Gilbert and Goode Mining innovation at Polgrean Place

Constructing Excellence

Gilbert and Goode (G&G) embarked on an ambitious demolition and regeneration project; to replace 66 outdated homes, flats and commercial units for Clients Ocean Housing Limited (OHL). In their place, 60 new homes: providing a mix of general needs and dedicated older persons flats, 2 & 3 bedroom houses, along with 2 commercial units were to be delivered.   

Despite desktop surveys, trial trenches and the consultation of mining experts, the regeneration of Polgrean Place was halted by the discovery of a hole that had opened up in the temporarily closed Adopted Highway. This discovery started a chain of events that almost saw the scheme abandoned and 60 much needed affordable homes mothballed. Following initial ground investigations by local mining experts, a 16-week period of trial digs commenced exposing 16 shallow mine workings. These workings, which were thought to be early exploratory digs searching for mineral deposits, extended the length of the adopted highway suggesting any resolution would likely be expensive, difficult and time consuming. To complicate matters, remediation works would need to include the underpinning of a main road link, the A390, whilst keeping the road open and safe for motorists.  

Once the scale of works was understood, a team of experts and stakeholders assembled, conducting numerous design and technical team meetings. A principal concern for the Project Delivery Team was how to put machinery, plant and people safely to work in the area to carry out any remedial works. Options such as grouting, excavation and fill were investigated, but the winning idea was to form an underground bridge, using piled foundations as a ‘safe leading edge’ from which to work. The story of the mine remediation works at Polgrean Place is one of severe adversity and challenge, resolved by innovation, collaboration, partnership and team work – and in our opinion is a worthy winner of this award, as recognition of all our project team have accomplished together and the challenges they have faced and overcome, keeping  focus of the importance of affordable housing delivery in Cornwall, never losing sight and always being at the forefront of this project. 

Three Winning Facts:
  1. Delivery of first subterranean bridge in Cornwall to remedy instability of historic mineworks.
  2. Successful collaboration with multiple third-party stakeholders to deliver scheme.
  3. Delivery of affordable housing in the face of adversity.