On 04.12.2012 a 4.15 m-diameter Robbins TBM made its final breakthrough in Zurich, Switzerland. The Milchbuck safety tunnel required two methods of excavation due to a split in geology: 1,000 m of TBM tunnel was bored through molasse rock of UCS about 80 MPa from the north access, while a 400 m conventionally dug section was located in unconsolidated rock, mainly Moraine, from the south access.  For more read the press release, click ch/53 for tunnelbuilder archive and here. Visit www.robbinstbm.com. 02/13.