STUDY OF THE STABILITY OF PREPARATORY WORKINGS SECURED WITH ANCHORAGE, THOSE WHO FIND THEMSELVES IN DIFFICULT EMERGENCY SITUATIONS WHEN WORKING OUT COAL SEAMS AT THE MINES OF KUZBASS

Due to intensive development of information technologies and the onset of 4th industrial revolution the number of robotic industries is steadily growing. The volume of production and the use of robots is also increasing. At the same time, the support and the management of digital production is being rapidly developing. The robotic systems are incapable of completely excluding a person from the technological chain, since they need timely maintenance and personnel working out the emergency situations. One of the solutions to reduce the risk of unexpected breakdowns is a predictive approach to the maintenance. The implementation of this approach is carried out using data analysis tools. This study presents the results of applying machine learning methods to analyze data from industrial robots in order to predict potential failures

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Surrounding Rock Movement of Steeply Dipping Coal Seam Using Backfill Mining

Shock and Vibration ◽

10.1155/2021/5574563 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Wenyu Lv ◽

Kai Guo ◽

Jianhao Yu ◽

Xufeng Du ◽

Kun Feng

Keyword(s):

Numerical Simulation ◽

Coal Seam ◽

Surrounding Rock ◽

Maximum Deflection ◽

Coal Seams ◽

Physical Similarity ◽

Working Face ◽

Rock Structure ◽

Backfill Mining ◽

The Stability

The movement of the overlying strata in steeply dipping coal seams is complex, and the deformation of roof rock beam is obvious. In general, the backfill mining method can improve the stability of the surrounding rock effectively. In this study, the 645 working face of the tested mine is used as a prototype to establish the mechanical model of the inclined roof beam using the sloping flexible shield support backfilling method in a steeply dipping coal seam, and the deflection equation is derived to obtain the roof damage structure and the maximum deflection position of the roof beam. Finally, numerical simulation and physical similarity simulation experiments are carried out to study the stability of the surrounding rock structure under backfilling mining in steeply dipping coal seams. The results show the following: (1) With the support of the gangue filling body, the inclined roof beam has smaller roof subsidence, and the maximum deflection position moves to the upper part of working face. (2) With the increase of the stope height, the stress and displacement field of the surrounding rock using the backfilling method show an asymmetrical distribution, the movement, deformation, and failure increase slowly, and the increase of the strain is relatively stable. Compared with the caving method, the range and degree of the surrounding rock disturbed by the mining stress are lower. The results of numerical simulation and physical similarity simulation experiment are generally consistent with the theoretically derived results. Overall, this study can provide theoretical basis for the safe and efficient production of steeply dipping coal seams.

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Peculiarities of using classification indicators of the coal metamorphism degree for predicting the hazardous coal seams properties

E3S Web of Conferences ◽

10.1051/e3sconf/202020101014 ◽

2020 ◽

Vol 201 ◽

pp. 01014

Author(s):

Mykola Antoshchenko ◽

Elvira Filatieva ◽

Vladyslav Yefimtsev ◽

Vadym Tarasov

Keyword(s):

Spontaneous Combustion ◽

Chemical Activity ◽

Mining Engineering ◽

Coal Seams ◽

Mining Operations ◽

Emergency Situations ◽

Specific Composition ◽

Geological Conditions ◽

Definition Of ◽

Mining Coal

Currently, there is no reliable regulatory framework for determining the hazardous properties of coal seams, including the propensity of coal for spontaneous combustion. Under relatively identical mining engineering and geological conditions for mining coal seams, the probability of emergency situations is determined to a large extent by the genetic properties of coal. The research methodology is based on the classical definition of metamorphism, which characterizes the change in the composition and properties of coal. The analysis involves indicators that directly or indirectly characterize the elemental composition of organic and mineral mass, chemical activity and physico-mechanical properties. This will allow to establish a specific composition and properties that contribute to the manifestation of certain hazardous properties of coal seams during mining operations. It is shown that the modern industrial classification does not take into account the change in the organic and mineral constituents of coal, which does not make it possible to use it unchanged to predict the hazardous properties of coal seams.

