The article is devoted to the conversion of mining enterprises from open way of development of ore deposits into underground method of development. The aim is regulation of the main preparation stages of the mining industry to diversifi mining and ore processing. The research methodology includes a critical analysis of the theory and practice of production processes, development of recommendations and justifi of effi of modernization of the existing situation. The results of the research . The paper features a characteristic of mining methods and an analysis of their advantages and disadvantages. It formulates the present state of the mining industry in Russia in conditions of the market and toughening of requirements to environmental management. The article explains the environmental and resource essence of the technology of fi the mined-out space with hardening fi mixtures. It offers a description of the technology with the solvent extraction of metals from ore with a focus on underground solvent extraction of off-balance ore in the frame of the combined criterion of completeness of metal extraction technology. The model presented in the article is based on the effectiveness of mechanochemical activation of raw materials for the preparation of hardening fi mixtures. It defi the profi from the involvement of off-balance ore into the manufacture. The paper features the concept of state management of ore-bearing massifs on the basis of the regulation of natural and technogenic stress levels by fi the technological voids with hardening mixtures. Another concept described in the article is the production of metals by solvent extraction and aspects of its implementation, including that by disintegrator. The scope of the results implementation includes mining and processing enterprises, mainly non-ferrous ore exploiting metallurgy. Conclusions . Conversion to underground deposit development requires development of technologies of fi the technological voids with hardening mixtures. These technologies are based on utilization of tailings processing benefi and metallurgy after extracting from them the residual metals by, for example, mechanochemical activation. Comprehensive modernization of technology development increases the completeness of the use of sub-soil resources, contributes to the improvement of the economy of mining enterprises and to improvement of the environment.