The technogenic impact of mining on the environment is analyzed and the transition to geotechnology with stowing to reduce the impact of mining operations is proposed. The results of the research work devoted to the justification of parameters of the development of salt deposits with stowing and the definition of the influence of stowing on the dynamics of deformation of the underworked rock massif are presented. The relevance of research aimed at creating a safe and efficient technology for the transition from systems with natural maintenance of stoping space to systems with stowing has been substantiated.  The results of studies on qualitative and quantitative assessment of the state of the rock massif (by the finite element method using FLAC3D software), worked out by combines, are given and the dynamics of the impact of mining operations on the rock mass and the change in the maximum stresses during the hardening of the stowing in the chambers are revealed. The numerical modeling method is used to analyze the conditions of change in the state of the underworked rock mass, to establish the mechanisms of its deformation at various stages of development. It is recommended to use this approach for geotechnical assessment of the rock mass state in conditions of using development systems of different classes.

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There are many methods of enhanced oil recovery and stimulation of oil inflow, and in order to find their most effective application, it is necessary to study the object of works, candidate wells, as well as their impacts on these wells. One of the methods of production intensification, which makes it possible to improve profitability of oil extraction, is hydraulic fracturing.

The article proposes to consider the problem of comprehensive assessment of project risks as applied to the energy industry. The authors of the research focused on the description of the applied solution. A real investment project on replacement of a bark boiler at Mondi Syktyvkar enterprise was chosen as an object for testing the results. We proposed to divide the risks accompanying the project into 2 categories: risks for which there is necessary and statistical information for their quantitative assessment and risks for which this information is absent. As a technique of a quantitative assessment of risks from the first category it is expedient to apply a method of Simulation modeling of Monte Carlo. In this case, the authors of the article conducted a significant analysis of existing methods for assessing project risks and the choice of the Monte Carlo methodology is due to the practical orientation of the study. In practice, the real enterprise is quite problematic to use more complex methods of assessment, such as methods of Real Options or methods of fuzzy logic, neural networks, etc. As a method of qualitative risk assessment (from the second category) the method of expert evaluation with subsequent calculation of risk premium in the discount rate was chosen. This method is common in practice and easy enough to implement. According to the results of the analysis (statistical and expert) the most dangerous risks of energy projects were identified: Production and technological risks (the risk of choosing the wrong technological scheme, the risk of reducing the quality of internal controls, the risk of incorrect calculation of the design capacity of energy production, the risk of industrial safety), security risks (the risk of hacking attacks on information systems of energy enterprises), as well as country risks. Among the most influential risks (based on the analysis of their impact on the main technical and economic indicators of the project) are: the risk of rising prices for purchased gas (fuel), the risk of high volatility of the dollar exchange rate. The results of the study were used in a real project and the risk assessment methodology was implemented in the project activities of Mondi Syktyvkar enterprise.

The article describes the mathematical model of a hydraulic support system of the powered support sections with impulse-free continuous regulation of its resistance to the roof rock lowering. Safety valves of the hydraulic support perform only protective functions. Mathematical modeling was carried out using the Runge-Kutta method and the Wolfram Mathematica computer algebra system. The results of modeling the transient process of the hydraulic support system with a built-in block for regulating its resistance during impulse loading of the support section with a collapsed roof rock block at “Polosukhinskaya” mine are presented.