Home – Home – Jornals – Journal of Mining Sciences 2022 number 4

The article describes a technical approach to justification of pitwall parameters based on an integrated geomechanical research of pitwall rock mass using cores from specially drilled earth bores. The sizes of structural blocks, the rock mass quality index and structural weakness coefficient are determined. The strength characteristics of rocks and their physical properties are studied on a laboratory scale. Estimates of pitwall stability using different methods show a good agreement. The optimal pitwall parameters are recommended.

The experimental and theoretical studies show that plane deformation of granular medium induces formation of clusters with sizes of the order of 10-15 diameters of particles. The process of biaxial compression is examined. It is found that deformation has four basic modes conformable with different shapes of clusters. The modes feature a very complex alternation behavior. The process of deformation possesses memory with the Hurst exponent of 0.84. The limit loads in different modes can differ by 2 or 3 times. In problems on deformation of granular media, the calculation of mechanical condition of domains less than 80-100 diameters of particles in size should use not the continuum models but the discrete element method.

The article describes a new method proposed for the mine geometry-based prediction of location and vertical amplitude of faults within the boundaries of an extraction panel using the data on survey network coordinates. A survey network is split into cells-convex quadrilaterals with their vertexes representing the survey grid points. For each quadrilateral, the geometric uncertainties of the coal seam hypsometry are estimated as closure errors and are eliminated in the course of the survey grid adjustment by means of correction of heights. The method consists in calculation and analysis of corrections for the measured absolute heights of the coal seam points arranged in mine roadways, the introduction of which eliminates the interpretation uncertainty of geological data. The corrections are only assumed to be the weights of the measurement and interpolation errors in the neighborhood of specific measurement points. A fault is predicted when there is a jump between the values of the correction for the neighbor measurement points.

To enhance the scientific nature and the reliability of physical modeling of tailings dams, the present developments and main achievements are discussed from four perspectives: dam break, downstream evolution, stability evaluation and protection tests. The experiment materials, methods of measurement and instruments used are summarized. The problems and shortcomings of physical model tests are investigated in terms of the difference between a physical model and a prototype, nature of the experiment, methods of measurement, etc. Emerging technologies such as artificial intelligence and 3D printing to improve safety of tailings dams are discussed. The scope of the review embraces environmental impact of tailings dams in case of accidents.

The article describes the studies into the geological conditions and geotechnologies of coal mining in brachysyncline-type fields. It is found that such coalfields have some specifics which governs the choice of the open pit mining technologies to be efficient. The authors propose an approach to justification of a sequence of mining and to selection of geotechnologies for coalfields in brachysynclinal folds.

In mid-May 2014, heavy rainfall caused unprecedented floods in Serbia. Kolubara Mining Basin, the greatest coal producer in the Electric Power Industry of Serbia, has suffered enormous material damage. Coal production at four open-pit mines was suspended and the operation of four thermal power plants was threatened. The consequences of the uncontrollable water, physically visible on open-pit coal mines, were felt in all system sectors. Intersectorial analysis was used to view and diagnose the situation of the system’s production sectors. The paper gives the summaries of uncontrollable water, mining and energy system structure, the implementation of the intersectorial model in the analysis, comments on the analysis results, evaluation, and a conclusion from the aspect of efficiency and reliability of application in solving practical problems.

The author proposes a determination procedure for calibration factors for current frequency converter of a tunnel fan motor with regard to air flow rate control time at each train density. The ranges of three quality criteria of ventilation control in subways are determined. The ventilation energy consumption at a subway station is analyzed as function of an opening angle of air governor flaps in the ventilation connection at the station, and the economic runs are selected for the flap air governor. The change in the air flow rate at a station versus the flap air governor setting angle serves the basis to create the automatic air control algorithm for a shallow subway with ventilation due to the piston effect in the absence of tunnel fans. The algorithm allows maintenance of the required air renewal at subway stations in rush hours.

The article presents an algorithm of automatic determination of fan influence zones under conditions of their dynamic change. The use of fuzzy logic enables stabilization of crossing influence zones of fans and allows compensating impossibility of their strict differentiation when determining the most difficult-to-ventilate direction. The solution to the problem of the real-time air distribution control in a mine ventilation network is stable and close to optimality. The practical relevance of the proposed fan control algorithm and the correctness of the formulas are proved by the result of simulation modeling of automatic ventilation control operation in mine 4RU of Belaruskali.

The authors study the processing behavior of luminophore-containing blends of zinc and cadmium chalcogenides with a view to using them for the modification of the kinetic and spectral characteristics toward enhanced recovery of weakly and abnormally luminescent diamonds usually lost in X-ray luminescence separation. It is shown that zinc and cadmium sulfides activated by copper and silver have the kinetic and spectral characteristics which are the most similar to natural diamonds. The procedure developed for the improvement of the processing behavior of luminophores with zinc and cadmium sulfides includes the circuits of surface activation with copper cations and subsequent treatment in the potassium butyl xanthate solution. The visiometric analysis reveals that the increased oil receptivity of luminophores and the dispersing agents ensure selective attachment of luminophores to diamonds. The bench testing proves feasibility of complete extraction of diamonds to concentrate, including weakly and abnormally luminescent crystals.

