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

An analysis of the competitiveness of the Polish hard coal mining sector was performed. The most important conditions in which it operates were presented—the size of the resource base, the current organizational structure, and operating conditions. By presenting the most important sources of competitiveness, factors requiring special attention were identified. After presenting the SWOT analysis of

The authors study theoretically the non-isometric natural convection of pore water in rock mass subjected to artificial ground freezing. The mathematical model is developed for a permeable water-saturated layer of rocks under artificial freezing. The model assumptions allowed transition to a two-dimension axially symmetric model. The numerical computation gives critical Rayleigh number values such

We investigated elastic wave attenuation characteristics using a PCI-2 acoustic emission system. A lead-break test was employed to carry out attenuation experiments in granite, marble, red sandstone, and limestone. Because the centroid frequency variation of the red sandstone differs significantly from the other rocks, a pendulum steel ball impact test was also performed to study the attenuation characteristics

The authors find that morpholine dithiocarbamate (MDTC) and S-cyanoethyl N, N-diethyl dithiocarbamate (CEDETC) are capable to form stable compounds with gold in the solution and to form an adsorption layer on the surface of gold-bearing sulphides, which points at them as new selective collectors for gold recovery from rebellious ore. The coating area of MDTC on the surface of chalcopyrite, arsenopyrite

The article discusses geomechanical justification of undermined ground evaluation methods. The proposed method of subsidence assessment allows analyzing influence of underground mining on ground surface in development of horizontal and flat-dipping uniform and interstratified beds with different deformability. The predictive assessment procedures for the subsidence trough profile in case of uniform

The article analyzes statistics on micro-solid emissions in mineral mining and discusses features of micro-emission in atmosphere in large-scale blasting in open pit mines. The gas-dynamic calculations of dust and gas cloud elevation after blasting for localization of solid micro particles and determination of their concentration in the troposphere are presented. The influence of large-scale blasting

The procedure is developed for permeability prediction in deep-level fractured coal. Coal permeability and microstructure are experimentally studied on samples taken from Tikhov Mine. The predictive relationships between the occurrence depth and permeability of coal in parallel to master and side cleavage are obtained for the Nikitinsky, Tambovsky and Tarsminsky fields of the Leninsk geological-economic

The authors range low-grade copper-nickel ore and mining waste represented by overburden dumps, mill tailings and slag in the territory of the Murmansk Region by the criterion of potential ecological hazard. The determinants of mobility of heavy metals formed in oxidation of sulphides are the content of barren minerals (silicate matrix), pH of pore solutions and exposure to atmospheric weathering (acid

Justification of slope parameters for benches and pit walls in clayey rock mass bases on studies into geological structure and physical and mechanical properties of rocks of various lithological varieties. The upper layers of pit walls occur in weak clayey overburden, in the crust of weathering and in transition zone with conglomerates, up to 150 m in total thickness. In this case, it is required to

The paper presents the discussion on problems involving the reproduction of the acceleration field of ground vibrations based on the pointwise registration carried out in coal mines subjected to seismic hazard. Simple model that takes into account directional effects of seismic wave attenuation has been presented. It has been accepted the assumption that the contours of the peak ground accelerations

The authors construct a continuum approximation for the model of a medium with internal structure and internal self-balancing stresses. The presupposition of diffeomorphism, i.e. existence of partial space derivatives of displacements is largely slackened. The information brought to the closed model of a geomedium by this presupposition is comparable with the information brought by the constitutive

The process of roof caving at face during its advance is impossible to describe by static and kinematic solutions. It is necessary to take into account unsymmetry of deformation due to the dynamic component of the roof caving process. To that end, it is required to undertake experimental and theoretical studies into the unsymmetrical displacement distribution. It seems to be possible to obtain additional

The statistical analysis results on methane release in coal faces in Kuzbass are presented. The parabolic curves of methane release have maximums as regard to feed velocity and productivity of shearer. Methane release from broken coal is an inverse proportional function of linear hyperbolic dependence and has maximum as regard to feed velocity and productivity of shearer. The analysis of the found

The article presents the procedure for the experimental and theoretical estimation of fracture toughness in salt rocks in testing of samples with wedge-shaped cut and by numerical modeling of the tests in ANSYS. The values of the stress intensity factor and the energy release intensity factor in tensile fracturing are presented for salt rocks of the Upper Kama Potash Salt Deposit.

