which Gloucester was amply supplied
with iron and venison". In 1220 King Henry the Third ordered all forges
to be removed, except for those having a Royal Charter.
Prior to this time the Monks of Flaxley Abbey suddenly discovered
the mineral wealth of this area. For a period of nearly five centuries
the iron trade was carried on in different parts of the Forest, at almost
any spot where there was a flowing stream, a dense wood and a good supply
of ore.
In the early 1600's, iron mining became much more economical,
due to improved forges, and the use of charcoal, but by 1650 Parliament
had become concerned about the rise of power in the Forest, and the amount
of oak needed for ship building. All but a few forges were closed and by
1674 the industry was in decay. Iron was still being mined but had to be
smelted outside the Forest incurring, crippling transport costs. The Laws
of the Free Miner are described on pp 15 - 17. The gale or boundary of
each mining concession is allotted by the King's representative - "the
keeper of the gawle" or "gaveller". Even today the Gaveller’s permission
is needed to visit abandoned mines in the Forest of Dean. The Gaveller’s
Office in Coleford is also the legal depository for abandoned mine plans.
Improved blast furnaces in the 1800's made mining economical
once again, although pumping was needed to reach the remaining ores at
lower levels.
Most of the mines closed between 1890 and 1900 because of the
thinning of the ore with depth, the problems involved with deep pumping
and also increasing competition from cheaper Spanish ore.
During the First World War, Wigpool, Easter, New Dunn and Old
Sling Pit amongst others were re-opened, but most had closed again by 1926.
New Dunn, however, remained open and was taken over by the Ministry of
Supply during the Second World War and closed in 1946 after more iron had
been put in (rails, supports etc.) than was taken out!
HISTORY OF COAL MINING
Coal mining undoubtedly pre-dates the Roman occupation, but there
is scant evidence. The Romans used Dean coal in their villas near Gloucester
but charcoal was employed for their iron smelting. In 1282 it is recorded
that "the Earl of Warwick takes likewise some seacoale [=coal as distinct
from coale which was charcoal] in his wood of Lidney [sic]". Outcrops were
exploited in the 13th century, but deeper mines were opened up in the 17th
century.
The rights and customs of the Forest are set out in the Book
of Dennis and this covers both iron and coal mines. The Free Mining Rights
were established in the reign of Edward I (1272-1307) in a record entitled
"The Laws and Customs of the Miners in the Forest of Dean" as a reward
for the part played by the Forest miners in the Siege of Berwick-on-Tweed.
Between 1668 and 1777 a Court of Mine Law met at intervals in the Speech
House, to deal with disputes amongst the miners. It was presided over by
the Constable of St Briavels Castle, with the Gaveller and Clerk of the
Court attending and verdicts were given by a jury of 12 Free Miners.
To become a Free Miner a man had to be born within the Hundred
of St Briavel and to have worked a year and a day in an iron or coal mine
within the hundred. Even today a Free Miner has to apply to the Deputy
Gavellor with a signed and witnessed document. Eventually the Court of
this Society fell into disuse, disputes concerning ownership of the gales
were frequent and an Act of Parliament became necessary to clarify the
position. Acts 1 and 2, Vict Cap 43 established the Dean Forest Mining
Commissioners who issued a Report (Sopwith 1841) which re-defined the rights
of the Free Miners.
These rights lead to a proliferation of small coal pits: in
1787 there were 121, by 1856 there were 221. In 1904 the Gaveller was empowered
to amalgamate the gales and 44 were grouped into 7 large areas for coal
mining. By 1920 most colliers were employed in the 20 or so big or deep
pits. Here water was a problem and stories of "pumping 100 tons of water
per ton of coal" were not uncommon.
In 1948 the National Coal Board nationalised all the larger
pits, but this period of modernisation was short lived as the last NCB
pit closed at Christmas 1965. Today, only the Free Miners work the small
drifts and levels, whilst above ground open cast mining by outsiders is
set to raise its ugly head.
GEOLOGY
From Chepstow, the Carboniferous limestone extends northwards through
St Briavels, Clearwell, Coleford, and Symonds Yat where it veers to the
east through Joyford, Westbury Brook, Buckshaft and Lydney and forms a
basin, underlying the Coal Measures and Millstone Grits which lie unconformably
upon them. An undulating plateau is deeply incised by the River Wye which
exposes the limestone at many points. This is shown in Fig 1.
FIG 1, THE GEOLOGY OF THE FOREST OF DEAN
|
The coal measures are naturally divided, as will be seen from Fig
2, into three distinct series.
FIG 2, THE MAIN COAL SEAMS
After Sopwith 1841
nb Coleford = Coleford High Delf
The upper series consists of four thin seams of coal called the
Woorgreen Delfs, none of which have proved hitherto of sufficient thickness
to be worth working.
