## 3 Results and Discussion  
Based upon the theoretical underpinnings and initial assumptions, the numerical procedure was applied to model the mining conditions in panel XVII/1 as of the dates the two rockbursts of concern were studied. In the case of the first event (end of Year 3), the area of concern is indicated in Figure 2 outlined with the red line (area of concern #1), in the case of the other rockburst (end of Year 6), it is likewise shown in Figure 3 (area of concern #2). Simulation results are compiled and presented in the form of contour maps and characteristic ranges (sketched in colours) of the variability distribution patterns:  
* Shear strain energy density factor (\(k(A_{f})\)) on the level of burst-prone layers of the main roof (the dolomite-anhydrite interface), defined as \[k\Big{(}A_{f}\Big{)}=\frac{A_{f}}{A_{f}^{raw}}\] (5) where \(A_{f}^{raw}\)--density of the primary shear strain energy associated with gravity-induced stress exclusively, J/m\({}^{3}\). * Effort factor (\(\Omega\)) related to the same roof horizon, \(-\). Actually, all assessments of mining-induced behaviour of rock strata can rely on broader analyses, exploring the stress/strain behaviour, displacement and strain elastic energy or effort parameters. In consideration of the underlying objectives of the study and the adopted synthetic approach, the analysis was restricted to two relatively universal parameters. Strain energy density and effort allow for coupling the deformation and stress-related parameters to mechanical properties of rocks. In relation to the elastic strain energy, the scope of the present study was limited to analyses of the component associated with shear strain as a more reliable indicator in consideration of the subject matter of the study. According to energy-effort criteria [47], the measure of effort is assumed to be the shear strain elastic energy density plus a fraction of volumetric strain energy. Pertinent results obtained for the mining conditions at the end of Year 3 (Figure 2) are shown in Figure 6 (\(k(A_{f})\)) and in Figure 7 (\(\Omega\)); those relevant to the conditions at the end of Year 6 (Figure 3) are given in Figure 8 (\(k(A_{f})\)) and Figure 9 (\(\Omega\)). Each of the contour maps reveal the locations of rockburst events in the energy class in excess of \(10^{4}\) J (Figures 6 and 7--covering the period of the first three years of mining operations, Figures 8 and 9--Year 6). For better clarity,the respective ranges of analysed parameters and the energy classes of registered events are referenced in the legend. The presence of a tremor of \(10^{9}\) J shown in Figures 6 and 7 merits an explanation as it was not included in earlier statistics (Table 2). The established location of its focus is correct yet the tremor occurred in consequence of mining activities in the neighbouring panel, before working panel XVII/1. A rigorous analysis of shear strain energy density factor (\(k(A_{J})\)) and effort factor (\(\Omega\)) distributions reveals that the variability ranges for the analysed events (in Year 3 and Year 6) are similar. It is reasonable to conclude, therefore, that potentially burst-prone roof formations (including the anhydrite layer) were subject to strong deformations, which is evidenced by the gradients of investigated parameters, particularly in the case of the first event (Figures 6 and 7). It should be assumed that the current state of deformation of the main roof must be the consequence of extensive mining activities in the neighbouring panels alongside panel XVII/1. The zones of shear strain energy density concentration and those of maximal effort are irregular and are basically found in two distinct areas, each overlying the undisturbed one body:  
Figure 6: Shear strain energy density (end of Year 3). Figure 7: Effort factor (end of Year 3).