224 the roof was fully stable when roof separations (rr) did not exceed 25 mm, moderately stable when 25 < rr < 50 mm, partially unstable when 50 < rr < 75 mm, and unstable when rr > 75 mm. Figure 3 – Multi-point roof extensometer installed in the roadway axis Figure 4 - Instrumented rock bolts installed in the roadway roof 4. MEASUREMENT RESAULT 4.1. Extent of the fractured zone To assess the extent of the fractured zone in the roadway roof, a total of 17 boreholes were drilled successively during roadway development. The degree of rock mass disintegration was evaluated using an endoscopic camera, which enabled direct observation of borehole walls and identification of existing structural discontinuities (Fig. 5). Measurements were carried out in the roof, directly behind the excavation face, at intervals of approximately 20 m. This approach allowed for detailed identification of changes in geomechanical parameters along the analysed section of the roadway. The results revealed a distinct variability in both the extent of the fractured zone and the number of discontinuities as a function of roadway length (Fig. 6). Particularly unfavourable geological conditions were identified in the initial part of the analysed section, especially in the vicinity of chainage 250–300 m, where a simultaneous, significant increase in the number of discontinuities and the maximum extent of the fractured zone was recorded, locally reaching approximately 7.2 m. This indicates intensive disintegration of the roof rocks, most likely associated with the presence of lithologically weakened layers and zones affected by water inflow. In the subsequent section, between approximately 350 m and 600 m, geological conditions remained variable; however, the extent of the fractured zone gradually decreased despite local increases in the number of recorded discontinuities. In the final part of the analysed roadway section (beyond 600 m), the extent of fracturing was markedly smaller and, in most cases, did not exceed the length of the installed cable bolts, indicating a relative stabilization of roof conditions. The observed relationship between the number of discontinuities and the maximum extent of the fractured zone confirms the significant influence of local geological
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