## 3 Results of Conducted FEM Simulations for LW501 and LW502 Longwall Panels Exploitation  
The development of the subsidence trough, observable on the observation line during the operation of the LW501 and LW502 longwalls, is presented in Figure 5. Due to the significant distance of the observation line points from the operation carried out from June to December 2021, i.e., the LW501 longwall, the recorded subsidence does not exceed 4 cm at the end of November 2021. Only the exploitation of the LW502 longwall carried out directly under the observation line leads to larger displacements of the terrain surface. Exploitation was carried out in direction from point 40 to point 1, which shows the development of the subsidence trough in Figure 5. The operation was completed at the end of May 2022, and a slight increase in subsidence between the last two observation series (12 May 2022 and 4 August 2022) indicates the presence of residual subsidence on the land surface. The maximum observed subsidence on the observation line equals \(\text{s}_{\text{max}}^{\text{obs}}=661\) mm at point 23. The second series of land surface subsidence measurements were carried out at the end of November 2021. As of this day, the face advance of longwall panel 501 was determined at a distance of 500 m from the beginning of the longwall. The maximum measured subsidence was 36 mm and it was located in point no. 23. Having this information, the parameters of the rock layers were calibrated using ABAQUS 2022 hf4 software and author's Python 3.9 script in order to adjust the simulated subsidence to the real values. The estimated values of mechanical parameters are listed in Table 5 and the plot of fit is shown in Figure 6.  
Figure 5: Land surface subsidence along the observation line. Figure 6: Comparison of the observed and simulated subsidence—25 November 2021. \begin{table}
\begin{tabular}{c c c c c c c c} \hline  & \(\mathbf{G_{12}}\) & \(\mathbf{G_{13}}\) & \(\mathbf{G_{23}}\) & \(\mathbf{E_{1}}\) & \(\mathbf{E_{2}}\) & \(\mathbf{E_{3}}\) & \\  & [**GPa**] & [**GPa**] & [**GPa**] & [**GPa**] & [**GPa**] & [**GPa**] & [**GPa**] & \(\boldsymbol{v_{12}}=\boldsymbol{v_{13}}=\boldsymbol{v_{23}}\) \\ \hline Quaternary & 0.01 & 0.02 & 0.02 & 0.02 & 0.02 & 0.02 & 0.41 & 0.15 \\ Sandstone & 0.10 & 0.21 & 0.21 & 0.23 & 0.23 & 3.79 & 0.15 \\ Silstone & 0.21 & 0.45 & 0.45 & 0.48 & 0.48 & 8.00 & 0.15 \\ Coal & 0.13 & 0.29 & 0.29 & 0.31 & 0.31 & 5.14 & 0.15 \\ \hline \end{tabular}
\end{table} 
Table 5: Final mechanical parameters of rock mass layers—mining situation—25 November 2021. In Figure 7, the distribution of land surface subsidence based on FEM analysis is shown. For the analyzed mining situation, the maximum subsidence of 433 mm was obtained. The fifth series of land surface subsidence measurements were carried out at the beginning of August 2022. As of this day, the mining of the longwall panel 501 and 502 have been completed. The maximum measured subsidence was 637 mm and it was located in point no. 23. Having this information, the parameters of the rock layers were calibrated using Abaqus software and Python script in order to adjust the simulated subsidence to the real values. The estimated values of mechanical parameters are listed in Table 6 and the plot of fit is shown in Figure 8. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & \(\mathbf{G_{12}}\) & \(\mathbf{G_{13}}\) & \(\mathbf{G_{23}}\) & \(\mathbf{E_{1}}\) & \(\mathbf{E_{2}}\) & \(\mathbf{E_{3}}\) & \\  & \([\mathbf{G_{F}}\mathbf{a}]\) & \([\mathbf{G_{F}}\mathbf{a}]\) & \([\mathbf{G_{F}}\mathbf{a}]\) & \([\mathbf{G_{F}}\mathbf{a}]\) & \([\mathbf{G_{F}}\mathbf{a}]\) & \([\mathbf{G_{F}}\mathbf{a}]\) & \(\mathbf{v_{12}}=\mathbf{v_{13}}=\mathbf{v_{23}}\) \\ \hline Quaternary & 0.02 & 0.03 & 0.03 & 0.04 & 0.04 & 0.61 & 0.15 \\ Sandstone & 0.15 & 0.32 & 0.32 & 0.34 & 0.34 & 5.69 & 0.15 \\ Silstone & 0.31 & 0.67 & 0.67 & 0.72 & 0.72 & 12.00 & 0.15 \\ Coal & 0.20 & 0.43 & 0.43 & 0.46 & 0.46 & 7.71 & 0.15 \\ \hline \hline \end{tabular}
\end{table}