Complete Enabling Works Package

Client / Britannia Construction/Deeley Freed Estates
Site / Tesco, Risca
Value / £4.8m
Timescale / 9 months

Summary

Sanctus undertook a Phase II Geotechnical and Environmental Site Investigation to determine the extent of contamination and to identify Geotechnical issues, this provided Sanctus with sound information to design a detailed but cost effective remediation and flood defence scheme, which was approved by the EA, and led to Sanctus being awarded the remediation and enabling works for the scheme.

Sanctus produced a Remediation Method Statement for the site, which was agreed in conjunction with the Environment Agency and Local Authority.

Sanctus were retained by the client as Environmental Consultant for the project and carried out the following works onsite:

  • Demolition of above and below ground structures associated with the former foundry, including removal of original basement to depth, and the processing of some 10,000m3 of stockpiled demolition waste
  • Site clearance including the eradication and hand-picking of Japanese Knotweed and Himalayan Balsam using a mobile picking station, and tree and vegetation clearance with close involvement from ecological consultants
  • Removal of fly-tipped waste including asbestos, and former foundry waste left on site
  • Onsite remediation of contaminated soils including hydrocarbon hotspot removal, ex-situ bioremediation and chemical oxidation of soils, including chemical analysis of soils, to enable re-use onsite
  • The excavation and processing of asbestos contaminated soils, with disposal of asbestos containing materials at a suitably licensed facility under full duty of care
  • A six month groundwater pump and treat scheme to remove free product from the underlying groundwater to protect the River Ebbw, where groundwater would be treated, stored and tested, before being discharged under EA regulations
  • Sanctus produced a Materials Management Plan and directed the classification, segregation and disposal of surplus soils at suitably licensed facilities
  • A mass Cut and Fill operation was required to achieve the design levels determined by flood risk assessment. The earthworks exercise comprised the excavation of ~120,000m3, ~65,000m3 was selected for reuse and the surplus ~ 55,000m3 was exported from site
  • Following the Cut and Fill exercise, ground improvement was required to achieve a uniform CBR Value across the site. Sanctus utilised the Rapid Impact Compaction technique to achieve the performance criteria required by the specification provided by the project engineers.

Sanctus worked in close contact with the statutory undertakers, using chemical analysis to display that the remediation scheme had been successful and that there was an ongoing environmental improvement as a result of the works.

All works packages were undertaken on a fixed-price all-risk basis. Sanctus’ works were independently monitored and verified by an external multi-national consultant.

The Tesco Extra Superstore was opened on-time, just 9 months after Sanctus started onsite.