In recent years, we have closely examined the geological underground in the three potential siting regions for a deep geological repository. Investigations included extensive geological measurements and deep boreholes. We are now in a position to say that we know the underground very well.
Geologist Rodney Garrard has many years of experience exploring the underground. During the deep borehole campaign, one of his tasks included the coordination of so-called "stress measurements" in the boreholes. Thanks to these measurements, we understand how the rock behaves when forces act on it. This is important, for example, during the construction of the emplacement drifts and for the period following waste emplacement. Each rock layer that was drilled through was examined separately.
The data obtained are unique worldwide in terms of information density and are central to the detailed planning of a deep geological repository:
- 15 different rock formations tested
- around 185 measuring points in eight different boreholes (total > 1200 measurement cycles)
- 900 operating hours
At the annual meeting of the American Rock Mechanics Association, the documentation of these stress measurements was awarded as best research paper.