Carn Brea Methodist Church, Carn Brea Village, Redruth, TR15 3BA

Statement Heritage

Land West of ‘Texaco’ Garage, A3047,Scorrier, Cornwall NGR SW 716 314 (North part of Treskerby Mine)

Heritage Impact Assessment within a World Heritage Site SH Ref WTEXA1220 preapplication submission for planning. 12/12/2020

Statement Heritage with Adam Sharpe

STATEMENT HERITAGE, 8 PAR LANE, PL24 2DN WWW.STATEMENT-HERITAGE.COM 01726 339217

Statement Heritage : West of Texaco, Scorrier

All content © Statement Heritage unless stated otherwise.

Evidential research and fieldwork elements of this project was carried out by Adam Sharpe BA(hons) MCIfA, with management, policy analysis, impact assessment and recommendations developed by Daniel Ratcliffe BA(hons) MA MCIfA in December 2020. We would like to thank the Cornwall Historic Environment Record, Client and Planning Agent for their assistance in preparing this report.

Views and recommendations expressed in this report are solely those of Statement Heritage and are presented in good faith on the basis of professional judgement and on information currently available. It should not be used or relied upon in connection with any other project than that intended.

Historic Ordnance Survey Extracts provided by Groundsure Insights. “Crown Copyright and Database Right 2020 Ordnance Survey 100035207

Historic Tithe Extract © National Archives, provided by ‘The Genealogist’

Statement Heritage : West of Texaco, Scorrier

Executive Summary

This assessment identifies the heritage values of a site to the north of the A3047 at Scorrier, which is proposed by our clients for light industrial / commercial development. The report comments on the implications of national and local planning policies focussed on the historic environment, assesses the ‘in principle’ impacts of the proposed development and makes recommendation for its close design aimed at avoiding, minimising or mitigating such impacts.

The site forms a part of the 18th-19th century Treskerby Mine (tin and copper). Further remains of the mine lie to the south of the A3047, now within woodland and included within the boundary of the Cornwall and West Devon Mining Landscape World Heritage Site.

Various statutorily designated heritage assets lie within 500m of the site, but, following fieldwork, are not considered to be affected by this proposal.

The assessment identifies that the northern boundary of the site follows the historic administrative boundary of Gwennap and Redruth Euny parishes. A Cornish hedge following this boundary is identified along this boundary and should be treated as a ‘non-designated heritage asset’ with local architectural, historic and archaeological value.

The assessment also identifies the location of 5 shafts within the site, one of which may be open, but choked with refuse and vegetation, and is surrounded by a traditional Cornish hedge safety barrier this feature having some local architectural and historic value, although now largely concealed by scrub vegetation. The other identified shaft locations may or not have been adequately capped and are covered or completely buried with later mining spoil, which now supports a mosaic of heathland and scrub vegetation. It is likely that further shafts and shallow mining features lie within the site as buried archaeological features. In the view of Statement Heritage the mining features of the site no longer contribute meaningfully to the ‘setting’ of the World Heritage Site, due to their concealment by later vegetation, but the features within the site and the potential for further buried features to be identified within the site should be treated as non-designated heritage assets of local to regional architectural interest.

It is recommended that if possible the extant shaft is preserved ‘in situ’ with restoration of its surrounding Cornish Hedge, whilst a programme of archaeological work be developed to be carried out alongside the preparation and development of the site to record, or where reasonable to do so, to preserve other mining features within the site.

Statement Heritage : West of Texaco, Scorrier

Contents Executive Summary ...... 3 1. Introduction and Methods ...... 7 2. Location and Designations ...... 8 3. Topography and Historic Characterisation ...... 9 4. Site Inspection ...... 14 5. Statement of Significance ...... 18 6. Policy Requirements...... 20 7. Impact Assessment ...... 22 8. Conclusions ...... 23 9. Bibliography ...... 24

Statement Heritage : West of Texaco, Scorrier

Common acronyms and specialist terms found in Statement Heritage Reports.

Architectural terms are generally taken from the Oxford Dictionary of Architecture and Landscape Architecture online version here; the glossaries provided by Pevsner Architectural Guides here and within RW Brunskill’s ‘Vernacular Architecture’ Archaeological terminology is generally compliant with Historic England Thesauri available here. Historic England’s ‘Introductions to Heritage Assets’ and ‘Designation Selection Guides’ are particularly useful for thematic discussions of heritage asset classes. These may be freely downloaded here. Archaeological Evaluation. The field testing of land by either remote sensing or direct interventions (digging) to establish the presence / absence, extent, type, date, significance and potential of archaeological features. Archaeological Interest. The potential for a heritage asset (building, landscape or monument) to hold evidence of past human activity worthy of investigation. AOD: Above Ordnance Datum. Heights given in ‘AOD’ are quoted in metres relative to ‘Ordnance Datum Newlyn’ CIfA: Chartered Institute for Archaeologists. Professional institute. Individual grades are MCIfA (Member); ACIfA (Associate); PCIfA (Practitioner). CSHER / HER : Cornwall and Scilly Historic Environment Record. The definitive record (for planning purposes) of the historic environment of Cornwall and the Isles of Scilly, managed by Cornwall Council. CLP: Cornwall Local Plan. https://www.cornwall.gov.uk/media/22936789/adopted-local-plan-strategic-policies- 2016.pdf . Planning determinations are expected to be in conformity with local planning policy. CRO: Cornwall Record Office. References prefixed CRO indicate the local record office reference number of archive documents. Designated Heritage Asset. A World Heritage Site, Scheduled Monument, Listed Building, Protected Wreck Site, Registered Park and Garden, Registered Battlefield or Conservation Area designated under the relevant legislation. DTM: Digital Terrain Model GI, GII*, GII etc. Listed Buildings and Registered Parks and Gardens are graded according to their importance. GI and II* are the highest grades triggering consultation by LPAs of Historic England and specific protections under the NPPF. HE: Historic England. The Government’s statutory advisory body on the historic environment. Historic Environment. ‘All aspects of the environment resulting from the interaction between people and places through time, including all surviving physical remains of past human activity, whether visible, buried or submerged, and landscaped and planted or managed flora’ (NPPF) HIA: Heritage Impact Appraisal. A document assessing the presence / absence, significance of, and impacts to heritage assets, usually prepared in preparation of LPA consent processes. HLC: Historic Landscape Characterisation. A technique of historic landscape analysis based on the identification of areas sharing common features, patterns and attributes related to their historic development.

