Value: £2.5 million
This large colliery remediation project involved the excavation, biophysical treatment and reclamation of soils on a former colliery and coal carbonisation plant to form an engineered development platform.
The former brownfield Rossington Colliery site has been redeveloped for housing and commercial use together with an earthworks section of FARRRS regeneration route which has opened up access to the M18 Motorway.
Works involved excavation and placement of 300,000m3 of made ground up to 4m deep including screening and moisture conditioning, excavation of 32,000m3 of hard materials and processing to 6F2 grading for reuse onsite as capping to the engineered development platform.
Part of the site was a former coal carbonisation plant and elevated concentrations of Napthalene, Benzene, Phenol and Ammonia were present. VHE successfully treated the contaminated materials by biophysical treatment to render the materials reusable on site, below the capping levels. In total 1600m3 was treated using biophysical remediation and reused on site.
The excavated material was then processed to form a new engineered platform using end product compaction. Validation testing including zone and settlement tests were also required for this project. Further works included a thrustbore under an existing railway line and the installation of associated drainage systems.
The site was capped utilizing the washed discard from the adjacent coal recovery site (54,000m3) which was engineered to reduce its OMC (option moisture content) to suitable levels.
Throughout the project VHE had to plan and deal with a number of ecological issues which included working adjacent to a river, nesting birds and the felling of 300no trees.
Further challenges were encountered and overcome during this project which included working adjacent to a live rail head liaising with both the adjacent coal recovery contractor and the main contractor constructing the FARRRS route. There was also a requirement for segregation of several streams of excavated materials which had the potential to cause logistical difficulties. Despite this the project was delivered on time and was deemed a huge success.