Reasons for Designation
The extraction of iron ore by way of opencast workings was a long established
practice in Britain dating back to the centuries before the Roman invasion and
continuing into the early 19th century. However, the demand for iron as a
result of the Industrial Revolution and the need for wrought iron rails to
serve the expanding railway network led to greater and far more costly efforts
at exploitation from the early decades of the 19th century onwards. From this
time good quality iron ore was sought at depths which could be reached only by
mining and hundreds of prime ore-bearing sites were explored including those
in the counties of Cleveland, Cumbria and Yorkshire. In the South West of
England mines were opened in Cornwall and on Exmoor. The mines on Exmoor,
which owed much to imported Welsh coalmining techniques, were created by
driving one or more adits (horizontal passages) into the hillside until the
lode was reached. The lode was then followed and mined in a series of side
passages (levels), the mined ore being transported back along the adit to the
surface for onward transit to smelting and production sites.
The iron ores on the Brendon Hills on Exmoor were found to be of particularly
high quality and serious mining got under way on the Hills in the middle years
of the 19th century; in total some 30 ironstone mines were active on Exmoor in
the latter half of that century. The Brendon Hills Iron Ore Company was
founded in 1853 and some eight or nine mines were opened under its auspices.
The ore from these mines was transported to Watchet on the specially
constructed West Somerset Minerals Railway where much of it was sent over the
Bristol Channel to the South Wales steel industry. Imports of cheaper ore from
abroad led to the closure of the Brendon mines in 1883 although abortive
attempts to carry on mining continued until 1907.
Within England, the Bearland Wood Iron Mine chimney stack is believed to be
the most complete example which relates to iron mine ventilation and it is in
a far better state of preservation than the only recorded colliery example in
South West England which is located near Bristol. It is also the only example
of its kind known to have been constructed on the Brendon Hills. The flue has
been studied and recorded by the Exmoor Mines Research Group who have produced
measured drawings of the structure and who have researched its origins and
date of construction. The monument therefore retains what may be considered
unique surviving evidence of an iron mine ventilation system of the mid-19th
century and it provides important and surviving visible evidence of the
industrial exploitation of the Brendon Hills and the adoption of Welsh
coal mining techniques for the purposes of iron ore extraction in South West
England.
Details
The monument includes the standing chimney stack and part of the remains of a
stone-built ventilation flue which formerly served the Bearland Wood Iron Mine
on Langham Hill, at the western end of the Brendon Hills. The disused mine was
one of several opened by the Brendon Hills Iron Ore Company which operated
from the mid-1800s to the 1880s.
The ventilation flue was designed to expel foetid air, or the smoke caused by
blasting, by drawing in fresh air from the mine's main adit (passage) which
was located at a much lower level on the hillside. This was accomplished by
setting a fire in a specially constructed chamber known as a firebox located
within the chimney stack near to its base. The firebox comprised a hearth
built of brick supporting closely set horizontal firebars through which ash
could fall into a lower ash pit; the fire was loaded through a stoke hole in
the side of the chimney which could be closed off by means of an iron fire
door. At the base of the chimney was an air duct connecting to a vertical
shaft into the mine workings which were about 50m below the stack and 100m
into the hillside. A controlled fire, when lit in the firebox, resulted in
unwanted air and smoke being drawn from the working face of the mine into and
along timber ducts and on up the shaft to fuel the oxygen demands of the fire
thus causing draughts of fresh air to be sucked into the mine to replace it.
The Bearland Wood ventilation flue, as it is commonly known, survives with a
near complete chimney stack about 6.5m in height constructed of local ragstone
with a string course just below the top of the funnel. The chimney has a
diameter at the base of about 1.75m narrowing to 1.3m at the summit and it
sits on a plinth, 2.4m square, also of local stone. The iron frame of a fire
door is recessed within a stokehole on the eastern side of the chimney about
0.8m above the plinth whilst the hearth of the firebox itself is visible
through the aperture of the stokehole. A length of about 1.8m of the masonry
air duct leading to the vertical shaft survives leading outwards from the base
of the chimney on its northern side; the remainder appears to have been
destroyed. The duct is constructed of stone, 1.2m wide with a channel 0.4m
wide; it was once capped in stone but only a few of the capping stones have
survived in place. The vertical air shaft which served the duct has been
infilled.
Investigations by the Exmoor Mines Research Group have indicated that the
structure is likely to have been built in 1860; a broken slate datestone found
at the base of the chimney was inscribed with the Roman numerals ...CLX
(allowing a possible restoration of MDCCCLX). This slate fragmented after
discovery and no longer survives, but a rectangular scar on the eastern side
of the chimney bears witness to its original location. A construction date of
1860 would fit with the erection of the chimney under Morgan Morgans, the
Brendon Hills mines captain appointed in 1858, who came from a South Wales
colliery background.
MAP EXTRACT
The site of the monument is shown on the attached map extract.
It includes a 2 metre boundary around the archaeological features,
considered to be essential for the monument's support and preservation.