Statement Heritage : West of Texaco, Scorrier

IHBC: Institute for Historic Building Conservation. Professional institute LPA: Local Planning Authority. Mitigation. Measures to limit or avoid the harm of an action. Specifically used within archaeological work to refer to the processes of converting archaeological interest to an archive to advance understanding of a heritage asset, sometimes known as preservation by record. NA: National Archives. References prefixed ‘NA’ indicate the reference number of archive documents held in the National Archives. NHLE: National Heritage List for England. https://historicengland.org.uk/listing/the-list/. The definitive record of protected (designated) heritage assets in England. Non-designated Heritage Asset. ‘Buildings, monuments, sites, places, areas or landscapes identified by plan- making bodies as having a degree of heritage significance meriting consideration in planning decisions but which do not meet the criteria for designated heritage assets’ (NPPF). Buried archaeological remains may fall into this category, unless their significance is ‘demonstrably equivalent to Scheduled Monuments’ (NPPF footnote 63). Some assets without statutory protection e.g. through Listing or Scheduling will attract greater planning weight when contributing to designated areas such as World Heritage Sites or Conservation Areas. NPPF: National Planning Policy Framework. Central Government framework for planning in England. OS: Ordnance Survey OS NGR: OS National Grid Reference. OUV: Outstanding Universal Value. Used within World Heritage Site practice to describe the heritage values that make it worthy of inscription as such. Preservation by Record. See mitigation. Preservation ‘in situ’. The simplest and best form of archaeological mitigation is to leave the evidence undisturbed, i.e. through an informed foundation design. Setting: ‘The surroundings in which a heritage asset is experienced. Its extent is not fixed and may change as the asset and its surroundings evolve. Elements of a setting may make a positive or negative contribution to the significance of an asset, may affect the ability to appreciate that significance or may be neutral.’ (NPPF) SPD: Supplementary Planning Document. Supplementary Planning Documents (SPD) build upon and provide more detailed guidance about policies in the Local Plan. Legally, they do not form part of the Local Plan itself and they are not subject to independent examination, but they are material considerations in determining planning applications. WHS: World Heritage Site. ZTV: Zone of Theoretical Visibility. A computer-generated prediction of the visibility of a point or group of points within a ‘bare earth’ model of a landscape (i.e. one in which trees and buildings are imagined to have been removed). Such models deliberately over-estimate inter-visibility in order to increase the confidence by which non-visibility can be predicted.

Statement Heritage : West of Texaco, Scorrier

1. Introduction and Methods

1.1. This report was commissioned by the client to inform feasibility work at Land West of ‘Texaco’ Garage, A3047,Scorrier, Cornwall (figure 1) in advance of detailed planning for the redevelopment of the site in light commercial / industrial use. 1.2. The report responds to requirements in the NPPF (P189) (MHLG 2018) and Cornwall Local Plan (Policy 24) (CC 2016) to ensure that all applications for development are based on a proportionate assessment of the significance of any heritage assets affected, including any contribution made by their setting. 1.3. The report was commissioned by client as part of proactive pre-application discussions and to inform emerging design solutions. 1.4. This assessment, the overall methodology of which is informed by Cornwall Council’s adopted Supplementary Planning Document for the WHS and by Historic England’s best practice note Making Changes to Heritage Assets (Historic England, 2016) will:

• Describe via a full regression exercise of large scale (1:2500) Ordnance Survey historic maps, the development of this part of the WHS and the date of the buildings within the site’s immediate setting. • Draw on archive and bibliographic sources. • Describe and assess the results of our own field-based assessment of the site and existing buildings. Field assessment has been informed by the results of online consultation of data provided by the Cornwall and Scilly Historic Environment Record and desk-based assessment by consultation with relevant bibliographic and archive sources. • Describe the significance of the assets assessed. • Consider the impacts to the significance, and Outstanding Universal Values of the assets affected according to the relevant policy principles and the WHS Management Plan and SPD. • Consider mitigation recommendations.

Statement Heritage : West of Texaco, Scorrier

2. Location and Designations

2.1. Address: Land West of ‘Texaco’ Garage, A3047,Scorrier, Cornwall 2.2. NGR: SW 716 314 2.3. Designations (see figure 1ii) 2.3.1. The site falls outside but immediately adjacent to the northern boundary of Area 5 (Camborne and Redruth Mining District) of the Cornwall and West Devon Mining Landscape World Heritage Site. 2.3.2. The WHS property is inscribed by UNESCO for its Outstanding Universal Value which is expressed through “a series of 10 Areas comprising the distinctive patterns of buildings monuments and sites which together form the coherent series of distinctive cultural landscapes created by the industrialisation of hard rock mining processes in the period 1700- 1914 (Cornwall Council , 2012, p. 18) 2.3.3. 3 GII Listed Buildings are within 500m of the proposal site. 2.3.3.1. NHLE 1253199 GII Calcining Plant at Treskerby Mine (GII) is described by Historic England as follows : Calcining plant. Late C19. Calciner built of coursed granite blocks with galleting to mortar; St Day brick dressings to openings; labyrinth built of rubble with similar dressings to openings; stack of coursed granite with stepped cornice to St Day brick flue. PLAN: calciner of square plan sited to NE of labyrinth with baffles which is connected to stack to SW. Calciner has segmental-arched openings to 3 sides, including entry for removal of ash to NE and former furnace entrance with its splayed sides to former iron doors to SE. The interior has circular-plan walls which encased riddler sitting on squared walls to ash box at lower level; to SW corner is a hole for the exit of gases into the labyrinth. The labyrinth has lost its original brick roof where the gases condensed and the arsenic was scraped off; some springers to originally segmental- vaulted ceiling remain; narrow round-arched access doors at regular intervals; there is a splayed opening for draught inlet at NW end and slots for portcullis doors for the control of gases; granite lintels over final baffle area next to stack. Treskerby mine was an important producer of 18th and 19th century copper ore. The calcining plant here, exceptional for its completeness as an example of this building type, probably reflects a late re-use of this site, when copper burrows would have been re-crushed and calcined for arsenic. The site of this asset lies within secondary woodland to the site within the area of the former Tresekerby Mine to the south of the A3047 and is not intervisible with the proposal site 2.3.3.2. NHLE 1162268 Milepost on South Side of A30 at SW 719 438 (GII) is a Probably early 19th century …roughly hewn granite monolith [upright stone] with rounded top, the front inscribed with crudely-shaped lettering:- FROM TRURO 7 MILES related to the turnpiking of this route in the early 19th century.

