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Mathematical modeling investigates the influence of an underpump tubing string on the longitudinal vibration intensity in the oilwell tubing and pumping unit assembly during operation of an electric submersible pump (ESP). The use of the underpump tubing strings with a length of ¼ wavelength with a dominant frequency of longitudinal vibrations of ESP reduces the vibration rate at this frequency by 2-3 times, and the diameter of the underpump tubing string is of no importance. Such underpump tubing strings in producing oil wells can help improve reliability and service life of ESP. When an underpump tubing string is set on the well bottom and pressed to the casing string along a spiral line, the longitudinal vibrations of the underpump tubing string transform into variable side stresses which influence the casing string and the reservoir rocks in the bottomhole formation zone, while no increase in the longitudinal vibration rate takes place in the pumping unit. The working ESP with the underpump tubing string rest on the well bottom conditions continuous vibration effects on a pay zone in the course of the well operation, which improves permeability of rocks in the bottomhole formation zone.

Support design in underground mining and tunneling excavations is dependent on the geological and geotechnical behavior of rock mass. The rock mass rating (RMR) and Q-System are the key parameters to design support system. The existing support system in tunneling projects along Himalayas were studied, and it was observed that the support was lighter in some cases and heavier in others. Based on the real time data obtained from active tunneling projects and geologic conditions along Himalayas, the modified support criteria (RMR₁₉) using back calculations and incorporating stress factor in RMR and Q have been applied in this study. The stress reduction factor of the Q-system was also studied. The existing and modified RMR and Q are statistically correlated with a significant R² value.

The article presents a theoretical substantiation of a dynamic adaptation process to adjust drilling and blasting patterns to structurally complex deposits and open pit mining using the integration of zoning theory and blast impulse theory. The key stages of approaches to drilling and blasting pattern designing are discussed. Emphasis is laid on the theory of rock fracture zoning with description of the zones of deformation, fracturing and seismic effect depending on the blast impulse. The calculation formulas are proposed to determine the blast impulse, radii of fracture zones and energy balance to ensure efficient rock fragmentation and minimization of adverse effects. It is critical to introduce artificial intelligence systems capable to analyze geological data in real time. The principles of creation of the intelligence control systems for drilling and blasting adaptable to varying geological conditions are developed. This can enhance safety and efficiency of drilling and blasting at mines operating at structurally complex deposits in Russia.

It is most effective to fracture very hard rocks by impact. On the other hand, application of the dynamic rock fracture method needs optimal parameters selected using modern techniques of estimation of rock fracture resistance dependent on the properties of rocks. The features of dynamic loading of an operating tool are discussed, and the classification of the dynamic rock testing methods is proposed. The rock crushability testing procedure is recommended. Resistance of rocks to fracture under dynamic loading is estimated, and the main estimation criterion is the volume yield of crushed material -7 mm in size. The strength characteristics of rocks from different testing methods were compared with the estimates of rock resistance to fracture by the selected criterion. The comparison shows a good agreement of the results, sufficient for engineering design.

The article discusses capacities and benefits of stripping with direct dumping within the mixed-type mining technologies for structurally complex deposits of solid minerals. The authors emphasize practicality of this technology in different geological and geotechnical conditions of mineral mining, and develop a procedure to determine a reasonable application range of the technology within the mixed-type mining systems. The resource-saving process flowsheets are proposed for dragline mining of centroclinal fold-type, water-encroached and steeply dipping bedded deposits. The most feasible ways of enhancing efficiency of overburden removal with direct dumping are discussed.

The studies find out that permeability of loam is 51.6 times less than permeability of coal mass. Thus, this disperse sediment can be used to prevent spontaneous combustion of coal and carbonaceous rocks. The major insulating effect is provided by a loam layer with a thickness of 0.06-0.08 m, which reduces permeability of an insulated mass by 5 times. The increase in this loam layer thickness has a minor effect on the permeability. Water sprinkling yet more decreases the permeability of loam but drying-out initiates cracks in the insulating material and they give access for air to oxidizable coal. Recovery of the insulating effect after exposure to water requires ripping and compaction of loam.

The authors propose a model of activation of sphalerite flotation by lead ions using the mechanism of physisorption of a collecting agent. Flotation tests determined the recovery of zinc and the quality of the concentrate depending on the volume densities of lead and xanthate, the ratio of their mole concentrations and pH of the flotation system. The ratio of lead and xanthate mole concentrations of the increased sphalerite floatability, which is condition of casual activation of sphalerite, is found. The causes of suppression of sphalerite floatability at the increase in a certain concentration of the activating agent or xanthate are disclosed. On the basis of sphalerite floatability suppression, it is recommended how to enhance selectivity of separation of sulphides in the lead flotation circuit.

The review of literature and research findings exhibit current situation and the most challenging problems in theory of flocculation of mineral suspensions. With a view to enhancing efficiency of flocculants, it is advisable to have a science-based concept of selecting flocculants and their compositions, including functionally modified flocculants, with branched macro-molecules, with regard to laws of adsorption of flocculants at the surface of minerals. In the light of the revealed strength characteristics and laws of destruction of floccules, it is shown that for the further development of the theory, it is important to find interconnection of these parameters and fluid dynamics, and to study recombination of floccules. It is undoubtedly interesting to determine small concentrations of flocculants both for the analysis of formation of floccules and to disclose conditions of smart use of flocculants in the industry.

Because of the need to expand the range of promising Russian-manufacture reagents to replace import analogs, the authors study effect exerted by reagents from class of dithiocarbamates on the surface of sulfide minerals in composition of complex gold ore. New research methods are used to examine interaction of the test reagents with the gold-carrying minerals in flotation of complex ore. It is found that a new reagent of bis-piperazine dithiocarbamate is an efficient selective collector of mineral carriers of noble metals in flotation of complex gold ore. The test methods were UV spectroscopy, wetting angle measurement, scanning electron microscopy and laser scanning microscopy. Different adsorbed phases of the reagent on the polished section are determined and visualized. Selective attachment of the reagent at ore minerals can ensure their selective extraction in different concentrates in flotation of complex ore.

The article proposes technology of processing and modification of zeolite-bearing rocks from the Shivyrtui and Talan-Gozagor deposits with a view to producing high-quality adsorbents to recover rare alkali elements from hydromineral resources. The mineral composition of zeolite-bearing rocks is described, and their electromagnetic and electrostatic separation is reported. Using a model solution with cations of rare alkali elements, the sorption capacity of initial, concentrated and modified zeolite-bearing rocks from the Shivyrtui and Talan-Gozagor deposits is analyzed. Sorption of rare alkali elements is studied as function of a solution/sorbent ratio. The influence of cations in the model solution composition on the capacity of zeolite is examined. The water treatment tests show high results which ensure the required quality of effluents.