1459 2.4. Calibration Calibration was performed iteratively by adjusting rock mass strength parameters within the GHB/GSI framework to achieve agreement between simulated and measured convergence trends across the monitoring network. The calibration window covered two consecutive months of observations, allowing the fitting to reflect both spatial variability and the deformation response associated with mining progress. To reproduce the observed contrast between higher deformation in the active mining zone and lower deformation in long-life excavations, the model was subdivided into four geomechanical zones with separate parameter sets (Figure 6). This zoning approach allowed spatial differentiation of rock mass quality and disturbance (GSI and D), improving consistency between simulations and field observations. Figure 6 - Division of the model into smaller geomechanical structures (zoning used for calibration): - Undisturbed rock mass, - Large pillars, - Technological pillars, - Goaf/backfilled (liquidation) zone Calibration was executed in three iterations. The final (third) iteration provided satisfactory agreement with the measured convergence values across the panel (Figure 7). The validated model was then used for comparative scenario analyses of pillar geometry and identification of zones of elevated geomechanical risk. Figure 7 - Results of convergence measurements (field) and numerical simulations (iterations) used for model validation The final, calibrated parameter set was subsequently used in all scenario simulations to ensure that the comparative assessment reflects realistic in-mine conditions. The calibrated rock (and, where applicable,
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