Richard Storey, Balfour Beatty's lead tunnel examiner, will return to Blaengwynfi to examine "the dark side" - the 100m of tunnel at Blaengwynfi that has been sealed since the late 1970s. D-Drill engineers succeeded in drilling a large hole in the over 2m thick concrete wall to allow access. Inside, we know that the trackbed is flooded to at least 40cm so those entering will need waders. We shall also be examining how the drainage in the tunnel works, and going back to the original drawings that were laid before parliament in the 1880s for clues.
The examination of the material used to fill the approach cuttings by Earth Science Partnership has one more task before completion. They have to drill boreholes down the track bed level at both portals. The difficulty has been the need to get the boring rig to the locations on waterlogged ground. The recent dry weather is very much helping.