## 1 Introduction  
Rock burst is a catastrophic phenomenon occurring in underground mines and geotechnical openings during which rocks are violently ejected into the excavation space. As a result of this dynamic phenomenon, the underground opening or its part including support, machines, and devices are damaged or destroyed. In most underground mines or underground geotechnical structures, rock bursts have a stress cause. The stress level in the rock mass in the vicinity of the opening is so high that the strength of the rocks is exceeded, and they suddenly break. Of course, the ability of rocks to accumulate strain energy and release it rapidly is also essential. In underground hard coal mines, a rock burst can be defined as a sudden release of strain energy accumulated in the rock mass, correlated with high-energy vibrations of rock mass, and acoustic effects and shock waves causing the structural destruction of a coal seam or its roof or floor rocks, and, simultaneously, an ejection of rocks into the excavation [1]. The dynamic destruction of an opening in a coal seam, having a stress origin, is usually referred to as a coal bump. However, due to its characteristic geological structure (i.e., thick layers of competent rocks), other types of rock bursts, called stroke rock bursts, can be found in coal mines [1, 2]. Stroke rock burst is caused by the dynamic load pulse resulting from the fracture of thick layers of competent rocks, which affects the part of a coal seam close to an excavation [2]. However, the coal seam need not be stressed [2]. This dynamic load pulse may also impact the partially stressed sidewall part. Such a mixed rock burst is referred to as a stress-stroke [2]. The occurrence of rock bursts in coal mines is conditioned by many factors, making their prediction very challenging. The ability of the coal seam to accumulate strain energy and violent disintegration (i.e., the proneness of the coal seam to burst and the stress level in the coal seam) is of great importance [1; 2]. The stress level in the coal seam may result from the thickness of the overburden, mining remnants, protective pillars, and geological disturbances [1; 2]. Additionally, mining works performed in the same coal seam may significantly determine the risk of rock bursts in subsequent openings [2]. A neighborhood of goals in the same coal seam or excessive bed cutting may affect the level of rock burst hazard [2]. A floor heave may occur when the seam is thick or weak rocks are deposited in its floor (e.g., shales). This phenomenon is often associated with a rock burst, especially when the top layer of a thick seam is mined first, and there is coal on the floor of the excavation. The presence of thick sandstone layers in the deposit structure is also a factor that may affect the occurrence of stroke or stress-stroke rock bursts. The proneness of the seam and the surrounding rocks for the occurrence of rock bursts may be considered together. In addition to those above-mentioned, mining and technical factors may also determine the occurrence of rock bursts. Releasing stress from the coal seam or fracture of strong roof rocks (e.g., by blasting) can significantly reduce the occurrence of rock bursts. Moreover, strengthening the support of openings may make them more resistant to rock bursts. In such cases, the rock burst may not occur, or its damage may be minimized. As presented above, the multitude of factors influencing and minimizing the occurrence of rock bursts is significant in coal mines. The risk of rock bursts is one of the basic threats in coal mines in the Upper Silesian Coal Basin (USCB). In mines located in the USCB area, the mining hazard assessment method estimates the potential risk of rock bursts. This method is a part of the complex method for assessing the state of rock burst hazards in coal mines [2].