Statement Heritage : West of Texaco, Scorrier

2.3.3.3. The ‘setting’ of milestones of this type can fairly be said to be limited to the roads along which they originally marked distances. The stone lies c200m east of site and its historic values are unlikely to be affected by the current proposals. 2.3.4. NHLE1161923 Chimney Stack at SW713442 The list description states Chimney stack at SW 713 442 II Isolated chimney stack on site of former Great North Downs Mine. Probably early C19 or earlier. Large blocks of granite rubble brought to courses, and brick. Circular plan. Three short stages successively set back, the top-most of brick with brick cornices at each end. History: North Downs was worked for copper from the beginning of the C18, and was then the largest copper venture in Cornwall (reference D.B.Barton A Guide to the Mines of West Cornwall, 3rd edn. 1973, p.33). A small but sturdy structure whose strong visual quality is much enhanced by its now smoothly-grassed and otherwise featureless surroundings. 2.3.4.1. This chimney has been truncated by partial burial, and we are advised is a very late feature of the site associated with a re-working phase, not to the main period of activity of North Downs Mine (Adam Sharpe pers com) 2.3.4.2. The setting of this asset, which lies outside of the WHS area is principally the area of the former North Downs Mine where a number of open shafts remain within land which was reverted to agricultural use during the 20th century, although parts have been developed since 2010 in connection with the expansion of a creamery to the east. The chimney is separated from the proposed development by the A30 dual carriageway, embanked at this point, and by the main rail line to Penzance. As such it is not considered likely that development of this site will have a meaningful effect on the appreciation of the heritage values of this structure. 3. Topography and Historic Characterisation By Adam Sharpe 3.1 This site (figure 1 Location), currently an area of rough ground, extends to approximately 450m2, is centred at SW 71626 43855 and is located immediately to the north of the A3047 linking Redruth and Truro via Chacewater. The main line railway through Cornwall runs a short distance to the north. The eastern outskirts of Redruth at Shallow Adit are 450m away. The small settlement of Scorrier to the east consists of groups of short rows of miners’ cottages to the north of the A3047, together with a cluster of buildings around the Gwennap road junction and the nearby public house. The route of the A3047 was created as part of the Truro turnpike network in 1754, mostly following a road which had existed in 1699 (HER MCO620139), but which was locally realigned to take the new route to the north of the parkland associated with Scorrier House. 3.2 Historically the site is bounded to the north by the ecclesiastical parish boundary between Gwennap to the south and Euny Redruth to the north, the boundary between the parishes following a hedge-line through the site, and shown as incorporating a line of boundary stones on the Gwennap Tithe Map (figure 2i) and OS 1st and 2nd Edition County Series surveys (1880 figure 2ii and 1908 – figure 2iii)

Statement Heritage : West of Texaco, Scorrier

3.3 The local topography is relatively level, occupying a dissected gently north-sloping wave-cut platform extending out to the coast; the site itself is at 125m OD. The site rises slightly from east to west, though its topography has been substantially modified by the presence of spoil dumps associated with the historic operation of its shafts. The underlying bedrock geology is predominantly the metamorphosed grey and grey-green slates with interbedded siltstones of the Mylor Formation, these overlying the north-east flank of the Carn Marth granite at depth. The zone of metamorphosis extends out from the granite contact to a short distance to the north of the A30, the lodes traversing this area often being rich in copper at shallow depths. The lode strikes are generally aligned east-north-east to west-south-west, though are crossed by a number of mineralised cross courses. 3.4 By the Historic Landscape Characterisation (Cornwall Council, 2011) the site is recorded as part of a substantial area of post-medieval enclosures extending from Blackwater westwards to the north of Redruth and Pool, these predominantly being associated with the development of miners’ smallholdings on former downland. However, the land to the north of this section of the A3047 is increasingly being developed to light commercial use; the plot immediately to the west of the site has been developed as a self-storage facility, whilst that to the east sites a filling station and food retail unit. The site itself has developed over the past 200 years into a small pocket of heathland, within which are stands of mature conifers, stunted oaks and other native trees, and areas of Rhodondenron ponticum. Evidence for 18th and early 19th century copper mining formerly dominated this tract of the Cornish landscape, but much of the surrounding area has reverted to agriculture since the abandonment of mining operations or has been developed for commercial or other uses. 4. Desk-based research By Adam Sharpe 4.1 The place name Scorrier was first recorded in 1337 and is thought to refer to the waste from smelting operations, suggesting that this area had been a site of early industrial activity. The placename Treskerby, referring to a farmstead to the south of the road, was first recorded as Treskerebig in 1394. The name may be composed of the Cornish words tre- (farmstead) plus an unknown suffix, or may represent a combination of the Cornish ros (heathland) + cribek (ridged), the name having acquired an intrusive initial ‘T’ as if it had originally been a tre- placename. 4.2 Treskerby Mine: The proposal site falls within the historic mining sett1 of Treskerby – an elongated early mining sett worked over a lengthy period, and including the early Wheal Derrick and eventually Wheal Chance and Park-an-Chy to the east and south-east respectively. The sett of this formerly important copper mine straddles the turnpike road from Redruth to Truro, the southern, larger section of the mine lying within the woodland forming part of the Scorrier Estate, the seat of

1 ‘Sett’ is the term used in Cornwall, Devon and the Isle of Man for a defined area within which mining rights were licenced to specific companies or individuals.

Statement Heritage : West of Texaco, Scorrier

the Williams family: local landowners and one of the most prominent mineral lords and mine promoters in Cornwall during the 18th and 19th centuries 4.3 Treskerby Mine is very poorly documented. Henderson (2018) suggests that this part of the mine might previously have been worked as Wheal Derrick. Treskerby Mine was adjoined by Wheal Boys to the west and Wheal Chance to the east. Hamilton Jenkin (1962, 29) claimed that this, along with its neighbours was one of the oldest mines in Cornwall, though gives no basis for this statement and does not provide any detail of the history of the mine. Whilst the mine might have been operational during the earlier decades of the 1700s, activity here seems to have intensified considerably during the boom in copper in Cornwall during the late 18th century, as it did at the neighbouring mines on North Downs to the north-east and at Great Wheal Busy near Chacewater. Treskerby seems to have weathered the threat from the development of massive deposits of copper on Parys Mountain on Anglesey during the last decades of the 18th century and in 1818 Thomas (1818) claimed that it was one of the largest mines in the Gwennap mining district at the time, employing 400 men, having been sunk to 128 fathoms from surface, and being equipped with two pumping engines, one of 50” cylinder diameter and one of 58” (Thomas 1818 quoted in Barton 1961, 51). Brown (in Johnson and Sharpe 1991) also noted that a whim engine was sited close to one of the mine’s shafts in 1817. 4.4 The mine was, during the late 18th century and the early decades of the 19th century, a significant producer of copper ore, which, from 1815, was exported to South Wales for smelting using a purpose-built branch of the Portreath Plateway – Cornwall’s first true railway. Dines (1956) notes that both Treskerby Mine and the neighbouring Wheal Chance had been significant producers of copper ore prior to 1800, and by 1828 had made a profit of £200,000 (around £12 million in today’s money), but in this year the neighbouring mines were amalgamated as Treskerby and Wheal Chance. This appears to have marked a significant decline in their fortunes, however, as pumping was immediately stopped and the lower levels of the mines allowed to flood (Collins 1912). It is perhaps not unsurprising that the combined operation closed in 1832. Treskerby and Wheal Chance were partially re-opened and de-watered in 1860, though no records of any production have been located, suggesting that this re-working was a failure. Dines (ibid) notes that 18,500 tons of copper were raised during a working undertaken between 1922-7, but it is unclear where within the enlarged sett the related operations were undertaken; the minerals are likely to have been recovered from dump recycling operations, probably from sites within the woodland to the south. C18th and early C19th Cornish copper mines 4.5 The surface areas of mines developed during this period in this area of Cornwall are characterised by relatively closely-set ventilation and access shafts located on or close to the outcrops of the predominantly east-north-east to west-south--west aligned lodes. Dines (1956) mentions eighteen principal shafts within the Treskerby sett, but archive maps show additional examples. It is likely that some of the early shafts had been abandoned by the early decades of the 19th century, work being concentrated at a smaller number of key locations. 4.6 The original close spacing of the shafts along the lode outcrops facilitated the working of relatively narrow, hand-worked extractive areas underground by separate small teams of miners,

