Aker Wirth was commissioned in February to construct and deliver a gripper TBM by ARGE Zugangsstollen Limmern (AZL).
The E20M (US$27.5M) TBM will be used for the expansion of the Linth-Limmern power plant in Switzerland, boring approximately four kilometres from the access gallery to the new machine cavern.
AZL is a joint venture consisting of Rothpletz, Lienhard & Cie; Baresel GmbH; Wayss & Freytag; G Lazzarini & Co; Andrea Pitsch; and Ragotti & Webber Bau.
The borehole has a diameter of 8.03m and rises from 800m to approximately 1800m above sea level with a constant gradient of 24 per cent. The project will be the largest inclined shaft completed by TBM, with previous diameters of up to 6m.
The TBM will be come fitted with a backup system constructed by Rowa Tunnelling Logistics where materials can be conveyed between the machine and portal, in addition to the securing and lining of the tunnel walls drilled.
The TBM will be constructed at the Erkelenz plant. It will be subject to an in-plant test run before being transported and assembled at the site.
Drilling of the headrace galley will start at the end of this year.
