Details

The monument, which lies within two areas, is situated on the south west side
of Herdship Fell, to the north east of the River Tees. It includes the ruined
earthwork and buried remains of a late 19th century lead mine and the well
preserved remains of a complex ore works with associated waste heaps. It does
not include the more dispersed remains of levels and shafts which were also
part of the mine.
The earliest known reference to Green Hurth Mine was in 1799 when a 21 year
lease was granted to John Surtees and Co. This lease had to be surrendered
early because the company failed to start mining operations within the
allotted time, and it is not until 1828 that there is any record of work being
done at Green Hurth. Between 1845 and 1852, the area was worked as part of a
group of small mines operated by Sherlock and Co, but production was only
in the region of 500 tons per year. In 1864 the Green Hurth Lead Mining
Company was formed which raised over 5000 pounds in working capital to develop
the mine.
Most of the visible remains at Green Hurth date to after c.1868 when mining
operations are thought to have begun. It proved to be a profitable mine with
the silver content of the ore increasing with depth to 12oz per ton of lead,
double that more commonly expected. The mine produced over 18,000 tons of lead
before flooding forced abandonment in 1902.
The standing remains of a c.12m by 4m stone and concrete built wheelpit lie at
the southernmost corner of the first area of protection. A published 19th
century photograph shows it to have held a large pitch-back waterwheel, linked
to a system of flat rods that transferred the power generated by the
waterwheel to Swan's Shaft, 530m to the east. The mountings for the balance
bobs (which counteracted the weight of the flat rods) are still in situ at the
east and west ends of the pit. The line of the flat rod system, leading up
hill to the shaft, can be traced as an intermittent trench with occasional
mountings. One concrete setting, c.80m from the wheelpit, retains evidence
that power was also transferred from the main rodway to the ore works via a
second set of flat rods. Swan's Shaft, named after the company's managing
director, was the main drawing shaft for the mine. It lies at the far east end
of the first area of protection. Sunk in the 1870s, the shaft has since
collapsed and now forms a pond surrounded by a drystone wall. Immediately to
the west of the shaft there are the stone and concrete remains of machinery
settings, with a number of in situ iron holding-down bolts protruding from the
ground. These relate to shaft top equipment shown in a second published
photograph taken when the mine was operational. Also close by there is a
grassed over heap of cinders and boiler ash. All these features are included
in the scheduling. Attached to the east side of the wall around the shaft are
the remains of a small building, now used as a sheepfold, and to the north
there are the collapsed remains of a further three shafts. These remains have
been modified since the mine's closure to such an extent that they have not
been included within the scheduling.
Extending from Swan's Shaft, for c.400m downhill WNW, is the embankment for a
single tracked tramway incline. Approximately 300m from the shaft there are
the 0.2m high earthwork remains of a group of buildings which cover a 15m by
20m area just to the north of the incline. To the west of these remains, there
are the 1m high earthworks of a c.30m long dam, and beyond this, the partly
collapsed remains of a level. All of these remains are included in the
scheduling.
At the mouth of the level and at the end of the tramway, there are the well
preserved remains of a c.60m by 40m mine spoil heap that lies on top of a set
of larger heaps of mine spoil and hand picked waste covering a triangular area
c.140m by 100m. On top of the larger heap, south east of the mine spoil heap,
there is a level area of ore processing wastes which retains evidence of
partly buried timber and stone built features. This is considered to be the
remains of the mine's original ore processing (dressing) area.
To the south west of the large waste heap there are the well preserved remains
of the ore works that are thought to have been at least partly powered by the
large waterwheel, and were constructed by the Green Hurth Company after 1868.
The works are built on a series of terraces which retain footings of buildings
and the remains of ore processing equipment. Each terrace is covered by a
spread of dressing waste that relates to the ore process which was carried out
on that terrace, the waste becoming progressively finer downhill. After hand
sorting and crushing, the high relative density of lead ore was exploited with
the aid of water to separate it from the lighter waste minerals. The remains
of the Green Hurth ore works include a network of water courses including both
timber and stone lined trenches, sometimes as little as 0.1m wide, as well as
a c.0.5m wide stone arched culvert that emerges from underneath the spoil heap
to the north. Remains of the ore processing equipment include: the timbers
thought to relate to a set of powered jiggers (which agitated gravel sized
material on sieves in tanks of water); a pair of c.3m diameter stone built
circular buddles (where finer particles were carried in a stream of water from
the centre to the circumference of a shallow angled cone, the lead particles
depositing first); and the nearly complete timber remains of a c.1m by 4m
trunk buddle (which was similar in operation). Immediately to the south east
of the ore works is a c.40m by 70m rounded spoil heap of processing waste, and
extending from the lowest terrace is a leat that carried the waste water to
the large wheelpit to the south.
The open entrance to a level lies c.60m to the north of the wheelpit. There is
no trackway link to the ore works, and this level is thought to have been used
for drainage: it is still issuing water. The ruined remains of two cottages
lie c.50m to the east of this level. These were used by the mine manager and
the washing master, the ore works supervisor. Just uphill from these ruins
there is the low earthwork of a partly silted c.30m by 40m reservoir, and
further water management features survive as earthworks between this and the
incline to the north.
Approximately 200m to the south east of Swan's Shaft are the standing remains
of a single storey c.3m by 4m stone building, within the second area of
protection. The east end, including the gable wall, survives to eaves height
and is backed by a 1m high, 1m wide stone platform. This building is thought
to have been the explosives store for the mine.
The drystone wall around Swan's Shaft is excluded from the scheduling, however
the ground beneath it 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.

Green Hurth is a good example of a late 19th century lead mine. The ore works
retains particularly well preserved features including timber features, such
as launders and a trunk buddle, as well as a series of discreet deposits of
ore processing wastes. These features, with their associated spreads of waste,
retain important technological information which will contribute to our
understanding of ore processing. The waterpower features, the wheelpit with
its associated water supply and power transmission systems, are also well
preserved, and are nationally rare survivals. Given the range of features and
their level of preservation, the whole site should be considered as an
important resource for the understanding of the mining technology of this
period.

Source: Historic England