Home – Home – Jornals – Fundamental and applied issues of mining 2020 number 1

For the conditions of the Rogunskaya HPP, according to the measurement results of convergence of side surfaces of the engine room, an assessment of the character of their values was given. The extrapolation results of full-scale observation data by the functions reflecting the damping and continuous character of change in the convergence of engine room lining are presented. It was found that, under unchanged external conditions, the convergence of side surfaces in the sections of the engine room was continuous by the end of 2018, which indicates a rheological process taking place in the adjacent rock mass and in the lining.

In this work, the propagation of a hydraulic fracture in a poroelastic medium containing a circular cavity is considered. Numerical studies are based on the extended finite element method. It is shown that under conditions of hydrostatic compression, the path of crack development depends both on the stress state of the medium, the field around the cavity, and poroelastic effects.

Predictive assessment of the stress-strain state of underopencast rock mass was made during underground mining at the Internatsionalnaya mine of PJSC Alrosa. For the conditions of stress distribution in an intact rock mass, in accordance with the hypothesis of A. Geim and A. N. Dinnik, the features of stress formation in ore ceiling and observation working of geomechanical monitoring at various mining stages were determined. An upper estimate is given for the stress values in the vicinity of the observation working.

This article discusses the international field assessment systems of the CRIRSCO and JORC family, for the transition to the JORC system when estimating mineral deposits in the Kyrgyz Republic.

An increase in the level of uncertainty, complexity and variability in the operation of the mining industry is shown, leading to the need for an integrated use of the expanding capabilities of digital technologies to improve business. It is noted that enterprises related to coal mining are at a lower level of digital technology use compared to the oil and gas industry. The possibility of borrowing the experience accumulated here for the development of the “digital deposit” concept and the “industry 4.0” programs in relation to the coal industry, as the basis for the stable tactical and strategic functioning of mines, is considered. It is indicated that the digitalization of geo-resource, geotechnology and management methods in the development of deposits contributes to the prompt receipt of a more complete and accurate picture of production and sales processes, an increase in the efficiency of work in exploration, production, processing and consumption of coal. The expediency of using the results of 3D-modeling, assessing reserves, taking into account their refined quality and bedding conditions, for more accurate adjustment of the operation of enterprises for various competitive scenarios for the development of fields with complex structures, has been determined.

It is shown that as a complex probabilistic system, the mining company works on the contact of the geological and market environments. These environments include different categories of uncertainty which affect the successful development of the enterprise. The prerequisites for differentiating the mineral and raw potential of a coal deposit during its transformation from the inherent possibility to reality during development are considered. The types of potential are identified: limiting, attainable, and investment. A typology of the deposit potential is presented, taking into account the stage of geological exploration, knowledge of the coal properties, stage of development of the subsoil object. The concepts of uncertainty categories are revealed: static, ergodic and non-ergodic.

A schematic flow diagram of a method for the production of hardening mixtures using granulated slag, cement, anhydrite, crushed stone and tailings of metallurgical waste is presented. The largest specific weight of backfill types is shown, technical equipment of backfill components. The production of backfill mixtures at the Komsomolsky mine is described. It is found that the use of plasticized additives for backfill mixtures allows improving performance, increasing the operating efficiency of a backfilling system and decreasing the operating costs.

It is shown that the reserve for increasing production consists in increasing the capacity of the main production machines operating in the coal mines of Kuzbass. Analysis of the data showed that the excavator fleet has a significant amount of its own time reserves. For a fleet of excavators with high performance requirements, even taking into account the manufacturer’s technical utilization rate, the underutilization of the time fund is more than 8.2 - 10.2 %, the underutilization of the guaranteed productivity (shift-day) is 75 - 77 % in the short term and not less than 58 - 60 % in the long term (a week or more).

The article presents the mining and geological characteristics of the Mountain Shoriya rockburst-hazardous deposits. The experience of measuring the stress state of the rock mass at the Tashtagol and Sheregesh iron ore deposits and the results of the refinement of current stresses are presented. Stresses in the rock mass are determined to select the type of support for workings while lowering the level of mining.

To protect the rock mass on the boundary of open-pit edges from failure and reduce the seismic impact of drilling and blasting operations on it, it is planned to set the edges of the open-pit mines to the limit position by the method of controlled blasting. It is shown that, when the direction and angles of bench slope coincide with the direction and angles of slope of the rock mass weakening (dikes, cracks, bedding, etc.), rock caving occurs at the stage of controlled blasting, followed by sloughing of highly fractured rocks fragmented by blasting. Rock stability zones were determined at different horizons of the Bystrinsky 2 and Verkhne-Ildikansky open-pit mines. The schemes for the location of charges and their design under various mining-geological and geotechnical conditions are proposed.