Extended milling/mechanical activation properties of zinc plant residue was investigated using two different milling systems, namely, high speed vibrating ball mill and ring mill, comparatively. The zinc plant residue was mixture of gypsum, anglesite, massicot, quartz, maghemite, and franklinite. Zinc plant residue was milled for 1–30 min in high speed vibrating ball mill and ring mill. The obtained

The behavior of acoustic emission in uniaxial cyclic loading of rock salt samples from the Kaliningrad deposit is determined. The samples were tested under varied temperatures and ratios of maximal stresses in sequential loading cycles. The experimental curves of acoustic emission activity and maximal stress and temperature of the previous cycle are obtained. Stress memory in acoustic emission manifests

A brief appraisal of probable gold in dredge and sluice tailings dumps at placers in Russia’s Far East is given. In terms of mining waste piles and operating placer mines in the Khabarovsk Territory, Jewish Autonomous Province, Amur and Magadan Regions, a probable gold content of dredge and sluice tailings dumps is predicted. The calculation used different combinations of estimation parameters: loss

In mid-May 2014, flooding caused by unprecedented rainfall wreaked havoc_on Serbia. In the night between May 14 and 15, the swollen Kolubara River with its tributaries flooded the Tamnava West Field and Veliki Crljeni coal open-pit mines. The paper describes the course of flood events, the consequences of the outflow of about 214.4 million m3 of water into the depressions of the open-pit mines, and

Part of large-scale industrial test results of milling fineness influence on lead, copper and zinc minerals flotation results in the Rudnik flotation plant are shown in this paper. Based on industrial research it has been concluded that one-stage milling and two-stage classification of complex Pb-Zn-Cu ore leads to so-called “differential milling”. Namely, galena has much faster comminution than other

Realization of good returns in the mining venture needs careful planning, scheduling, design and optimization of all mining activities which are dependent upon reliable resource estimates. The mineral resource estimation method employed in a deposit thus plays a major role in reduction of risks associated in mining. In this study, indicator kriging, ordinary kriging and inverse distance weighting methods

The aim of this study is to investigate the applicability of artificial neural networks (ANN) and game theory in the development of an underground mining method selection model. To realize this, six different ANN models that can evaluate geometric and rock mass properties of an underground mine, environmental factors and ventilation conditions to determine mining methods that satisfy the safety conditions

The theoretical model is proposed, which allows tracing continuation of seismic vibrations after cessation of blast load by the analysis of velocigrams recording on ground surface during underground explosions. The comparison of the model and experimental velocigrams of massive blasts shows validity of elliptical filters for second-order low frequencies in modeling waveforms of the velocigrams. The

The particle size distribution and the material constitution of samples taken from old milltailings of sulfide and oxidized ore are studied. It is shown that more than 50% of gold occurs in fine size grade of −0.044 mm. The method of gas adsorption reveals large specific area in the samples, which is important for re-entrainment and migration of gold and associate components. It is found that gold

The authors present an efficient modification method of X-ray fluorescence separation with mineral and organic luminophores used to adjust spectral and kinetic characteristics of anomalously luminescent diamonds. The mechanism of attachment of luminophores at diamonds and hydrophobic minerals is proved, including interaction between the organic component of emulsions and the hydrophobic surface of

A physical model is created to describe stage-by-stage fracture of rock mass by deep-hole blasting. The analytical dependences are presented for main parameters of massive blasting. The zones of intense and passive crushing are identified in a blasted bench. The formulas are obtained to calculate volumes of different size particles in these zones. The automated determination procedure of particle size

A new method is proposed for predicting rock pressure with regard to statics, kinematics and dynamics. The static approach calculates strain state using the known classical method based on the mining guidelines. The kinematic approach takes into account the weight of overlying strata and makes the kinematic approach more specific. Dynamics is traced as nonlinear deformation in the course of mining

