Statement Heritage Poultry houses at, Nanturras, Goldsithney, Penzance, TR20 9HE Heritage Impact Assessment within a World Heritage Site: SH Ref NANT0121 16/02/2021 v2 STATEMENT HERITAGE, 8 PAR LANE, PL24 2DN WWW.STATEMENT-HERITAGE.COM 01726 339217 Statement Heritage : WAYF0919 Wayferers, Relubbas Lane, St Hilary, Penzance, TR20 9EF All content © Statement Heritage unless stated otherwise. This statement was prepared by Adam Sharpe MA MCIfA and edited by Daniel Ratcliffe MA MCIfA – responsibility for errors lies with Statement Heritage The views and recommendations expressed in this report are 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. 2 Statement Heritage : WAYF0919 Wayferers, Relubbas Lane, St Hilary, Penzance, TR20 9EF Executive Summary This assessment examines the impacts on historic environment assets of proposals to replace existing poultry houses at Nanturras near Goldsithney, with ‘beehive units’ for commercial and light industrial use. The site lies within Area 3 of the Cornish Mining World Heritage Site but not close to any other designated heritage assets. The key issue in terms of historic environment planning policies is therefore identified as the effects of the proposed development on the significance (Outstanding Universal Value in UNESCO parlance) of the World Heritage Site – lying in the degree to which it helps to illustrate the distinctive mining landscapes of the period 1700-1914. The site lay historically within a common grazing area known as Perran Downs. A record on the Tithe Award suggests ‘burrows destroyed by mining’ lay to the immediate east of the site. These may have been Bronze Age barrows, or potentially early mining spoilheaps as the word is used in Cornish dialect for both kinds of earthworks. The assessment identifies the creation of enclosures within which the proposal is located, and the track which will provide access to the development as being laid out between 1748 and 1840. By 1840 the enclosure pattern was one of small straight sided enclosures, dispersed homestead cottages, with row housing predominating in Goldsithney itself. To the immediate east of the site was West Nanturras Mine which produced tin. Spoilheaps and shafts were also mapped to the north west of the site. Nanturras Mine was out of use (with the exception of some small scale, little documented re-working in the early 20th century) by 1878. The current poultry units were in place by 1972 and are considered of likely mid 20th century date. They are of no heritage value. The laying out of concrete hard standings across the site may have impacted any surviving earlier archaeological remains. The boundaries of the site are identified as having some residual OUV, however the site is well screened, whilst the surrounding historic landscape much altered by 20th century change. As such the potential development is not considered likely to harm the OUV of the World Heritage Site and as such heritage policies should not present an obstacle for development assuming existing boundaries are maintained 3 Statement Heritage : WAYF0919 Wayferers, Relubbas Lane, St Hilary, Penzance, TR20 9EF Contents Executive Summary .......................................................................................................................................3 1. Introduction. .....................................................................................................................................5 2. Historic Background. .........................................................................................................................6 3. Statement of Significance (including assessment of the contribution of the site to OUV) ........... 12 4 Policy Requirements. ..................................................................................................................... 13 5 Impact Assessment, Mitigation Recommendations and Conclusion. ............................................ 14 6 Bibliography ................................................................................................................................... 16 4 Statement Heritage : WAYF0919 Wayferers, Relubbas Lane, St Hilary, Penzance, TR20 9EF 1. Introduction. 1.1. This report has been commissioned by the client to meet the requirement of the Local Planning Authority (acting on the advice of the Cornish Mining World Heritage Site Management Team) for a proportionate heritage impact assessment to accompany an application for development within the World Heritage Site (hereafter WHS). 1.2. It is understood the proposals will involve the demolition of existing 20th-century poultry units and construction of ‘beehive units’ for commercial use. 1.3. Applications with the potential to affect the ‘Outstanding Universal Value’ of the WHS, as defined in the Management Plan for the site (Cornwall Council 2012) fall subject to the requirements of the NPPF (P189) and Cornwall Local Plan (P24) which require expert but proportionate assessment of the significance of heritage assets and their settings affected by proposed development and the impacts on that significance of such development. 1.4. This assessment, the overall methodology of which is informed by Cornwall Council’s adopted Supplementary Planning Document for the WHS (Cornwall Council 2017), and by Historic England’s best practice note Making Changes to Heritage Assets (2017a) 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 at hand. • Describe and assess the results of our own photographic and desk-based assessment1 of the site, which follows the approaches set out within Historic England’s Setting of Heritage Assets (2016) and Understanding Historic Buildings (2017b) guidance documents. Field assessment has been informed by the results of online consultation of data provided by the Cornwall and Scilly Historic Environment Record via the Cornwall Interactive Mapping. • Describe the significance of any assets affected. • Consider the impacts to the significance of the assets affected according to the relevant policy principles. 1 Due to being carried out during the third national lockdown of the 2020-2021 Covid 19 pandemic photography for this project was supplied by client. 5 Statement Heritage : WAYF0919 Wayferers, Relubbas Lane, St Hilary, Penzance, TR20 9EF 2. Historic Background. Designations. 2.0 The site (see figure 1) lies within Area 3 Tregonning and Gwinear Mining District of the Cornwall and West Devon Mining Landscape World Heritage Site. The site, inscribed in 2006, is described by UNESCO within its overarching statement of significance as comprising ‘the most authentic and historically important components of the Cornwall and west Devon mining landscape dating principally from 1700 to 1914, the period during which the most significant industrial and social impacts occurred. The ten areas of the Site together form a unified, coherent cultural landscape and share a common identity as part of the overall exploitation of metalliferous minerals here from the eighteenth to twentieth centuries’2 2.1 Desk-based appraisal using data from the National Heritage List for England (NHLE) indicates that no Listed Buildings, Scheduled Monuments or other designated heritage assets will have a significant visual relationship with the proposed development. Description of Site. 2.2 The proposed development site (figure 1 and 2) is currently occupied by three disused timber framed and clad single storey poultry houses with corrugated galvanised iron roof coverings surrounded by hard standing. 2.3 Geologically The underlying bedrock geology consists of hornfelsed slates and siltstones of the Devonian Mylor Slate Formation (BGS 2021), these having been metamorphosed through the emplacement of the Tregonning Hill granite which outcrops 5km to the east; the British Geological Survey Geology of Britain online mapping records the junction formed this bedrock and the un- metamorphosed slates and siltstones of the Mylor Series as lying immediately to the west of the site. Metamorphic processes also saw the emplacement of sub-vertical mineralised lode structures carrying tin and copper on generally east-north-east to west-south-west strikes (note however that mapped information shows that locally, many significant lode strikes were aligned east-south-east to west-north-west, including those worked n West Trevelyan and East Trevelyan). The landscape is also traversed by a number of broadly parallel elvan dykes of Permian date – some of these are also noted as being mineralised. 2.4 Topographically, Nanturras Poultry Farm is located between the settlements of Goldsithney and Perran Downs, West Cornwall, and is centred at SW 55077 30665 just to the south of the B3280 between Goldsithney and Relubbus. It is in the northern part of the civil parish of Perranuthnoe and was in the ecclesiastical parish of St. Hilary. The site is at 55m OD on a gently south-sloping dissected wave-cut platform. 2 https://whc.unesco.org/archive/2010/whc10-34com-8E.Adde.pdf 6 Statement Heritage : WAYF0919 Wayferers, Relubbas Lane, St Hilary, Penzance, TR20 9EF 2.5 Historic Background 2.6 This area, formerly an extensive tract of heathland known as Perran Downs was partly enclosed to agriculture during the medieval period; further