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The authors perform the aerodynamic design of axial fans with impeller and inlet guide vane to reverse air flow direction via killing rotation of the impeller while putting the guide vane into rotation. This approach can substantially enhance fan efficiency in reverse mode. The newly developed blade angle analysis procedure allows finding air flow parameters in reversal. The parametric regions in aerodynamic designs of axial fans, where the proposed approach of reversal is effective, are delineated. Design of a fan having similar aerodynamic characteristics in the forward and reverse air flow is undertaken. The swirl ratios of flow in the guide vane are correlated with the axial velocity ratios toward geometrical similarity of blade profiles of impeller and guide vane at an average radius.

A brief review of machines for pit wall scaling is given. The inertial impact technique is compared with the surface miner operation. The authors describe an inertial impact machine with a hammer rotor for pit wall scaling. The procedure and data of the numerical and lab-scale testing of the machine are presented. The tests produced the rational range of lip angles for hammer plates and the preferable impact frequency, which ensure the minimized energy intake of the rotor motor and the least counterforce of rock mass to the bearing seat of the rotor at the preserved efficiency of fracture process.

The found interaction mechanism between a mineral-diamond mixture and a modifying agent includes the stage of adhesive attachment of luminophore at grains of diamonds and kimberlite. The selected compositions of modifying agents and the modification process parameters ensure efficient attachment of luminophore-bearing compositions at diamonds. The proposed criterion of selective action of modifying agent on spectral characteristics of diamonds enable choosing modes of recovery of weak and high luminous diamonds from kimberlite ore in X-ray luminescence separation. The rational variation parameters are determined for the organic collector composition, water phase of a modifying agent and for the process of modifying treatment of diamond-kimberlite products before the X-ray luminescence separation. The test of the selected compositions of modifying agents and the diamond-bearing product treatment modes proved almost complete extraction of weak and high luminescence diamonds to concentrate at minimized yield of kimberlite.

The literature review discloses preferability of using the time of induction rather than the wetting angle as a criterion of coal floatability. The authors analyze kinetics of coal flotation as function of surface properties of heteropolar collectors relative to the gas-liquid interface. The correlation between the spreading velocity of collectors on water surface and the coal flotation kinetics is determined as a case-study of fat coal slurries. Justification is given for using the time of displacement of the boundary between three states of aggregation as the time of induction. From the correlation of the spreading velocity of a collector, displacement time of the contact line (induction time) and the flotation velocity, it is found that flotation activity of the collector is governed by its properties relative to the gas-liquid interface.

The article proves the promising nature of joint roasting of rebellious oxidized and sulfide lead-and-zinc ore from Ozerny deposit at the stage of ore preparation for flotation. The joint roasting of lead-and-zinc ore and sulfide ore initiates generation of sulfur-containing agents and sulfidation of rebellious oxidized lead and zinc. It is experimentally proved that selective oxidation of pyrite proceeds together with disintegration of lead and zinc along the interphase boundaries. The main products of such interaction are ZnS, PbS, Fe₃O₄ and Fe₂O₃, which can greatly facilitate flotation later on. This method of complex ore processing can potentiate commercialization of oxidized lead-and-zinc ore and rebellious sulfide ore, can prolong service life of mines and mitigate the environmental impact of the industry. The produced samples are analyzed and described using the X-ray phase analysis, differential scanning calorimetry, optical microscopy, chemical analysis, Rietveld refinement and program TOPAS.

Consumable supplies in mines (explosives and explosive devices, oil, lubricants, rubber, protective devices, spare parts for machinery and equipment, flotation reagents, etc.) should be sufficient for stable production. However, for mining operations, supplies are burden costs, as storing supplies increases operating costs. The logical question is how to achieve the balance between mine production stability and minimization of costs of supplies, that is, how to optimize supplies. The paper presents a quantitative model of stochastic supplies optimization as a possible answer to this question. The application was demonstrated in the specific case of polymetallic ore lead, zinc, copper, and silver mine flotation with value indicators.

The authors discuss the mineral resources and mineral reserves of the Russian Far East in terms of their volume and production of certain minerals. The key challenges of subsoil use, which complicate advancement in the mining sector at the present time, are identified. The growth prospects of the mining sector can build on the processing industry and on the transition from mineral extraction to mineral production at high degree of conversion. The economic efficiency of subsoil use depends on the professional corporate management, transportation and power generation infrastructure, sound scientific grounding and on the development of the processing industry which uses products of the mining industry. The main trends of the spatial development in subsoil use are proposed. The large infrastructural projects are described, which can promote social and economic progress in the Far East Federal District of Russia. Emphasis is laid on improvement of personnel potential and on introduction of scientific supervision in the mining and processing industry in the region.

The authors present a multi-factor algorithm for making provisions for geological/geotechnical constraints and operation timing criteria subject to availability of resources. The algorithm enables embracing a variety of possible combinations of heading or stoping conditions at each specific underground mine facility. The algorithm is a part of the digital tool of automated underground mine production planning in geological and mining information system MINEFRAME.

The authors examine the present-day hydrogeological situation and its post-mining phase forecast in the Chelyabinsk Coal Field. Geotechnical facilities in the areas of Krasnaya Gornyachka Mine and Kopeisk and Korkino Open Pit Mines are discussed. The problems to arise during flooding are identified. The hydrological forecasts and an action plan to prevent underflooding in the study areas are presented.

The article presents the case-study of properties of domestic binders in dust suppression at tailing storage facilities at a mining and processing plant in the Murmansk Region. The strength development dynamics of the binder-formed blankets and the change in the strength in the wetting-drying mode are determined, the impact of chemical agents on water permeability of treated tailings is estimated, and leaching of polymerized concentrates in weakly acid and alkaline media is carried out. The authors emphasize essentiality of an integrated research for the well-founded choice of a binder.