NHBC’s Land Quality Service (LQS) team include geotechnical and geo-environmental specialists who support the remediation and redevelopment of land to make it suitable for future housing, including challenging brownfield sites such as former collieries, chemical works and other industrial sites.
Background:
The 43-hectare area in Bircotes, Doncaster is the former site of Harworth Colliery, which was demolished in 2013. Named after Tom Simpson, one of Britain's most successful professional cyclists who lived in Harworth, work began to create Simpson Park on the former colliery site in 2018.
This is a long-term redevelopment project involving major remediation and infrastructure work, which is expected to be completed in 2025. The early-phase plots have been completed and occupied, with the remainder to follow completion of the current remediation project.
The plan:
When complete the Simpson Park development will create approximately 1,300 new homes. The site, designed and developed by Harworth Group, will also incorporate a new public green space, linking the development to the existing Harworth village.
A large development, the site has been developed over three phases and the LQS team provided assistance to ensure each phase was suitable for residential use for housebuilders.
The challenge:
Due to the previous use of the land as a colliery and coking works, the site necessitated a series of ground investigations, remediation and earthwork phases before it could become suitable for development.
The complex site had extensive infrastructure associated with coal mining including two 1km deep shafts, a gas extraction system and a former coking works. The area also featured wide-ranging concrete infrastructure, tunnels and unused, mined colliery spoil across the site.
Finding the right solution:
There was significant colliery spoil, with some soils unsuitable due to potential combustibility. These were dealt with and placed at depth within the earthworks and a suitable clean cover system was employed to break the pathway to enable future housebuilding.
For the specific and significant challenge of the two mine shafts, material was infilled in two phases with each one taking between six and nine months to fill, which is to be followed by an exercise to construct permanent caps over the top of the shafts.
In addition, the area for the coking works underwent extensive remediation including turnover and groundwater abstraction and treatment ensuring the long-term use for housebuilding and public open spaces.
Securing a Stage 1 to 3 Certificate of Land Quality:
Land Quality Certificates have been issued for Phases 1 and 2 at Simpson Park. Stage 1 to 3 Certificate for phase 3A has also been completed, with work on phases 3B and 3C ongoing but due to be completed in 2024 and 2025.
Michael Brown, Project Director at Harworth Group said
“The LQS team have provided a great service in support of our remediation and redevelopment of Simpson Park. The land quality service was delivered on time and was well managed at each stage to achieve our wider requirements for the development and provided benefits throughout. We have found that the certification provided by the LQS team on our remediated platforms provides benefit to housebuilders when appraising the site.”
