Abstract The experimental version of a bidimensional measurement facility allows recording displacement of rock blocks in the normal direction relative to a fault and their shear displacement relative to one another. In 2020 the facility was deployed at Zarnitsa open pit diamond mine, and was included in the long-term geodynamics monitoring in the zone along a fault which cuts the open pit. It is found

Abstract The article presents the experimental data of seismic and acoustic monitoring in a fully mechanized longwall mining face. The predictors of the rock mass behavior are selected to be the acoustic emission activity and the increase in the pulse recurrence rate at the same time in the neighbor roof support unit. Crack formation in the longwall mining face zone is calculated.

Abstract The article discusses the mathematical modeling results on formation of concentration zones of failure stresses in annular space of a well during hydraulic fracturing of productive formations from vertical or nearly vertical boreholes. The rigid connection between the cement lining and rocks fails because of a thin clay layer in-between, which leads to unsealing of the annular space and to

Abstract The subcool zone length is determined in lining of an extra-long railway tunnel subjected to deep influence of piston effect. The air temperature distribution in the outer air–tunnel lining contact zone is determined as function of the velocity of train and the outdoor temperature in the cold season. The authors review the de-icing methods of tunnel lining: warming-up using a self-tuning heating

Abstract The action of the arbitrary physisorbed species of a collector at a mineral is compared with the theoretical evidence on particle–bubble attachment. The lack of the correlation between the hydrophobic behavior, characterized by the wetting angle, and the floatability of minerals, as well as the correlation between the inductance time and the mineral recovery are discussed. The causes of disagreement

Abstract Large-scale mining methods are taking over the leading role in exploitation of low-grade and deep mineral deposits considering its high productivity, low cost, and satisfying ore recovery and ore dilution. In order to improve properties of existing block and sublevel caving methods, researches were carried out in laboratory conditions on physical model of similarity. Results of the research

Abstract The authors analyze the influence of the semi-autogenous (SAG) mill parameters on the mill grinding efficiency, energy consumption and the tangential cumulative contact energy. This paper provides a new liner parameter design and optimization method, which offers theoretical guidance for the optimization design of liner parameters.

Abstract The samples of anthracite and bituminous coal are studied in cyclic freeze–thaw at different water contents. In the freeze–thaw cycles, the samples were subjected to continuous ultrasonic sounding. It is found that different contents of water have an essential influence on the spectrum of recorded signals. Regarding the water-unsaturated check samples, the spectrum change is reversible, and

Abstract The capacity of novel selective dithiocarbamate collectors, namely, morpholine dithiocarbamate (MDTC) and S-cyanoethyl N, N-diethyldithiocarbamate (CEDETC) to form complex compounds with gold on the surface of sulphide minerals containing fine gold under conditions of flotation is experimentally proved. MDTC adsorption at the surface of chalcopyrite without gold takes places due to formation

Abstract Uniaxial compression test of outburst coal was conducted to explore the mechanical characteristics of coal with outburst tendency in low gas pressure environment. The mechanical properties of coal were analyzed, the surface crack morphology of coal was obtained and the energy characteristics of coal during loading were determined. Results are as follows. In the pressure range of 0.03–1.0 MPa

Abstract The authors construct an exact solution to the problem on the stress–strain behavior of rock mass at the boundary of an underground excavation of an arbitrary geometry if the vectors of the Cauchy stresses and displacements are assigned simultaneously at this boundary. All explicit components of stress and strain tensors, as well as the components of rotation vector are determined as functions

Abstract In this article, the recovery of the Y, La, Nd, and Ce rare-earth elements (REE) from apatite concentrate by acid leaching and digestion-water leaching processes were studied. The maximum REE recovery of 62% in the acid leaching process with sulfuric acid was obtained for La in the condition of 12 M acid concentration, leaching time of 4 h, process temperature of 25°C , and a liquid to solid

Abstract The experience of high-frequency pneumatic hammer design to run on increased compressed-air pressure is reviewed. Arrangement of a coupled shock-pulse generator composed of two pneumatic hammers is described, and its stable operation conditions are determined. The synchronized operation of the hammers in the coupled generator is implemented through the smooth percussion frequency control of

Abstract In deeper level mining in Tashtagol deposit, during extraction of ore reserves from safety pillar, the stresses and inelastic strain zones increase 2–4 times. In safety pillar in Sheregesh deposit, the tensile stress zones, where failure of undermined rocks intensifies, enlarge as mined-out stoping void grows. During mining in the Eastern and Northwestern sites of Tashtagol deposit, at the

