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Date submitted2021-05-08
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Date accepted2022-07-21
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Date published2023-12-25
Technologies of intensive development of potash seams by longwall faces at great depths: current problems, areas of improvement
- Authors:
- Vladimir P. Zubov
- Denis G. Sokol
The results of the analysis of practical experience in the development of potash seams using longwall mining systems at the mines of OAO “Belaruskali” are presented. Positive changes in the technical and economic indicators of mines and an increase in the safety of mining operations were noted with the introduction of resource-saving technologies without leaving the pillars between the excavation columns or with leaving the pillars between the columns with dimensions at which they are destroyed by mining pressure in the goaf. It is noted that the use of mechanized stoping complexes characterized by high energy capacity, combined with large depths of development, is the main reason for the temperature increase in longwalls to values exceeding the maximum permissible air temperature regulated by sanitary standards. Based on production studies, it was concluded that the temperature regime along the length of the longwall face is determined by the temperature of rocks in the developed longwall space, heat emissions from the equipment of the power train, and the temperature of the rock mass ahead of the longwall. The conclusion has been drawn about the feasibility of using developed technological schemes in deep mining conditions, which provide a reduction in longwall temperature by 6-9 °C or more through isolated ventilation of longwall and power trains, as well as heat exchange between the airflow entering the longwall and the rocks in the developed space.
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Date submitted2021-10-31
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Date accepted2023-03-02
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Date published2023-12-25
Improvement of technological schemes of mining of coal seams prone to spontaneous combustion and rock bumps
On the example of the Alardinskaya mine, the problem of underground mining of seams prone to spontaneous combustion and rock bumps in the conditions of the Kondomsky geological and economic region of the Kuznetsk coal basin is considered. The contradictions in the requirements of regulatory documents for the width of the inter-panel coal pillars in the mining of seams with longwalls in conditions of endogenous fire hazard and in the mining of seams that are dangerous due to geodynamical phenomena are discussed. These contradictions impede the safe mining of seams using traditionally used layouts with the danger of spontaneous combustion of coal and rock bumps. A mining-geomechanical model is presented, which is used for numerical three-dimensional simulation of the stress-strain state of a rock mass with various layouts for longwall panels using the finite element method. The results of the numerical analysis of the stress state of the rock mass immediately before the rock bump are presented, and the main factors that contributed to its occurrence during the mining of the seam are established. A dangerous degree of stress concentration in the coal seam near the leading diagonal entries is shown, especially in conditions of application of abutment pressure from the edge of panels’ gob. The analysis of the features of stress distribution in the inter-panel pillar at different widths is carried out. Recommendations for improving the layout for the development and mining of coal seams that are prone to spontaneous combustion and dangerous in terms of rock bumps in the conditions of Alardiskaya mine have been developed. The need for further studies of the influence of pillars for various purposes, formed during the mining of adjacent seams, on the stress-strain state of previously overmined and undermined seams is shown.
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Date submitted2021-04-19
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Date accepted2022-05-25
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Date published2022-07-13
Development of the technology of stowing the developed space during mining
- Authors:
- Evgenii R. Kovalskii
- Kirill V. Gromtsev
An analysis of the world experience in the development of potash deposits shows that the main problems arising during their development are a high level of mineral losses, an increased risk of flooding of mine workings as a result of water-proof layer discontinuance and the development of emergency water inflows in the mined-out spaces. Reduction of potash ore losses can be achieved by using a long-pillar mining system, but this method is limited by the peculiarities of the geological structure of the potash deposits and the need to preserve the continuity of the water-proof layer during its underworking. The safety of underworking of the water-proof layer can be improved by using the stowing of the developed longwall space. However, the question of the influence of the stowing on the height of the zone of water supply cracks development remains little-studied. The world experience of stowing the developed spaces in the development of layers with long pillars is analyzed and the technology of placing the stowing masses, which can solve these problems, is proposed. The considered technology and the proposed solutions are supported by laboratory tests of stowing materials and mathematical modeling of deformation zones in the overlying rocks.