Using the methods of UV spectroscopy, potentiometry, laser and electron microscopy, the authors give a scientific ground and prove experimentally the mechanism of interaction between new complexing agents MDTC and CEDETC and low-dimensional gold on the surface of gold-bearing sulfides. The different surface coverage of sulfide minerals with CEDETC ensures selective hydrophobization and effective recovery of micro and nano gold from complex gold-bearing ore. The behavior of the chalcopyrite electrode potential confirms the active chemical adsorption of MDTC with the formation of the strong MDTC-Cu compound and the domination of CEDETC physisorption in the adsorption layer of minerals. The lab-scale testing of a gold-bearing ore sample from Olimpiada deposit shows that the use of MDTC and CEDETC in combination with butyl xanthate ensures the higher quality of the concentrate and the increased gold recovery by 6-7%.

The article describes the lab-scale tests aimed at development of an efficient technology for nepheline concentrate production from high-silica nepheline-bearing raw material to be a non-bauxite import-substituting feedstock for the aluminum industry in Russia and in the other countries with limited or totally unavailable high-quality bauxite reserves. The improved process flowchart ensures production of nepheline concentrate which satisfies requirements of subsequent processing by sintering with lime and contains not less than 26.4% of alumina and not more than 2.3% of total iron, with alumina recovery of not less than 90% at the silica modulus of 0.6 and alkali modulus of 0.5.

The leaching and agitation tests of gold-bearing tailings from Hassai Mine in Sudan are carried out to find the particle size to ensure the maximum recovery. The column tests revealed that it is easy to apply and recover about 65.52% of Au content from the Au-tailing heaps at Ariab mining company by heap leach process. The obtained recovery indicates that the economic commercial viability of the process to be applied for extraction of Au in the huge tailing heaps at Ariab mines.

The new methodological approach to modern integrated geomechanical monitoring of large-scale subsoil use facilities in Siberia uses the multimodal and digital factories of diversified experimental and theoretical geoinformation. The main elements of the geoinformation system are described with definition of communications implemented via systems of orchestration of the data containers. The information aggregation and transmission technologies use the Internet of Things and include data storage, processing and systematization stages with regard to the available information on subsoil use assets. The trials of the information system in its different modes and options are described as a case-study of Kuzbass and Norilsk mining industry. The authors propose a new energy-based approach to the integrated analysis of nonlinear deformation waves and seismic emission processes within the framework of theory of pendulum waves.

The manmade acoustic signal properties are determined for rock mass monitoring aimed to predict main roof subsidence in coal longwalls. The limit properties for the automatic problem algorithm are defined. The dynamics of the informative parameters of a manmade acoustic signal is demonstrated as a case-study of the main roof subsidence areas in longwalls in Yalevsky Mine, Kirov Mine and Komsomolets Mine. The parameter stability of the integral resonance frequency energy at different distances from a setup room lengthwise an extraction panel is studied in three longwalls in coal mines of SUEK-Kuzbass in order to find correlation between relative stresses and intensity of interlaminar strains. The proposed and proven prognostic parameter enables timing of main roof subsidence and evaluation of the process dynamics.

Soil-water characteristic curves (SWCC) are extremely important in solving practical engineering problems. Most of SWCC are measured based on the specimen in equilibrium, which has long test time, high specialization of test equipment and complicated test operation steps. Moreover, based on the existing equipment technical conditions, the determination of SWCC in the process of dehumidification and moisture absorption requires a variety of tests. Taking Jiangxi laterite, granite residual soil and expansive soil as the research object, SWCC based on the conventional geotechnical test is obtained. SWCC of dehumidification under no vertical load and vertical load and the soil water characteristic curves of dehumidification and moisture absorption are studied by conventional geotechnical tests. Compared with SWCC measured by geo experts pressure plate instrument, SWCC measured based on conventional geotechnical test is very close to that measured by pressure plate instrument.

Gas and dust clouding after large-scale blasting at Sitovo Quarry in the Lipetsk Region and the resultant pollution of the neighborhoods of the nearest towns is studied. The concentrations of solid particles less than 2.5 µm in size are determined in real time using modern equipment. The electronic filming of a large-scale blast and the dust cloud transfer with the wind within the limits of the quarry allowed considering a theoretical partial problem on propagation of fine-dispersion dust from the upper portion of the cloud from a height of 50-100 m to the recording points on ground surface beyond the quarry limits. The methods of computational fluid dynamics are used to model flow at the bottom of the atmospheric boundary layer disturbed by the wind interaction with the quarry topography. It is shown that turbulent diffusion ensures vertical dispersion of micro particles down to the recording points. An explanation is proposed for the revealed non-monotonic maximal concentration of dust over ground surface with an increasing distance from the quarry.

The new dust suppression method using chemical agents has been developed, patented and put in use in some surface and underground mines in Kuzbass, in the Novosibirsk Region and in Khakassia. As compared with the known solutions, this method allows enhancing efficiency of dust suppression in combination with extra effect of decreased freezing of coal during transportation.