221 loading (Gray & Gibbon, 2023). Understanding the magnitudes and orientations of these stresses has led to the development of the concept of directional mining, which involves driving roadways parallel to the maximum horizontal stress component. This approach reduces the extent of damaged zones and increases excavation advance rates (Mark, 2001). Technological and mining factors are also of considerable importance, including the selection of bolt type, length, spacing, and installation method. Experience indicates that the effectiveness of rock bolt support depends not only on bolt length but also on bolt differentiation, orientation, and the justification for applying pretension, which depends on the bolt type and the degree of rock mass fracturing. In addition, under Polish mining conditions, the stability of underground roadways is significantly affected by the edges of previously extracted seams located above, the number of which may reach up to twenty. These generate a pronounced increase in stresses within the rock mass of underlying seams. Currently, the design of rock bolt support systems increasingly combines empirical approaches (such as the use of geotechnical classifications, e.g., RMR or GSI), analytical methods, and numerical modelling, with particular emphasis on the analysis of monitoring results and their statistical interpretation (Nicholson, 2016). All these approaches, however, require detailed identification of the geomechanical properties of the rock mass, including rock strength, deformability, bedding, discontinuities, and resistance to water action (Małkowski et al., 2016; Bednarek & Mejcherczyk, 2020). These parameters, determined through laboratory and in situ investigations, exhibit significant variability and therefore require regular verification. It should be noted that simplified loading models and empirical methods for determining the extent of the fractured zone were developed for shallower mining conditions, typically at depths of 400–600 m (Barczyk et al., 2001). At present, these approaches are no longer applied due to their limited consideration of influencing factors, particularly the lack of reference to actual stress conditions and the averaging of geomechanical parameters of rocks surrounding mine workings. Given the great mining depth, variability of rock properties, and the presence of numerous mining and geological factors—such as the edges of overlying extracted seams or faults—only continuous analysis of roadway behaviour can ensure its proper maintenance. 3. STUDY AREA AND RESEARCH METHODOLOGY The investigations were conducted in a roadway with a total length of 1,970 m. Due to a change in the driving direction resulting from the proximity of a fault, this paper presents the results of analyses for the section between 230 m and 1,040 m. The roadway was developed within a coal seam of 2.5 m thickness, with claystone roof and floor, locally sandy, and locally interbedded with a sandstone layer. During roadway development, the rock strength was continuously monitored using a penetrometer, and the Rock Quality Designation (RQD) of drill cores was also locally assessed. The results indicate (Table 1) that the in situ uniaxial compressive strength of the roof rocks to a depth of 10 m ranged from
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