Safe mining of granites at the manganese ore deposits of Ukraine

The main scientific and practical results of safety improvement of the granite development at the manganese ore deposits of Ukraine in energetically fractured zones of rock massifs are described based on the example of the development of the reserves of Nikopol basin. In this case, the improved methods were used concerning mining, laboratory and mathematical studies, theoretical and physical modeling, as well as the analysis and generalization of the obtained results using various methods. Issues were studied related to the development of gray granites in the energetically fractured zones of the rock massifs taking into account the manifestation of the energy of rock pressure around the underground workings, physical essence of the phenomenon of zonal encapsulation is revealed. Physical properties of the rocks were studied, new hypotheses about rock pressure were tested. Assessment of the degree of outcropping stability was considered, the regularities of their deformation and destruction were identified, the parameters of structural elements of the development systems, methods of support and the corresponding types of lining were determined. Process solutions were systematized releted to the control of the mined-out space, which consider technogenic factors influencing energy state of the massif, and predetermine the ways to increase safety of granite development at manganese deposits. The method was proposed concerning mining of the gray granite in the conditions of attenuation of mining operations on production of manganese ore reserves in the mining branches of the mine fields of Nikopol-Marganetsky basin. This approach allows to improve the parameters of the operational blocks of the pillar-and-room development system, to reduce twice the cost of production and significantly extend the life of manganese deposits instead of liquidating them. The new technology is recommended for producing monolithic blocks of gray granite in accordance with the regulatory requirements of the stone-processing industry of Ukraine.