Analysis of measured and predicted land surface subsidences caused by retreat mining

This article presents the impact of the retreat mining (i.e., involving an intended collapse of the excavation roof, subsequent to extraction) on the subsidence of the ground surface. The analysis was carried out for two areas of coal underground mining located in the Upper Silesian Coal Basin (Górnośląskie Zagłębie Węglowe). The assessment of the influence of exploitation on the ground surface was based on the results of geodetic measurements performed over a long period of time, whereas the land deformation prediction was made with the use of the EDNOPN program. The calculated and the predicted values were further compared, and the parameters of theory were determined. The results discussed in this paper have been shown by way of diagrams. The observed differences in the processes of vertical displacement were used in the analysis which took into account the degree to which the rock mass had been disturbed during the previous excavations, as well as the type of incumbent rock in the area under study.