Sustaining the stability and load-bearing capacity of open-pit mine slopes is a critical and complex condition for the transition to open-pit-to-underground mining methods. For this reason, the research in this study aimed to provide a geomechanical justification for the stability of the technological elements of the open-pitto-underground mining complex. This justification, conducted using a developed model, aimed to determine the influence on the formation of the rock mass’s stress-strain state, exemplified by the quarries of the Kryvyi Rih mining and processing plants. In this work, mathematical and numerical methods were applied to predict the influence of the open pit on subsequent underground extraction, including the finite element method, as well as statistical and factor analysis. Additionally, to investigate the stress-strain state of the rock mass surrounding the depleted open pit, the software “Ansys, Inc. Products 2019 R3” was used. It was established that the magnitude of the maximum vertical displacements of the pit slope increases from 13-14 mm on the upper benches at depths of 30-45 m from the ground surface to 60-63 mm on the lower benches at depths of 270-300 m at the bottom of the depleted pit. The dependence of the magnitude of the maximum vertical displacements of the pit slope elements on the depth of excavation is described by a logarithmic function. It was also established that the stress magnitude ranges from 0.7-1.2 MPa at the pit bottom to 4.6-4.9 MPa beneath the pit floor at the depth of the future underground stopes. The dependence of the magnitude of the maximum stresses in the rock mass beneath the pit floor on depth is described by an exponential function. The calculations made it possible to obtain quantitative data on the change in the stress state of the rock mass depending on depth. The practical significance of the work lies in using these indicators to ensure a safe and effective transition to underground mining technology
Oleksandr Shepel (Wed,) studied this question.