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Date submitted2021-07-05
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Date accepted2022-01-24
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Date published2022-04-29
Ensuring the excavation workings stability when developing excavation sites of flat-lying coal seams by three workings
- Authors:
- Oleg I. Kazanin
- Andrei A. Ilinets
On the basis of analysis of mining plans and field studies at mines of JSC SUEK-Kuzbass, it is shown that in conditions of increasing the size of excavation columns during the development of flat-lying coal seams the stress-strain state of the rock mass along the workings length changes significantly. The necessity of predicting the stress-strain state at the design stage of the workings timbering standards, as well as subsequent monitoring of the workings roof state and its changes in the mining operations using video endoscopes, is noted. The results of numerical studies of the stress-strain state of the rock mass during the development of excavation sites by three workings for various combinations of width of the pillars between the workings for mining-geological and mining-technical conditions of the “Taldinskaya-Zapadnaya-2” mine are provided. The stresses in the vicinity of the three workings are compared with the values obtained during the development of the excavation sites by double drift. A set of recommendations on the choice of the location of the workings, the width of pillars, timbering standards that ensure the stable condition of the workings throughout the entire service life at the minimal losses of coal in the pillars is presented.
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Date submitted2021-01-18
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Date accepted2021-05-21
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Date published2021-09-20
Improving the efficiency of the technology and organization of the longwall face move during the intensive flat-lying coal seams mining at the Kuzbass mines
The reasons for the lag of the indicators of the leading Russian coal mines engaged in the longwall mining of the flat-lying coal seams from similar foreign mines are considered. The analysis of the efficiency of the longwall face move operations at the JSC SUEK-Kuzbass mines was carried out. A significant excess of the planned deadlines for the longwall face move during the thick flat-lying seams mining, the reasons for the low efficiency of disassembling operations and the main directions for improving the technology of disassembling operations are revealed. The directions of ensuring the operational condition of the recovery room formed by the longwall face are considered. The recommended scheme of converged coal seams mining and a three-dimensional model of a rock mass to justify its parameters are presented. Numerical studies using the finite element method are performed. The results of modeling the stress-strain state of a rock mass in the vicinity of a recovery room formed under conditions of increased stresses from the boundary part of a previously mined overlying seam are shown. The main factors determining the possibility of ensuring the operational condition of the recovery rooms are established. It is shown that it is necessary to take into account the influence of the increased stresses zone when choosing timbering standards and organizing disassembling operations at a interbed thickness of 60 m or less. A sufficient distance from the gob of above- or undermined seams was determined to ensure the operational condition of the recovery room of 50 m, for the set-up room – 30 m. Recommendations are given for improving technology and organization of the longwall face move operations at the mines applied longwall mining of flat-lying coal seams with the formation of a recovery room by the longwall face.
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Date submitted2020-06-12
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Date accepted2020-10-28
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Date published2020-11-24
Spatial non-linearity of methane release dynamics in underground boreholes for sustainable mining
- Authors:
- Ada K. Dzhioeva
- Vladimir S. Brigida
