Geomechanical substantiation of parameters for safe completion of mining the coal reserves adjacent to main workings

Abstract

Purpose. Geomechanical substantiation of the parameters for conducting stope operations, ensuring the operational state of main workings. Methodology. The research is performed using an algorithm which includes the sequential execution of interrelated stages: analysis of mining-geological and mining-technical conditions for maintaining the network of main workings; mine observations of their state with the identification of specifics of rock pressure manifestations and predicting the probable negative consequences of conducting stope operations in the immediate vicinity; preliminary substantiation of possible technological options for mining the coal seam, taking into account the preservation of operational state of main workings. Scientific calculations for determining the most expedient option are based on the development of geomechanical models of the rock mass behavior around the main workings when mining the adjacent extraction site; analysis of the mass stress-strain state with the prediction of probable rock pressure manifestations; development of recommendations for limiting (or completely eliminating) the negative consequences of conducting stope operations near main workings. The above algorithm of actions uses a combination of experimental mine research methods with technologies for performing computational experiments based on the finite element method. Findings. A systematic analysis of the mining-geological and mining-technical conditions for maintaining the network of main workings has been performed, the results of which are used to substantiate ideas about the mechanism for the occurrence of specifics of rock pressure manifestations, recorded during instrumental observations of their state. Three options have been developed for completing the mining of the extraction site adjacent to the mine horizon main workings. For each of them, a geomechanical model has been constructed for calculating the stress-strain state of the adjacent coal-bearing mass. Its analysis makes it possible to formulate a number of recommendations regarding the rational parameters for conducting stope operations, as well as structural and technological solutions to increase the stability of the main workings and maintain the conditions for their safe operation. Originality. New dependences of influence of the extraction sites on the main working network stability depending on the texture and mechanical properties of lithotypes have been obtained based on the research on the stress-strain state of a weakly metamorphosed mass. For the first time, geomechanical models have been developed of the mutual influence of main workings on the parameters for conducting stope operations. Practical value. The presented recommendations simultaneously reduce the loss of coal reserves and preserve the network of main workings in proper operational state.