Statement Heritage : West of Texaco, Scorrier

encouraging natural ventilation and providing a ready means of bringing minerals and spoil to surface. The substantial volumes of waste produced by these mines had necessarily to be disposed of within the leased area, and extensive spoil dumps typified the surface arrangements of early copper mines such as Treskerby, as is shown on the 1880 OS 25” mapping (figure 2ii). The partial or wholesale removal of this material from site for subsequent reprocessing for residual minerals, or for use as hardcore (particularly during the 20th century) has considerably modified the appearance of many abandoned copper mines, though in the case of this section of Treskerby the spoil appears to have remained almost wholly untouched and many parts of it now support a well-developed heathland flora. Where buildings had been constructed to serve such mining operations, the more substantial of these were almost always demolished and their stonework recycled for other uses soon after they became disused; almost all had disappeared from the landscape by the late 19th century, though their buried foundations may survive. 4.7 Recent excavations at a broadly contemporary copper mine at Hallenbeagle during the development of a business park (Sharpe and Thorpe 2014) have shown how complex the near- surface mine workings often were on early mining sites, whilst investigations at Wheal Chance not far to the east in 2007 (Sturgess 2007, Sharpe 2007) demonstrated how seemingly featureless sections of the landscape in this area can be underlain by the near-surface evidence for loosely- backfilled tunnels and shafts associated with both early phases of prospecting and primary exploitation along the strikes of local lodes, as well as features associated with later deep mining. 4.8 Engine houses were relatively rare structures within this part of the landscape given the early date at which the mines were in operation, though Treskerby is recorded as having two early medium- sized pumping engines and a whim engine, one of these possibly being located adjacent to Foxe’s Shaft in the south-western part of the site. Following the development of the Great County Adit – a hugely ambitious scheme promoted by John Williams of Scorrier from 1748 to assist in the drainage of mines in which he had interests - the formerly high costs of pumping their workings clear of groundwater utilising beam engines was greatly reduced, given that these relied on the import of large tonnages of coal from South Wales - a very considerable expense. This very extensive and pioneering adit drainage system eventually drained most of the Scorrier and Blackwater mines, those in Gwennap and Chacewater parishes and a number on the eastern outskirts of Redruth, Treskerby being connected to the system during the 1790s. At its peak of operation in 1839, 66 million litres of water were being discharged by the Great County Adit into the Carnon Stream at Twelveheads on a daily basis. 4.9 The success of copper mining within this area, though initially spectacularly successful and encouraging speculative mine developments across west central Cornwall, was relatively short- lived, and most smaller operations of this type did not survive the exploitation of a massive deposit of readily-accessible copper minerals at Parys Mountain on Anglesey during the 1780s and 1790s. This threat to the Cornish copper mining industry was short-lived, however, and spurred very considerable development in pumping technology within Cornwall, potentially making the operation of local mines far more economically viable. However the capital required to adopt these new technologies considerably increased operational costs, discouraging investment in small mines,

Statement Heritage : West of Texaco, Scorrier

or those with unproven potential, and many small copper mines operated during the 18th either closed for ever, or were only reworked as parts of much larger, heavily capitalised operations. Initially successful mining activities seem to have been curtailed by these factors during the third decade of the 19th century, and its subsequent history was unremarkable. Though the mine is recorded as having been re-tried in the 1860s, this venture was evidently a failure, whilst the recovery of copper minerals from the sett during the early 20th century probably reflects dump recovery from sites in the southern part of the sett. It is likely that no significant mining activity has been undertaken on the current proposal site since the second decade of the 19th century.

Historic map regression • 1843 Gwennap Tithe Award (figure 2i) mapping and apportionment shows three shafts on two lodes traversing the area, but no other detail. The course of the turnpike through the site is not clearly shown and it is likely that the route consisted of an unfenced ‘desire line’ or at most an unfenced track through the site at this time. • c1840 Euny Redruth Tithe Award mapping and apportionment -covers the triangular area to the north of the cross-site parish boundary; this lies outside the proposed development footprint. No mining or other features were depicted. • The 1880 OS 25” mapping (figure2ii) shows the ground to the south of the boundary wholly covered in spoil, and three hedged shafts on two lodes to the north of the road. The site is labelled as Treskerby Mine tin and copper disused. ‘Boundary Stones’ are shown along the parish boundary running along the northern edge of the site with a mereing given for the boundary as being 3ft from the southern ‘face of fence’ along its course. To the south of the road, still unfenced are further areas of spoil, scrub and some agricultural enclosures. • The 1908 OS 25” mapping (figure2iii) shows a site with similar appearance, though omits the central and eastern shaft and adds a roadside smithy just to the east of the end of the site at SW 71762 43886. To the south of the road, the landscape is much as described by the 1880 mapping. The parish boundary and its stones are described as in 1880. • A 1946 RAF vertical aerial photograph (held by Cornwall Council ref CO5 3069, RAF ref: 106G/UK 1663 12 July 46//F/20”//541 SQDN, negative no 3069) (figure 3i) shows three hedged shafts within the site, as well the evidence for at least one additional shaft and what appears to be a small engine pond at the eastern end of the site. To south of the road it is clear that deliberate reclamation of the land has been undertaken, with young plantations clearly visible across areas both areas previously shown as spoil and within former agricultural enclosures. These woodlands form an essentially ornamental extension to the parklands of NHLE 1162430 Scorrier House (GII Listed) lying 816m ESE of the site. • The 1971 1:2500 National Grid survey (figure 3ii) depicts much of the site as rough ground with some scrub, with a rectangular area of some coniferous trees shown centrally. The northern parish boundary is no longer depicted as marked by boundary stones, and its 3ft mereing is now given metrically (0.91m) and related to a root of hedge rather than face of fence perhaps

Statement Heritage : West of Texaco, Scorrier

indicating a change of boundary fabric since 1908. The wooded cover shown on the mid 1940s maps and mostly continuing today to the south of the site continued to be mapped by the OS. • 2003 ‘Landline’ 1:1250 digital OS data (figure 3iii) shows very little detail within the site, however this should not be taken as absence of vegetative cover as 2000 and 2005 aerial photography shared via the Cornwall Council interactive mapping portal shows an area overgrown with scrub and some mature trees, and as a result there is no visible evidence on this source for any mine shafts, spoil dumps or mine structures.

