Channel formalisation and erosion control at former mine adit with GCCM
Location of work/project:
Coalcleugh mine channel lining, Hexham, England
Concrete Canvas Ltd
On a difficult to access, former mine adit site situated within the North Pennines Area of Outstanding Natural Beauty, Concrete Canvas® provided a lower carbon erosion control solution than traditional methods, with BBA certified durability of 120 years, to accommodate high water levels, rapid flow rates and prevent river contamination.
This project involved the formalisation of a channel required to divert the River West Allen away from heaps of metal-contaminated wastes left by mining activities in the 19th and early 20th century, and serves as intervention to help prevent half a tonne of lead, cadmium and zinc polluting the river each year.
A lining solution was required for the formalised channel to prevent erosion and ensure the structure can accommodate high water levels and rapid flow rates. The client, Coal Authority, has successfully used Concrete Canvas® in the past, and therefore specified the Geosynthetic Cementitious Composite Mat (GCCM) from the offset.
The contractor, JN Bentley, faced complexities including a remote location, restricted access to the channel and the environmental sensitivity associated with working in an Area of Outstanding Natural Beauty. However, CC’s properties made it the ideal solution.
CC can be specified in bulk or batched rolls which can be transported manually on site by two to three people; as a result, a single, small excavator was required, with no other specialist equipment needed for installation. The GCCM has a very low alkaline reserve and low washout rate, allowing installation directly into live watercourses without adverse effects on the ecology or the need to treat runoff. Finally, CC can be installed up to ten-times faster than sprayed or poured concrete, saving time and overall project costs.
A total of 7000m² of CC8™ were installed by just four people over several weeks, despite difficult weather and site conditions. Concrete Canvas® GCCM and the chosen transverse layup allowed works to be halted quickly during the scheme due to several extreme weather events and floods.
The project was funded by the Coal Authority, Environment Agency and DEFRA’s Water and Abandoned Metal Mines programme and the North East Local Enterprise Partnership.