Substantiation of resource-saving technologies for supporting and protecting mine workings at their repeated use

Purpose. To determine the effective parameters of a resource-saving technology for supporting and protecting a panel entry during its repeated use based on experimental studies and multifactor computer modeling. Methods. The study employed both experimental and numerical research methods. The experimental part included in-mine observations of rock pressure manifestations in repeatedly used extraction workings of the Western Donbas. The state of the workings was assessed by the displacement of the drift contour and parameters of frame support deformation in key cross-sections. Numerical modelling of the geomechanical state of the rock mass and support systems was performed using the ANSYS software package based on the finite element method (FEM), taking into account the texture of the coal-bearing stratum, physical and mechanical properties of lithotypes, moisture content, fracturing, rheological properties of rocks, and disruption of contacts between adjacent layers. Findings. Based on experimental studies and numerical modelling, the effectiveness of using rope crown runners in combination with a combined roof-bolting system has been proven. It has been established that the proposed support scheme reduces the intensity of rock pressure manifestations and ensures significant savings in material and labour resources during the repeated use of mine workings. The feasibility of its application for supporting prefabricated drifts under complex mining and geological conditions of the Western Donbas has been confirmed. Originality. The features of the formation of the stress-strain state of the rock mass surrounding an extraction working during its repeated use have been established, and the effectiveness of a combined roof-bolting system with rope crown runners for reducing rock pressure manifestations has been substantiated. New data on the redistribution of stresses in the roof and side rocks of the working have been obtained, explaining the mechanism of increasing its stability when using the proposed support system. Practical implications. The results of the study can be used in the design and selection of resource-saving support schemes for repeatedly used drifts under conditions of weak surrounding rocks and increased rock pressure manifestations.