5. Site Inspection 5.1 The site was visited on behalf of Statement Heritage on the morning of 30th November 2020 by Adam Sharpe BA(hons) MCIfA. The weather was overcast. The main impediment to survey consisted of large stands of dense Rhododendron ponticum in some areas of the site, predominantly towards its eastern end and near its centre. Additional site visits to check the potential for setting impacts were made to nearby areas of Scorrier Wood and the Listed arsenic calciner, labyrinth and chimney it contains, to the former Radnor Chapel to the north-east, to a publicly accessible location near the Listed chimney 450m away on North Downs, and to the Scheduled Wheal Peevor complex 875m to the north-west. 5.2 General description: This partly ‘scrubbed in’ site currently preserves a small fragment of the formerly extensive 18th and early 19th century mining landscape focussed within this and neighbouring parishes. Locally, until the mid-20th century, this formed an almost unbroken band of mine workings and spoil dumps extending from Shallow Adit Farm in the west to Scorrier Crossroads to the east. The majority of the remainder of this early copper mining landscape has long ago been returned to agricultural use, built over during the 19th and 20th century expansion of former miners’ settlements or, in recent years, been adapted to site commercial or light industrial activities through shaft capping, the removal of residual mine waste and landscaping. Some of these processes can be seen to have applied to the site under investigation – in particular the backfilling of some of its mine shafts and the partial removal of spoil dumps, but otherwise this small site has remained largely unchanged since mining here was abandoned nearly two centuries ago. 5.3 Most of the site (figure 5) is covered with a layer of thinly vegetated mine spoil. The spoil dumps associated with discrete mine shafts rise up to 4m above the general site levels and against the northern boundary of the site the spoil can be seen to be around 1.5m above the pre-existing ground levels. The spoil is vegetated with, in places, dense bramble scrub at the western end of the site and with impenetrable Rhododendron ponticum in parts of the central and eastern parts of the site, but the majority of the ground cover consists of heathers and lichens. Between 1948 and 1971 (RAF / OS evidence) a substantial number of mature pine trees have been planted within the central part of the site; these have an understorey of stunted oaks, hawthorns and other native tree species. The site boundary is defined to the west by galvanised steel security fencing around the

Statement Heritage : West of Texaco, Scorrier

edge of the self-storage operation, and to the east by a 2m high timber panel fence between it and the Texaco garage. To the south it is adjoined by a footway flanking the A3047. 5.4 Dines (1956) notes that the abandoned Mine Plans relating to the operations of Treskerby Mine date to 1818 and are ‘difficult to interpret’, ten lodes having been worked within the extensive sett. Some of these are named: from north to south these being North, Old South, South, Harvey’s, Williams’, Williams’ South, Teagues, Water, Moyle’s and Roskrow’s. The plans and sections apparently record exploitation down to a maximum of 150 fathoms (approximately 300m) from surface, though the majority of the recorded exploitation seems to have been from relatively shallow levels. Some of the shafts shown on the archive OS mapping are not shown on these plans and a correlation between the shafts shown on archive plans and sections and those recorded by the Ordnance Survey is difficult. The only shaft within the site under investigation which can be identified with any degree of certainty is Foxe’s Shaft in the south-western corner of the site (Cole 1999). It has been speculated (Brown in Johnson and Sharpe 1999) that this might have sited one of Treskerby’s three early beam engines. 5.5 The following specific sites are identified on figure 4 5.6 Shaft 1 – Foxe’s Shaft SW7159243820 (Figure 6i) - nb CSHER ref MCO55035 5.7 Foxe’s Shaft in the south-western corner of the site was shown on the circa 1840 Gwennap Tithe Map, the circa 1878 OS 1st Edition 25” and the circa 1908 2nd Edition OS mapping (all figure 2). It is recorded as having been capped in 2000 under Kerrier District Council’s Contract 13 Shaft Capping Programme (source HER reference MCO55035). However the site conditions suggest that this work was never undertaken, the shaft being surrounded by a 1.25m high, 3.25m wide Cornish hedge backed up with three strands of barbed wire on rotting timber posts. The shaft is choked near surface (possibly with rubbish dumped into it from the roadside) and its interior is overgrown with Buddleia. The shaft is associated with a very extensive vegetated spoil dump on its northern side, this stretching most of the way to the northern site boundary; to the north of the shaft it rises to a maximum of 4m and has been planted with pines. 5.8 Shaft 2 SW7163043835. (figure 6ii) This shaft is documented on the circa 1878 OS 25” mapping as having been sited 36m to the east of Foxe’s Shaft on the outcrop of the southern lode running through the site, and immediately to the north of the nearby highway. Visible and It was not shown on the circa 1908 OS 25” mapping (figure 2iii), but was clearly open in 1946 (RAF AP evidence figure 3i) and is still marked by a substantial spoil dump up to 4m high, there is now no indication of a central hollow. It seems likely that the shaft has been backfilled to surface with rubbish rather than having been formally capped. 5.9 Shaft 3 SW7169843855 This shaft was documented in the south-eastern corner of the site on the circa 1840 Gwennap Tithe Map and the circa 1878 1st Edition OS 25” mapping, but not on the circa 1908 OS 25” mapping. This area is almost completely level heathland, with no indications of a shaft or its spoil dump, and it seems likely that the shaft was capped or backfilled between 1880 and 1908, though to what standard is unknown. 5.10 Shaft 4 SW7162143876

Statement Heritage : West of Texaco, Scorrier

5.11 This shaft was documented on the circa 1840 Gwennap Tithe map (figure 2i) and the circa 1878 OS 25” mapping (figure 2ii), though not on the equivalent 1908 mapping (figure 2iii), but was clearly shown on the 1946 RAF aerial photograph (figure 3i), though had the appearance of no longer being open at this date. The area in which it is sited is covered by dense Rhododendron ponticum and as a result its documented site was not safely accessible. 5.12 Shaft 5 SW7158543871 5.13 This shaft was not documented on any edition of the OS 25” mapping, though is visible on the 1946 RAF aerial photograph (figure 3i) of the site close to the northern boundary. Its shaft safety hedge appears to have been damaged on this photograph and there are indications of disturbance in the area surrounding it, so It seems probable that the shaft was being backfilled at the time. An overgrown discrete spoil mound 18m in diameter and up to 2m high with a choked central hollow sited to the north-east of Foxe’s Shaft over the outcrop of the northern lode is assumed to represent this shaft site. 5.14 Possible reservoir SW 71663 43891 5.15 The aerial photograph taken by the RAF in 1946 (figure 3i) showed a rectangular feature measuring approximately 24m N-S x 12m E-W located in the north-eastern corner of the site. From its form this is assumed to have been a small mine reservoir, probably one created to provide a water supply for a beam-engine’s boiler. This feature is not depicted on any of the archive maps consulted. It is a considerable distance (approximately 90m) from Foxe’s Shaft, the most likely of the shafts on this part of the mine site to have been served by a beam engine. Given the dense scrub cover within this area of the site it did not prove possible to determine whether this feature survives, though given that the north-eastern part of the site does not seem to have been significantly disturbed since 1946, this would seem to be likely. 5.16 Parish boundary bank and documented boundary stones SW 71534 43858 to SW 71692 43926 (figure 6iii). The proposed development site is defined along its northern edge by a Cornish hedge which corresponds to the former boundary between the ecclesiastical parishes of Gwennap (to the south) and Euny-Redruth (to the north). The 1st and 2nd Editions of the Ordnance Survey 25” to a mile mapping (dating to circa 1878 and 1908 figure 2) show this to have been accompanied by a number of boundary stones, within this project area these being located at SW 71548 43863, SW 71581 43875, SW 71634 43890 and SW 71676 43916. These boundary stones are not shown on mid and late 20th century mapping. Post 1907 maps (figure 3) also show a change in the mereing reference from ‘FF’ (face of fence) to ‘RH’ (root of hedge) which may or may not indicate a change in the boundary fabric from which the boundary was measured2. The distance between the feature and the boundary location was 3ft (0.91m) throughout 5.17 Owing to vegetation conditions the boundary could only be accessed at a couple of points near its centre (figure 6iii), though it appears to survive along the whole of the northern boundary of the site. Where it was best accessible and capable of being recorded it measured 1.5m high and

-2 For more information on the ‘mereing’ determining the official location of administrative boundaries (generally a theoretical position offset from a fixed feature) and their depiction on OS maps see Oliver 2013, 78-79.