The paper is devoted to the problem of increasing energy efficiency of coalmine methane utilization to provide sustainable development of geotechnologies in the context of transition to a clean resource-saving energy production. Its relevance results from the fact that the anthropogenic effect of coalmine methane emissions on the global climate change processes is 21 times higher than the impact of carbon dioxide. Suites of gassy coal seams and surrounding rocks should be classified as technogenic coal-gas deposits, while gas extracted from them should be treated as an alternative energy source. Existing practices and methods of controlling coalmine methane need to be improved, as the current “mine – longwall” concept does not fully take into account spatial and temporal specifics of production face advancement. Therefore, related issues are relevant for many areas of expertise, and especially so for green coal mining. The goal of this paper is to identify patterns that describe non-linear nature of methane release dynamics in the underground boreholes to provide sustainable development of geotechnologies due to quality improvement of the withdrawn methane-air mixture. For the first time in spatial-temporal studies (in the plane of CH 4 - S ) of methane concentration dynamics, according to the designed approach, the parameter of distance from the longwall ( L ) is introduced, which allows to create function space for the analyzed process (CH 4 of S-L ). Results of coalmine measurements are interpreted using the method of local polynomial regression (LOESS). The study is based on using non-linear variations of methane concentration in the underground boreholes and specific features of their implementation to perform vacuum pumping in the most productive areas of the undermined rock mass in order to maintain safe aerogas conditions of the extraction block during intensive mining of deep-lying gassy seams. Identification of patterns in the influence of situational geomechanical conditions of coal mining on the initiation of metastable gas-coal solution transformation and genesis of wave processes in the coal-rock mass allows to improve reliability of predicting methane release dynamics, as well as workflow manageability of mining operations. Presented results demonstrate that development of high-methane Donbass seams is associated with insufficient reliability of gas drainage system operation at distances over 40 m behind the longwall face. Obtained results confirm a working hypothesis about the presence of spatial migration of methane concentration waves in the underground gas drainage boreholes. It is necessary to continue research in the area of estimating deviation angles of “advance fracturing” zone boundaries from the face line direction. Practical significance of research results lies in the possibility to use them in the development of scientific foundation for 3D gas drainage of a man-made coal-methane reservoir, taking into account spatial and temporal advancement of the production face.
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Date submitted2020-02-19
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Date accepted2020-04-17
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Date published2020-10-08
Decrease in coal losses during mining of contiguous seams in the near-bottom part at Vorkuta deposit
- Authors:
- Oleg I. Kazanin
- Valeriy V. Yaroshenko
The problem of formation of extended zones with high rock pressure (HRP) from safety pillars at the boundaries of extraction pillars formed due to the mine layout of complex geometry is considered at the example of JSC Vorkutaugol mines. A detailed analysis of the remaining reserves of the near-bottom part of the deposit was carried out to estimate losses and the impact of HRP zones from the Chetvertyi protective seam to mining operations on the Troinoi upper seam along with the possibilities for the reduction of sizes of HRP zones at the account of expanding the underworked space. Due to research on the near-bottom part of the Vorkuta deposit, within the framework of the accepted layout, a zone at the Komsomolskaya mine and two zones at the Zapolyarnaya-2 mine were singled out, at which losses at the boundaries of the extraction pillars amount up to 13-22 % of the total resources of the mine field. The high volume of losses in these pillars indicates the relevance of research on the priority extraction impact of protective seams on the efficiency and safety of mining operations in the working area of underworked and HRP zones. Based on the analysis of foreign and Russian experience in the pillar cleaning-up at the boundaries of working areas and the methodical guidelines and instructions, a technological scheme was developed that allows increasing the coal mining recovery factor in the near-bottom part of the Vorkuta deposit from 0.75 to 0.9 without fundamental changing of the ventilation and transport networks and also without purchasing any additional mining equipment. The conducted economic calculations confirmed the effectiveness of implementing the new technological scheme for cleaning-up reserves at the boundaries of extraction districts. The economic effect is from 0.079 to1.381 billion rubles of additional profit from coaxial extraction pillars, depending on the mining and geological conditions and the size of the pillars.
