A2168 Phase 1 Geo-Environmental Report Pennoweth Primary School, 53 Drump Road, Redruth, Cornwall, TR15 1PR For Macegroup Ltd, Balliol House, Southernhay Gardens, Exeter, EX1 1NP September 2020 Report Number: A2168-1 AGS Ground Solutions Ltd 4 Bond Street, Redruth, Cornwall TR15 2QB A2168 – Pennoweth Primary School Macegroup Ltd Phase 1 Geo-Environmental Report DOCUMENT CONTROL Client Macegroup Ltd Project Title Pennoweth Primary School Document Title Phase 1 Geo-Environmental Report Document No. A2168-1 Date Revision Changes Author Review Approved 08/09/2020 1 Interpretive JP PF i www.agsgroundsolutions.com A2168 – Pennoweth Primary School Macegroup Ltd Phase 1 Geo-Environmental Report CONTENTS Page 1. INTRODUCTION 1 2. SITE LOCATION AND LAYOUT 2 3. SITE HISTORY 3 4. ENVIRONMENTAL SETTING 6 4.1 GEOLOGY 6 4.2 SUPERFICIAL GEOLOGY 6 4.3 GROUNDWATER 6 4.4 SURFACE WATER 6 4.5 RADON 7 4.6 MINE SEARCH 7 4.7 OTHER GEOLOGICAL INFORMATION 7 4.7.1 Mining, extraction & natural cavities 7 4.7.2 Historical Land Use Information 8 4.7.3 Ground Stability Data 10 4.8 OTHER ENVIRONMENTAL INFORMATION 10 4.8.1 Environment 10 4.8.2 Flooding 11 4.8.3 Waste 11 4.8.4 Hazardous Substances 12 4.8.5 Industrial Land Use 12 4.8.6 Protected Locations - Environmentally Sensitive Receptors13 5. CONCEPTUAL SITE MODEL 14 5.1 CONTAMINANT SOURCES 15 5.2 PATHWAYS 15 5.3 RECEPTORS 15 5.4 DISCUSSION 16 6. LAND STABILITY ASSESSMENT 19 6.1 UNDERGROUND CAVITIES 19 6.2 UNSTABLE SLOPES 20 6.3 GROUND COMPRESSION / SHRINK / SWELL 20 7. SOIL GAS ASSESSMENT 21 7.1 CONTAMINANT SOURCES 21 7.2 PATHWAYS 21 7.3 RECEPTORS 21 7.4 CONCEPTUAL SOIL GAS MODEL 22 7.5 DISCUSSION 22 8. CONCLUSIONS AND RECOMMENDATIONS 23 7.1 RECOMMENDATIONS 23 ii www.agsgroundsolutions.com A2168 – Pennoweth Primary School Macegroup Ltd Phase 1 Geo-Environmental Report FIGURES: 1. Site Location Plan APPENDICES: 1. Site Photographs 2. Mine Search 3. Historical Maps 4. Geological Report 5. Ground Stability Report 6. Environmental Report iii www.agsgroundsolutions.com A2168 – Pennoweth Primary School Macegroup Ltd Phase 1 Geo-Environmental Report 1. INTRODUCTION AGS Ground Solutions Ltd (AGS) were commissioned by Macegroup Ltd (The Client) to undertake a Phase 1 geo-environmental site investigation on a site known as Pennoweth Primary School, Redruth. The site is currently used as a primary school. It is understood that part of the car park at the front of the school is to be redeveloped into additional single-story classrooms and school space. Also, further car park spaces are being developed on the northern boundary of the site. The aim of the investigation was to: • Examine site conditions and identify any potential risks of ground contamination resulting from historical and contemporary site usage. • Assess the likely geohazards on site and the risks posed by unstable ground. 1 A2168 – Pennoweth Primary School Macegroup Ltd Phase 1 Geo-Environmental Report 2. SITE LOCATION AND LAYOUT The site is located in Redruth and is centred approximately on Ordnance Survey Grid Reference SW 699 424. Access to the site was via Drump Road to the north of the site. A walkover survey was undertaken on the 1st September 2020, details of which are presented below. At the time of the walkover survey the site was irregular in shape, with access to site at the northern edge, that led from Drump Road which ran along the northern boundary of site. The site comprised of Pennoweth Primary School, with areas that were laid to hardcore and grass, with the northern section containing a car park and drop off zone. The entire site appeared tidy, well-tended and organised. Minor cracks were observed in occasional walls and on the curbs of the car park. A single gas isolation point was observed on the north-western boundary of site. There is some existing hedge and tree vegetation along the north, east and southern boundaries with a low block wall and some fencing along the western boundary, between the buildings, the neighbouring Redruth Children’s Centre and residential properties. The natural ground profile fell gently to the north. The following features surrounded the site: • To the north; Drump Road with residential dwellings and Industrial parks. Additional residential dwellings beyond and roads were beyond. • To the west; Redruth Children’s Centre and Plain-an-Gwarry residential dwellings. Additional roads, fields and dwellings were beyond. • To the south; Residential dwellings, and the town of Redruth. Additional residential dwellings and roads were beyond. • To the east; A railway line, with fields, commercial and residential dwellings beyond. The ground rose to the east. Photographs taken during the Walkover Survey have been presented in Appendix 1. 