GBT: Piora Basin successfully mastered

The geologically sophisticated Piora Basin has been mastered. On February 3rd, 2009, the tunnel boring machine in the western tube of the Gott-hard Base Tunnel drove the final metres of the Piora Basin. The tunnel boring machine in the eastern tube completed the task on October 15th, 2008. No particular problems ensued during the penetration of the western tube just as had been the case with the eastern one. The TBM in the western tube passed through the 150  m long Piora Basin from Jan. 20th to Feb. 3rd with a daily rate of advance of between 10 to 12  m reaching the “Medelser Granit” located to the north of the Piora Basin. The rock remained stable: no deformations worth mentioning were discovered in the dolomitic rock nor was any water encountered.
Some 7.3  km of tunnel has still to be driven in the western tube up to the breakthrough between Faido and Sedrun and around 6.4  km in the eastern one. It is estimated that the main breakthrough in the Gotthard Base Tunnel will take place at the beginning of 2011 so that commercial scheduled services can start at the end of 2017.
G. B.