The site located on a hillside to the west of Blaina in Gwent has a history of landslip instability due to over-steep glacially eroded slopes and the effects of undermining the coal and ironstone extraction.
Landslip movements of up to 14 metres have been recorded, the greater part having taken place since 1995.
The work carried out by Walters UK Limited included removal of some 110,000 cubic metres of surplus material and the installation of some 4,000 linear metres of rock filled buttress drains up to 5.5 metres deep, and 1,700 metres of sub-horizontal, rotary bored, groundwater relief drains with associated toe drains and channels.
To gain access up to the site it was necessary to construct more than 1.5 km of haul roads up slopes as steep as 1 in 2.0 for Volvo A25 dump trucks.
A 27 metre span temporary bridge was built on reinforced earth abutments to cross over the A467 Abertillery – Brynmawr road into a deposition site on the Rising Sun Industrial Estate.
The installation of toe drains and piped buttress drains at the base of an active landslip at the south end of the site.
Client – Blaenau Gwent County Bough Council Value – £2 million Duration – 2000-2001
