MARINE COLLIERY DRAINING TUNNEL
CLIENT: THE COAL AUTHORITY
DESCRIPTION OF WORK
A drainage tunnel that was driven through a sandstone aquifer below the spoil tip on the hillside above the village of Cwm, Ebbw Vale by the former British Coal Corporation required repair and maintenance work. Due to falls of the overlying rock above the tunnel over the years the mesh between the steel arches along the roof section had started to fail and the tunnel had to be re-roofed along a distance of approximately 700 metres.
All work had to be carried out manually with no mechanical or electrical plant and equipment permitted due to the confined space, the amount of water flowing through the bore holes driven through the sandstone strata above into the aquifer and the constant flow of water through the base of the tunnel.