EXPERTISE FOCUS: Large Scale Industrial Site

TENDER VALUE: £0.6M

CONTRACT: CARRINGTON REDEVELOPMENT

CLIENT: HIMOR CARRINGTON LTD.

The investigation encompassed a former petrochemical site within Carrington, Trafford, and Greater Manchester as well as other offshoot areas of interest immediately adjoining the main site. Accordingly for manageability and future development planning the investigation was subdivided into four key area each having different environmental characteristics.

At the time, principal ecological constraints included breeding birds, Great Crested Newts (GCN) and badgers. In addition, steps were put in place with respect to tree root protection. Due to the potential presence of GCNs, toolbox talks were given to all site staff detailing the measures to be undertaken should evidence be found in proximity to the exploratory hole locations. A qualified Ecologist was present on site for the duration of the site works and fingertip searches undertaken as required. Non-intrusive geophysical surveys were undertaken to identify any possible shallow unexploded ordnance, together with a walkover strategy in order to mitigate the UXO risk. All site personnel were given Explosive Ordnance Safety and Awareness briefings and site instructions.

Specialist Continuous Multichannel Tubing (CMT) were installed into selected boreholes to allow discrete depth monitoring and sampling of groundwater across a range of depths. The CMT wells were installed using centralisers to maintain verticality at approximately 3m intervals. Each response zone was carefully backfilled with gravel and bentonite as appropriate.

To reduce the risk of cross contamination all equipment (including drill bits, casing and excavator buckets) was washed down using a pressure washer after the completion of each exploratory hole. A set-aside washdown area was used for such activities which incorporated a lined and bunded trench and collection IBC units. All site personnel were equipped with appropriate overalls and personal gas alarms at all times during the site works. When contamination was encountered coveralls, masks and visors were provided as an extra protective measure. In addition, a decontamination unit was present on site at all times for site personnel which included delineated ‘dirty’ areas following HSE Guidance Booklet 66.

Management of the long-term monitoring and sampling requirements which needed to be adequately resourced and scheduled throughout a 12 month period. The supervision of a multi-disciplinary ground investigation was key, as well as the associated requirement to handle the overarching ecological, contamination and site constraint issues. One of the major difficulties was the sheer volume of information that was generated by the investigation and its subsequent control and distribution to various stakeholders.

Maintaining good levels of moral within the site work force in an environment that was significantly challenging was extremely important throughout the main investigation and subsequent long-term monitoring programme.