Features of the development of longwalls that extract the underworked sylvinite layer in the deep horizons of the Starobin potash salt deposit

A study was made of the features of rock pressure manifestation and the deformation nature of development and assembly workings depending on the binding of the roof and its location relative to the longwalls mined by the chamber system for layers 2, 2-3, 3, as well as of the panels mined by the chamber system in the extraction conditions of the worked out fourth sylvinite layer of the Third potash horizon at a depth of more than 600 m. It was established that the service life of newly designed workings depends on their location on the panel, the roof binding and fastening parameters. The longest service life of workings will be noted when they are located in the mined space above the mined longwalls along the lower layers, and the shortest service life will be marked when they are carried out in the central part of the safety intercolumn pillars. Based on the studies performed, the recommendations were made on the selection of locations, roof bindings and on the protection and maintenance of development workings for the sites of the mine fields of the JSC “Belaruskali” mines extracting the worked out fourth sylvinite layer at depths over 600 m. The developed recommendations are aimed at improving the work safety and efficiency when extracting abandoned mineral reserves. Using the study results, the project was developed to conduct development workings of a new panel of the longwall 11-5 that provides the necessary stability of workings for the entire period of winning operations and, ultimately, safe extraction of potash ore in the amount of at least 2 million tons.