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Summary

Remains of china clay workings consisting of eleven settling tanks in three groups

Location

Protected Status

• SHINE: Earthwork remains of the early 20th century China Clay works at Redlake Mine and the associated railway, as well as prehistoric remains on Ugborough Moor

Other References/Statuses

• Old DCC SMR Ref: SX66NW/61
• SHINE Candidate (Yes)

Monument Type(s) and Dates

• CLAY WORKINGS (Edwardian to Early 20th Century - 1910 AD to 1932 AD (Between))
• SETTLING PIT (Constructed, Edwardian to Early 20th Century - 1910 AD to 1932 AD (Between))

Full description

Royal Air Force, 1946, RAF/CPE/UK/1890, 4275 (Aerial Photograph). SDV169268.

Harris, H., 1968, Industrial Archaeology of Dartmoor, 95 (Monograph). SDV149229.

Western Whitebarrow, china clay workings. The China Clay Corporation Ltd. 1911-1932, made extensive use of the land here. Some of the filter beds and drying beds are in Ugborough parish. The beds are stone built with some brick and concrete, but only the ruins survive, and the purpose of each one is not obvious.

Royal Commission on the Historical Monuments of England, 1985, Aerial Photograph Project (Dartmoor) - Dartmoor Pre-NMP (Cartographic). SDV319854.

Two deserted buildings and a leat visible on the 1946 aerial photograph.

GeoInformation Group Ltd, 2010, 1:625 2010 Colour (12.5cm resolution) (Aerial Photograph). SDV346026.

Visible on the aerial photograph.

Ordnance Survey, 2014, MasterMap (Cartographic). SDV355681.

Structures depicted on the modern map.

Newman, P., 2018, Erme Valley Survey data (GIS and Excel spreadsheet) (Cartographic). SDV361913.

Settling tanks shown on survey.

Newman, P., 2018, The Upper Erme Valley, Dartmoor National Park, Devon: An Archaeological Survey, Appendix 1, Figures 54-56 (Report - Survey). SDV362921.

Ruined china clay settling tanks, or concentrators, at the Greenhill clayworks, north-west of Western White Barrow. This clayworks was operated by the China Clay Corporation from about 1913 to 1932 to refine the clay from Redlake Pit (MDV107445), 1.3 kilometres to the north. The tanks were created by excavating a hollow into the slope then reinforcing the downslope side with the earth removed from the excavation, and lining the hollow with mortared stone and concrete. The majority of the stone used in construction is of a metamorphic type found around the borders of Dartmoor which does not occur on the upland and must have been transported to the site via the Redlake Railway along with various type of brick used to build some structural details including manhole linings. Surplus spoil created in the excavation of the hollows was dumped downhill of each settling tank. The upper set of four tanks is sited just below and to the west of the mica drags (MDV5169) comprising a large square pit, 23.8 metres by 23.8 metres, sub-divided into four separate pits of 11 metres by 11 metres by cross partition walls, 2 metres thick. The concrete floor in each pit slopes in two directions towards the centre giving a maximum depth of 3.4 metres. Although the floors and main outer wall survive in situ, the cross partitions appear to have been deliberately demolished. Remnant sections of glazed ceramic pipes, which fed the settling tanks are traceable on the surface, and others remain buried. Just above the south-east corner of the installation, a partly demolished rectangular structure 3.7 metres by 1.8 metres by 1 metre high was the point from which the flow of slurry into the pits was controlled. Parts of a large-bore ceramic pipe leading to this structure from the drags, remain in situ above ground. A larger set of six tanks is located 30 metres to the west, and was the likely destination for the clay slurry once drained from the upper pit, in a continuance of the filtering process. These are 15.7 metres by 15.7 metres and 3.6 metres deep. The floor of each slopes in four directions to the centre, where the main sluice was located. Collapsed brickwork in the base of the tanks, and rectangular brick foundation measuring 1.2 metres by 0.6 metres in two of the tanks, may represent remains of the support for a pinhole launder. Each tank also has an iron sluice outlet built into the top of the wall in one corner, which could be adjusted to various depths to allow cleaned surface water out of the tank. This water was collected in rectangular chambers 1 metre by 2 metres and over 1.5 metres deep from where it could be directed to the return pipe. Remnant sections of glazed ceramic pipes, which fed the settling tanks are traceable on the surface, and others remain buried. Some of these lead to or from raised brick structures spaced around and below the installation. Eight of these structures, arranged in two lines adjacent to the tanks, all approximately 1 metre square, accommodated sluice valves just below ground, used to direct the flow of slurry. Two slightly larger brick structures were associated with the main outflow pipes to Bittaford, and probably served as inspection hatches and perhaps housed shut off valves. A third, just to the north served the same purpose on the return pipe which carried waste water back to Redlake Pit. A single settling tank is located 80 metres to the south-east of the others. Clearly of a similar design, it measures 17 metres by 17 metres by 3.3 metres deep. However, it appears to have been robbed of the stone that was used to line the sides, which is mostly missing though some vestiges survive. Its isolated position and the survival of a feed pipe direct from the drags suggests it may have been installed to refine lower grade mica clay, or that it was needed to provide greater capacity to the other settling tanks.

Various, 2018-2020, PALs Condition Recording forms, UE-10 (Worksheet). SDV362781.

(23/01/2019) Recorded by experienced volunteer condition assessor. Condition assessed as very good. These substantial remains are probably largely unchanged. All the tanks show signs of major damage on one wall or another and it would seem likely that this was done, if not at abandonment, soon after to enable any livestock falling in to climb out. Some vegetation encroachment is visible within the tanks. Moss and fine grasses.

Various, 2018-2020, PALs Condition Recording photographs (Photograph). SDV363073.

Photographs taken in January 2019.

Sources / Further Reading

Associated Monuments

Associated Finds: none recorded

Associated Events

• EDV8082 - Survey of the Upper Erme Valley

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