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Assessment of parting rock weak zones under the joint and downward mining of coal seams

E3S Web of Conferences ◽

10.1051/e3sconf/20186603001 ◽

2018 ◽

Vol 66 ◽

pp. 03001 ◽

Cited By ~ 4

Author(s):

Volodymyr Bondarenko ◽

Iryna Kovalevska ◽

Hennadii Symanovych ◽

Mykhailo Barabash ◽

Vasyl Snihur

Keyword(s):

Stress Component ◽

Stability Loss ◽

Coal Seams ◽

Security Systems ◽

Relationship Patterns ◽

Instrumental Observations ◽

Set Up ◽

The Stability ◽

The Relationship ◽

Weak Zones

The aim of the forecasting effort is to identify troublesome zones of stability loss by a parting lengthwise of the extraction panel under the joint and downward mining of coal seams. Analyses have been carried out of active stress component curves for a 3-D model computational experiment compared with the strength characteristic of each lithotype of a parting. An algorithm has been developed for the stability assessment of a parting lengthwise along the extraction panel. The relationship patterns have been estimated between the sizes of the parting rocks discontinuity zones and the main geomechanical parameters. A scientifically grounded basis has been created for the detection of the parting rock weak zones lengthwise along the extraction panel for the calculation of the mounting and security systems of the development works. A complex of underground instrumental observations was made, which was used to set up a correspondence of patterns to indicate the variation in rock pressure manifestation intensity and the tendencies for changes in the parting structure. All of this confirms the adequacy of the techniques for parting state forecasting, which is recommended for use in the engineering documentation for the joint and downward mining of coal seams.

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Criteria for the difficulty of working out coal-bearing zones of quarry fields

E3S Web of Conferences ◽

10.1051/e3sconf/201913401018 ◽

2019 ◽

Vol 134 ◽

pp. 01018

Author(s):

Alexei Selyukov ◽

Nuray Demirel

Keyword(s):

Complex Structure ◽

Uneven Distribution ◽

Open Pit ◽

Coal Seams ◽

Mining Methods ◽

Coal Reserves ◽

Working Out

Coal-bearing zones of open pit fields are represented by formations of coal seams from inclined to steep bedding with unstable thickness, both in dip and strike with different dip angles even within the same strata, with varying rock inter-layers and strength. In addition, most coal seams have a complex structure, including rock layers inside. In most cases, there is an uneven distribution of coal seams, and, consequently, coal reserves over the area of quarry fields. In this regard, for the analysis of quarry fields, there is a need to select criteria for assessing the complexity of coal-bearing zones for the purpose of systematizing them and choosing directions for constructing technological schemes for excavation and loading operations and mining methods.

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Searching for the Optimal Parameters of the Thick Steep Seams‘ Under-Level Development

E3S Web of Conferences ◽

10.1051/e3sconf/20184101002 ◽

2018 ◽

Vol 41 ◽

pp. 01002

Author(s):

Svetlana Kostyuk ◽

Nikolay Bedarev ◽

Oleg Lyubimov ◽

Nikolay Kovalyov

Keyword(s):

Tensile Strength ◽

Bulk Density ◽

Optimal Parameters ◽

Coal Seams ◽

Technical Result ◽

Immediate Roof ◽

Working Out ◽

Excavation Site ◽

Coal Region

At the present time the problem to search for variants for the development of steep thick coal seams is highly interest. Here there are, for example, variants for managing the workings’ roof by caving or laying the worked out space. The authors proposed a number of methods for it, which are protected by patents. The permissible span of the roof exposure is estimated as a function of the type of the immediate roof of the mine, its thickness, bulk density and tensile strength, and the height of the underlevel is also determined. The technical result is provided by the presence of the protective inter-horizon strips and inter-sectional pillars, by the order of working out the excavation site and by the value of the step of the binding of the worked out space. The above solutions are acceptable for the Prokopyevsk-Kiselevsk coal region in Kuzbass.

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Stability of Split-Level Gob-Side Entry in Ultra-Thick Coal Seams: A Case Study at Xiegou Mine

Energies ◽

10.3390/en12040628 ◽

2019 ◽

Vol 12 (4) ◽

pp. 628 ◽

Cited By ~ 4

Author(s):

Junwen Zhang

Keyword(s):

Coal Mine ◽

Coal Pillar ◽

Peak Stress ◽

Coal Seams ◽

Solid Coal ◽

Stress Fluctuation ◽

Pillar Mining ◽

The Stability ◽

Rock Specimens

Split-level longwall gob-side entry (SLGE) has been applied as a special form of small gate pillar mining (or non-coal pillar mining) in thick coal seams. The stability of the coal pillar directly affects the rationality of the layout of the SLGE. Starting from the mining-induced influence around the SLGE, this paper compares the mechanical properties of coal under different mining effects, and studies the rationality of “zero pillar” location against the Xiegou coal mine. The study shows that the key to success of the application of the SLGE is the existence of an intact zone within the triangular coal pillar in spite of double disturbances due to tunneling and coal mining extraction. Laboratory testing shows that the density and uniaxial compressive strength of rock specimens obtained from the triangular coal pillar are smaller than that from the other part of the panel which is concluded to be due to the varied degree of mining-induced influence. The numerical modeling results show that most of the triangular coal pillar is intact after extraction of the panel, and that the peak stress is located in the solid coal beyond the triangular coal pillar. The plastic zone of the triangular coal pillar is only about 1 m after the excavation of the tail gate of the next split-level panel. The physical modeling shows that the tail gate of the next panel is in the destressed zone with only a very small stress fluctuation during the extraction of the next panel. The study shows that the location of the SLGE at Xiegou coal mine is reasonable. SLGE is preferable for ultra-thick coal seams.

