Reasons for Designation
Soughs were horizontal tunnels dug specifically for draining water away from
underground mine workings. Although they are common features in association
with Derbyshire lead mines, they are rare elsewhere in the country. Well
preserved examples are, therefore, considered to be of national importance.
Hillcarr Sough is a functioning, well preserved and well documented example
associated with the important lead working landscape centred on Alport. Its
importance is further enhanced by its association with other well preserved
remains relating to the survey and construction of the sough.
Details
The monument is located below the eastern edge of Stanton Moor in the eastern
gritstone moorlands of Derbyshire. It includes part of Hillcarr Sough, a lime
kiln associated with the construction and maintenance of the sough and a paved
trackway extending between three shafts sunk down to the sough. Also included
is a large spoil tip containing material removed during the excavation of the
sough. Further remains relating both to the sough and to other industries
survive in Hillcarr Wood. These additional remains are not included in the
scheduling, however, as their full extent and state of preservation is not
sufficiently understood.
The entrance to Hillcarr Sough lies at the bottom of a steep east-facing slope
in Hillcarr Wood and consists of a corbelled gritstone arch measuring c.1.5m
wide by c.1.5m high. In the keystone of the arch is a metal pin which once
hinged a cover. This cover, a metal grille, lies discarded to the north of the
entrance.
Next to the entrance is a small flight of steps which relates to a track
approaching from the north. The steps are flanked by a jetty and both steps
and jetty relate to the removal of material from the sough by boat. This
material was stacked in spoil heaps, an example of which lies immediately to
the north. The spoil heap consists of a roughly oval flat-topped mound
measuring c.30m by c.20m by c.3m high.
Eastwards from the entrance, the sough comprises a leat or water channel lined
with gritstone blocks and extending for c.160m to the River Derwent. Although
partly collapsed in places, the section of the leat through Hillcarr Wood
shows its construction very clearly and illustrates that the sough was
originally c.1.5m wide by c.1m deep. Upon leaving the wood, it widens and, in
places, is up to c.3m wide due to the collapse of the sides. Its original
width outside the wood would have been in the region of 2m. The water flowing
through the open section is c.1m deep.
Two bridges cross the section of the sough outside Hillcarr Wood: one at the
edge of the wood and one where it opens into the river. The latter is the
narrower, being c.2m wide while the other is c.3m wide. Both are corbelled
gritstone structures but the wider one has been repaired and mortared whereas
the narrower retains its original unmortared appearance. Immediately west of
the riverside bridge, the sough widens into two diamond-shaped ponds divided
by a weir. The pond west of the weir is c.10m in diameter whereas the one to
the east is c.5m in diameter. Originally there was a sluice-gate in the weir
but this is no longer extant. The weir has been repaired with concrete but
much of the original construction remains. Two drains with metal covers empty
into the smaller pond.
Immediately south of where the sough meets the river are the remains of a
circular limestone structure with a diameter of c.4m. A partly buried draw
tunnel, visible in the side facing the river, shows it to have been a lime
kiln used in the production of quicklime. Its well constructed appearance and
its association with the sough indicate that it was not the ephemeral type of
lime kiln known as a `pudding' or `pie' kiln, but the longer-lived `running'
kiln in which limestone was stacked with combustible material and the stack
replenished through the top of the kiln as it burned down. Quicklime was
sometimes used in blasting at lead-related sites but gunpowder is documented
as being in use in the excavation of Hillcarr Sough, so it is more likely that
the quicklime from this kiln was used for mortar inside the underground
sections of the sough. The limestone would have been imported into the region
from the limestone plateau to the south.
Westward from its entrance, the sough lies underground. To understand the
remains west of the entrance, it must be appreciated how the construction of
the sough was carried out.
Underground excavation proceeded by sinking a shaft to the level of the sough
then excavating horizontally through the hillside to meet it. When this
objective was achieved, a second shaft was sunk further on and the process
repeated. Further shafts would have been sunk as necessary, the whole
excavation being carried out over a long period of time on a pre-surveyed
route. On the hillside above Hillcarr Sough there are three shaft mounds
located west of the entrance at 50m intervals. They are believed to represent
a construction period of between 15 and 30 years dating to the early stages of
the sough.
The longevity of the operation is indicated by the construction of a 1m wide
stepped paved track from the sough entrance, up over the first two shaft
mounds to the third. The exact purpose of this track is unclear but it was
clearly to facilitate the movement of men and materials since, from the bottom
of the hill, it joins a 2m wide cart track which parallels the open section of
the sough on its south side and extends as far as the bridge on the edge of
the wood. In addition, around the sough entrance there is a great deal of
broken roof slate and building stone, including a dump of partly buried
dressed stone. These remains relate to site buildings and represent a long
period of occupation. This is also indicated by the third shaft mound which is
not only reveted with drystone walling but is flanked by an enclosed
rectangular space interpreted as a yard. The yard measures c.20m by c.10m and
is reached via the paved track which, at this point, ends on a walled track
approaching from the north. The third shaft mound is of particular interest
because it includes a lined open shaft, capped with dressed stone sleepers,
adjacent to a platform for winding gear. It is not clear why this shaft is a
more complex arrangement than the other two but it may be speculated that it
relates to an operation additional to the excavation of the sough. Also of
note is the occurrence of slag on the third shaft mound. Slag is a waste
material from the process of lead smelting, but it is not clear whether the
slag here relates to a smelting mill in the vicinity of the sough or whether
it has been imported.
Hillcarr Sough was begun in 1776 and was both surveyed and constructed for the
specific purpose of draining the lead mines of the Alport region. Throughout
the 18th and 19th centuries, various branches and extensions were added and,
by the 1840s, there were four water pressure engines in place to pump water up
from mineworkings sunk to a level deeper than the sough itself. After the
installation of these engines, many of the mines were worked to over 100 feet
below the level of the sough. However, by the 1850s, fluctuations in the lead
market led to the engines being advertised for sale and all the Alport mines
but Prospect Mine being closed. The efficiency of the sough as a drain and its
good state of preservation are both still evident in current outflow of water.
A modern drain north of the weir, modern walling and fencing crossing the
monument, a modern stile and the surface of the track leading to the
gamekeeper's lodge in Hillcarr Wood, are all excluded from the scheduling
though the ground underneath is included.
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.