Abstract The authors compare the effect exerted by copper ions and sulphide copper nanoparticles on flotation of Gorevka deposit sphalerite using potassium n-butyl xanthate and in reagent-less regime. Covelline-like colloid particles 4–8 nm in size, obtained in interaction of copper (II) and sulfide ions in aqueous solutions, are characterized using the methods of dynamic light scattering, electron

Abstract The mechanism of change in the surface morphology, physicochemical properties, adsorbability and floatability of eudialyte concentrate as a result of exposure to high-power nanosecond pulses and dielectric barrier discharge in air under the atmospheric pressure is analyzed. The research methods were the Fourier-transform infrared spectroscopy, analytical electron microscopy, atomic force microscopy

Abstract The mining of iron ore, an essential raw material for iron and steel industry, is of prime importance among all mining activities undertaken by any country. Therefore it is important that the iron ore mining should be environment-friendly and sustainable. Ripper Dozer combination is one of the most commonly used excavation methods in Iron ore mines of Goa because of the presence of soft and

Abstract Results of modernisation of an on-line X-ray fluorescent analyzer are presented, and its new capabilities are considered when investigating the composition of materials on the conveyor. The metrological characteristics of the analyzer are improved owing to the use of modern electronic components in the instrument part and new analytical software.

Abstract The authors put forward a concept of modeling objects within a mining technology. The concept integrates the technology content and state change of an object, and allows processing and storage of temporal data on digital mine twin. A set of such models shapes a joint dynamic model of evolution of all mine objects in the course of mineral mining. Using this approach, the time-variable vector

Abstract The removal of heavy metals from the wastewater solution using a novel zeolitic material was conceived and experimentally probed. The natural zeolite was ground in a planetary ball mill to increase negative surface charge and amorphization of the material as well as a conventional ball mill. The ground materials were used for the removal of heavy metals from the wastewater solution. The maximum

Abstract The article presents the manufacturing procedure and the test results for a synthetic layered and jointed medium with a preset internal structure and the pronounced anisotropy of properties. The laboratory installation for hydraulic fracturing of large-size cubic models under independent triaxial loading, the laboratory installation hydraulics and the measurement-and-recording equipment are

Abstract The fluid flow modeling procedure used ABAQUS environment and the extended finite element method. The procedure is meant for calculating pore pressure distribution and gas and fluid flow directions in rock mass in the course of solid mineral mining using hydraulic fracturing. The authors discuss the standard model and case-studies of the procedure-based calculation of gas flow rates in coal

Abstract The mathematical methods of structural design optimization using the optimality criteria are reviewed. The resultant and nearly optimal design of a fan bade ensures the design goals at the selected criterion. The optimal design based on topology optimization was carried out in ANSYS. The optimization problem solution provided optimal distribution of the impeller blade mass for axial mine fans

Abstract The authors discuss a mathematical model of rock mass with regard to accumulation and release of stored energy. Self-balancing stresses are described using internal variables introduced. The type of a closed system of equations is examined. An algorithm is proposed for the numerical modeling of softening jumps within a quasi-static problem. The problem on deformation of rock mass around a

Abstract The review of copper ore processing flow charts in application at ore mills in Russia and abroad is presented. The scope of the analysis embraced the reagent regimes and flotation performance. Brief information about collecting agents, frothers and depressants is given. The influence of actuation medium in flotation of copper–nickel ore is studied in terms of bulk copper–nickel concentration

Abstract Underground mining of hard coal seams is carried out in the Polish part of the Upper Silesian Coal Basin with an increasing level of rockburst hazard. This hazard is combated by the application of active rockburst prevention, where long-hole destress blasts take an important role. The seismic energy of the provoked tremors can be a determinant of blast effectiveness. To estimate blast effectiveness

Abstract The authors propose a mathematical model of the effect exerted by a blast-induced seismic wave on nonuniform (multi-layer) enclosing rock mass around a tunnel. The developed numerical algorithm implements the Godunov splitting method, and a computer system is constructed. The numerical calculations determine safe drilling and blasting parameters to preserve integrity of underground structures

Abstract The aerothermodynamic parameters of air are studied in shafts of mines of NorNickel’s Polar Division. The total pressure and temperature measurements, as well as the air density calculations in KS-2, GS and VC-4 shafts in Oktyabrsky Mine show the linear total pressure dependence on the shaft depth and the essentially nonlinear dependence of air temperature and density on the depth of shafts

Abstract The authors study dynamics of heavy particle attached to the surface of free air bubble in liquid. The bubble with its surface vibrations and the particle are considered as a single mechanical system with geometric constraint. It is assumed that the main forces to govern interaction of these objects are the inertia force due to surface vibration of the bubble and the capillary adhesion force

