Brofiscin Quarry - Capping Scheme

Brofiscin Quarry is a former Carboniferous Limestone Quarry situated to the North of the village of Groesfaen in the county borough of Rhondda Cynon Taff. The Quarry site covers approximately 1.5 hectares of land. When operations ceased in 1965-1970 the resulting void was used for the disposal of industrial waste.

Following investigations in 2005 the site was determined as contaminated land under the Environmental Protection Act 1990. Subsequent to this a human health study was commissioned, which concluded that the site contains materials which present a significant harm to human health.

As a result of these findings Geotechnology completed a water balance report, which identified a capping solution to the site. The principal aims of the capping scheme is to prevent entry of rainfall into the waste mass and to completely and permanently prevent direct contact and ingestion of the waste by humans and animals.

McCarthy's Role

As the main works contractor McCarthy's were responsible for the actual physical completion of the contract as a whole. The capping scheme itself consisted of many separate entities which combined to provide an overall solution, these are summarised below in chronological order: -

• Vegetation strip including removal of small trees and scrub
• Placement of a regulating layer consisting of imported soils upon the existing Quarry surface
• Placement of a separator Geotextile on the Northern part of the site
• Placement of leachate collection drainage blanket and pipework in Northern part of site onto existing waste surface
• Placement of a pressure relief Geocomposite, comprising Pozidrain, which has a 7mm cuspated HDPE core with Geotextile fused to both the upper and lower surface
• Placement of pressure relief trenches and pipework
• Placement of protector Geotextile beneath 2mm HDPE membrane around Quarry edge
• Installation of a 2mm HDPE barrier membrane, comprising GSE 2mm smooth/double rough sided high density polyethylene acting as the main precipitation ingress and vapour egress barrier
• Lay restoration soil under drainage Geocomposite comprising Pozidrain, which has a 7mm cuspated HDPE core with Geotextile fused to both the upper and lower surface
• Lay silt/clay as a minimum 700mm restoration soil layer
• Installation of surface water drains to collection and discharge points
• Placement of additional cover of soils to achieve a seeded vegetation cover
• Placement of shredded vegetation from initial site clearance