Geotechnical, environmental and development support for a surface mining site in north-west England
The development division of a major British coal industry client is retaining RSK to provide a broad range of engineering and environmental support services at a surface mining site in north-west England. The operational surface mining site includes areas of ecological interest, several watercourses and one of the largest colliery spoil tips in Europe. It is a complex and challenging site constrained by historical deep and surface mining activities and the current opencast mining.
The current surface mining commenced in 2006 working to a restoration plan that envisaged a return to agricultural use. However, in 2007, the site was identified for potential strategic commercial development, given its excellent links to the motorway network and substantial unfulfilled demand for commercial and industrial space in the area.
Working with other partners in the development team, RSK was faced with the challenge of making the site developable without affecting the already operational surface mining activities. Particular challenges arose from the nature of the material in the former spoil tip, which is potentially combustible, and from the deep uncompacted backfill of the surface mining voids. RSK completed an initial status report for the site, a critical document that identified and assessed the impacts of the constraints for future development of the site and enabled a series of investigation and assessment tasks to be defined and undertaken.
Eight areas of geotechnical and environmental assessment were identified to support the proposed redevelopment masterplan:
- The settlement of opencast backfill, both recent and dating from the 1950s
- Ground treatment by surcharging and measurement of induced settlement
- Assessment of backfilling and compaction options
- Investigation and assessment of colliery tips
- Hydrological and groundwater studies
- Assessment of shallow underground workings and mine entries
- General site investigation
- Materials handling protocol.