Headrace tunnel Lünersee injection into core ring

Underground Mining Special projects

Project data

Vorarlberger Illwerke AG
Order sum
0.25 million EUR
Period of implementation
January 2013 - January 2013

Sekretariat Untertagebau
+43 5556 7181-817

Due to significant water losses, the almost 60-year-old core ring stretch of the Lünersee headrace tunnel (diameter of 3.05 m) needed in some places to be reinforced by means of injection. To this end, star-shaped holes were sunk in a 1.5-m grid over a section of about 100 m. In order to penetrate the approx. 50-cm-thick, heavily reinforced wall ring level, core holes were drilled first to allow the injection star to be sunk to a depth of approx. 2 m by means of hammer drilling.

This special project was particularly characterised by the extremely short preparation time of just a few days, the tight time window during the closure of the Lünersee pumped-storage plant and the difficulty of access via cable cars and on foot.

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