The results of an experimental study of the effect of multiple weak impacts on the creep of a sample of equivalent geomaterial loaded with a static pressure are presented. It is found that at long-term weak impacts, the creep rate initially increases and then decreases to a stationary value. Weak impacts initiate the elastic strain wave passing through the sample. The propagation velocity of this wave increases non-monotonically with an increase in the number of impacts. It is related to the change in sample internal structure due to external loads.

The article analyzes the existing problems and innovative approaches at the macro and micro levels in the mining sector.

The stress-strain state of rocks and rockburst-hazard degree at the Tashtagol and Sheregesh deposits of “EVRAZ ZSMK” were analyzed during large-scale and technological blasts. The geodynamic state of the rock mass in the maximum bearing pressure zone is estimated. The zones of the distribution of shocks with different seismic energy in the rock mass during the preparation and mining of blocks are determined. The influence of tectonic disturbances ahead of the stoping front on the geomechanical condition of rocks in the mine field is determined. The developed methodology for calculating and constructing zones of increased rock pressure allows determining the location of hazardous zones depending on thickness of ore bodies, main horizontal stresses, ultimate compressive strength of rocks, etc., when mining several bodies simultaneously in rockburst-hazardous deposits.

A plane mathematical model taking into account the property of the geomedium to store the energy of internal self-balanced stresses is constructed on the basis of the concept of a rock mass as a medium with internal sources and sinks of energy. A numerical FEM-algorithm is proposed for calculating quasi-static problems of deformation of a rock mass near openings, taking into account dynamic softening jumps. It is shown that boundary unloading can result in stability loss of the opening.

The results of studying the impact of a shock wave of technological underground blasts are presented. Instrumental measurements of the actual pressure values at the front of an air shock wave (ASW) during blasting operations at the Magnezitovaya mine were carried out. Safe distances for the effect of air shock wave excluding injury to people are determined on their basis. The calculation of the excess pressure at the air shock front is made taking into account the local resistance of mine workings. A comparison of the recorded values of excess pressure with the maximum permissible values for workers, wooden lintels, ventilation pipelines, electrical equipment and power grids is carried out.

The intact rock mass stresses can be calculated in terms of stresses and displacements only with formulation of an additional problem. The intact rock mass stress state can be recovered using the experimental determination of opening of cracks lying at an angle to a horizontal line. The diagram of tensile stresses at an extension of a cut can be plotted using the tension diagram of a reference sample.

The prospects of involving technogenic reserves into dragging are estimated and their brief description is given. The problems associated with the reworking of dredge landfills having technogenic reserves with very unstable parameters and a heterogeneous structure of productive deposits are noted. The need to improve existing methods for calculating the parameters of dredge dumps in the conditions of productive deposits with an unstable cross-section is determined. A graphic-analytical method for substantiating the parameters of dredge dumps is proposed, which allows assessing the capacity of the mined-out space for tailings arrangement more accurately and take the necessary measures in advance to prevent ephelic bedding of a dredge boat and stacker filling.

The paper considers the capabilities of well-known laboratory facilities for hydraulic fracturing simulation in conditions of true triaxial loading. Test facilities which allow creating a crack in large cubic samples with an edge length of 200 mm or more are of great interest. In this case, it is possible to reduce the influence of edge effects from sample boundaries on the propagation path of the fracture. This review includes research results obtained from 10 different facilities located in major scientific centers

The results of studies on the emission of toxic gases, such as carbon dioxide, carbon monoxide, nitrogen oxides, sulfur dioxide, hydrogen sulphide and carbon in blind drifts of mines with pyrite-polymetallic ores are presented. Studies to determine the composition of air under conditions of heated sulphide ores, hydration of binders and rotting and/or pyrolyzed wooden elements of tightening and backfilling of framed metal support were carried out in mine conditions and in an accredited testing laboratory. In laboratory conditions, the concentration and intensity of the emission of poisonous gases and oxygen absorption from sulphide ores, wood and backfill were determined under conditions of mine regulated temperatures and during heating. The calculation results of toxic gas emission in a blind unventilated drift at natural ambient temperature are presented.

The plane deformation of an elastic body should be described by five constitutive equations. Hook’s law contains only three equations. Two more equations are implicitly contained in the assumption of displacement field smoothness. In the paper a difference scheme is constructed to solve a plane elastic problem. The scheme is based on five constitutive equations and two difference meshes embedded in each other with a certain step. The numerical implementation of the scheme and examples of solving the boundary value problems are considered.

