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

Abstract The article presents a case-study of thickening and dewatering of tailings slimes from Zhezkazgan Concentrating Plant using UltraflocTester machine and different Kemira’s Superfloc series flocculants. From among the test flocculants containing various polar groups, the anion-type A-150 flocculant has demonstrated the highest efficiency towards tailings slimes. Relatively dense slimes (100

Abstract The influence of jointing on the stability of adjacent rock mass is analyzed using the coefficient of structural weakening and the joint spacing. The gravity–tectonic stress field of ore bodies in Gornaya Shoria, including the azimuth of the principal horizontal stresses is characterized. The laboratory tension tests of combinations of support systems as well as the small-scale extension tests

Abstract The article reports the experimental data on brittle rock strength from the bending tests of beams and from diametrical fracture of disk specimens with an axial hole. The author uses the nonlocal fracture approach and compares the strength from the tests with the tensile strength of rocks. It is shown that the different geometry fracture tests allow determining the structural parameter of

Abstract The geomechanical conditions of underground gold ore mining in thin and steeply dipping ore body under open pit bottom are assessed using the dedicated 3D parameter-oriented model of mine design. The numerical model has produced the forecast stress pattern maps of ore and rock mass disturbed by mining operations. Stability justification is implemented for a sill pillar at a depth of 140 m

Abstract Based on the analysis of the effect of underground closed explosion on geological bodies, a physical model of underground seepage of closed gas explosion is obtained. The model considers the changes of porosity and permeability due to crushing, fragmentation and fracturing of the surrounding body caused in the underground closed explosion zone. The relationship between the proportional radius

Abstract The authors have developed a procedure for selecting models and number of draglines for overburden removal in direct dumping within the hybrid opencast/underground mining in gently dipping coal seams. The potential opencast production capacity algorithm uses the data on the available workable reserves, life of assets, and geotechnical conditions of mining. The article presents a case study

Abstract The article reports the studies into surface wetting of sphalerite, chalcopyrite and pyrite after treatment in saltish solution and in artificial sea water with concentration of 2, 8 and 16‰. The collecting agents were potassium isopropyl xanthate and sodium isopropyl dithiophosphate (Aeroflot). The results show that depending on concentration of sea salt and collector as well as on collector

Abstract This paper proposes an approach to select the optimum maintenance policy for mining equipment using risk-based maintenance (RBM). RBM constitutes the process of risk assessment that identifies high-risk components of equipment, and analytic hierarchy process (AHP) that helps selecting an optimum maintenance policy for individual components. By applying RBM, three high-risk components of dragline

Abstract In order to recycle valuable elements from solid mine waste, this study took iron-bearing tailings as the research object and involved existing Hanging Vibrating Cone (HVC) concentrator separation technology to explore and determine the most appropriate processing parameters of this equipment for the experiment sample processing. The iron concentrates obtained by the experiment meet the Chinese

Abstract Ultimate pit limit optimization plays a major role in the mining industry as it serves as the elementary foundation of all the activities in mine planning. This paper reviews and documents some methods used in ultimate pit limit optimization and gives a clear insight of these algorithms, their functionalities and limitations to open up more research opportunities. The algorithms reviewed are

Abstract The process flow chart of hydraulic impact on coal and rock mass is examined. The double-sided packer design is presented for the implementation of the chart in uncased wells of large and varied diameters. The laboratory tests of axial displacement of packer seals are described. The DEM-based stress–strain analysis is performed in rock mass in the vicinity of a well subjected to pressure from

Abstract In order to solve the problems of coal pillar loss and relieve the tension of mining replacement in the coalface of a coal mine, this study proposes an adaptive method of retaining roadway along gob with supporting body (pier column) near loading roadway. The supporting technology of pier column retaining roadway along gob is studied through theoretical analysis and numerical simulation. The

Abstract The stress–strain behavior of piecewise-homogenous rock mass surrounding a horizontal longwall is defined by the natural stress field and by mechanical constants of rocks and coal. The developed algorithm of successive approximations for the characteristics of rock mass with a longwall integrates all known partial algorithms into a class of difficult problems. The authors propose solving inverse

Abstract The values of pH, temperature and initial concentrations of valuable components have influence on recovery efficiency of zirconium and rare earth elements (REE) from pregnant solutions of nitric-acid leaching of eudialyte concentrate by the chemical deposition method. Zirconium and rare earths exhibit selective recoverability of 99.95% and 87.50%, respectively. The loss of REE is 8.0% with

Abstract The water-blocking action of the clay Cenozoic overburden layer is an important factor that affects safety of thin bedrock coal seam mining. The change of thin bedrock thickness has an important influence on the deformation and failure of overlying soil layer. In this work, similarity simulation experiment is used and two indexes of failure height and crack density in soil layer are selected

The authors study the process of the induced stress field formation in mining with the conventional and nature-like geotechnical systems, including frame and honeycomb mine structures. The rate of change in the natural stress field during mining is estimated using a new index—coefficient of influence. Based on the data of experimental mine research, as well as physical and numerical models, with regard

The article discusses feasibility of frozen wall construction supervision in salt rock mine shafts using seismology techniques. Shallow seismic survey locates wakened areas and intense water flows in rock mass near shafts. Borehole seismics, including crosswell shooting and vertical profiling by the common depth point method, allow estimation of frozen rock thickness. The proposed package of seismology

The author study gas content of coal seams in the face areas in mines of SUEK-Kuzbass. It is found that gas content of coal samples from newly exposed face ranges between 2.4 and 13.5 m3/t and makes 32–60% of natural gas content of studied seams. The coal seams with lower gas content in face area have more ordered microstructure estimated by mean of plotting entropy–structure complexity diagrams based

