1456 2. MATERIAL AND METHODS 2.1. Geology The case study was conducted in a selected copper-ore mining panel in the Rudna mine (KGHM Polska Miedź S.A., Poland), operated at a depth of approximately 1.23 km and characterized by elevated geomechanical and seismic hazard conditions. The orebody is thin (typically ~1.5 m) and gently dipping, which makes the local stability strongly dependent on pillar geometry, extraction sequencing, and roof–floor interaction. Figure 1 - Scheme of actual and planned excavations in the analysed mining panel Geologically, the deposit is stratiform and developed within the Lower Zechstein carbonate–shale sequence and the uppermost Rotliegend sandstones. Mineralization occurs in both the carbonate–shale and sandstone series, while local variability in thickness and cementation may be observed. The immediate roof is dominated by calcareous dolomite (order of ~10 m), overlain by a massive anhydrite unit (order of ~20+ m), whereas the floor is formed by quartz sandstones with clay cement (order of ~10 m) underlain by red Rotliegend sandstones. Minor tectonic features (e.g., small-displacement faulting and fracture sets) are documented within the panel. Figure 2 - Average uniaxial compressive strength of the deposit and surrounding rocks (roof, orebody, floor) used for geomechanical characterization 2.2. Model preparation A large-scale 3D numerical model was developed using the finite element method (FEM) in GTS NX to reproduce stress redistribution and deformation associated with room-and-pillar mining with roof dolomite sandstone Lithological profile Mining profile anhydryte dolomite sandstone roof floor ore -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 40 80 120 160 200 H [m] Rc [MPa] -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 2 4 6 8 10 H [m] Rr [MPa] -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 10203040506070 H [m] Es [GPa]
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