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Date submitted2019-05-30
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Date accepted2019-09-04
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Date published2020-02-25
Prospects for industrial methane production in the mine n.a. V.M.Bazhanov using vertical surface wells
The estimated methane resources in the coal stratum of Donbass are 798.5 billion m 3 , including 119.5 billion m 3 in the Donetsk-Makeevsky area. Such significant potential implies that methane can be used not only for industrial production and energy purposes but also as a commodity for the chemical industry. However, in practice, commercial production of methane from coal seams, as is done in the fields of the USA, Canada, India, and China, is not carried out, and methane, obtained as a by-product, is utilized for ensuring the safety of the main technological processes for coal mining. The main reasons for this are the difficult mining and geological conditions of bedding, low thickness and permeability, which does not allow to separate methane production into an independent type of activity due to its low profitability, especially with the use of new technologies based on hydraulic fracturing of coal seams. The assessment of the possibility of industrial methane production in the mine n.a. V.M.Bazhanov in the Donetsk-Makeevsky area of Donbass, which reserves equal to 23.7 billion m 3 , showed that a significant part of the methane reserves is concentrated in coal seams and interlayers with a gas content of 18.5-20.7 m 3 /m 3 . Moreover, in the host rocks, methane is practically in a liberated state. This circumstance makes possible the commercial production of methane for its utilization from the unloaded rock mass by wells drilled from the surface, without the use of hydraulic fracturing technology. The paper discusses the technology of methane extraction by a degassing well drilled from the surface into a coal-bearing stratum unloaded from rock pressure in a mining field of the 4th eastern face of the m 3 seam of the mine n.a. V.M.Bazhanov and its subsequent use as the fuel of an electric generator. It is shown that over the entire period of operation of the pilot well, the volume of actually produced methane exceeded the design value by 23 %, and the cost of the gas produced amounted to 1535 rubles per 1000 m 3 , which is more than 3 times lower than the market price for natural gas for consumers in the Russian Federation. This made it possible to make a conclusion about the possibility of industrial extraction of mine methane using vertical surface wells for its subsequent utilization in power plants, which does not imply the usage of hydraulic fracturing technology.
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Date submitted2019-01-10
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Date accepted2019-03-02
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Date published2019-06-25
Modeling of the welding process of flat sheet parts by an explosion
- Authors:
- M. A. Marinin
- S. V. Khokhlov
- V. A. Isheyskiy
The list of materials subject to explosive welding is very extensive and amounts to several hundred combinations of various alloys and metals, and the variety of explosive welding schemes has more than a thousand options. In almost all technical solutions, the process involves the sequential creation of physical contact of the materials to be welded and their connection due to plastic deformation of the contacting surfaces. The strength of such a connection depends on the mode of the welding process. With the correct selection of the parameters of the mode, it is possible to obtain a high-quality connection of the required strength. However, the experimental selection of such options is a very laborious and costly process. Computer simulation and application of mathematical models for solving dynamic problems of explosion mechanics simplifies the search for optimal parameters and allows to predict the expected result in the shortest possible time. The article discusses the issues of modeling of explosive welding of metals, calculations related to the parameters of the process of formation of the weld using the Ansys Autodyn software package. A model is presented for analyzing the deformation process of explosion welding of a plate and its connection with a matrix. The main parameters of explosion welding (velocity, pressure, time) are determined. The adequacy of the obtained values was evaluated in the systems aluminum – copper and copper – steel. It also provides a comparative analysis of simulation results and field experiments. Based on numerical calculations, a conclusion was substantiated on the suitability of the model obtained for a preliminary analysis of the main welding parameters at the preparatory stage.
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Date submitted2018-01-23
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Date accepted2018-02-25
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Date published2018-06-22
Influence of post-welding processing on continuous corrosion rate and microstructure of welded joints of steel 20 and 30KHGSA
- Authors:
- A. M. Shchipachev
- S. V. Gorbachev
Welded joints of structure steels have lower corrosion resistance in comparison to base metal. To increase corrosion resistance of welded joints and heat-affected zone they use longtime and energy-consuming methods of thermal and mechanic processing. The article covers the possibility of using the superplasticity deformation (SD) effect for processing of welded joints. The effect of SD is that metals and alloys with a small grain size (of the order of 10 μm) under conditions of isothermal deformation at a certain temperature acquire the ability for unusually large plastic deformations while reducing the deformation resistance. Grain-boundary sliding during superplasticity provides a high degree of structural homogeneity. If the metal does not have the small grain size, then during isothermal deformation at appropriate temperature the SD effect will not be fully manifested but will cause relaxation of residual micro and macro strains, recrystallization, which can be used during processing of welded joints to ensure their full strength. There have been carried out the investigation of processing methods impact - SD, thermal cycling and influence of post-welding treatment on corrosion rate and microstructure of steels 20 and 30KhGSA. It is shown that after deformation in superplasticity mode there is low corrosion rate and more favorable microstructure in the studied samples of steel. Post-welding processing of welded joints in SD mode provides low tool loads and low energy costs.