It is from the middle series that the great supply of coal was
drawn from the extensive collieries in the neighbourhood of Parkend and
Cinderford. These veins are:- The `Smith Coal', or `Twenty Inches'; the
`Parkend High Delf', or `Lowrey'; the `Starkey'; the `Rockey'; the `Churchway
High Delf', and the `Brazilly'. These veins were worked on the long wall
system and, as in most cases, there is a good holing above, or under the
coal, very little is lost by waste in working.
With the exception of the coal that was made into coke for the
use in the Iron Furnaces in the Forest; all that was raised from these
seams was sold for household purposes for which its large size, hardness
and good burning properties make it especially suitable.
The intervening strata of the upper and middle series consists
almost exclusively of argillacious shale, with only here and there thin
beds of sandstone. Below the Brazilly vein the character of the measures
undergoes a decided change and instead of the softer ground of the upper
and middle series, we find hard sandstone which continues with little variation
down to the Coleford High Delf vein.
The coals of the lower series are the `Nags Head'; the `Whittington';
or `Yard Delf'; the `Coleford High Delf', or `Hill Delf'; and the upper
and lower `Trenchard' veins. Of these the first two have been worked to
a small extent on the western side of the Forest, where also the Coleford
High Delf vein has been chiefly worked. This vein extends a considerable
distance beyond the general line of the coal basin on the Western side
of the Forest, and that the outlying portion of the vein is divided by
a fault called `The Horse' a tract of barren ground varying in width from
200 to 300 yards.
It has been surmised, by some geologists, that this fault occupies
the bed of a river, which is thought to have cut away and removed the soft
vegetable matter forming the seam of coal, and afterwards been filled up
by the sandstone which overlies it. Two smaller faults called the `Lows'
have also been considered as tributary streams. This theory however does
not appear to be borne out by the evidence afforded by recent drifts through
`The Horse'. The coal has been found to thin out gradually on both sides
towards the middle of `The Horse'; in some places as a single vein; whilst
in other places it is split up into number of veins, each becoming thinner
until all traces of coal are lost in the compact sandstone of which `The
Horse' is formed.
The Coleford High Delf vein is worked on the pillar and stall
system; the absence of sufficient material for packing prevented the adoption
of the long wall system. It is remarkably clean and free burning coal,
and is largely used for forge and steam purposes.
The Coleford High Delf is the most prolific seam. Due to faulting
and surface topography it is found at varying depths from 400 feet to 600
feet. It varies in thickness, on average from 3.5 to 5 feet but its chief
characteristic is the variation in thickness from seams less than 2 feet
to other over 7 feet and in one freak case to 20 feet thick. Because the
mines are comparatively shallow they are consequently very wet. The deeper
mines of say, Yorkshire, are protected by layers of impervious rocks and
tend to be dry and dusty. Consequently the working faces have to be constantly
sprayed with water to keep down the coal dust which is inflammable and
injurious to health causing pulmonary silicosis. The mines of the Forest
are a startling contrast, being extremely wet. They are also free of fire
damp or methane and for many years carbide and other naked flame lamps
were used.
The Farewell rock, or Millstone grit, which underlies the coal
measures throughout the Forest, contains a bed of iron ore in its lower
bed, which has been worked extensively since Roman times.
In the Forest many of the caves appear as iron mines. In Triassic
times iron bearing solutions filled these caves with iron ore such as haematite,
goethite and lepidocrocite. Other sediments were formed in situ by the
oxidation of iron sulphides and other iron bearing compounds. Iron compounds
are highly insoluble, so that these materials tend to form crusts and coatings
in caves. Another theory suggests that a mixture of acidic iron-bearing
solutions corroded cavities in the limestone and in so doing were neutralised,
causing precipitation of iron compounds which filled the newly formed voids.
These `churns' often contained many thousands of tons of ore, for the most
part soft and easily worked. The quality of the ore varies considerable
from the `Brush' ore, frequently containing 60 to 65% iron, to the poorer
kinds being mixed with calcite yielding only 15 to 25% iron.
Mining operations from Roman times to the 1930's have left a
complex network of phreatic tubes connected by chambers which are locally
called `churns'. The iron ore is mainly found in the Crease and Lower Whitehead
limestone beds and one way of finding the ore-bearing levels was to follow
the obvious boundary between the two limestones. As the map shows (Fig.
1), most of the mine entrances are to be found round the edge of the limestone.
The dip angle in the east of the Forest is steep. Here, the iron can be
found as deep as 1000 feet and most of the mines in this area require tackle
for exploration. However, in the west the dip angle is shallow, the iron
deposits are not found below about 500 feet and the workings are consequently
nearer the surface. Minor, localised pockets of iron ore have been found
in the lower part of the Limestone Shales, the Lower Dolomite and the Drybrook
Limestone. This explains why many iron mines fail at depth. Outcrops of
iron ore appear to encourage the growth of Yew trees and it is thought
that this is the clue which first attracted the early miners to the area.
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