The physicochemical analysis of distribution of useful components in processing of ash and slag of the thermal energy sector plants is performed. The article describes thermodynamics and kinetics of chemical reactions during agglomeration of feedstock and ammonium hydrofluoride at the temperatures of 50–200 °C, sublimation of ammonium hexafluorosilicate in the temperature range of 350–550 °C, production

The article presents the analysis of seismic observations in mine roadways. The recorded seismic signals are connected with dynamic deformation of rock mass under massive blasting. The source of induced seismicity are dynamic movements deformation of rocks with an amplitude of 3–30 µm along fractures 1–15 m long. These events feature low values of reduced energy, probably, due to shallow depth of mining

The authors discuss the problem connected with insulation of exposed rock surface areas against the aggressive influence of mine atmosphere and rock falls during mining. The lab-scale tests determine the moisture effect on the strength of rocks in the Orlov Ore Field. The tensile strength of samples of isolation membrane as well as their adhesion to rocks and shotcrete is assessed. The technology of

The article discusses feasibility of secondary mining of natural–manmade sylvinite seam KrII* in the Upper Kama Potassium Salt Field. The full scale tests of large samples were carried out to determine mechanical properties of seam KrII*. Mathematical modeling provides estimates of load exerted on nonuniform safety pillars after secondary mining. The authors propose alternative flow charts for the

The authors examine Kaiser effect in sandstone in nonproportional triaxial cyclic compression tests with stage rotation of an assigned stress ellipsoid through an angle of 90°. The load program consists of three pairs of cycles such that the maximal nominal stress of the second cycle exceeds the first cycle stress by 20 MPa at the constant side support. Cyclic loading is applied to sandstone in three

The article considers extraction of rare elements from monazite and their leaching. In this study, phosphate decomposition process was conducted using alkaline roasting. The results showed that the phosphate decomposition of monazite from Bangka Island increased with increasing temperature and increasing monazite/NaOH mass ratio. Analysis of the decomposition rate on the basis of shrinking core model

The article presents a case-study of mathematical modeling of electromagnetic and electromechanical processes in a downhole vibration exciter EM drive. The authors propose the mathematical model of EM drive on the basis of a double-acting EM machine. This model maintains a wide-range analysis of transient and quasi-stable operating regimes. The algorithm and implementation of the model using the structural

The article addresses processability of old copper–zinc ore flotation tailings. Potential reserves and processability of mining waste are considered in terms of Uchaly Mining and Processing Plant. The mineral composition and chemistry of old tailings are determined. The analysis of modes of interaction between gold and tailings minerals reveals inefficiency of conventional technologies in extraction

Blasting still dominates as the most suitable and economic processes of exploitation of minerals from the ground. Although there have been many advancements to optimize blasting to inhibit the impacts due to ground vibration caused by it, still there is a long way to go. Some empirical formulas from the past have helped in designing the mining process and served us well in configuring the blast design

The author gives methodological ground for the assessment of ecological sustainability of the mining industry areas based on the mechanism of interaction between the natural and technical subsystems. The list and values of the required ecological stability indicators are presented for the environmental risk classification of industrial facilities.

The studies into the mechanism of activation of sphalerite flotation by ions of heavy metals show that neither ion exchange nor electrochemistry explain the experimental facts, namely, activation of flotation of copper mineral by lead ions, activation of sphalerite flotation by zinc, or flotation in the presence of non-conducting surface layer with silver or mercury. The authors put forward the hypothesis

Scaled distance equations used for estimating peak particle velocity have been developed by some researchers. The most widely used equation among these is the equation developed by Duvall and Fogelson. However, the equation has not exactly estimated the peak particle velocity correctly. In this study, peak particle velocity values were measured by a number of blast tests that were conducted in four

This study discusses the importance of phreatic surface in the stability of slopes. It describes the development of phreatic layer based on Dupuit and Forcheimmer assumptions in the slope. To understand the water flow behavior through slopes, design of prototype was prepared and later the set-up was fabricated in the laboratory. The set-up includes simulated conventional dump made up of soil type material

The authors perform numerical modeling for the comprehensive stress-strain analysis of roof rocks above powered roof support units in the longwall top coal caving technology. Passive control of top coal prefracture fails to maintain efficient disintegration and well-proportioned flow feed on armoured face conveyor. The relations between the residual and initial strength of coal and the prop of the

The authors perform numerical modeling of processes which create individual history of mechanics and mechanical condition of salt rocks nearby a roadway. The influence of a sampling point (roof or sidewall) and life time of the roadway on the residual stress level and quality of a sample is estimated with regard to microinhomogeneity. The effect of the specified factors on the mechanical characteristics

The article reports the modeling results on direct dumping of overburden by cast blasting. The cast factor variation as function of seam occurrence and explosion block parameters is found. Potential improvement of cast blasting to displace overburden to mined-out pit area is described. The ways of enhancing efficiency of direct dumping in gently dipping coal extraction by combination of truck-and-shovel

The authors justify and exemplify the disintegratability procedure for geomaterials in impact crushing. The procedure distinguishes between two simultaneous processes of destruction and disintegration based on grading analysis of crushing products. The quantitative results on disintegration are obtained for metalliferous geomaterials of different texture and mineral composition. Disintegration is an

The author studies the influence exerted by the boundary conditions and diameter of a circular hole on tensile fracture initiation in brittle and quasi-brittle geomaterials subjected to nonuniform compression with regard to the size effect. The calculation of the critical stress uses the modified nonlocal and gradient fracture criteria. The calculation results are compared with the experimental data