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Date submitted2017-10-25
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Date accepted2018-01-17
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Date published2018-04-24
Innovative technology of large-size products manufacture
- Authors:
- S. N. Sanin
- N. A. Pelipenko
Advantages and prospects for the use of mobile robotic machine-tools in the manufacture of large parts in the mining, cement and nuclear industries are considered, as well as the importance of using welded structures to reduce production costs. Schemes for finishing mechanical machining of welded large-sized parts such as bodies of revolution with the use of mobile robotic machine-tools equipped with a belt-grinding tool, an enlarged description of the technological process for manufacturing a large-sized shell of a welded structure are presented. The conclusion is made that it is necessary to take into consideration the use in the industry of frameless production technology, especially for the machining of large-sized parts, and the use of small mobile robotic machine-tools is a productive approach and has a prospective character. The technological approaches proposed in the article make it possible to remove the restriction on the overall size and mass of the parts being manufactured, which are proposed to be manufactured directly at the site of future operation. The effectiveness of this technology is confirmed both by theoretical research and by practical data of the authors. It was noted that the production by the domestic machine-tool industry of mobile universal and special robotic machine-tools will allow the country's engineering industry to be brought to a new, high-quality world level.
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Date submitted2017-08-30
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Date accepted2017-11-23
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Date published2018-02-22
Basic provisions and problems of ELW technology for the manufacture of aluminum-magnesium alloys constructions
- Authors:
- E. I. Pryakhin
- N. I. Sharonov
Existing problems of electron beam welding of aluminum alloy constructions are considered. For research purposes, the aluminum-magnesium alloy of grade 1561 up to 60 mm thick was used. The thermal field in the heat influence zone is studied experimentally and analytically on the basis of the finite element method (the «Ansys» program). The effect of electron beam movement (scanning) influence on the quality of welded connections and the surface of the welded parts was studied. On the basis of metallographic studies and mechanical tests of welded metal, it is proved that high quality of welded joints is ensured when the beam moves along a curve of the «compressed brackets» shape. A special generator is designed to control the electron beam, which allows to implement a new type of scanning (compressed brackets). The fundamentals of welding technology for alloy 1561 up to 60 mm thick are outlined. Specific recommendations are given, and two new methods are proposed that will allow the successful use of the developed technology in factories in the production of new products and in the repair processes. Examples and analysis of thermal cycles obtained by calculation and experimental method are given. The patterns of heat distribution along the trajectory of the beam movement for different types of scanning are established. The main types of defects in the formation of the welded joints and those formed in the metal during crystallization are considered. Their interrelation with the parameters of the welding mode is shown.
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Date submitted2016-09-06
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Date accepted2016-11-13
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Date published2017-02-22
Justified selection of a seam degassing technology to ensure safety of intensive coal mining
- Authors:
- S. V. Slastunov
- E. P. Yutyaev
The paper contains main aspects of methodological approach to objective analytic assessment of maximum permissible output of the mine faces from the viewpoint of gas factor. Analytic forecast is centered around the assessment of methane inflow into the face area from all possible sources, based on fundamental physical laws, modern tools of mathematical modeling and in-situ tests of main properties and state parameters of the gas-bearing coal formation. Objective and reliable estimation of permissible outputs is a starting point for justified selection of a seam degassing technology, that has to be based on time factor and predicted value of gas recovery from a coal seam to a degassing well. Recommendations have been formulated on the selection of degassing technology for the coal seam «Boldyrevsky» of the Kirov mine, based on the use of cutting-edge technological schemes (hydraulic fracture, carried out from development workings, etc.), successfully implemented on the mentioned site.
