Details

The monument includes the structural, earthwork and buried remains of the
Prosperous smelt mill, mines and ore processing works, and is located on the
south bank of the Ashfold Side Beck, 200m north of Providence House. It
includes the remains of a water-powered smelt mill complex, with an unusual
flue and revetted dressing floors.
The smelt mill is a rectangular sandstone building with two main chambers.
Further chambers housed pump gear (to the west) and a small roasting hearth
(to the east) where ore was prepared for smelting. Underground waterwheels in
the neighbouring shaft, west of the smelt mill, would have powered a pump to
drain the lead mine. Part of the pump gearing protrudes from the shaft, with
some of its timber frame intact. A substantial stone loading stands to the
north of this shaft. Collapsed material inside the smelt mill building is
thought to preserve two wheelpits, and further interior divisions.
Water was brought to the mill wheels by a launder, two wooden posts of which
survive south of the smelt mill. Water from the western wheel ran to the
building, where the smaller wheel used it to power a bellows which in turn
served a double ore hearth. Against the eastern wall of the building, the
external roasting hearth is attached to a substantial arched flue. The
well preserved flue runs south east for approximately 170m, interrupted by an
unusual beehive condenser (where lead fumes were collected) which stands to
1.5m, and terminates in a square chimney base of 1.5m width. At the eastern
end of the smelt mill is a range of small three-sided chambers known as bouse
teams, where ore was stored prior to processing.
North west of the smelt mill are the remains of a wash kiln, where unprocessed
ore was first washed, and other dressing features are believed to survive
beneath the ground surface in this area. In the north east part of the site,
on a small platform near the Ashfold Side Beck, is an intact slag heap, which
is included in the scheduling and will retain important technological
information about lead smelting processes.
The south western portion of the monument includes intact spoil heaps, and
retaining walls which form a series of revetted dressing platforms. The full
layout of these platforms is partially obscured by spoil slip, and it
is expected that undisturbed remains of dressing floors will be preserved
beneath. A section of revetment in the extreme south west of the monument,
surviving to 2m in height and pierced by a culvert, is thought to run
continuously under accumulated spoil for 40m, defining the upper edge of the
dressing area. The plan of the site is typical of contemporary lead processing
sites, where the early stages of processing took place higher on a slope (in
this case, to the south west), allowing water to be reused in later stages of
processing lower down the slope (to the north).
The history of the site is well documented from the 1780s onwards, though
mining in the area predates this and earlier remains on this site are possibly
preserved beneath later stratigraphy. Roman mining and leadsmelting is known
from the Greenhow area and the nearby Providence vein was mined from at least
1225; however there is little information specific to the Prosperous lead
mines until a lease of 1781. The mill itself, serving not only the Prosperous
but also the Providence and Stoney Grooves mines, (situated west of the
Prosperous) is said to date from 1785. In the 1830s, following a severe
depression in lead prices, the mine fell into disrepair. The Nidderdale Lead
Mining Company took over in the 1860s but despite investment, output remained
small, and in 1873 the Prosperous mine's plant was sold for use at Stoney
Grooves and the neighbouring Merryfield mines. The mineral rights were bought
by the Bewerley United Lead and Barites Mining Company Limited, whose
activities ceased in 1889. The mine and mill became redundant from that date.
The ruined engine house and shaft which lie to the south of the Prosperous
site, near Providence House, are believed to belong to the Providence mine.
Given the quality of remains and disturbance of the area by modern reworking
they are not considered to be of national importance and are not therefore
included in the scheduling.
The surface of the modern trackway is excluded from the scheduling, although
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.
Ore hearth smelt mills were introduced in the 16th century and continued to
develop until the late 19th century. They were the normal type of lead smelter
until the 18th century, when they were partially replaced by the reverberatory
smelt mill. The ore hearth itself consisted of a low open hearth, in which
lead ore was mixed with fuel (initially dried wood, later a mixture of peat
and coal). An air blast was supplied by bellows, normally operated by a
waterwheel; more sophisticated arrangements were used at some 19th century
sites. The slags from the ore hearth still contained some lead. This was
extracted by resmelting the slags at a higher temperature using charcoal or
(later) coke fuel, normally in a separate slag hearth. This was typically
within the ore hearth smelt mill, though separate slag mills are known.
Early sites were typically small and simple buildings with one or two hearths,
whereas late 18th and 19th century smelt mills were often large complexes
containing several ore and slag hearths, roasting furnaces for preparing the
ore, refining furnaces for extracting silver from the lead by a process known
as cupellation, and reducing furnaces for recovering lead from the residue or
litharge produced by cupellation, together with sometimes complex systems of
flues, condensers and chimneys for recovering lead from the fumes given off by
the various hearths and furnaces. The ore hearth smelt mill site will also
contain fuel stores and other ancillary buildings.
Ore hearth smelt mills have existed in and near all the lead mining fields of
England, though late 18th and 19th century examples were virtually confined to
the Pennines from Yorkshire northwards (and surviving evidence is strongly
concentrated in North Yorkshire). It is believed that several hundred examples
existed nationally. The sample identified as meriting protection includes: all
sites with surviving evidence of hearths; sites with intact slag tips of
importance for understanding the development of smelting technology; all 16th-
17th century sites with appreciable standing structural remains; 16th-17th
century sites with well preserved earthwork remains; and a more selective
sample of 18th and 19th century sites to include the best surviving evidence
for smelt mill structures, and flue/condenser/chimney systems.

The Prosperous smelt mill and its ore processing complex survive well and
include an unusually complete range of features, representing a
well organised, medium scale mine and processing centre of the 18th and 19th
centuries. The smelt mill retains evidence of arrangements of hearths, bellows
and power systems. The survival of elements such as in situ gearing and a
beehive condenser enhance the unusually high quality of remains, and will
provide important technological information about the operation of the mill.
Deposits of slag and ore processing waste will allow further technological
analysis, whilst the surrounding earthworks and buried remains will contribute
to an understanding of the site's layout, development and operation throughout
its lifetime.

Source: Historic England

Sources

Books and journals
Clough, R T, Lead Smelting Mills of the Yorkshire Dales and Northern Pennines, (1980)
Raistrick, A, Lead Mining in the Mid Pennines, (1973), 13ff
Dickinson, J M, Gill, M C, 'British Mining' in The Greenhow Lead Mining Field (A Historical Survey), , Vol. 21, (1973)

Source: Historic England