2 A2168 – Pennoweth Primary School Macegroup Ltd Phase 1 Geo-Environmental Report 3. SITE HISTORY A map search was carried out for the site and extracts of the following Ordnance Survey maps were obtained covering the period between 1880 and 2020. Maps marked (*) are obtained from Russian Military Mapping, not Ordnance Survey. These are presented in Appendix 3 and the relevant historic details are summarised as follows: Period Scale Observations The site is comprised of several fields and wooded hedgerows. The northwest corner of the site has been shown to be the site of an amphitheatre, however no permanent buildings are seen and it appears to be a field. Adjacent to the southern site boundary is a tree nursery. Beyond the tree nursery at around 80m south of the site are terraces of residential dwellings. Immediately to the north of the site is a road called Drump Road, which trends east-west. Beyond Drump road are a number of dwellings and nursery’s with fields beyond that. Immediately adjacent to the most eastern part of the site is a railway trending north adjacent to the site boundary. The railway is 1880 1:2500 partially in a tunnel. Approximately 20m east of the most eastern part of the site beyond the railway are a number of mineshafts associated with Pedn- an-drea Mine. Approximately 50m to the south east of the most south eastern corner of the site is a mine shaft known as Tregay’s Shaft. Approximately 100m east of Tregay’s Shaft is Jack’s Shaft. Approximately over 100m south east of the most south eastern corner of the site is Forth’s Shaft. Approximately 150 m east of the northern part of the site on the other side of the railway is a Boot and Shoe Manufactory. Approximately 80 m east of the northern part of the site is an old shaft. 300 m east of the northern part of the site is an old quarry. 1888 1:10560 No significant changes. Development of residential area and terraces of dwellings (Higher and Lower Bellevue), to the south of the site and partly in the tree nursery to the south of the site. More residential development to 1908 1:2500 the west of the site, with Claremont Road beyond 100 m of the site. Shafts to the east of southeast corner of the site no longer annotated. Building seen immediately adjacent to the north-northwest corner of the site. 3 A2168 – Pennoweth Primary School Macegroup Ltd Phase 1 Geo-Environmental Report 1908 - 1909 1:10560 No significant changes. 1938 1:10560 No significant changes. Approximately 200m northeast of the site is a 1963 1:10000 series of railway lines connected to the main railway line. Development of a number of dwellings immediately to the south of the site, in the location of the old tree nursery. Development of buildings approximately 20m north of the site on the other side of Drump road. Buildings known as the Curnow Centre and Trecarrel Govt Office. The Old Shaft approximately 80 m east of the northern part of the site is no longer annotated. A small square 1967 - 1968 1:2500 feature is seen on the site in the south east corner of the site. Area of playing fields to the east of the site beyond the railway, approximately 30-40 m. Adjacent to the area of railway lines approximately 200m northeast of the site is an Abattoir. Approximately 160m north of the site is Lower Cardrew Farm. Approximately 250 m southwest of the site is a Bacon Factory. Development of more buildings approximately over 1971 1:2500 100 m from the north northeast of the site. Cardrew County Primary Junior School seen on the site, in the centre/ Southwest part of the site. With 1973 - 1975 1:1250 a slope running north to Drump Road from the school buildings. Another slope is also seen in the northwest corner of the site. Approximately 150 m northeast of the site is 1974 - 1979 1:10000 Cardrew Business Park. 1974 - 1989 1:1250 No significant changes. 1976 1:1250 No significant changes. More development of the school on the site, with more buildings seen and a road running from the school north to Drump Road. Tregay’s Shaft 1977 - 1989 1:1250 approximately 50 m to the south east of the most south eastern corner of the site is no longer seen and the area has subsequently been built upon. 1981 1:10000 No significant changes. Building immediately to the west of the northwest 1982 - 1989 1:1250 corner of the site has been developed and extended to the south. 1991 - 1993 1:10000 No significant changes. 1992 1:1250 No significant changes. 1994 1:1250 No significant changes. Site comprised of a school in the centre, with open fields of grass in the north western and southeaster 1999 1:2500 parts of the site.