Geological Exploration Work
The aim of the planned geological work is to acquire geological, structural, hydrogeological, geochemical, geomechanical and geophysical data and its subsequent interpretation so that it can be employed for safety and engineering evaluation purposes and a comparison of the sites being considered for the construction of the deep geological repository.
The geological work project forms a part of the initial search phase. Technical work as defined in Decree No. 369/2004 Coll., as amended, will not be conducted during this phase (e.g. deep borehole drilling).
One of the most important outcomes of this phase will consist of the gathering of specification and localisation data with a view to the performance of technical work during the exploration stage, provided that the relevant exploration area is, on the basis of a safety and engineering comparison, considered appropriate for the next exploration phase.
The various planned exploration methods and activities were defined in the official application for the establishment of exploration areas and subsequently confirmed and supplemented by a decision issued by the Ministry of the Environment. It is planned that the following activities will be performed in compliance with this documentation:
- the study, evaluation and reinterpretation of previously compiled geological and geophysical final reports, assessments and measurements;
- application of the remote sensing (RS) method;
- basic geological research and targeted geological mapping;
- basic hydrogeological surveys and hydrogeological mapping;
- surface geophysical surveys;
- application of surface geochemistry;
- study and analysis of rocks and water;
- creation of a database of the relevant geological features and phenomena;
- the continuous and comprehensive evaluation of the various research findings.
Prior to the commencement of actual fieldwork, a study and evaluation and/or reinterpretation of all existing relevant documentation will be performed, including: geological, structural, hydrogeological, hydrological, geophysical and geological reports and maps, structural geology and geotechnical reports, primary data, rock and water properties, etc.
Regarding the remote sensing, SÚRAO employs optimal data for the study of structural conditions (long wavelength radar data, aerial orthophotography, optical satellite data, and fourth or fifth generation digital relief models).
The study and mapping of surface rocks, cover formations and structural-geological conditions will be conducted in the framework of basic geological research and mapping work. The results of the geological mapping of cover formations will consist of the creation of engineering-geological site-specific maps, which make up a prerequisite for the planning and design work connected with the positioning of the surface complex. In addition, information gathered via the above-mentioned geological fieldwork will also be used in the compilation of such maps.
Hydrogeological research will focus on improving knowledge and imaging regarding the occurrence of local groundwater and surface water systems and the regimes that govern them, the hydraulic parameters of the rock mass and the chemical composition of the water in the exploration area. The main purpose will be to compile specific-purpose hydrogeological maps and the revision of published medium-scale hydrological and hydrogeological maps. In addition, a database will be created of the relevant hydrogeological features in the area. Hydrogeological monitoring will also be conducted as part of the research.
A further important part of the research will consist of surface geophysical surveys which are expected to provide new data on the surveyed areas. Surveys will be conducted covering the whole of the respective site or only on selected profiles. Urban areas and excluded areas defined by the Ministry of the Environment will not be subjected to this research. Geophysical methods will be used for the locating and tracking of tectonic lines on the surface and deep within the rock mass, for the physical distinction of the different types of rock present and the monitoring of the interfaces between them and determination of the strength and saturation of the weathered and Quaternary cover etc.
Some areas will also be subjected to surface geochemical analysis which will determine the geochemical background and identify geochemical anomalies indicating areas with above-average or below-average contents of the elements monitored.
The analysis of rock and water samples will focus on the study of the petrography of the rocks, microstructural characteristics and rock geochemistry so as to determine the relevant petrophysical, mechanical, deformational, thermal, and technological properties, such as the water chemistry. Analytical work will chiefly concern general geological, hydrogeological, surface geochemical and engineering geology characteristics.
A database will be created of the monitored parameters which will contain archive data gathered in previous surveys as well as new and updated data. The final phase of the research will consist of the comparison of the studied sites based on the parameters set out in the resulting documentation Requirements, suitability indicators and criteria for the selection of potential deep geological repository sites.