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Date submitted2016-09-02
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Date accepted2016-11-08
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Date published2017-02-22
Mathematical models of gas-dynamic and thermophysical processes in underground coal mining at different stages of mine development
- Authors:
- M. V. Gryazev
- N. M. Kachurin
- S. A. Vorobev
New trends have been traced and the existing ones refined regarding filtration and diffusive motion of gases in coal beds and surrounding rock, spontaneous heating of coal and transport of gas traces by ventilation currents in operating coal mines. Mathematical models of gas-dynamic and thermophysical processes inside underworked territories after mine abandonment have been justified. Mathematical models are given for feasible air feeding of production and development areas, as well as for the development of geotechnical solutions to ensure gas-dynamic safety at every stage of coal mine operation. It is demonstrated that the use of high-performance equipment in the production and development areas requires more precise filtration equations used when assessing coal mine methane hazard. A mathematical model of pressure field of non-associated methane in the edge area of the coal seam has been justified. The model is based on one-dimensional hyperbolic equation and takes into consideration final rate of pressure distribution in the seam. Trends in gas exchange between mined-out spaces of high methane- and CO 2 -concentration mines with the earth surface have been refined in order to ensure environmental safety of underworked territories.
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Date submitted2015-10-21
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Date accepted2015-12-16
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Date published2016-08-22
Flow instability in producing well at flash-steam fields
- Authors:
- A. N. Shulyupin
Theoretical foundations are presented for forecasting operation instability of producing wells at flash-steam fields. The considered topic gains actuality because of the new conditions for developing geothermal power industry which call for solicitous use of the wells fund. Instability mechanism is considered: increased discharge results in the growth of the force generating the flow, which in turn results in still higher discharge. The force grows due to weakening of gravitational component which counteracts the flow in the result of depletion in the density of flash-steam mixture. It is demonstrated that due to the specifics of development of such instability in a geothermal well the reaction of well foot pressure to change in the discharge cannot influence the stability in any effective way, while the reaction of wellhead pressure may work as a stabilizing factor. Principal weaknesses are pointed out of former ideas on flow instability in flash-steam wells. The condition of stable flow should be the positive value of the derivative on discharge of the internal well foot pressure defined as the sum of wellhead and internal pressure drop.
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Date submitted2015-07-11
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Date accepted2015-09-17
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Date published2016-02-24
The mechanism of rock burst leading to ground destruction of mine openings
- Authors:
- M. G. Mustafin
The article deals with the main issues of studying of one type of rock bursts which lead to gound destruction of coal mine openings. The research is focused on rock burst prediction. Some cases of rock bursts are analised. The paper points out factors affecting this kind of rock failure. It also presents some simulation models and numerical examples. The results of the research show that it is possible to plan safe mining operations under different mining and geological conditions.
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Date submitted2014-12-28
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Date accepted2015-02-21
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Date published2015-12-25
Modeling of rock massif geomechanical state at gas extraction from coal seams
- Authors:
- M. G. Mustafin
The article describes the method of modeling a coal seam stress-strain state and an enclosing rock massif when degasified. An approach to defining the model input parameters, calculated with the porosity and gas pore pressure coefficient, was shown. The importance of preliminary calculations, indicating possible coal seam shrinkage and surface subsidence was underlined. It shows formation mechanism for coal seam zones with elevated gas pressure, where gas recovery is efficient.
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Date submitted2014-11-01
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Date accepted2015-01-18
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Date published2015-10-26
On the design features of underground multiple gassy coal seam mining
- Authors:
- O. I. Kazanin
The analysis of the industry regulatory requirements and the world design experience of underground multiple coal seam mining is provided. The main problems of intensive longwall mining of multiple flat gassy coal seams as well as methods for determination of high rock pressure zone parameters and seams interaction are considered. The examples of a number of mines in the Kuzbass and Pechora coal basins show that the design of multiple seam mining and the choice of longwall panel parameters were often made without taking into consideration influence of surrounded seams that leads to essential complication of conditions for mining operations and decreases the technical and economic indicators of mining. The existing industry regulations do not allow considering complex influence of factors in multiple coal seams mining fully. On the basis of field, laboratory, and numeric research results it is noted that recommendations for pillar positioning in contiguous seams ensuring efficiency and safety of multiple seam longwall mining can significantly differ in case of liability of coal seams to spontaneous combustion, high natural gas content, influence of multiple seam mining onto daily surface, and difficult conditions of entries maintenance. The importance of having information on the stress-strain condition of the rock mass at a design stage and its changes in the process of multiple seam mining is shown. The need for industry regulations updating for the purpose of a more detailed definition of a form, size and a location of high rock pressure zones as well as stress parameters in these zones is noted. A set of recommendations for effective and safe multiple seam mining is developed.
