The coal exploitation in the Upper Silesia region (along the Vistula River) triggers the strata seismic
activity, characterized by very high energy, which can create mining damage of the surface objects, without
any noticeable damages in the underground mining structures. It is assumed that the appearance of the
high energy seismic events is the result of faults’ activation in the vicinity of the mining excavation. This
paper presents the analysis of a case study of one coal mine, where during exploitation of the longwall
panel no. 729, the high energy seismic events occurred in the faulty neighborhood. The authors had analyzed
the cause of the presented seismic events, described the methods of energy decreasing and applied
methods of prevention in the selected mining region. The analysis concluded that the cause of the high
energy seismic events, during the exploitation of the longwall panel no. 729 was the rapid displacements
on the fault surface. The fault’s movements arose in the overburden, about 250 m above the excavated
longwall panel, and they were strictly connected to the cracking of the thick sandstone layer.
The paper presents a new geotechnical solution indicating a possibility of effective building structures protection. The presented solutions enable minimization of negative effects of underground mining operations. Results of numerical modelling have been presented for an example of design of preventive ditches reducing the influence of mining operations on the ground surface. To minimize the mining damage or to reduce its reach it is reasonable to look for technical solutions, which would enable effective protection of building structures. So far authors concentrated primarily on the development of building structure protection methods to minimize the damage caused by the underground mining. The application of geotechnical methods, which could protect building structures against the mining damage, was not considered so far in scientific papers. It should be noticed that relatively few publications are directly related to those issues and there are no practical examples of effective geotechnical protection. This paper presents a geotechnical solution indicating a possibility of effective protection of building structures. The presented solutions enable minimization of negative effects of underground mining operations. Results of numerical modelling have been presented for an example of design of preventive ditches reducing the influence of mining operations on the ground surface. The calculations were carried out in the Abaqus software, based on the finite element method.
Coal is the main energy source in China, but its underground mining causes surface subsidence, which seriously damages the ecological and living environments. How to calculate subsidence accurately is a core issue in evaluating mining damage. At present, the most commonly used method of calculation is the Probability Integral Method (PIM), based on a normal distribution. However, this method has limitations in thick topsoil (thickness > 100 m), in that the extent of the calculated boundary of the subsidence basin is smaller than its real extent, and this has an undoubted impact on the accurate assessment of the extent of mining damage. Therefore, this paper introduces a calculation model for surface subsidence based on a Cauchy distribution for thick topsoil conditions. This not only improves the accuracy of calculation at the subsidence basin boundary, but also provides a universal method for the calculation of surface subsidence.
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