Abstract The article describes preparation and implementation of experimental research into strength, deformation and acoustic characteristics of physical models of frame and honeycomb underground structures designed at the Research Center for Applied Geomechanics and Convergent Technologies in Mining at NUST MISIS College of Mining. An integrated test bench for physical and optical modeling of geophysical

Abstract The article presents the analytical model and calculation results on fracture growth in layered rock mass during blasting and hydraulic fracturing in oil reservoirs. The stress state of fractured elastic rock mass is found using 3D boundary element method. The influence of strength characteristics of layered rock mass on the shape, size and area of radial fractures is determined. The presence

Abstract The study focuses on the theory of zonal disintegration in gas-bearing coal seams and on gas-dynamic phenomena in underground structures. The concept of unstable geomechanical behavior of coal seams is conditioned by instability of deformation during micro-cracking and macro-cracking. In the zone of disintegration in a gas-bearing coal seam, occluded methane releases from coal substance. As

Abstract The article presents the analytical research data on the convective motion dynamics and air temperature variation in a mine tunnel after cutoff of a drag source during fire. The single-valued prediction is only possible based on the stability theory of convection currents. The mathematical modeling of advection currents of counter air flows in a tunnel is performed at longitudinal gradient

Abstract The theoretical and experimental research is aimed to improve pretreatment and concentration of rebellious ore from the Rubtsovsk deposit. Radiation modification of lead–zinc ore properties stimulates milling efficiency and enhances processing efficiency. After radiation modification, percentage of free grains of galenite and wurtzite in milled product increased from 40.7 and 65.7% to 66.4

Abstract The author presents the mathematical model of an autooscillating one-way action and positive-displacement system with two piston arresters. The dynamic criteria of similarity are determined, including: stiffness ratio of springs of the accumulator and percussion assembly; proportional value of the ratio between potential energy of the accumulator and kinetic energy of the piston at the preset

Abstract The article presents a case-study of change in the seismic energy absorption coefficient with changing mining and geological conditions during the exploitation of one of the longwalls at the Polish coal mine Ruda. Several stages of longwall excavation exploitation, differing in stress conditions, were selected for the analysis. The results obtained show that low attenuation occurs in areas

An Erratum to this paper has been published: https://doi.org/10.1134/S1062739120057227

An Erratum to this paper has been published: https://doi.org/10.1134/S1062739120057239

Abstract Modern heavy-duty shearers cut coal with high production of dust particles. The screen tests of coal from Zarechnaya Mine are reported. Methane flow rate is theoretically calculated as function of dispersion phase in coal from Zarechnaya Mine at different particle size distribution of coal. It is found that methane flow rate reaches its maximum in fine coal 0–25 mm in size.

Abstract Shock wave travel in a roadway with impermeable safety barriers is modeled numerically in the equilibrium and non-viscous formulation. Inclined and arched barriers are studied at the varied porosity in a range from 0 to 0.8. The inclined and arched barriers decrease the load exerted on the barrier structure by the shock wave owing to formation of a reflected wave which is oblique, or radial

Abstract In hydraulic fracturing of producing formations in oil and gas reservoir engineering, as well as in coal gas drainage, hydraulic fractures are propped by solid particles—proppant that prevents closure of fractures under the action of compressive stresses in rocks. It is shown that alongside with lateral earth pressure, the compressive stresses in fractures are governed by additional compression

Abstract The article describes the long-term in-situ observations and inspection of concrete lining in air inlet shaft No. 3 in Uralkali’s mine, which reveal the main causes of the lining failure at intersections with horizontal tunnels and in the areas of instable rocks. Numerical modeling of rock creeping and damage areas in lining at intersections with tunnels is performed in the axially symmetric

Abstract The authors analyze gas control readings obtained in Butovskaya Mine, Kemerovo Region, in step-down phase of seismicity and after blasting operations. It is estimated how seismic waves induced by blasting influences methane drainage in coal seams. It is found that methane release from coal seam to roadways increases after seismic impact.

