Home – Home – Jornals – Journal of Mining Sciences 2021 number 4

The author proposes an R&D program for deep-level mineral mining in Siberia and Russian Far East. The article exposes the formulation and solution of the problems connected with the analysis of physical state of the subsoil, and describes the concept of engineering and modernization of mining machines, as well as development of resource-saving technologies for mining coal, metallic and barren minerals, including justification of process flow diagrams and robotization of operations involved in mineral mining, processing and conversion, and subsoil management.

The implemented research aimed to assess the impact of open pit coal mining in Gorlovka deposit on the seismicity in the Iskitim area of the Novosibirsk Region. The seismic vibrations induced by large-scale blasting are analyzed, the seismic event potential is estimated, and the strain accumulation at a high-stress fault under seismic load is assessed. A key potential trigger was assumed as the change of the stress field parameters. Relaxation of rock mass from stresses due to formation of a pit and the extra loading of rock mass by dumps are calculated numerically and estimated analytically as two major factors of induced effect on static stresses. For the correct selection of computation parameters, the geology and the main physical/mechanical properties of rocks mass in the coal mining area are analyzed, and the main mechanical parameters of the most significant structural faults are selected.

There are large amounts of waste deposits around mines and mineral processing plants, and their instability is one of the major concerns in mining industries. One of the methods to amend the waste deposit stability is the strength enhancement. Biocement is a method for improvement of the ground using microorganisms to precipitate calcium carbonate between geomaterial particles. For this process, Sporosarcinapasteurii bacteria is used to activate the calcite precipitation to increase the strength of Angouran mine. In this research, the effect of biocementation on increasing the strength of waste is investigated. The results of laboratory tests show that wave velocity and uniaxial compressive strength were considerably increased with number of injections. Also, the compressive strength of samples under initial load is increased in comparison to unloading modes. Therefore, utilizing the proposed method promotes the mine waste stabilization.

Fracture toughness of compact samples and polymethyl methacrylate double-cantilever beams in tension is investigated experimentally and theoretically. In loading mode I, the critical loads and propagation paths of cracks in these samples differ noticeably. The theoretical model presented is based on the energy concept. It allows predicting instability of crack propagation paths. The model includes stresses in front of the crack tip and the T- stress. The theoretical model is proved using the fracture test data on a few samples with mode I cracks. The computer modeling of crack propagation is performed in the geometrically and physically nonlinear formulation. The calculation and testing data comparison shows that the crack path instability essentially depends on geometry and can be avoided by changing the sample geometry or the type of loading.

During the backfilling mining process, the strength of backfilling body is continuously affected by the temperature. Unconfined compressive strength (UCS) tests were performed on cemented tailings backfill (CTB) samples cured at different temperatures. The results show that UCS increases linearly with the increase of curing temperature during the age of 3 to 7 days, while it shows an exponential relationship with the curing temperature during the age of 7 to 28 days and the growth rate gradually slows down. As the curing temperature and age increases, the microstructure becomes denser, meanwhile, UCS becomes more sensitive to variances in age, and the failure patterns of CTB samples change from crushing failure to tensile failure. The established formula can well describe the coupling effect of curing temperature and age on UCS, which can provide a certain reference for CTB strength design and mining.

The common constraints of coal production under conditions of deeper level mining and methane release in mined-out voids in Kuzbass are described. The theoretical calculations of gas release from coal seams during multiple hydraulic fracturing are elaborated. The revised procedure of gas flow rate from coal seams, based on the data obtained in gas drainage boreholes during multiple hydraulic fracturing is theoretically and experimentally justified.

The newly presented structure of integrated monitoring includes geological and geotechnical conditions of mineral mining, peculiarities of the production and infrastructure objects, as well as specifications and manuals of measurement tools. The monitoring-embraced hazardous objects are listed and grouped. Each group of the hazardous objects is described with the common features, properties, criteria and other characteristics meant for the monitoring supervision toward efficient and faultless operation. A prototype monitoring system for instability of mine objects is implemented using mining and geological information system MINEFRAME, and the data base on the objects of monitoring is composed.

The impact of pressure fluid-air interaction on endurance of hydraulic drives is discussed. It is proposed to employ the enclosed hydraulic drive to isolate the pressure fluid from air, solid impurities and moisture. The functional flow chart of the enclosed hydraulic drive with hydraulic motors and hydraulic cylinders is designed. The design procedure is validated for an ejector pump and a hydropneumatic accumulator to ensure the boost pressure at the main pump inlet and to provide the drainage leek return to the system subjected to the excessive pressure. The new ejector design enables adjustment of the ejection factor and the total flow pressure at the pump outlet. The cavitation procedure is presented for the ejector tests at different values of the running, drainage and total flow rates.