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Date submitted2013-07-27
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Date accepted2013-09-30
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Date published2014-03-17
Influence of disjunctive dislocations on parameters of secure zones on flat-lying adjacent coal seams
- Authors:
- V. P. Zubov
- E. R. Kovalskii
- A. V. Nikiforov
The article focuses influence of disjunctive dislocations on parameters of secure zones on flat-lying adjacent coal seams is considered.
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Date submitted2013-07-25
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Date accepted2013-09-29
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Date published2014-03-17
Assessment of the longwall face length influence on gas emission at longwall panels of the OJSC «Vorkutaugol» coal mines
- Authors:
- O. I. Kazanin
- A. M. Sufiyarov
Results of researches of the longwall face length influence on gas emission at the coal seam «Chetverty» longwall panels of the OJSC «Vorkutaugol» mines are given. Dependences of the longwall production and longwall face length are specified. Range of rational values of the longwall face length according to the gas emission control efficiency is determined.
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Date submitted2013-07-16
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Date accepted2013-09-21
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Date published2014-03-17
Gas emission control parameters determination for sublevel caving mining systems at the «Kiselevskaya» coal mine
- Authors:
- O. I. Kazanin
- A. A. Sidorenko
- V. V. Sementsov
The results of the aero- and gas-dynamics processes numerical researches for the sublevel caving mining system with mechanized roof support in conditions of «Kiselevskaya» coal mine are given in the article. It is shown, that reliable and effective panel ventilation is provided with the technological scheme with three entries at the each sublevel. The parameters of the technological scheme are determined.
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Date submitted2013-07-18
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Date accepted2013-09-02
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Date published2014-03-17
Rock mechanics problems decision algorithm for bottom layers of potash salt deposits
Decision algorithm for rock mechanics problems for bottom layers of potash deposits is suggested. Flow chart for the algorithm and it’s parts is shown. The algorithm represents the method to choose excavation technology for multi-layer potash deposits.
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Date submitted2013-07-28
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Date accepted2013-09-27
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Date published2014-03-17
The analysis of the stress-and-strain state in vicinity of mining excavations
- Authors:
- A. A. Sankovskii
- E. R. Kovalsky
Estimation of the strain-and-stress state and displacement of the waterprotective layers in vicinity of mining excavations in conditions of SKRU-3 mine (Uralkali Group) is done. It is shown that loadings on pillars on layer Kr.II exceed 15-20 % loadings on layer AB.
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Date submitted2010-07-15
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Date accepted2010-09-13
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Date published2011-03-21
Experimental setup for research Influence of vibromechanical treatment on mechanical properties of welded joints
- Authors:
- O. F. Khafizova
- V. I. Bolobov
The description of developed experimental setup for welding product that made of pipeline steels with application of applying vibration with intended frequency approximating to natural-vibration frequency of welded construction unit of pipelines during the welding cycle is presented.
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Date submitted2010-07-07
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Date accepted2010-09-06
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Date published2011-03-21
Improvement of quality of dissimilar welded joints made of pipelines steels by application of vibromechanical treatment in welding
- Authors:
- O. F. Khafizova
The article describes opportunity of improvement of physical-mechanical properties of welded joint made of different strength grade pipeline steels (Steel 20 of K42 strength grade and 16ГС – K52) by applying vibration during the welding cycle. It’s shown that maximal positive effect is achieved by vibration frequency approximating to natural-vibration frequency of welded construction.