Details

The monument, which is divided into two areas, is situated within a steep
sided valley which runs northwards from Westgate village. It includes the
ruined structures, standing earthworks and other remains of a pair of
organisationally linked 19th century lead mines with their associated ore
works. The monument also includes all deposits of mining and dressing wastes
within the areas of protection.
The two mines that form the monument (Low Slit and Middlehope Shield Mine)
are approximately 400m apart, but are linked by a tramway and leat system. A
major producer from the early 19th century, they were worked in conjunction
with one another by the W B Beaumont Company, which rivalled the London Lead
Company as the largest mining concern in County Durham. In the 1860s a large
dam was built and a hydraulic pumping engine was installed at Low Slit Mine.
White's Level (the main level of Middlehope Shield Mine) was worked out by
the mid-1860s and most production had also ceased at Low Slit by 1872. In
1882 the lease passed to the Weardale Lead Mining Company which produced
small quantities of ore from the workings up until 1895. The lead mines
uphill to the east and west, which were also worked opencast for iron ore,
were operated by a separate firm, the Weardale Iron Company. These mines are
not included in the scheduling.
The remains of Middlehope Shield Mine forms the northern area. At the north
end of this area lies the drainage level which has lost its portal but is
still open and issuing water, being some 1.5m high and 1m wide. Adjacent to
the entrance are the 1.2m high earthwork remains of a twin-celled, 6m by 4m
building. A tramway runs immediately to the rear (north) of the building from
an ore slide above the level entrance. This c.16m long stone built chute
allowed the transfer of materials from a standard gauge mineral railway (a
branch of the Stanhope & Tyne railway) to the narrower gauge tramway. To the
west of the level entrance is a curving, flat-topped finger tip of mining
waste extending over 40m southwards, forming a flood barrier against the burn.
Immediately to the south of the building lies a spread of coarse jigging waste
(ore processing waste up to 4cm diameter discarded after being agitated in
water to separate the heavy ore from the lighter waste material). The
discharge from the level enters a c.18m by 14m reservoir extending 12m from
the level, southwards. The east side is terraced into the hill with a
revetment wall standing to 1.6m above the water level, the west side is dammed
by the 0.5m high tramway embankment. To the west of the tramway is an open
leat that becomes culverted south of the reservoir and feeds the ore works
which lie c.140m to the south of the level. The works lie within a flat
bottomed area c.14m by 40m north-south, bound on all sides except the south
west by quarry faces and revetment walls up to 3m high. On the west side are
the stone footings of a two-celled building, the southern cell measuring c.2m
by 2m and the northern one c.3m by 3m. On the east side are the 0.8m high
ruins of a wheelpit with the foundations of a crushing plant, all being
obscured by rubble, together with the ruined remains of three stone piers
which carried the tramway over the wheelpit and crusher. The rest of the area
is a dressing floor (where ore was processed to remove waste rock and
concentrate the lead minerals) and is thought to retain evidence of manual ore
processing equipment and the settings for the mechanical jiggers that were
also powered by the waterwheel (jiggers were devices consisting of a sieve
held in a tank of water, and worked by agitating gravel sized particles to
cause the heavier lead ore to separate from the lighter waste material).
Immediately to the north west of and above the level area are the 1m high
remains of a c.3.5m by 4.5m single-celled building. Above and to the east of
the crusher is a c.8m by 12m terraced area formed by a c.3m high revetment
wall which forms the back of a set of three bouse teams (storage bays for
unprocessed ore). Approximately 15m south of the reservoir a tramway branches
off the track to the crusher to run along the edge of the terraced area, past
the mouths of the bouse teams, and then along the east side of the stream
gorge to the southern protected area of Low Slit Mine.
Low Slit Mine straddles Middlehope Burn which is culverted for 13m by a c.4.5m
wide, flat arched culvert (the arch drawn from three centres). Four metres
south west (down stream) the burn passes under a 7m wide bridge formed by a
single 4m wide round arch. A shaft, capped with an unsecured 5m by 5m steel
plate, lies 16m to the north of the bridge. Immediately to the north east lies
a 6m by 12m by 4m deep stone lined pit bisected by a c.0.7m wide, 12m long
wheelpit in line with the shaft. This narrow wheelpit is choked with rubble to
within 1m of its top. The base of the larger pit is also obscured by rubble.
Immediately to the south east is a 8m by 4m wide single-celled building
surviving as an earthwork except for the 3m high remains of the north east
wall. The wheelpit is thought to have been used for powering winding machinery
working the shaft. The 2m high bed for a hydraulic pumping engine lies c.22m
SSE of the shaft on the opposite side of the burn. The engine bed is complete
and lies within a 6m by 10m stone built engine house which mainly survives as
footings except for the 4m high south east wall. The hydraulic engine, which
formerly stood here, was built at the Armstrong engineering works at Elswick
in Newcastle upon Tyne and was powered by water pressure provided by water
held in the West Slit Dam c.50m above, 140m to the west. The dam is intact and
still holds water and is formed by a horseshoe-shaped bank 5m high. At the
base of the bank, the valve at the head of the pipeway to the engine can be
seen surviving in situ.
Extending 15m to the north east of the engine house are the ruined remains of
a 5.5m wide, three bayed building terraced into the hillside. The north east
wall of this range survives to 2m and retains the remains of a flue for a
stove. The ruins of a further three smaller buildings survive extending from
10m to the south west of the engine house. These are also terraced into the
hillside and lie immediately above and east of the narrow terrace for the
tramway from Middlehope Shield Mine. The 2m to 2.5m high lower revetment wall
for the tramway forms the rear wall of a bank of six bouse teams, whose side
walls survive as footings. Extending approximately 35m south east of the
southern end of these bouse teams is a further set of eight bouse teams formed
by 6m long walls extending out from the natural cliff face. The easternmost
six of these bays are nearly complete with side walls up to 4m high. It is
thought that the tramway was supported on these side walls, allowing the bays
to be filled from above. Between the bouse teams and the burn (which loops to
the west) there is a dressing floor covered in spreads of dressing wastes.
These deposits are thought to bury the remains of manual ore processing
equipment. The eastern bank of the burn is stone built and contains a number
of culverts which issue water from the dressing area into the stream.
All drystone fieldwalls and modern fencing are excluded from the scheduling,
however the ground beneath is included.