A comprehensive approach to predicting the parameters of geomechanical processes in the rock mass during mining of coal seams of complex structure is proposed. In order to match the calculated and full-scale data of roof displacements of preparatory workings, the formula for determining the calculated resistance of host rocks has been upgraded. The results of field observations on changes in the values of roof rock displacements at benchmark stations in the advanced working of the Yubileynaya mine when the stoping face approaches it are presented. The relations which allow predicting the values of roof displacements of advanced workings depending on the distance to the face are presented.

The problems of roadway construction and support in unstable rocks are discussed. The stress-strain state of the rock mass and support was modeled when filling inrush in the roof and sides of the mine with phenol resins. The results of calculations when increasing the height of inrush zone in the mine roof are discussed.

The paper presents the analysis of geomechanical and geotechnological features of mining solid mineral deposits in the North of Russia and their negative and positive influence on the efficiency and safety of mining production. The article reports new results of researches conducted by the Chersky Institute of Mining of the North, SB RAS to improve the existing and develop fundamentally new, efficient and ecologically friendly innovative technologies, methods, equipment for mineral mining and processing, taking maximum account of the specific conditions for mining solid mineral deposits in permafrost.

The geological structure of the Makmal deposit is considered, which is characterized by metamorphic, sedimentary and intrusive rocks. The physico-mechanical properties of rocks (granites, marbles, silicified ore bodies, marbled limestones, carbonate breccia, quartz-feldspar, etc.) are analyzed. The physico-mechanical properties of rocks of the Makmal deposit taken from adits no. 6 and no. 11 are determined under laboratory conditions.

A laboratory study was conducted to investigate the effect of bedding angle on strength properties of shale and siltstone samples under shear loading with compression. The selected rocks had significant anisotropy of strength properties when tested for compression and tension. The samples of shale and siltstone were tested under shear loading with compression at various combinations of the orientation of bedding angles Ψ relative to the sample axis and the orientation of angles of shear plane Δ relative to sample bedding. Experimental dependences “ultimate shear stress τ - normal stress s” and adhesion value C ₀ on Ψ and Δ angles are obtained. The study concluded that the ultimate shear strength and adhesion was determined by a combination of angles Ψ and Δ. For samples with a bedding angle of Ψ = 90°, the angle Δ has a much more significant effect on the character of failure than the values of normal stresses. The combined effect of the angle Δ and the values of normal stresses σ on the character of failure is observed for the samples with Ψ = 45°. For samples with the orientation of bedding angles Ψ = 90°, the shear strength does not depend on the angle Δ and is determined only by the value of normal stresses.

When assessing the stress-strain state of the rock mass of a ledge of the Sheregesh deposit, it was found that zones of inelastic deformation are formed near the mined-out spaces in the southwestern part of the pillar. It is shown that location of the relief holes at elevation +195 m, providing decompaction of the rock ledge in its peripheral regions, causes additional unloading of the rock mass. In this case, the compressive horizontal stresses in the boundary part of the ledge are reduced, the corresponding shear stresses comparable with the rock mass adhesion are reduced by 40 - 50 %, which leads to a decrease in inelastic deformations in the rock ledge.

The effect of a large-scale tectonic disturbance on the intensity of seismic and geodynamic phenomena is assessed. Geodynamic activity was determined when mining ore sections of the Sheregesh deposit. The stresses and zones of inelastic deformations, shock energy in a rock pillar between the ore ections are determined.

Demonstration results of calculating joint roughness coefficient (JRC) for rock specimens are presented depending on the position of the discontinuity profile under uniaxial load conditions. To obtain these results, shear failure surfaces of test specimens were scanned. Using additional software processing, the surfaces were cut into multiple profiles in the direction of load applied. Depending on the shear cut, the JRC was calculated for each profile, its average value was determined for the entire discontinuity surface, which was recommended for estimating roughness.

The problem of penetrating an absolutely rigid indenter in the form of a round cone into a weighted rock (an axisymmetric plasticity problem) is being solved. Limiting load is determined, depending on the internal friction angle of rock, adhesion, angular opening at the top of cone, rock weight. The dependence of load on the above parameters is given.

The problem is to determine the state of the rock mass around the mine according to the data of simultaneous measurement of Cauchy stress vector and displacement vector (Cauchy problem) on its boundary. The overlimiting deformation is taken into consideration. The obtained solution allows estimating the remaining reserve of material strength both on the mine boundary and near it.

