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Switzerland, Gotthard Base - ch/19

Amsteg Section High Speed Railway

This adit will be 1.784 km long x 60 sq m at 1% downgrade to the Alptransit tunnel horizon where a further 200 m of preparatory work will be required to open out the four running tunnel faces. Ed Ast is undertaking the main development using an Atlas Copco 353E drillrig under moderate blasting restrictions achieving 12-16 m/day advance in Aar Massiv and Erstfeld gneiss. A full face comprises 105-110 holes of depth 3-4 m which are primed with Dyno experimental aluminised slurry using a pump and Nonel detonators. Swellex rockbolts with Dramix steel fibre reinforced shotcrete to support roof and walls. Rock flowed through Pegson crusher located 150 m inside portal and by conveyor to surface and dumps. Ast will complete end-November. Prequalification late-May for 11.4 km main tunnels, but method still under discussion. Elsewhere on the Gotthard base tunnel, the alignment of the section from Uri to the portal is still undecided. Contact info@alptransit.ch for further information. May 2000.Open invitation to tender for lot 252 running tunnels 2 x 11.4 km long to be constructed from base of 1.78 km-long adit currently under drill/blast excavation by Ast-Holzmann using underground crusher with conveyor system to surface for removal of spoil by rail. Cross-passages 40 m-long at 320 m intervals between main tunnels. Deadline 22nd January, 2001. Contact Lucerne office, fax +41 412 260600, e-mail info@alptransit.ch or visit www.alptransit.ch July 2000. Lot 252 for 2 x 11.4 km-long running tunnels towards Sedrun awarded to Strabag/Murer jv using Herrenknecht TBMs. 1.88 km-long x 3.5 m-diameter TBM drive for cable tunnel underway between new transformer cavern and existing Amsteg power station. 27/02.  Herrenknecht has completed the assembly of the first Gripper TBM, machine S-229, for the Gotthard base tunnel north. The 9.58 m-diameter TBM will excavate the eastern tube (11,350 m) of the Gotthard base tunnel between Amsteg and Sedrun. Assembly at the jobsite in Canton Uri will start in mid-March 2003. AGN, the JV consisting of Murer and Strabag, ordered two Herrenknecht hard rock TBMs for this section in February 2002. The second TBM will drive the western tube (11,350 m).Both machines weigh 1,200 tonnes each without the backup system.Representatives of AGN took delivery of the machine on 16th January in the presence of AlpTransit Gotthard AG. The machine is now being disassembled to be transported to Switzerland where pre-assembly is scheduled from March at the tunnel portal prior to full assembly in the start cavern. Excavation will start end of May. The second machine (S-230) will start three months later on the western tube.Herrenknecht has its own subsidiary in Amsteg, in close proximity to AGN's jobsite. The Swiss affiliate works in close cooperation with cutting tool supplier RUAG in Altdorf to achieve the best efficiency on AlpTransit projects, both at the Gotthard and Lötschberg.Four Herrenknecht Gripper TBMs will be in operation at the Gotthard base tunnel, the longest railroad tunnel worldwide with a total length of 2 x 57 km, to excavate a total of 75 km of tunnel. Visit www.herrenknecht.com and www.alptransit.ch 06/03.