I worked on the tunnel from day one till completion, my father was the Works Superintendent and very sadly lost his live in a crane accident at the Beachley site. The two rock header tunnel machines proved to be too slow and so drill and blast was used to speed the works. Water ingress pump up the shaft at Beachley was at 1800 gals per minute. Reduced to 25 gals per week from the total length of the tunnel works. I helped install the steel arches and the cable tubes used to cool the installed cables that seanwatts spoke about in the comment below. Some one removed the draw wire for the cables, new ones were installed using a Jack Russel dog owned by the gate keeper. I spent the rest of my working life on tunnel projects around the world retiring in 2015 after working on the KL Metro Malaysia.
Me and four work colleagues from walters engineers swansea took all that pipework out and replaced it also the pumps while subbing to mono pumps uk, it took us 5 months travelling from Swansea each day, this was in 2005, it would take 7 wealso ran 2km of 6"abs pipe into the tunnel from aust to beachley, all drilled and chain brackets to walls, we had no injuries on that job
