GCCM used for channel lining at former copper mine to prevent contamination of local river

Location of work/project:

Company:

Summary:

Avoca Mines, Co. Wicklow, Ireland

Concrete Canvas Ltd.

A series of newly constructed drainage channels at the former Avoca copper mine were lined with GCCM to provide water management around a contaminated spoil site prevent contamination of the local river and ecology.

Copper mining was active in the Avoca River valley from around 1720 until 1982, leaving behind an environmental legacy comprising of open pits, shafts, adits, spoil piles, buildings and structures.

The river flows southwards through the Avoca mine site and is overlooked by upland areas known as the East and West Avoca mine areas. Water discharge from the abandoned mine is acidic and metal laden, impacting water quality in the Avoca River. The project site is situated between a railway line and the East Avoca mine area.

Remedial works consisted of regrading and capping spoil areas and constructing boundary channels to redirect upstream drainage around the capped area rather than through it.

The original design specified precast concrete channels and a HDPE liner and riprap channel. The long lead times and risks associated with installing these solutions on the steep slopes meant Concrete Canvas® GCCM (CC) was specified instead.

CC was installed in a transverse layup which could accommodate bends in the channel. On the steepest sections, concrete steps were installed within the channel invert and covered with CC to create baffling in order to reduce flow velocity.

CC’s specialist high early-strength concrete has a limited alkaline reserve and low washout rate; combined with the volume of water required for hydration, these characteristics mean the runoff can be directly discharged into the river without prior treatment. One bulk roll of CC can replace two 6m³ concrete trucks and can be deployed from an excavator and spreader beam, reducing deliveries and plant required on site. Therefore, CC was the ideal solution for this project.

1520m² of the 13mm thick Concrete Canvas® (CC13™) were installed within just two weeks and will provide long-term scour and erosion protection to the drainage network, which will effectively manage runoff and protect the river from contamination.