In autumn 2021, BM Manfred Gratz GmbH was commissioned to carry out drilling in the tunnel systems and at the dam wall of the ÖBB-Infrastruktur AG in the Glacier World Weißsee. The aim was to ensure the drainage of the mountain with deep boreholes of up to 28 m to increase the stability of the Amersee dam.

All the individual steps were planned in detail in advance by our customer, BM Manfred Gratz GmbH. Services. In order to be able to implement the project the best way possible, the lifetimes and a wide range of proposals for the procedure were determined in collaboration with the technical support of TYROLIT.

In total, 28 vertical drainage boreholes with a diameter of 82 mm were drilled at the prescribed angle in the Glacier World Weißsee. The longest boreholes were 28 m through the dam wall into the tunnel system. The total running metre of the project was an impressive 350 m and the material processed ranged from concrete, gneiss and sand to granite. In order to achieve peak drilling times in concrete of up to 18 cm per minute, the segmented drill bits were sharpened beforehand. The average peripheral speed was about 3.5 metres per second. The longest drainage holes achieved up to 6 hours of pure drilling time and the removal of the cores was carried out by using a specially constructed time-saving pulley.

The work was successfully carried out by using TYROLIT PREMIUM CDNX-DCI and CDNX-DCIF (FAST-CUT version) deep core drills, the SR68 drill motor from our partner WEKA Elektrowerkzeuge KG and several TYROLIT extensions of 500 and 1,000 mm.

The drilling work was particularly challenging due to the altitude of 2,250 m. The users were transported to the site by cable car. In addition, the last 7 kilometres to the construction site had to be overcome by ATV (All-Terrain-Vehicle) or bicycle. The tools and machines were flown up the mountain by helicopter. An emergency generator on the dam wall provided the necessary power supply.

The project was successfully completed within three months and the TYROLIT deep core drills proved to be the optimum solution for the complex drilling work in extreme conditions.