1480 4.2 Separations The maximum values of roof rock separations recorded during roadway development are presented in the form of bar charts for individual measurement horizons (A, B, and C) as well as their cumulative values. This representation enabled a detailed analysis of the temporal development of roof deformation. The analysis covered two measurement stations located at chainages 564 m (Fig. 7) and 936 m (Fig. 8). At each station, measurements were conducted at three characteristic points of the roadway crosssection: at the left sidewall, along the roadway axis, and at the right sidewall. At both analysed stations, an intensive increase in roof rock separations was observed during the initial period. This phenomenon was particularly pronounced during the first several dozen days, indicating rapid adjustment of the rock mass to the new stress conditions induced by excavation. The highest cumulative separation values were recorded at the left sidewall, reaching approximately 34 mm at the 564 m station (Fig. 7a) and approximately 32 mm at the 936 m station (Fig. 8a). Such significant deformations correlate with a higher number of structural discontinuities, a greater extent of the fractured zone, and the influence of maximum horizontal stresses, confirming the impact of local geological and mining conditions on roof behaviour. Analysis of separation distribution within individual measurement horizons showed that, in all cases, deformations were dominated by horizon A, corresponding to the shallow anchorage zone. This horizon contributed the largest share to the cumulative separation values, both during the initial phase and in the later stages of observation. Separations recorded in horizons B and C were significantly smaller and exhibited long-term stabilization, indicating gradual load transfer to deeper roof strata. Along the roadway axis (Figs. 7b and 8b) and at the right sidewall (Figs. 7c and 8c), separation values were generally lower and more uniform over time. This may indicate more favourable geomechanical conditions and a more even stress distribution in these zones. In particular, at the 936 m station, a clear stabilization of separations was observed following the initial period of rapid changes, suggesting effective performance of the applied support system. The obtained results clearly confirm the key role of the shallow anchorage zone in maintaining roadway roof stability and demonstrate significant variability of deformation depending on the location within the roadway cross-section. The use of extensometers installed at three points across the crosssection enabled a comprehensive assessment of roof behaviour and identification of zones most susceptible to deformation development. a) b)
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