Improving the calculation method for rock bolting parameters of coal mine workings in influence zones of contiguous coal seams
Research objective is to improve the calculation method for rock bolting parameters in section developing entries in the coal mines located in the influence zone of high rock pressure, formed by stable interpanel pillars established in the course of contiguous coal seams development. Methods of research include an analysis of modern methodological approaches to coal mine rock bolting parameters calculation, that are contained in the relevant regulatory documents, as well as an analysis of the world’s experience of ensuring the operational condition of section developing entries in the course of contiguous coal seams development by longwall mining with interpanel pillars. Results. The necessity is shown of improving methodological approaches to rock bolting parameters determination in the influence zone of the edge parts of massif and pillars formed in the course of contiguous coal seams development. The pillar width influence on its stress-strained state is analyzed. The paper justifies the calculation formulae that are based on the width of the pillar established in the course of contiguous overlying and underlying coal seams development. Promising directions are determined for the improvement of schemes and ways of coal mine developing entries support, that make it possible to improve the speed of section developing entries advance for timely preparation of new working areas in the course of intensive coal extraction. Conclusions and scope of results. The parameters of pillar influence zones formed in the course of contiguous coal seams development are largely determined by their width. Taking into account the influence zones of increased manifestations of rock pressure caused by pillars is a prerequisite for the correct calculation of support standards for section mine workings supported by rock bolting. The recommendations for the improved calculation of section developing entry wall bolting parameters and the values of the expected shifts in the areas of increased rock pressure manifestation caused by pillars make it possible to improve the accuracy of the expected shifts prediction. They serve as a theoretical basis for successful implementation of the two-stage schemes of mine support that increase the rate of sinking in the course of intensive coal extraction. The research results can be used to confirm the developing entry bolting standards in the zones of increased rock pressure manifestations formed by the pillars established in the course of contiguous coal seams development.