End of Tunnelling at Mont SionFurther to completing the west bore of the Mont Sion tunnel in June 2007, "Adélaïde" - the TBM produced by Herrenknecht - completed the east tube on 6th March, 2008 in the afternoon. The machine pushed through the rubble to make the breakthrough amid music and fireworks and to the cheers and applause of the workers. The breakthrough marks the end of a major civil works site on the A41 North. Click here and here. Visit www.herrenknecht.comThe tunnel boring machine just needed six months to finish the second drive. Further to completing the west tunnel, the TBM was partly disassembled and trucked back to the north portal in Présilly. Reassembled and tested, it commenced digging the east bore in September 2007.Not only the crews of tunnellers achieved the challenge of constructing a 3.1 km twin bored tunnel in only 17 months but also they finished it three weeks early. They progressed underground at an average advance rate of 24 m/day. The TBM excavated 680,000 cubic metres of rock and installed 18,000 concrete segments of 15 tonnes each to build the two tunnels. The tunnel is the main civil engineering piece on the 18.8 km highway section that will link Geneva, Switzerland and Annecy in the French Alps. Tunnelling of the second tube lasted six months without major incident so that the highway should be opened within schedule in December 2008. The tunnel accounts for nearly 20% of the total length of the future A41 North. It crosses Présilly, Saint-Blaise and Andilly and ambitions to be an example in terms of safety and integration of the highway in the environment.The 12 m-diameter, 180 m-long and 2,200 tonne TBM will now be pulled apart to be trucked back in parts to Germany. Click fr/56. Visit www.adelac-a41.com 12/08.