MAP EXTRACT
The site of the monument is shown on the attached map extract.

Source: Historic England

Reasons for Scheduling

Approximately 10,000 lead industry sites are estimated to survive in England,
spanning nearly three millennia of mining history from the later Bronze Age
(c.1000 BC) until the present day, though before the Roman period it is likely
to have been on a small scale. Two hundred and fifty one lead industry sites,
representing approximately 2.5% of the estimated national archaeological
resource for the industry, have been identified as being of national
importance. This selection of nationally important monuments, compiled and
assessed through a comprehensive survey of the lead industry, is designed to
represent the industry's chronological depth, technological breadth and
regional diversity.
Nucleated lead mines are a prominent type of field monument produced by lead
mining. They consist of a range of features grouped around the adits and/or
shafts of a mine. The simplest examples contain merely a shaft or adit with
associated spoil tip, but more complex and (in general) later examples may
include remains of engine houses for pumping and/or winding from shafts,
housing, lodging shops and offices, powder houses for storing gunpowder, power
transmission features such as wheel pits, dams and leats. The majority of
nucleated lead mines also included ore works, where the mixture of ore and
waste rock extracted from the ground was separated ('dressed') to form a
smeltable concentrate. The range of processes used can be summarised as:
picking out of clean lumps of ore and waste; breaking down of lumps to smaller
sizes (either by manual hammering or mechanical crushing); sorting of broken
material by size; separation of gravel-sized material by shaking on a sieve in
a tub of water ('jigging'); and separation of finer material by washing away
the lighter waste in a current of water ('buddling'). The field remains of ore
works vary widely and include the remains of crushing devices, separating
structures and tanks, tips of distinctive waste from the various processes,
together with associated water supply and power installations, such as wheel
pits and, more rarely, steam engine houses.
The majority of nucleated lead mines with ore works are of 18th to 20th
century date, earlier mining being normally by rake or hush and including
scattered ore dressing features (a 'hush' is a gully or ravine partly
excavated by use of a controlled torrent of water to reveal or exploit a vein
of mineral ore). Nucleated lead mines often illustrate the great advances in
industrial technology associated with the period known as the Industrial
Revolution and, sometimes, also inform an understanding of the great changes
in social conditions which accompanied it. Because of the greatly increased
scale of working associated with nucleated mining such features can be a major
component of many upland landscapes. It is estimated that several thousand
sites exist, the majority being small mines of limited importance, although
the important early remains of many larger mines have often been greatly
modified or destroyed by continued working or by modern reworking. A sample of
the better preserved sites, illustrating the regional, chronological and
technological range of the class, is considered to merit protection.

Middlehope Shield and Low Slit Mines retain a concentration of well-preserved
features set within a wider lead and iron mining landscape. Of particular
importance are the various water-powered features, especially the hydraulic
engine bed, with pipeway and reservoir, which was used to pump out the shaft
workings at Low Slit Mine. The two dressing floors are also of high
importance, being well preserved mid-19th century examples that were not
modernised towards the end of the 19th century (which is the case at many
other mining sites). The floor at Middlehope Shield, being waterlogged, is
thought to retain preserved timber features, and the Low Slit dressing area is
considered to retain relatively deep archaeological deposits. The layout of
the two mines, with their internal and external transport and water power
links, are good examples of mid-19th century organisation.
Both areas of protection lie on a major public footpath, the Weardale Way,
which follows the tramway route between the two mines. The monument thus forms
an important educational resource and public amenity.

Source: Historic England

Sources

Books and journals
Burt, R , The Durham and Northumberland Mineral Statistics, (1983), 70-71
Other
Tyne & Wear Industrial Monuments Trust, Lead working sites in Co Durham recommended for protection, 1989, Typescript report

Source: Historic England