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Holmbush Mine: Hitchen's Shaft complex

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: Holmbush Mine: Hitchen's Shaft complex

List entry Number: 1020435

Location

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

County:

District: Cornwall

District Type: Unitary Authority

Parish: Stokeclimsland

National Park: Not applicable to this List entry.

Grade: Not applicable to this List entry.

Date first scheduled: 18-Sep-2001

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: 15555

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

For several millennia the south west peninsula has been one of the major areas of non-ferrous metal mining in England, its more important and prolific products including copper and tin along with a range of minor metals and other materials, notably arsenic, which occur in the same ore bodies. Before the 16th century, exploitation of this region's non-ferrous metal resources almost exclusively involved tin. Extraction focussed along valley floors and hillslopes on and around the granite uplands of the south west where tin ore had accumulated after natural erosion from the parent lodes. These accumulations were exploited by streamworks, using carefully controlled flows of water to expose and then concentrate the ore, leaving behind distinctively deepened valley floors with various patterns of spoil heaps. By the early post-medieval period, most substantial deposits susceptible to streamworking had been exhausted and exploitation transferred to the mineralised lodes themselves, a change which marks the appearance of copper as an important product of the south western mining industry. The early post-medieval exploitation of the lodes was restricted by the ability to drain the cut, resulting in relatively shallow workings directly into lode exposures at the bedrock surface, often by pits called lode-back pits and sometimes enlarged to form longer openworks along the lodes. By the 18th century, ore extraction and processing rapidly expanded to meet growing demands, aided and promoted by technological development. Surface workings became larger and more extensive, and deeper extraction was achieved from shafts, the water pumped from larger mines by early steam engines or drained through near-horizontal tunnels called adits which also served to access the lodes. Horse-powered winding engines lifted ore from the shafts while larger and more efficient water wheels served ore-processing areas. By such means, west Cornwall became England's main producer of copper ore in the 18th to early 19th century. Intensification accelerated in the late 18th to early 19th century with more efficient steam-powered pumping engines allowing deeper shafts from which extensive underground workings spread out. By the mid-19th century, steam also powered winding and ore-processing operations, the engines, boilers and ancillary machinery housed in distinctive masonry buildings grouped around the main shafts and dressing areas. Later in the century, compressed air was used for underground extraction equipment, fed from steam-powered compressors on the surface. Ore-processing became increasingly mechanised, along with the development of more effective methods of separating and retaining different ores, particularly in the production of arsenic which became a major saleable product in the 19th century, adding a further range of distinctive processing and refining components to some mines. With these advances, east Cornwall and west Devon became one of the world's main sources of copper and arsenic ore until the later 19th century, while in west Cornwall, copper ores became exhausted and replaced as that area's main product by the tin ores present at deeper levels. From the 1860s, the south western mining industries began to decline in competition with cheaper sources of copper and tin ore overseas, especially from South America, leading to a major economic collapse and widespread mine closures in the 1880s, though limited ore-extraction and spoil reprocessing continued into the 20th century.

The Hitchen's Shaft complex at the Holmbush Mine survives well as a very good example of the range of features and structures grouped to serve the needs of a mid- to later 19th century shaft head in a non-ferrous metals mine. Within that grouping, the survival of a copper crusher house is rare, despite some collapse of its walling, while the enlargement of the balance bob slot to support a water tank is unusual and shows the ingenuity employed in resolving such difficulties as maintaining the mine's adequate water supplies. The good body of supporting documentation allows the development of the complex to be understood and shows well how that development reflected the mine's economic fortunes and its wider context in the world market for its products. The good survival of this complex also provides a highly visible and tangible reminder of the ongoing impact of the 19th century mining boom on settlement patterns, accounting for the development of Kelly Bray which remains a substantial settlement in the local landscape.

