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Safety detonation above the Länta SAC hut

Vals GR 2019 - present

In September 2019, a safety detonation planned by GEOTEST Ltd eliminated the acute rockfall hazard at the Länta SAC hut. Since then, the protection dam built for the purpose of the detonation has continued to safeguard the hut against rockfall as a long-term measure.

In June 2019, the Länta SAC hut was seriously damaged by two boulders. Detailed geological investigations demonstrated that this boulder strike was merely a harbinger of an impending, much larger rockfall event. The Länta hut and its immediate surroundings were in acute danger. After a thorough examination of all possibilities, the Bodan section of the SAC decided in favour of the detonation measures proposed by GEOTEST.

In September of the same year, a safety detonation was performed about 300 metres above the Länta hut. In the process, around 4,000 m3 of rock – roughly the volume of 550 truckloads – was released.

Thanks to a protection dam erected as an emergency measure about 50 m above the Länta hut site, only minimal damage was caused to the hut. The debris collected behind the dam was then emptied and the dam was widened slightly. The dam now serves as a permanent measure to protect people in and around the Länta hut from falling stones and boulders.

GEOTEST assumed responsibility for the construction management and project management of the safety detonation, as well as the initial assessment after the event, the detailed hazard and risk assessment, the evaluation of protection measures, and the detailed planning of the best variant.

The damaged Länta hut in June 2019.

Boulders intercepted during the detonation.

A protection dam provides long-term protection for the Länta hut.

The acute danger was eliminated and the Länta hut is now better protected against rockfall than ever before.

Thomas Bickel, project manager GEOTEST

Video: Safety detonation above the Länta SAC hut

Contact person

Thomas Bickel

Diplom-Ingenieur (Dipl.-Ing.)

Projektleiter, Standortleiter (Stv.)

+41 81 410 35 02

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