With the Stadel-3 borehole, Nagra enhanced its knowledge of the Nördlich Lägern siting region. Drilling was conducted from December 2020 to July 2021. The Stadel-3 borehole in the Hasliboden area reached a depth of just over 1,280 metres.
Borehole near the Haberstal
The Bülach, Bachs, Stadel-2 and Stadel-3 boreholes supplement the overview of the geological conditions in the region. In the south-eastern part of the siting region, the Opalinus Clay shows quiet bedding,
The Stadel-3 borehole penetrated a representative section of the siting region near a fossilised coral reef. The Bülach borehole is also located near this coral reef and the Stadel-2 borehole to the west of it.
In addition, various tests were carried out in the Stadel-3 borehole, providing valuable information on the overall picture of the geological subsurface in the region. The Stadel-3 borehole is located in the immediate vicinity of the Haberstal, which is foreseen as the access point to the deep geological repository.
Earlier boreholes
Data for the Nördlich Lägern region are already available from a deep borehole previously drilled in the community of Weiach in 1983 (see photo on left). The Weiach exploratory borehole reached a final depth of 2,482 metres. As a result, for the first time, it was possible to prove beyond doubt the existence of the so-called Permo-Carboniferous Trough, which is sunk deep into the crystalline bedrock.
Investigations using so-called 3D seismic measurements – similar to probing the subsurface by means of ultrasound – revealed fault zones in the deep subsurface in the northern part of the Nördlich Lägern siting region. For a deep geological repository, the geology has to be undisturbed. Nagra therefore withdrew the other applications for boreholes in Weiach and Glattfelden that had been submitted as part of the 2019 – 2022 deep borehole campaign. No new findings were to be expected.
Find out more about the Weiach exploratory borehole in Technical Report NTB 88-08.
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Further deep boreholes
Stadel-2 borehole
The Stadel-2 borehole was the third deep borehole to be drilled in the Nördlich Lägern siting region as part of Stage 3 of the site selection process.
Bachs-1 borehole
The Bachs borehole was the fourth deep borehole to be drilled in the Nördlich Lägern siting region as part of Stage 3 of the site selection process.
Bülach borehole
Bülach was the first deep borehole to be drilled in the Nördlich Lägern siting region as part of Stage 3 of the site selection process for a deep geological repository.
Trüllikon-1 borehole
The Trüllikon borehole was the first deep borehole to be drilled in the Zürich Nordost siting region as part of Stage 3 of the site selection process.
Marthalen borehole
The Marthalen borehole was the second deep borehole to be drilled in the Zürich Nordost siting region as part of Stage 3 of the site selection process.
Rheinau-1 borehole
The Rheinau borehole was the third deep borehole to be drilled in the Zürich Nordost siting region as part of Stage 3 of the site selection process.
Bözberg-1 borehole
Bözberg-1 was the first deep borehole to be drilled in the Jura Ost siting region as part of Stage 3 of the site selection process.
Bözberg-2 borehole
Bözberg-2 was the second deep borehole to be drilled in the Jura Ost siting region as part of Stage 3 of the site selection process.
Work report