The mathematical model of the one-way hydraulic positive-displacement system with two piston stop tools includes the design variables of the system and its interaction with rock mass, namely, dry friction in the impact facility body-piston couple, pressure losses in the hydraulic system branches and piston velocity recovery factor. The dynamic similarity criteria, which are dimensionless analogs of the listed characteristics, are determined. The numerical calculation is performed, the influence of the similarity criteria on the dynamics and integral characteristics of the test system is analyzed, and the main behavioral patterns are revealed. It is found that these criteria influence the shape of the domains of the single impact travel and back run, two-impact and multi-impact limit cycles. It is possible to reduce the difference between the system characteristics in the impact travel and back run by means of changing the piston coordinates such that the valve stations are changed.

The modification procedure for the kinetics and spectral characteristics of fluorescent diamonds using luminophores ensures the simultaneous increase in the amplitudes of the long- and short-persistent luminescence signals at a preset ratio (1:1). Abnormally and weakly fluorescent diamonds after luminophore modification have elevated amplitudes of the kinetics and spectral characteristics, and are identifiable as natural crystals with the required luminescence intensity. This approach allows the simultaneous increase of the collapse and the decay constant of X-ray luminescence signal. As a result, abnormally and weakly fluorescent diamonds acquire higher values of these characteristics, become detectable as natural diamonds and are recoverable in X-ray fluorescent separation.

The authors have developed and justified the method to describe overall particle-size indexes of coal as a case-study of Bezymyanny and Vnutrenni seams of Prokopyevsk-Kiselevsk coal region in Kuzbass using the problem-oriented programming equipment for the yield and ash content prediction in mineral dressing. It is found that test data approximation, solely, is incapable to provide the uniformly accurate calculations of yields and ash contents in pooled size grades within the sieve mesh size range from 0 to 100 mm.

The authors find the collecting activity criteria for slack coal flotation agents. The collectability tests used kerosene, straw oil, thermal gas oil, KETGOL and FLOTEC agents. Efficiency of these agents in slack coal flotation is determined, and the velocities of their films on water surface are found. It is found that the spreading velocities of the collecting agents are correlated with the slack coal flotation performance. The article proposes a new concept of particle-bubble attachment and the floatability criteria for slack coal flotation agents.

The author offers the calculation procedure for minimum exposure time of ore and mining waste containing polymineral aggregates, as well as for sizes of grains such that limit stresses are only achieved at the grain boundaries. With regard to the calculated mechanical stresses, the ways of increasing recovery of fine valuable components of minerals are identified.

The ore from Baiyinchagan mine is typical increasingly refractory as the mine get deeper, especially the increasing lead and zinc contents, which not only detrimentally affects the product quality of copper concentrate, but also results in the loss of lead and zinc resources. In order to solve the problem, two routes were conducted: first, depress liberated lead and zinc minerals from the raw ore; second, float lead minerals from the copper concentrate. Sodium sulfide was used as detoxification, polysulfide-as copper depressant and diethyldithiocarbamate-as lead collector. The quality improvement and efficiency of copper rough concentrate were realized.

The material constitution and structure of mineral particles in fluorite ore mill waste at Yaroslavskaya Mining Company are estimated. The set of factors having influence on the efficiency of sample preparation for flotation is determined. Alongide with the complex mineralogy and structure of primary ore, dressability of mining waste is affected by mineral properties acquired in prime processing and during long-term tailings storage. It is necessary to take care when selecting the process conditions and the composition of agents for flotation. The studies into the influence exerted on flotation performance by a composiiton of carboxyl collectors with different contents of fat acids and different structures of hydrocarbon radical identified the best effective conditions. It is feasible to produce finely dispersed carbonate-fluorite concentrates from mining waste, at CaF₂ content of 95.21-95.6% and at fluorite recovery of 59.55-62.56%.

The authors review the methods of dust emission suppression at operated and abandoned tailings storages. The environmental impact of mineral dust particles and the after-effects are greatly varied. Dust suppression in surface layer of tailings ponds can use the most widely applied chemical methods, as well as mechanical and biological methods. The requirements imposed on binding agents are efficiency, dust catching, longevity and the environmental safety. Dust suppression control can utilize natural climatic events, e.g., seasonal freezing-thawing of tailing surface. The described engineering solutions concern techniques and equipment for spreading suitable chemical agents for dust suppression at overburden dumps and tailing storage facilities at mining and processing plants.

The authors have designed equipment for the stress-strain behavior assessment in granular medium and soil in shearing. The shear test machine enables investigation of stresses and dilatancy in granular materials subjected to multiple cyclical shears (tens thousands). Special sensors are designed for long-term stress and dilatancy measurements in granular media in lab-scale modeling of geomechanical processes.

In this study, the Shore hardness measurements are made on carbonate rocks using Durometer PCE-1000, Mitech MH310 Hardness Tester and C-2 type Shore Scleroscope, and the results obtained were compared. The usability of digital new generation Shore hardness test devices (Durometer PCE-1000 and Mitech MH310 Hardness Tester) to determine the Shore hardness of the rocks is investigated.

The article determines the three-level deviation correction equipment of mine conveyor belt. The experimental results show that the mine conveyor belt deviation detection system based on machine vision can effectively detect the deviation fault and control the deviation correction equipment, which has the advantages of high efficiency and fast processing speed. The mine conveyor image clarity in operation under high dustiness is greatly increased.