Blackwell competitively tendered for the Tannery & Penpoll remediation contract, which is a contract on two diagonally opposite former industrial sites. The remediation of the contaminated site between Hawthorne Road and the Leeds Liverpool Canal will enable the future development of 177 homes, retail units and public open space in the area.

The site has particular constraints including the presence of housing on adjacent sides which requires the careful management of our earthworks and remediation processes to ensure disturbance is kept to a minimum. The Tannery site is also bounded by the Leeds Liverpool canal which is a sensitive receptor and requires strict monitoring and control of our remediation operations at this boundary.

The key remediation issue was the presence of large volumes of radioactive tin slag on the Penpoll site. This required us to establish local radiological rules prior to undertaking the excavation and disposal of these materials. These rules included suitable monitoring regime to ensure all the material disposed offsite was below the ionising radiation threshold and provide contingency should any materials be encountered which exceed this level. These rules also needed to ensure the workforce and the general public were protected at all times during the excavation works and also provide a robust validation procedure.

Key Processes:

The main scope of the work includes the following:

Tannery site

• Site Clearance and demolition
• Excavation of oversite concrete slabs and foundations, processing
• Excavation of redundant tanks and tank contents, process and disposal.
• Excavation of indentified areas of made ground and process/ dispose plus filling of excavated voids with site produced granular fills
• Canal site boundary treatment to permit the excavation of made ground to encroach up to the site boundary.

Penpoll

• Site Clearance and demolition
• Excavation and disposal of radioactive tin slag
• Excavation of other made ground and process / dispose offsite
• Filling of excavated voids to final levels