Statement Heritage : West of Texaco, Scorrier

1.25m wide, and was accompanied by a ditch 0.75m deep and 1.3m wide on its southern side. No boundary stones were noted, but these are likely to survive, though currently obscured by scrub vegetation. In another area immediately to the east, spoil deriving from mining activity to the south extended up to the hedge, reducing its height above ground level to only 0.3m, though to the north where mining had not taken place the hedge face was 1.75m high. 5.18 Additional possible shaft sites (not shown on plan) The spacing between 18th century mine shafts sunk during the early stages of exploitation of Cornwall’s copper lodes has frequently been found to average around 35m (approximately 15 fathoms). If this is also the case on this site then there may be a wholly undocumented shaft at about SW 71669 43849 between Shafts 2 and 3, one near SW 71672 43901 in the north-eastern corner of the site and one near SW 71547 43859 in the north-western corner of the site, where the 1946 RAF aerial photograph shows an indistinct circular shape of equivalent size to the other nearby hedged shafts on the site. 5.19 Views out of the site to the south (figure 7ii) towards significant locations within Area 5 of the Cornish Mining World Heritage Site are entirely blocked by the mature woodland occupying the northern part of the Scorrier Estate. This woodland also blocks all views of other sites recorded within the 1km search zone in the Cornwall and Scilly Historic Environment Record that lie within this direction. 5.20 Views out to the west of the site (figure 5i) are currently obscured by scrub and tree vegetation and by the gently rising ground intervening between the site and the self-storage unit operation immediately to the west and the north-west of the site and the barrier fencing around the western, northern and eastern boundaries of this undertaking. 5.21 Views out from the site to the east (figure 7ii) are dominated by the Texaco filling station and the Oven Door food retail building and the barrier fencing along the western boundary of the filling station. Give the scale of these buildings, no views are available of sites documented in the HER further to the east. 5.22 Views out from the site to the north (figure 7i) are partially open, though currently substantially constrained by scrub vegetation Some glimpses of the landscape to the north are available, though the local topography, coupled with mature vegetation within these views (for instance that flanking the line of the railway), tends to significantly constrain the potential for intervisibility with recorded heritage assets within this part of the 1km search zone. The area of the landscape immediately to the north of the main line railway is already occupied by buildings occupied by commercial, industrial and other businesses, including the CORMAC depot. 5.23 In summary, views out from the site are currently significantly limited by the scrub and mature trees which currently cover almost the whole of the potential application area. If some or all of this vegetation were to be cut back some views would be opened up from within it, particularly to the north, potentially establishing some degree of intervisibility with sites such as the 19th century Radnor Non-conformist chapel (MCO330136), the Scheduled Wheal Peevor mining complex (MCO13074) and the Grade II Listed chimney on North Downs (MCO1161923). All of these sites are a considerable distance from the proposed development site, however, and thus would form only very minor elements within views from it.

Statement Heritage : West of Texaco, Scorrier

5.24 Views into the site from the WHS (figure 7iv) are currently significantly constrained by the scrub vegetation and mature trees which cover it. Should the site be developed this is likely to change, though this could be remediated to some degree by the retention of some of the site’s mature trees, and/or by new planting to provide a degree of screening from sensitive vectors. 5.25 Given the local topography, the flat viewing angles characterising the surrounding landscape and the existing mature vegetation within all views into or out of the site, coupled with the locations and nature of the recorded heritage assets within the 1km search zone, intervisibility between the site and potentially sensitive heritage assets is currently either wholly blocked or very partial, and is likely to remain so. 6. Statement of Significance By Statement Heritage 6.1 Outstanding Universal Value. ‘The Cornwall and West Devon Mining Landscape World Heritage Site’ was inscribed by UNESCO in 2006. The designation recognises the landscape that was ‘transformed during the period 1700-1914 by early industrial development that made a key contribution to the evolution of an industrialised economy and society in the United Kingdom, and throughout the world. Its outstanding survival, in a coherent series of distinctive cultural landscapes, is testimony to this achievement’ (Cornwall Council , 2012). Landscapes included within the site are recognised as being expressed via 6 landscape components or attributes physically expressing the ‘Outstanding Universal Value’ of the site. These include • Mine sites, including ore dressing sites • Mine transport (including maritime and terrestrial sites) • Ancillary industries (e.g. foundries, explosive, chemical works) • Mining settlements and social infrastructure (including the houses, public buildings and religious buildings of miners) • Mineworkers smallholdings • Great houses, estates and gardens • Mineralogical and other related scientific sites 6.2 This site lay within the area of Treskerby Mine the principal operation of which was through the 18th century until 1832, with two later working periods recorded the latter of which the above research suggests most likely involved the reworking of spoil in the currently wooded area of the mine to the south of the road. 6.3 The proposed development site lies outside the boundary of the inscribed WHS property, although it is directly adjacent to it. Consequently it is the degree to which the proposal site contributes to the ‘setting’ of the WHS is a relevant consideration here. 6.4 ‘Setting’ is described by the NPPF as “"The surroundings in which a heritage asset is experienced. Its extent is not fixed and may change as the asset and its surroundings evolve. Elements of a setting may make a positive or negative contribution to the significance of an asset, may affect the ability to appreciate that significance or may be neutral.”.

Statement Heritage : West of Texaco, Scorrier

6.5 The WHS significance of that area of Treskerby Mine within the WHS lies in its history as a mine site attribute of OUV. The site, now well wooded, likely a de facto extension of the park and woodlands around Scorrier House (GII Listed) are not of themselves of OUV, post-dating as they do the ‘period of interest’ (1700-1914 identified within the Statement of Significance for the site. Features most illustrative of the OUV of the site here include two surviving shafts recorded on the CSHER (MCO55037; MCO55037) and the Listed calciner (NHLE1253199). None of these features are legible from the road between the proposal site and the area of the mine included within the WHS. 6.6 Views from and two the area within the WHS have been shown by our fieldwork to be heavily constrained by the woodlands within the WHS area. As such the proposal site is considered not to make a visual contribution to the setting of those remains within it of OUV. 6.7 Setting impacts have also been considered in regards of designated sites to the north and north west of the proposal site including the Listed (GII) chimney at North Downs (NHLE1161923) and the listed, WHS and scheduled components of the Wheel Peevor site. The significance of these sites is considered to be best understood within the context of their immediate (100-200m) surroundings. Landscape relationships with the current proposal site are already substantially impacted by the interventions of the A30, the main line to Penzance and by the established industrial developments around the proposal site. As such the proposal site is assessed to lie outside the settings of these assets. 6.8 Values of the site in terms of ‘non-deisgnated heritage assets’: The historic, architectural and archaeological values of the proposal site should in our view be treated by the planning process as subject to policies within the NPPF and Local Plan relevant to non designated heritage assets. 6.9 Historically the site lies within the wider, non-designated Treskerby Mine sett. According to Hamilton Jenkin this was the site of ancient (pre1700) mining activity, although documentary evidence is scant. What can be said with certainty is that the mine was a significant one by 1818 when it was claimed as one of the largest copper mines in the Gwennap district, employed 400 men and was equipped with at least two engines before its closure in 1838. 6.10 Architecturally the mining sett here was defined by the traditional parish boundary between Redruth and Gwennap, still represented by a very overgrown Cornish hedge forming the north boundary of the site today, and by a set of boundary stones (probably low granite posts) shown on late 19th and early 20th century mapping – the survival of which is currently unknown. These currently undated features, where surviving, are of local architectural and historic importance in their illustration of a historic parish boundary. No buildings related to the mining use of the site survive here, although the circular and sub-circular structures around the surviving shafts are of 19th century date and locally distinctive ‘Cornish hedge’ construction. As such they are of local architectural and historic importance. The architectural value of all the historic structures of the site is currently concealed, obscured and likely put at structural risk of decay by invasive scrub vegetation. 6.11 Archaeologically: The spacing of the documented mine shafts on the two lodes traversing the site is typical of those sunk during the development of copper mines in Cornwall during the 18th century at an average of 35m (15 fathoms). Given that indications of one undocumented shaft

