From Drilling Core to Model: A Multimethod Approach to Subsurface Characterization at Asse Salt Dome

In accordance with § 57b of the German Atomgesetz, the Asse II potash and salt mine has to be closed down immediately after the retrieval of the stored radioactive waste. Due to the current technological and geological status of the mine, a new retrieval mine is indispensable for achieving this goal. Thus, an extensive exploration of the currently undisturbed part of the Asse salt dome in the southeast of the current mine is required.

Given the internal complexity of steep salt formations and the resulting challenges with exploring those, a cross-discipline approach was and still is irreplaceable for creating the required geological model of the Asse salt dome. This presentation discusses the used multi-method workflow starting with detailed drill core analysis utilising a combination of traditional geological core description and a variety of non-destructive and destructive geochemical analyses. The resulting lithology log is subsequently extrapolated into the 3D-space using mainly borehole ground-penetrating radar with different frequency ranges. In the last step a detailed model of the subsurface is constructed using the results of the afore mentioned methods in combination with modern surface based geophysical measurements like 3D seismic and rechecked or partially revised historical data like mine plans and drill logs. The approach contributes to best practices in geological modelling of salt structures (e.g., for deep geological repositories), and can serve as a template for similar projects in comparable geological settings.