History

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

Details

The monument includes a complex of mine features, mostly of 19th century date, around the Hitchen's Shaft of the Holmbush Mine, north of Kelly Bray near Callington in south east Cornwall. The Hitchen's Shaft complex was part of the overall extent of the Holmbush Mine, a copper, lead and arsenic mine operating mainly during the 19th century but developed from earlier activity, traces of which are included within this scheduling. The pumping engine house, winding engine house and their respective boiler house chimneys in this scheduling are Listed Buildings Grade II. The earliest mining at Holmbush, recorded from the 17th and 18th centuries, relates to lead ore extraction from a north-south lode by shallow workings into uppermost levels of the lode, a phase identified with uneven ground in this scheduling extending north and west from the 19th century features. Records indicate further activity in the 1790s and by the 1820s shafts were being sunk on copper-rich east-west lodes in two areas: that in this scheduling was called West Holmbush; East Holmbush, beyond this scheduling, was focussed on a valley 300m to the ESE. By 1826 the shaft at West Holmbush was served by a 36 inch (91.5cm) pumping engine and a horse-powered winding drum called a horse-whim. From the early 1830s, investment in progressively larger steam-powered pumping engines and the replacement of the horse-whim by steam winding engine allowed Hitchen's Shaft to be deepened to 175 fathoms (320m) by 1860. From the 1830s to the 1860s, the mine produced large quantities of copper ore with some lead and associated silver ore. During the period of peak production, from the 1840s to 1892, Hitchen's Shaft formed the main pumping, winding and access shaft for the Holmbush Mine, along with its chief ore-crushing facility and primary waste dump. With those functions it complemented the mine's service and administrative complex, ancillary shafts, dressing floors and their waste dumps, all sited beyond this scheduling in the valley to the east. The mine's workforce and supply needs promoted the growth of the nearby settlement of Kelly Bray and, from 1872, the siting there of the East Cornwall Mineral Railway's terminus. The developing structural complex around Hitchen's Shaft appears on the Stoke Climsland tithe map of 1841, calling it the `Little Hurldown Mine', but the shaft-head arrangement shown bears little relationship to the disposition of surviving structures. By contrast, a sketch of the 1860s shows a shaft-head complex by then containing several features still extant. These included the pumping engine house, to the south of the shaft, with walls surviving to full height though incorporating subsequent modifications when later engines were installed: by 1876 the engine house contained an 80 inch (2m) beam engine whose granite bedstones remain in the engine house. North of the pumping engine house, the mouth of Hitchen's Shaft itself has been covered by a low mound and is no longer visible. Immediately west of the shaft is a tall balance bob slot, 1m wide, in which a heavy balance bob was pivoted from the upper end of the pump rods to counter-balance their weight. The unusual 3.4m height of the slot walls reflects its function also as a plinth to support a water tank serving either the pumping engine's condensing needs or to power a water wheel sited to the west. To the west of the pumping engine house, its boiler house, shown on the 1860's sketch as a two-gabled building, survives with a rectangular sunken interior defined by extensive lengths of its lower walling; in its southern half are three elongated low mounds which steadied the three boilers. At the boiler house's south west corner its chimney survives to about 15m high, built of local rubble but with a brick upper section now partly collapsed. The 1860's sketch also shows some structures removed during later decades of the mine's operation, including a winding engine house with its winding drum, boiler house and detached chimney located east of Hitchen's Shaft in an area now covered by the southern lobe of the mine's later spoil dumps. A building shown west of the pumping engine boiler house may be a copper crusher house, later replaced by a larger crusher building still extant on the site. In 1876, the Holmbush Mining Company was formed to extract arsenic ore which, by the early 1880s, had joined copper ore as the mine's chief profitable products. The 1883 Ordnance Survey map shows the mine in this phase, confirming the presence of further features surviving in the Hitchen's Shaft complex. North west of the pumping engine boiler house is a water wheel pit, 7m long by 1m wide, with massive side-walls. Against its southern wall is a pit for the pitwheel taking the drive from the water wheel. To the south, the map shows a building, now gone, perhaps the copper crusher on the 1860's sketch. In addition to powering that copper crusher, the water wheel at this stage may have driven the Hitchen's Shaft winding gear as enlarged dumps had supplanted the winding engine east of the shaft by 1883 with no replacement evident. The water wheel was fed from a reservoir to its north west, shown in 1883 as rectangular, subdivided by a bank partitioning its western third, arrangement visible in the now dry reservoir ponds. After the arrangement shown on the 1883 map, further developments are evident from historical sources and the disposition of surviving remains. By 1884 three rock drills were in use and in the following year the mine achieved its highest annual production of copper ore, though falling ore prices severely diminished its value and greater profits were gained from arsenic production. The increased production reflects the addition, in the mid-1880s, of a winding engine house sited 60m west of the shaft and survivng with walls to full height, accompanied by masonry loadings of its crank pit and winding cage on the east. Along the north side of the engine house and extending to its west is its boiler house, its south wall surviving to 3m high but with its north wall partly collapsed. To the west of the boiler house, its chimney survives to full height, about 14m, of local rubble on brick lower courses and with a brick upper section. A rectangular reservoir was also added across the north of the earlier two, a pattern shown on the 1906 map and still clearly visible on the ground. Broadly contemporary with these changes, a larger copper crusher house was built west of the pumping engine bolier house, its walling now partly collapsed but with its south wall surviving to full height. In the later 1880s the mine became increasingly uneconomic against cheaper ores available from overseas; shaft-mining operations eventually ended in 1892, followed by limited and intermittent activity during the first half of the 20th century which included reworking parts of the mine's dumps. The monument includes a 2m margin considered essential for the monument's support and preservation where the mine buildings directly abut the modern field adjacent to the south. All modern fences, gates and posts, the water main and its trench, and the electricity supply cables and their posts are excluded from the scheduling, although the ground beneath all these features is included.

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

Selected Sources

Books and journals
Barton, D B , A Historical Survey of the Mines and Mineral Railways of East Cornwall and West Devon, (1964)
Booker, F, Industrial Archaeology of the Tamar Valley, (1971)
Todd, , Laws, , Industrial Archaeology of Cornwall, (1972)
Other
CAU Report to Cornwall County Council, Buck, C, Holmbush Mine Archaeological Assessment, CAU , (1998)
Title: 1:10000 Ordnance Survey Map SX 37 SE Source Date: Author: Publisher: Surveyor:

National Grid Reference: SX 35767 72031

Map

Map
© Crown Copyright and database right 2017. All rights reserved. Ordnance Survey Licence number 100024900.
© British Crown and SeaZone Solutions Limited 2017. All rights reserved. Licence number 102006.006.
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End of official listing