Statement Heritage : West of Texaco, Scorrier

were found in the north-western part of the site, it is considered that there is the potential for additional undocumented shafts to exist on the outcrops of both lodes traversing the site at approximately these spacings, as noted above. The spoil covering the site may also conceal evidence for early leats and for features associated with the primary stage of prospection for the lodes traversing the site. 6.12 On the basis of the scale of the spoil dump associated with Foxe’s Shaft and the information accessed by the late Kenneth Brown, it has been speculated that this site might have been the location of one of Treskerby’s three documented early beam engines (KB ref’s 515-516, 518, Johnson and Sharpe 1991) recorded between 1817 and 1828. No traces of wall footings close to the shaft were found during the site visit, but these could easily have been obscured by scrub vegetation, or might have been partly or wholly removed during the excavation of material to create the safety hedge encircling the shaft following its disuse. Future safety works to secure this shaft have the potential to reveal any surviving foundations of an early beam engine house at this location. 6.13 Treskerby Mine probably also sited a number of small, short-lived buildings constructed by its miners for use as shelters or stores. Whilst their roofing materials, doors, etc. would have been recovered when they went out of use, what remained of the buildings might have become buried in mine spoil as this material accumulated on site. Any future removal of mine waste from the site has the potential to re-expose these very little recorded early mine buildings. 6.14 The evidence suggests that there is a potential throughout the site for archaeological remains of shallow mining predating the mid 19th century. These remains have the potential to be of local to regional archaeological importance. 7. Policy Requirements. 7.1 National Planning Policy in regards of the historic environment states that heritage assets are an irreplaceable resource, and should be conserved in a manner appropriate to their significance, so that they can be enjoyed for their contribution to the quality of life of existing and future generations (NPPF P184) 7.2 In determining applications LPAs are instructed to take account of: a) The desirability of sustaining and enhancing the significance of heritage assets and putting them to viable uses consistent with their conservation b) The positive contribution that conservation of heritage assets can make to sustainable communities including their economic vitality; and c) The desirability of new development making a positive contribution to local character and distinctiveness. 7.3 P193 of the NPPF states that When considering the impact of a proposed development on the significance of a designated heritage asset, great weight should be given to the asset’s conservation (and the more important the asset the greater the weight to be). This is irrespective of whether any

Statement Heritage : West of Texaco, Scorrier

potential harm3 amounts to substantial harm, total loss or less than substantial harm to its significance. 7.4 In respect of the identification of harm to OUV the NPPF states: Not all elements of a … World Heritage Site will necessarily contribute to its significance. Loss of a building (or other element) which makes a positive contribution to the significance of a World Heritage Site should be treated either as substantial harm… or less than substantial harm…, as appropriate, taking into account the relative significance of the element affected and its contribution to the significance of the … World Heritage Site as a whole. 4 (NPPF P201) 7.5 Cases of less than substantial harm are dealt with according to P196 of the Framework. This states Where a development proposal will lead to less than substantial harm to the significance of a designated heritage asset, this harm should be weighed against the public benefits of the proposal… 7.6 P197 of the Framework deals with non-designated heritage assets, stating, The effects of applications on the significance of a non-designated heritage asset should be taken into account in determining the application. In weighing applications that directly or indirectly affect non- designated heritage assets, a balanced judgement will be required having regard to the scale of any harm or loss and the significance of the heritage asset. 7.7 P199 of the Framework requires that Local Planning Authorities should require developers to record and advance understanding of the significance of any heritage assets to be lost (wholly or in part) in a manner proportionate to their importance and the impact. However, the ability to record evidence of our past should not be a factor in deciding whether such loss should be permitted. 7.8 The Cornwall Local Plan (policy 24) requires that ‘Development within the World Heritage Site and its setting should accord with the WHS Management Plan. Proposals that would result in harm to the authenticity and integrity of the Outstanding Universal Value, should be wholly exceptional. If the impact of the proposal is neutral, either on the significance or setting, then opportunities to enhance or better reveal their significance should be taken.’ 7.9 Policy 24 requires that assessments identify the significance of all assets that would be affected by the proposals and the nature and degree of any effects, and demonstrating how, in order of preference, any harm will; be avoided, minimised or mitigated. 7.10 Policy 24 goes on to state that Any harm … must be justified. Proposals causing harm will be weighed against the substantial public, not private, benefits of the proposal and whether it has been demonstrated that all reasonable efforts have been made to sustain the existing use, find new uses, or mitigate the extent of the harm and the significance of the asset; and whether the works proposed are the minimum required to secure the long term use of the asset. 7.11 Relevant policies within the WHS Management Plan include • C2: New development should add to the quality and distinctiveness of the Site by being of high- quality design and respectful of setting.

3 The significance of heritage assets lies both in the assets themselves and in the degree to which their setting relates to and reveals those values 4 [edits relate to Conservation Areas not relevant to this case]

Statement Heritage : West of Texaco, Scorrier

• C7: The historic character and distinctiveness of the Cornwall and West Devon mining landscape should be maintained. • C8: Traditional materials and skills should be encouraged in the maintenance of the authentic historic fabric within the site. • PN2: The World Heritage Site should be interpreted as a distinctive, evolving, living landscape.

