Digitalization and Spatial Visualization of Exploration Drillhole Data Using the Open-Source GIS Platform QGIS: A Case Study of the Jasenie-Kyslá W-Au Ore Deposit, Central Slovakia, Western Carpathians

The study area is situated in the Low Tatras Mountains – a typical example of the Tatric crystalline basement of the Western Carpathians in Slovakia. The geological exploration took place between 1980 and 1991 and is considered one of the most complex and detailed tasks in Slovak ore-body exploration. As a result, a 2 km² mineral deposit was delineated and studied for scheelite-gold ore bodies. The deposit was considered economically marginal and non-economic for further search and mining under prevailing market conditions. However, in the field of geology, it represents an interesting and unique locality of tectonic development in the Low Tatras Mountains. The deposit is located in a highly fragmented area with a complex fault system, as there are 4 rock complexes on a relatively small area.

The complexity of the geological structure and the inconsistency of interpretations regarding the areaˈs development are common topics of discussion among experts. The use of modern geoinformatics technologies, which can process data from geological surveys, can help interpret the positions of rock complexes and bring new knowledge to discussions about the development of the area. The asymmetric nature of megaanticlines of crystalline basement is also shown here - the southern slopes consist of metamorphites, while the northern ones feature granitoids.

The result of the geological survey is a final report that contains detailed data of 220 exploration drillholes, forming a relatively dense network up to a depth of 650 m. These are essential for digitalization and spatial visualization in the GIS environment. For a long time, such visualizations were only obtainable using specialized software platforms, which are typically financially demanding items. Nowadays, freely available GIS technologies are capable of processing complex data to create simple visualizations of geological surveys. Probably the best example is open-source software QGIS – this popular platform with many available plug-ins focused on all kinds of geospatial themes. Geoscience is a dedicated plug-in for processing the data of a geological survey. Based on the coordinates of initial drillhole points, inclinometry, and lithological content of drillholes, the plug-in can create 3D line layers in a GIS environment that represent their real spatial extent.

196 underground and 24 surface wells were visualized, with a minimum length of 15.5 m (underground well No. 12) and a maximum length of 650 m (surface well No. 99). The boreholesˈ spatial paths, direction, and mutual orientations cover a large part of the deposit, as well as the area to the north-east.

Thanks to the number of work modules with a wide range of focus and their gradual development, QGIS will potentially represent a suitable alternative to commercial geological 3D modeling software in the near future. By checking the input data and possibly modifying it based on a simple initial visualization, the level of the database that can be worked with at a professional level is reached.

 

This abstract was supported by grant APVV-22-0092.