Geological assessment of the Asse salt structure
Country / Region: Germany
Begin of project: May 1, 2014
End of project: December 31, 2025
Status of project: December 12, 2023
Geological core processing and mineralogical characterisation of the cored rock in a thin section
Source: BGR
Project description
As part of the measures for decommissioning the Asse II mine, the construction of a retrieval mine and a new shaft is necessary for retrieving the radioactive waste. The geological composition of the salt structure needs to be explored and evaluated to find a suitable location for these new facilities. On behalf of the Federal Company for Radioactive Waste Disposal (Bundesgesellschaft für Endlagerung mbH, BGE), BGR has been actively involved since 01.05.2014 in the planning and implementation of geoscientific exploration work, as well as the quality assurance, evaluation and interpretation of these activities. The integrated evaluation of the exploration data collected in this way allows the coherent geological site description of the Asse salt structure.
Implementation (right) and structural-geological evaluation (left) of an optical borehole survey in an underground exploration borehole
Source: BGR
Project objectives
One of the main aspects involves the detailed geological processing and stratigraphic interpretation of the drill cores obtained from surface and underground exploration boreholes. Complemented by mineralogical/geochemical analyses, the penetrated evaporite and cap rocks as well as solutions and gases are characterised in terms of their composition and genesis. The structural-geological evaluation of various borehole logs (e.g., georadar surveys, cf. Geophysical investigations work package) allows conclusions to be drawn on the three-dimensional structure of the geological horizons.
The geoscientific exploration results are reviewed, jointly evaluated and interpreted. The resulting information on the geological structure and external shape of the salt structure is incorporated in a geological 3D model (cf. 3D-repository model work package) and forms the geological basis for the retrieval planning.
New findings in the south-east study area reveal a narrower and internally complex salt structure, which means that the existing model concepts of this part of the structure need to be revised.
In October 2023, drilling work began on the Remlingen 18 exploratory drilling, which is intended to confirm the suitability of the site for the new Shaft 5.