Twin tunnel to be bored by Marti jv using Herrenknecht ex Pomy. May 1998.
North tube breakthrough by Herrenknecht 11.7 m-diameter TBM achieved May, 1999 by contractors GTG, a jv of Marti, CSC, Comina and Pierre Freiburghaus. TBM dismantled and taken back to start for south tube to complete by October, 2000. Maximum daily advance 21.6 m with average of 13 m. Steelcord muck conveyor from TBM to portal with 400 m cassette. Korfmann fans and Grindex Matador pumps. Segment prefabrication at site produces six 1.8 m rings/day using forms supplied by Bernold and CBE. 28 cm-thick ring comprises 5 x 9 t segments plus key. Sept 1999.
