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.
Two Weeks of intense hard labour, but every second was another step towards the re-opening of the Rhondda Tunnel. The first 3 days saw us preparing the way for Balfour Beatty who was to carry out the Detailed Examination. Whilst Balfour Beatty began their Survey from the Blaencwm end, D-Drill began their work, stitch drilling the wall which had to be compromised for the Detailed Exam.
It took 7 days to drill through 2.5 metres of solid concrete. Finally, on Friday 4th May, at 5pm, the wall was broken through.
As it was very late breaking into the other side of the tunnel, it was decided to explore the 'Dark Side ' at a later date. As far as the eye could see was water, Crystal 'Gin' clear water. Blocked drain! We will find out within a few weeks.