New Stanton Park, Ilkeston
Groundwork, Contamination and Drainage
Site investigation Summary for Public Exhibition
The site comprises 79 hectares of predominantly rough ground following demolition of the former iron works and other industrial uses. It includes approximately 20 hectares of woodland.
The former uses of the site include:
- A former large foundry, including central melting plant, strategic overflow storage of metal raw materials/auxiliary materials, waste sorting and effluent treatment plant;
- The former Nut Brook Canal (close to the northern boundary of the site) which is open but disused in the west and then remnant disused culverted sections lie along the rest of its former route through the east of the site;
- Railway sidings;
- Tanks and electricity substations;
- Former tip areas associated with the foundry including an area used for tipping of asbestos for the former owners containing materials (ACMs) produced from on-site demolition processes.
The geological setting of the site was identified from the most recent and previous investigations to be:
- Made ground: variable thickness of brick, concrete, iron works slag, clay, ash, sand etc;
- Alluvium: Clay, silt, sand and gravel associated with the construction of the Nut Brook canal;
- River Terrace Gravels: sand and gravel associated with the River Erewash;
- Lower Coal Measures: grey mudstone and bands of sandstone. The LCM also contains three known bands of worked Ironstone (Honeycroft Rake, Civil Rake and Dale Moor Rake) Several coal seams are noted (Norton, Forty Yard, and Alton Seams) to be present. All of the Ironstone Rakes and Coal Seams are recorded to have been worked.
Verdant Regeneration has commissioned full site investigations to be carried out in addition to investigations which have supported previous applications. The recent investigations have comprised:
- 75 Boreholes (Cable percussion/Rotary) including 43 installed with gas/groundwater monitoring wells
- 91 Trial Pits (including 10NO hand pits)
- 14 Shaft search excavations
- samples tested for chemical composition
- samples tested for geotechnical purposes
- potential coal mine investigations
Limited instances of isolated contamination were recorded at various locations across the centre and east of the site. These instances largely comprised metals but with some limited organic contaminants. Less frequent contamination was identified in the West of the site.
Mine workings and mine entries were identified in the centre and east of the site.
These findings were similar to the findings of previous investigations.
In addition to the recent ground investigation works, our consultants have carried out a Controlled Waters Risk Assessment (CWRA) analysis of available boreholes from previous investigations, which concluded that there were no significant source-pathway-receptor pollutant linkages to controlled waters from the identified soil and groundwater contamination at the site. .
The remediation strategy in general will incorporate:
- Hand-pick removal of visible asbestos containing materials;
- A site specific asbestos risk assessment plan of works to address the risk of asbestos contaminated soils during earthworks;
- Excavation and recompaction of soils to 2m below development platform levels with removal of foundations and drains.
- Rolling Dynamic Compaction at the base of the excavation to improve the compaction of deeper soils.
- Treatment of Mine workings and mine entries by drilling and pressure grouting
- Treatment of as yet unknown contamination if identified during the earthworks.
A flood risk and drainage assessment has been undertaken of the site. All built development is proposed to be located outside of Flood Zones 2 and 3 (which have a medium to high risk of flooding). A surface water strategy has been prepared for the site, which addresses how run off from the site will be managed. This includes the provision of a new pond adjacent to the northern boundary of the site, to accommodate surface water run off. The existing ponds will also be retained for use by Stanton Fishing Club.