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The Blakethwaite Dams

List Entry Summary

This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Culture, Media and Sport.

Name: The Blakethwaite Dams

List entry Number: 1015855

Location

The monument may lie within the boundary of more than one authority.

County: North Yorkshire

District: Richmondshire

District Type: District Authority

Parish: Melbecks

National Park: YORKSHIRE DALES

Grade: Not applicable to this List entry.

Date first scheduled: 06-Aug-1997

Date of most recent amendment: Not applicable to this List entry.

Legacy System Information

The contents of this record have been generated from a legacy data system.

Legacy System: RSM

UID: 28903

Asset Groupings

This list entry does not comprise part of an Asset Grouping. Asset Groupings are not part of the official record but are added later for information.

List entry Description

Summary of Monument

Legacy Record - This information may be included in the List Entry Details.

Reasons for Designation

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. The ore works were an essential part of a lead mining site, where the mixture of ore and waste rock extracted from the ground were 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 size (either by manual hammering or by 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 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. Simple ore dressing devices had been developed by the 16th century, but the large majority of separate ore works sites date from the 18th and 19th centuries, during which period the technology used evolved rapidly. Ore works represent an essential stage in the production of metallic lead, an industry in which Britain was a world leader in the 18th and 19th centuries. Sites are common in all lead mining areas and a sample of the best preserved sites (covering the regional, chronological, and typological variety of the class) will merit protection.

The whole of Gunnerside Gill is an exceptionally well preserved lead mining landscape, containing a wide range of features. It is well documented historically from the 17th century onwards. The Gill is accessible to the public and the archaeological remains form an important educational resource and public amenity. The Blakethwaite Dams are an important part of the Gunnerside Gill lead mining landscape and contribute to the understanding of the 19th century development of the Blakethwaite mines. In addition they provide evidence for the formerly extensive water management system which supplied the Blakethwaite dressing floors and smeltmill.

History

Legacy Record - This information may be included in the List Entry Details.

Details

The monument includes the structural, earthwork and undisturbed buried remains of the Blakethwaite mine dams and includes two areas. It lies in the upper reaches of the Gunnerside Gill, 6.5km north of Gunnerside village, within an area of unenclosed grouse moorland. The Blakethwaite mines were recorded as part of the Surrender grant in the late 1790s. By 1806 the leases were split and the Blakethwaite mine sett leased to Thomas Chippendale and Co. In 1811 an ore shoot was being worked by adit and shaft. However it was not until the following year that the Blakethwaite Level was driven. The company also built a dressing floor, which is the subject of a separate scheduling, near the level entrance to process the ore. A second level (Blakethwaite Low Level) was begun in 1814 but abandoned in 1818. The abandonment may have been partly affected by Clarke and Co, a Chippendale partner, who took over the lease in that year. Early returns from the mines encouraged the building of the Blakethwaite Smelt Mill, also the subject of a separate scheduling, which began smelting in 1821. The lease was surrendered in 1836 and taken up by Messrs Tomlin (Strands and Co) who held the lease until Tomlin's death in 1846. The following year a new company headed by Thomas Bradley took over. The lease again changed hands in the early 1860s, but the mines gradually fell into decline. The Blakethwaite Dams lie approximately 120m apart and have been built across a narrow, steep sided gully in the upper reaches of Gunnerside Gill. They are believed to have been built after 1836 and were in existence by the 1850s. Bradley and Co were responsible for a major investment in the Blakethwaite mine sett during the mid-19th century including the development of the water management system. This period is likely to have seen the construction of the Moss Dam, situated 2.5km to the SSW, and the feeder leat which carried water from East Gill Head c.4km southward to the dam. Moss Dam, itself the subject of a separate scheduling, is believed to have been built to supply water to the west workings of the Blakethwaite Level where a hydraulic engine was installed in c.1842, and is also thought to have supplied water to the Blakethwaite Dams. The Blakethwaite Dams were primarily built to store water for the Blakethwaite mine dressing floors some 1km downstream to the SSE but also supplied water to power a hydraulic engine in West Sump c.1837-40. The upper dam, which is oriented north east-south west and measures 40m in length, consists of two parallel drystone walls, which average 1.5m wide at top (the upper wall increases to 2m in width toward the centre), with a central earthen core averaging 3m wide. The walls have vertical internal faces and external faces tapering outward with a stepped batter to the base. The external face of the outer wall is also buttressed by a substantial earthen bank contained by revetment walls either side of the central area. A square vertical slot, with two bolt holes and vertical in situ iron bar, cut down through the upper wall, is thought to form part of the sluicing mechanism. The crest of the dam is breached at this point. The former pond area behind the dam is now almost silt-filled, with a flat surface just below dam crest level. It originally formed a large body of water to the west of the dam, and a sample area of the floor of the pond is included in the scheduling. The lower dam, which is oriented NNE-SSW and measures c.30m in length, is of the same construction though the earthen bank and protruding revetment walls are absent.

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

Selected Sources

Books and journals
Dennison, E, Gunnerside Gill Phase II: Archaeological Survey, (1995), 24
Gill, M C, Gunnerside Gill: Historical Survey, (1995), 42-45
Raistrick, A, The Lead Industry of Swaledale and Wensleydale: The Mines, (1975), 57
Shaylor, A E, Almond, J K, Beadle, H L, Lead Mining and Smelting in Swaledale and Teesdale, (1979), 12

National Grid Reference: NY 93454 02988, NY 93563 02942

Map

Map
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The above map is for quick reference purposes only and may not be to scale. For a copy of the full scale map, please see the attached PDF - 1015855 .pdf

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This copy shows the entry on 21-Nov-2017 at 12:54:36.

End of official listing