Limberg II: Giant moles take up their task


Two gigantic tunnel construction machines will bore through rock until winter 2008 and create a technical masterpiece.

Decisive phase on Salzburg's largest construction site
The work on Salzburg's largest construction site for the new pumped storage power plant Limberg II at the rear of Kaprun valley is in full swing and has now entered into a decisive phase. In a celebratory act, the two giant milling machines were commissioned on 18 July 2007. One of the machines will create a 3.9 km-long water works tunnel in the mountain. With a diameter of seven meters, a weight of 900 tons and a length of 240 meters, the machine will remove an average 20 meters of mica shale per day until the end of January next year. The second milling machine, which is a little smaller with a weight of 400 tons, a length of 90 meters and a diameter of 5.8 meters, will also have to produce a technical masterpiece. Indicating that the weight of the milling machine and the bracing of the machine in the steep pressure shaft to ensure that it does not slip backwards is a great technical challenge, Dr. Herbert Schröfelbauer, Chairman of the Managing Board of VERBUND-Austrian Hydro Power AG explains: "The machine will excavate an average of 10 meters per day until the end of November to create a 750-meter pressure shaft with an angle of inclination of 45 degrees." The two giant milling machines dismantled into their individual components at the beginning of May, transported to the mountain and assembled by experts in self-excavated assembly caverns.

Construction in full swing: Four months ahead of schedule
Over the past months, the site development work was completed according to schedule and the actual construction of the power plant commenced. Thanks to the mild winter and excellent site organization, construction got under way four months earlier that planned in March following the excavation of the machine and transformer caverns.

Ecological conditions met down to the last detail
Approx. 220 workers will work on the Limberg II construction site until completion of the excavation work at the end of January 2008. After this, the two caverns and the works water channel will be completed. All work will be carried out under the supervision of the Institute for Ecology in Salzburg. Mag. Michael Amerer, Managing Director of VERBUND-Austrian Hydro Power AG: "We attach great importance to ensuring that all of the imposed ecological conditions are met down to the last detail during the construction of Limberg II and are also committed to restoring the natural landscape on an ongoing basis while the construction work is in progress. In the last months, the embankments of the access road to the new Lärchwand tunnel and the rock beds near Ebmattenalm have been planted. The traces of the construction work on the Drossen Dam which were still visible 50 years later were also removed during the construction of Limberg II and the entire area was returned to its natural state.

Tourist attractions not affected by construction work
In spite of the extensive construction work, the Alpine storage lakes "Wasserfallboden" and "Mooserboden" in Kaprun, one of the most popular tourist attractions in the province of Salzburg, will be almost fully accessible throughout the summer months. There may be short waiting periods but the footpaths were rerouted prior to the commencement of the construction work and can therefore be used as normal by the visitors.