Abstract The research methodology for anisotropic permeability of geomaterials due to nonuniform stress state is theoretically justified and tested on a laboratory scale. The poroperm properties of fine grain sand and cryogel are investigated in diametral compression tests of cylindrical specimens with a center hole. The time-independent flow rate is measured in various areas of side surfaces of the

Abstract It is technologically and economically advisable to optimize grading of low-quality fine and very fine sand with increased content of clay and dust particles used in preparation of cemented backfill mixtures by adding blast-furnace granular slag screenings 0–5 mm in size without preliminary treatment. The relationships of the size modulus, specific grain area and clay/dust particle content

Abstract The authors discuss artificial freezing of water-saturated rock mass during construction of mine shafts in terms of a simplified case of a single freezing pipe. The ice growing and holding stages are examined. Maintenance of a constant thickness frozen wall is simulated using the coolant temperature regulator model. The multi-criterion numerical modeling of freezing is implemented, and the

Abstract The author solves the problem connected with determination of shape of pillars which remain stable under any compression due to barrel distortion. The analysis of cylindrical structures uses the known Leibenson–Ishlinsky stability criterion. The boundary conditions of the problem and its solution are obtained: elasticity in the form of the critical load dependence on the height/radius ratio

Abstract This paper describes the development of statistical models for assessing the boulder count resulting from the limestone quarry blasting. A database of three hundred blasts was created for the development of the model. The database consists of number of holes per row, number of rows, average spacing, average burden, average depth, average stemming, explosive type, total charge fired in one

Abstract The authors describe the structure, features and application of a software using the extended finite element method in ABAQUS. The software is meant for modeling hydraulic fracturing of permeable rock mass with fracture path tracing in nonuniform stress field.

Abstract The authors present a new rock fracability evaluation procedure using the cluster analysis of log data on petrophysical properties of facies. The effect of the physical and mechanical properties of rocks on the fracability evaluation results is analyzed in combination with the geophysical log data. The triaxial compression tests of cores are carried out to determine their brittleness indices

Abstract In this study, the changes in the specific rate of breakage and breakage distribution function of the nepheline syenite sample were investigated by using alloy steel ball in five different sizes. Specific rate of breakage and breakage distribution function values were obtained from the particle size distributions acquired after the grinding periods. As a result of grinding tests, an increase

Abstract The article describes the experimental studies into hydraulic fracturing of thick-walled cylinders with a circular hole and made of cement-based GF-177 mixture. Limiting stresses are determined in four types of stress state of the bodies: uniaxial compression and tension, Brazilian Test and hydraulic fracturing. The data of the Brazilian Test and compression of rectangular parallelepipeds

Abstract Advancement of wave action stimulation and cross-well seismic imaging in mineral mining governs the need for downhole sources of elastic vibrations. The presented periodic electromagnetic seismic source is equipped with a mechanical–hydraulic drive for fixturing in a hole and for impulse transition to rock, and an electromagnetic impactor for pressure pulse generation. This article presents

Abstract The author addresses a method of creating directional conjugated fractures in a solid medium, integrating features of interaction of fractures and holes, specifics of fracturing by plastic materials and the use of holes as the front guides and limiters of created fractures. This method can be used to enhance efficiency of open pit and underground mining, as well as for creation of closed impermeable

Abstract In this study, time domain reflectometry (TDR) is engaged to observe coaxial cable deformity caused by slope movements. Laboratory shear tests were executed to measure the deformity magnitude caused by shear failure using two coaxial cables—RG-6 and RG-213. Two assessments are performed in laboratory testing, to determine the deformity magnitude—shear test and open-cast (OC) model. For shear

Abstract The thermal and mechanical tests of different porosity limestone show that an increase in the axial load results in the higher velocities of elastic waves while elevation of temperature decreases them. Higher temperatures act to raise velocities of P- and S-waves with increasing mechanical load, which enhances acoustic strain-sensitivity of rock. The spectral analysis of the recorded signals

An Erratum to this paper has been published: https://doi.org/10.1134/S1062739120046971

Abstract The analytical reagent dithiopyrilmethane (DTM) is investigated in combination with potassium butyl xanthate (PBX) in gold recovery from low-sulphide arsenical gold ore. Thanks to two heterocycling rings in the structure, DTM attaches to nonferrous and noble metals. Adsorption of DTM at arsenopyrite and gold is determined using the electron and laser microscopy, as well as by IR and IV spectroscopy

Abstract The vibroacoustic effect on poroperm properties of rock mass in case of directed upward water movement has been studied experimentally. The relationships of percolation velocity and sound load at different pressure gradients are obtained for fine sand. The experiments prove feasibility of multiple increase of percolation velocity in upward capillary movement of water solutions.

Abstract The article presents the model study into determination of block medium structure parameters by the seismic sounding method. The modeling was performed on a fragment of a brick wall. The wall was subjected to impulsive loading, and oscillograms of vibration accelerations in certain bricks were recorded. The velocities and spectral structure of waves were determined from the experimental data