The mining and geological characteristics of the Veduginsky deposit and physico- mechanical rock properties are presented. The results of calculating the quality index of rocks of the Central and Southeast ore zones of the Veduginsky deposit are presented. A methodology for determining rock stability by Q -rating is given. The rock stability of the deposit is determined on the basis of Barton’s rating classification of rock mass stability developed at the Norwegian Geotechnical Institute.

The geological, mining and technical characteristics of Tashtagol deposit are given. The location of the pressure zone during the development of the Eastern section is determined. Cases of rockburst and disturbances in the workings are considered. The estimation of the stress state of the rock mass using different methods for predicting geodynamic phenomena was performed; shock hazard category defined. Anomalous sections were revealed within the mine field in the area of workings no. 03 - 10, no. 22 - 25, etc. It was established that the combined factors for the preparation and collapse of blocks are the main factors affecting the stress state of rocks.

The possibility of activation of lead-zinc ore by products of non-stoichiometric interaction of potassium butyl xanthate with heavy metal salts is investigated. It is possible to regulate the collecting properties of the mixtures obtained by changing the ratio of components. To assess their activation efficiency, the criterion of “surface flow power” of the film of collector derivatives at the gas-liquid interface was used. A mechanism is proposed to reveal the causes of changes in flotation indices when using xanthate precipitates of various metals.

The issues of metallogenetic modeling of ore-forming systems for search purposes when studying flanks and deep horizons of the mined deposits are considered. The object of the study is the analysis of geological and geochemical conditions of ore accumulation of various mineral composition and the concentration of useful components in various sections of the Talnakh ore-forming system. Mineral and geochemical zoning of the deposits reflect the degree of contamination of primary silicate and magmatic melts with crustal material. On the western and southern flanks of the ore-forming system, ore mineralization is represented by low-sulfur associations of chalcopyrite minerals and is specialized in Cu - Ni - Co. A study of the geochemistry of isotopes δ³⁴S, ⁴⁰Ar/³⁶Ar, δ⁶⁵Cu, ⁸⁷Sr/⁸⁶Sr suggests that the process of ore formation on the flanks of the Talnakh ore-forming system occurs under intense influence of the crustal component (sulfur source evaporite rocks) and near-surface water on the fluid component fractionated by sulphide fusion enriched with copper, resulting in the formation of ores with chalcopyrite type of mineralization.

It is shown that high processing losses of a valuable component during sand washing and low efficiency of waste use as secondary raw materials reduce the rational use of mineral resources of placer gold mining. The concept of increasing the efficiency of combined low-waste process flow charts for the recovery of free fine gold and the separation of non-ore ephelial, clay and pebble products during the beneficiation and processing of rebellious metal-bearing sands is proposed. A scientific and technological substantiation of flow charts for the integrated use of dump waste products for the creation of resource-saving technologies at placer gold mining facilities with a purpose of using them as secondary mineral raw materials in the construction industry has been completed.

The problem of gold-bearing ore leaching by sodium cyanide is estimated. The prospects of using cyanide-free reagents in the processes of gold hydrometallurgy are studied. The possibility of introducing a cyanide-free reagent which is less environmentally hazardous than sodium cyanide is determined. The results of experimental studies on the comparability of leaching indices of gold-bearing ores using sodium cyanide and a reagent based on sodium cyanate are analyzed. The optimal parameters for the implementation of the technological process of ore gold recovery using the proposed reagent are found.

The collective ability of derivatives of oleic acid represented by the products of its interaction with lead salt is investigated. The effect of the obtained collecting agent on the indices of flotation recovery of apatite ore is determined.

The designs of lever percussive mechanisms with the largest piston-rod developed by S. Abdraimov for compacting soils are considered. The results of kinematics research of three varieties of S. Abdraimov’s schemes with the largest base are presented. The basic parameters of these schemes are determined and recommended for creation of high-frequency percussive mechanisms for compacting soils.

A scheme of a DTH air hammer is presented and the issue of reliability of a device with a three-stage hammer made according to this scheme is considered. The features of the bottom hole cleaning system of such devices are shown. The possibilities of using an elastic ring valve located at a larger stage of the hammer have been determined. The results of field tests of DTH hammers are presented.

The conditions of self-braking in harmonic drives with a flexible wheel made in the form of a bushing chain are considered. A special feature of the harmonic drive is the design which has a dual generator and a double-crowned sprocket. This design allows to avoid skewing the chain under load. The criteria for self-braking in chain harmonic drives are defined. It is found that for chain harmonic drives in the range of gear ratios over 30, the effect of self-braking is provided. In the range of gear ratios up to 30 to achieve the effect of self-braking, it is necessary to use extra-centroid gearing.