11 February 2010 - Aker Wirth has been commissioned to construct and deliver a gripper tunnel boring machine (TBM) by “ARGE Zugangsstollen Limmern". The order has a total value of over 20 MEUR.

The “ARGE Zugangsstollen Limmern” (AZL), consisting of

• Rothpletz, Lienhard + Cie AG, Aarau (Switzerland) 

• Baresel GmbH, Stuttgart (Germany) 

• Wayss & Freytag, Frankfurt (Germany) 

• G. Lazzarini & Co. AG, Chur (Switzerland) 

• Andrea Pitsch AG, Thusis (Switzerland) 

• Ragotti+Weber Bau AG, Netstal (Switzerland) 

commissioned the Aker Wirth TBM and will realise construction of the gallery.
The machine will be used for the subterranean expansion of the Linth-Limmern power plant in Switzerland, boring approximately four kilometres from the access gallery to the new machine cavern.

The access gallery portal is near the village of Linthal in the Canton of Glarus, south of Zurich. The bore hole has a diameter of 8.03 metres and rises from 800 metres to approximately 1800 metres above sea level with a constant gradient of 24 percent. The Aker Wirth TBM has been equipped with additional safety fittings for the ascending tunnel to accomplish this inclined shaft bore hole. Inclined shaft bore holes with diameters up to approximately six metres have been machined to date. Tunnelling of the Limmern access gallery currently represents the largest inclined shaft to be completed by a TBM.

“Aker Wirth TBM’s have been successfully used in inclined shaft projects since the mid-1960’s”, indicates CEO Christoph Kleuters. In 1967, the Erkelenz company entered the TBM market and one of the first hard rock TBM’s was a special machine of this style designed for inclined shaft tunnelling. “Our customers can rely on over 40 years of experience that we have gathered in the construction of these machines”, says Kleuters.

For the purpose of this special task, the Aker Wirth TBM is connected with backup construction where material can be conveyed between the machine and portal, in addition to the securing and lining of the tunnel walls drilled. This system is constructed by the Swiss cooperation partner Rowa Tunnelling Logistics AG from Wangen, a company that Aker Wirth has collaborated successfully with for many years.

The machine will be completed by mid 2010. Construction will take place at the Erkelenz plant followed by an in-plant test run before being transported and assembled at the jobsite. Drilling of the headrace gallery will commence in fourth quarter 2010.

The extension of the Linth-Limmern pump storage power plant is a highly anticipated future project which aims to expand the harnessing of electrical energy from hydropower. This environmentally-friendly technique, is an important method of generating performance and energy to continue its steady growth, expanding its position in the energy industry. After all, Copenhagen is not all that far away from Erkelenz.