Some of the coal mines use dragline for the overburden removal of coal top as its geometric, since the initial cost is high with low running cost. Most of the draglines operating in Indian mines have conventional analog control under Ward—Leonard method. To improve the efficiency of those, to reduce the power consumption and to provide maintenance-less operation in the electrical system, the microprocessor-based

The article presents studies into the microwave treatment effect on higher recovery of noble metals from rebellious carbonic ore. The rate of refractoriness of carbonic concentrates was determined using a package of thermal testing techniques. Bitumen is an additional criterion of the refractoriness rate of mineral dressing products. The influence of treatment time on heating of a sample is studied

The authors prove connection between the surface activity relative to gas-liquid interface and collecting ability in flotation for derivatives of xanthogenates (xanthogenates of heavy metals). It is shown that at nonstoichiometric ratio of xanthogenate and metallic salt concentrations, colloid particles are formed in solution. The influence of deviation from the nonstoichiometric ratio of xanthogenate

The authors have analyzed relative earth heat infiltration in artificial ground freezing in the context of formation of frozen wall in mine shafts. The artificial ground freezing modeling reveals a considerable dependence of the earth heat infiltration on the thermal properties of ground, process variables of refrigerating plant and time. The relative earth heat infiltration comes to a steady-state

Uniformity index n represents the range of fragment size distribution and it is applied to evaluate fragment size by Rosin and Rammler cumulative distribution function for a muck pile. The uniformity index n of fragment size distribution has been assessed by digital image analysis technique using Split-Desktop for several blasthole parameters and different zones of in-situ rock mass conditions in five

The author studied the process of copper removal from underspoil water at Blyavinskoe and Safyanovskoe copper ore deposits by cementation by iron. The influence of pH, consumption of cementation agent impurity ions Fe3+, Al3+ and Ca2+, as well as timing on the cementation performance was analyzed. The mechanism of the process was determined, and by-reactions resulting in over-consumption of cementation

The article considers the problem on compression of an isotropic medium with a variable-width slot with cohesive zones at the ends. Under the action of tectonic and gravitational forces in rock mass, contact zones appear between the slot surfaces. The author analyzes the case of a number of the contact zones between the slot surfaces. In a part of the contact zone, cohesion of the slot edges takes

The experimental results on operation of electrodynamic separator with pulsed traveling magnetic field in treatment of sand mixtures with metal particles −0.25 mm.

Based on the analysis, generalization and statistical processing of experimental data, the guideline values are determined for the physical and mechanical properties of loamy soil for construction of earthfill dams at liquid mining waste storages. A close parabolic relationship is found between the cohesion, internal friction angle and natural moisture content of soil. The authors present the method

The collected data on long-runout rockslides induced be large-scale underground blasts are presented. The critical conditions of the rockslides are determined as a function of the dynamic impact, rockfall volume, as well as the slope height and gradient. It is shown that the main condition for the mobile rockslides is their volume exceeding 106-108 m3. A collateral effect for rockslides in case of

The theoretical and experimental substantiation of the behavior of ferrous sphalerite in magnetic separation is given in terms of the Gorevka deposit ore. In sphalerite of this deposit, the content of isomorphous iron ranges as 4–9%. The Móssbauer spectroscopy showed the singlet and two doublet lines of iron, demonstrating separate arrays of iron atoms in sphalerite lattice, with formation of Fe-Fe

The classification of the methods available for diagnostic of mining machinery mounting groups with roller bearings is considered with indicated advantages and disadvantages. The model is constructed to describe formation of shock pulses in roller bearings when different defects are generated in them. This model is suitable for the availability monitoring of the machinery mounting groups. The applicability

In this study, the best possible location for an air deck in an explosive column during a surface blasting operation for the most efficient rock fragmentation is described. Volumes of air decks are proposed for the optimization. This study aims at helping guide blasting engineers to easily apply an air deck in a surface blasting operation.