Boichenko H. Comprehensive substantiation of measures to create safe working conditions for miners while supporting preparatory workings of steep coal seams

The dissertation solves an urgent scientific task regarding the comprehensive substantiation of measures to create safe working conditions for miners while supporting the preparatory workings of steep formations based on the disclosure of the features of geomechanical processes manifested during the unloading of a coal-bearing massif and the regularities of the deformation properties of flexible protective structures, when during the management of the condition of the roof in the process their compression causes a change in the speed of convergence of side rocks and a decrease in displacement growth on the contour of the preparatory workings, which are supported behind the cleaning pit, due to which their stable condition is ensured along the length of the excavation section, which prevents the collapse of side rocks in the excavation sections of coal mines. The idea of the work was to substantiate the measures to create safe working conditions for miners in mines that develop coal seams of steep descent due to the use of geomechanical processes manifested in the coal-bearing massif and the laws of deformation properties of the protective structures of the preparatory workings that are supported, which will ensure their stability along the length excavation site due to limiting the movement of lateral rocks on the contour and preventing the collapse of rocks. The purpose of the work was comprehensive substantiation of measures to create safe working conditions for miners while maintaining preparatory workings in excavation areas of coal mines that develop steeply falling layers. 9 In the work, the following tasks were set and solved: an analysis of industrial injuries from side rock collapses in the coal massif was performed and directions were established for substantiating measures to create safe working conditions for miners while maintaining preparatory works in the excavation areas of coal mines; theoretically and experimentally determined the conditions of stability of side rocks and their stress-deformed state around the preparatory workings, taking into account the method of protection to increase the safety of miners; laboratory studies of the stability of side rocks were carried out, taking into account the deformation characteristics of protective structures of preparatory mine workings to prevent collapses; mine instrumental studies of the stability of preparatory workings at excavation sites were carried out to assess the safe working conditions of miners; an assessment of the stability of roll-back sections was established using statistical analysis of failures of arch flexible fasteners, and technical solutions were developed to create safe working conditions for miners at mining sites. The object of the research was the processes of managing the state of the roof in the coal massif with preparatory works to ensure their stability and prevent the collapse of side rocks along the length of the excavation section. The subject of the study was the patterns of changes in the stress-strain state of side rocks with different methods of protection of preparatory works. The work used a comprehensive approach, which included: analysis and generalization of known research; analytical and laboratory studies of the stability of side rocks; methods of mathematical statistics and planning of experiments; mine instrumental observations of the process of deformation of rollback stretches; processing, analysis and interpretation of the obtained results.