8. Impact Assessment 8.1 This assessment was prepared at pre-application stage. At present we have not been provided with detailed proposals to assess and understand a variety of options for light industrial and commercial development of the site are under consideration. 8.2 The heritage values of the site identified within the Statement of Significance section lie in the remains of its northern boundary, a traditional Cornish hedge which follows the historic parish boundary, and in the illustration of its history as part of the Treskerby Mine (tin and copper) active in the 18th and 19th centuries through in situ mining spoil across the site and through a number of extant but probably choked mine shafts and their surrounding protective Cornish hedges. These heritage values should in our assessment be treated by the LPA as non designated heritage assets. 8.3 Any degree to which these features contributes to the setting of the World Heritage Site area to the immediate south, particularly the now wooded bulk of the Treskerby Mine Site has been largely lost by the degree to which the character of the site has been transformed in the 20th century by surrounding built development, deliberate tree planting and scrub regeneration. 8.4 As such this assessment finds no in principal reason why the proposed types of development should not be acceptable in heritage policy terms within the site, provided that the LPA finds sufficient public benefit in such development so as to provide appropriate balance to any harm to non- designated heritage assets that may prove necessary. 8.5 In planning such development we would note the strong emphases within the Cornwall Local Plan in regards to any harm to all heritage assets regardless of designation. Harm should only take place when it is clearly justified as necessary, with mitigation of impacts where possible and reasonable to ensure harm is in order of preference…. Avoided, minimised or mitigated. 8.6 Recommendations: • Plans should, if possible seek to avoid impacts to Shaft 1 (Foxe’s Shaft) and to the Boundary Bank and any surviving Boundary Stone’s retaining these features in situ, repairing and rebuilding as required any Cornish hedge features. Capping, ideally retaining access to any shaft opening, may be considered to Foxe’s Shaft. This will better reveal the significance of these features. • A ‘written scheme of investigation’ should be prepared to support any planning application setting out a programme of archaeological works designed to mitigate impacts to other features during the preparation of ground and remediation of any shallow mining features. Ideally recording should take place in a staged manner alongside various stages of site works, including vegetation clearance, geotechnical site investigation, landscaping and site

Statement Heritage : West of Texaco, Scorrier

remediation – with the results of each archaeological monitoring event informing the revision of the overall mitigation design. Statement Heritage would be delighted to advise further as proposals for the site develop. A well designed and supported programme of archaeological work will have the potential to minimise impacts (for instance where needless harm to features can be avoided through foundation or landscaping design) or to mitigate the loss of features where destruction is unavoidable. 9. Conclusions 9.1 This assessment has, through desk and field-based observations drawn out a better understanding of the history of the site proposed for development and advanced understanding of its significance in relation to the wider Treskerby Mine site and the history of metalliferous mining in Cornwall. 9.2 Our aim has been to provide a proportionate evidence base on which the client may develop proposals in conformity with local and national planning policy relating to the historic environment. 9.3 We have shown that the site consists of a relict section, essentially abandoned since at least the early 20th century, of the former Treskerby Mine. The site has been reclaimed by natural regeneration of scrub vegetation, although some limited tree planting may have also taken place. 9.4 The site contributes very little if anything to the ‘setting’ of the adjacent parts of Treskerby Mine within the World Heritage Site due to the degree of tree planting on that site since the early 20th century, during which it has become a de facto extension to the grounds of Scorrier House. 9.5 Nevertheless the proposal site is likely to retain archaeological evidence, which unlike many similar sites, is likely to have been little impacted by secondary working of spoil deposits in the 20th century. Remains are considered likely to survive here of shallow 18th century workings, which have potential to increase our knowledge of the techniques involved in such mining in Cornwall. These remains are a material consideration under planning policy requiring a balance to be struck between their significance (including their archaeological potential) and the public benefits of the redevelopment of their site. As the remains lie beyond the boundary of the WHS property and are not considered to make a meaningful contribution to its setting the ‘great weight’ accorded by the NPPF to the conservation of designated heritage assets does not apply. 9.6 Local planning policy requires that harm to non-designated heritage assets is carefully taken account of in the design of proposals, with reasonable efforts made to avoid, minimise and mitigate their damage. We have made recommendations above as to how each of these objectives should be pursued in this case.

Statement Heritage : West of Texaco, Scorrier

10. Bibliography

Databases Historic England 2020 National Heritage List for England (database) available at https://historicengland.org.uk/listing/the-list/ (accessed December 2020) Cornwall Council 2020 Cornwall and Scilly Historic Environment Record (database) available via https://map.cornwall.gov.uk/website/ccmap/ (accessed December 2020)

Bibliographic Sources

Barton, D.B 1961. A history of copper mining in Cornwall and Devon, Truro, Bradford Barton

Cornwall Council . (2012). Cornwall and West Devon Mining Landscape World Heritage Site. Truro: Cornwall Council.

Cornwall Council. (2011). Historic Landscape Characterisation Texts. Retrieved June 2, 2020, from Archaeology Data Service: https://archaeologydataservice.ac.uk/archiveDS/archiveDownload?t=arch-1641- 1/dissemination/pdf/Cornwall_Historic_Landscape_Character_Types_texts.pdf

Cornwall Council. (2016). Cornwall Local Plan. Truro: Cornwall Council.

Cornwall Council. (2020). Cornwall and Scilly Historic Environment Record. Retrieved August 2020, from https://www.cornwall.gov.uk/environment-and-planning/strategic-historic-environment- service/cornwall-and-scilly-historic-environment-record/

Cole, R. 1999 Shaft Capping, Contract 13: archaeological assessment, CAU report 1999R015 [unpublished client report]

Dines, H.G. 1956 The Metalliferous Mining Region of South-West England, HMSO

Gover J.E.B. 1948 The Place Names of Cornwall.

Hamilton Jenkin A.K. 1962 Mines and Miners of Cornwall Vol III: Around Redruth. Truro

Hamilton Jenkin A.K. 1963 Mines and Miners of Cornwall Vol VI: Around Gwennap. Truro

Henderson Mines Research 2018. Mining Search Report, Plot at Scorrier Rd TR16 5AW Report ref A131218MB

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Herring, P. (1998). Cornwall's Historic Landscape: Presenting a method of historic landscape characterisation. Truro: Cornwall County Council in associtation with English Heritage.

Historic England. (2015). Good Practice Advice Note 2: Managing Significance in Decision Taking in the Historic Environment. Swindon: Historic England.

Historic England. (2016). Making Changes to Heritage Assets: Historic England Advice Note 2. Swindon: Historic England.

Johnson, N.D. and Sharpe, A 1991 Minteral Tramways Project Engine House Assessment, CAU

Sharpe, A 2007 Scorrier WTS/HRP, Scorrier, Redruth, Cornwall: Archaeological watching brief during investigative trenching, Historic Environment Projects rep 2007R083

Sharpe, A and Thorpe, C. 2014 Hallenbeagle, Phases 1 and 2, Scorrier, Cornwall, CAU 2014R09084

Sturgess, J. 2007 Scorrier WTS/HRP Project, Cornwall: archaeological assessment, Historic Environment Projects rep 2007R004

Thomas, R 1818 A report on a survey of the mining district from Chacewater to Camborne.

LUC. (2016). Cornwall and West Devon Mining Landscape World Heritage Site. Truro: Cornwall Council .

MHCLG. (2019). National Planning Policy Framework. London: Ministry of Housing Communities and Local Government. Retrieved from https://www.gov.uk/government/publications/national-planning- policy-framework--2

STATEMENT HERITAGE, 8 PAR LANE, PL24 2DN WWW.STATEMENT-HERITAGE.COM 01726 339217

Statement Heritage : West of Texaco, Scorrier