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Stability Analysis and Derived Control Measures for Rock Surrounding a Roadway in a Lower Coal Seam under Concentrated Stress of a Coal Pillar

Shock and Vibration ◽

10.1155/2020/6624983 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Zhuoyue Sun ◽

Yongzheng Wu ◽

Zhiguo Lu ◽

Youliang Feng ◽

Xiaowei Chu ◽

...

Keyword(s):

Coal Seam ◽

Numerical Simulations ◽

Principal Stress ◽

Coal Pillar ◽

Control Measures ◽

Stress Difference ◽

Coal Seams ◽

The Stability ◽

Close Distance ◽

Close Distance Coal Seams

Numerical simulations have often been used in close-distance coal seam studies. However, numerical simulations can contain certain subjective and objective limitations, such as high randomness and excessively simplified models. In this study, close-distance coal seams were mechanically modeled based on the half-plane theory. An analytical solution of the floor stress distribution was derived and visualized using Mathematica software. The principal stress difference was regarded as a stability criterion for the rock surrounding the roadway. Then, the evolution laws of the floor principal stress difference under different factors that influence stability were further examined. Finally, stability control measures for the rock surrounding the roadway in the lower coal seam were proposed. The results indicated the following: (1) The principal stress difference of the floor considers the centerline of the upper coal pillar as a symmetry axis and transmits radially downward. The principal stress difference in the rock surrounding the roadway gradually decreases as the distance from the upper coal pillar increases and can be ranked in the following order: left rib > roof > right rib. (2) The minimum principal stress difference zones are located at the center of the left and right “spirals,” which are obliquely below the edge of the upper coal pillar. This is an ideal position for the lower coal seam roadway. (3) The shallowness of the roadway, a small stress concentration coefficient, high level of coal cohesion, large coal internal friction angle, and appropriate lengthening of the working face of the upper coal seam are conducive to the stability of the lower coal seam roadway. (4) Through bolt (cable) support, borehole pressure relief, and pregrouting measures, the roof-to-floor and rib-to-rib convergence of the 13313 return airway is significantly reduced, and the stability of the rock surrounding the roadway is substantially improved. This research provides a theoretical basis and field experience for stabilizing the lower coal seam roadways in close-distance coal seams.

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The Research of Fiber Optic Gyroscope Error Based on Insertion Loss and Beam-Splitting Ratio of Y-Waveguide

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.182-183.606 ◽

2012 ◽

Vol 182-183 ◽

pp. 606-610 ◽

Cited By ~ 1

Author(s):

Xin Wang You ◽

Ping Huang ◽

Shao Feng Lou

Keyword(s):

Insertion Loss ◽

Critical Parameters ◽

Fiber Optic Gyroscope ◽

Beam Splitting ◽

Splitting Ratio ◽

Measurement Principle ◽

The Stability ◽

Two Parameters ◽

Working Out ◽

Tail Fibers

Y-waveguide is widely used in the integrated optics,among which the beam-splitting ratio and insertion loss are the most critical parameters. The measurement setups and methods for the two parameters are introduced. The temperature is the most important factor to the stability of Y-waveguide. As for the insertion loss, the measurement setup was built up based on the measurement principle, and the factors which affected the measurement of the insertion loss were analyzed. As for the beam-splitting ratio, the output luminous power for two tail fibers of Y-waveguide was measured respectively. In different temperature condition, we study the error of FOG by various beam-splitting ratio after working out the beam-splitting ratio according to the formula. Then put into compensation implement.

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Modeling the Spatial and Temporal Evolution of Stress during Multiworking Face Mining in Close Distance Coal Seams

Advances in Civil Engineering ◽

10.1155/2021/5624972 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Yong Zhang ◽

Jinkun Yang ◽

Jiaxuan Zhang ◽

Xiaoming Sun ◽

Chen Chen ◽

...

Keyword(s):

Numerical Simulation ◽

Stress Distribution ◽

Temporal Evolution ◽

Coal Pillar ◽

Coal Seams ◽

Geological Conditions ◽

Coal Pillars ◽

The Stability ◽

Close Distance ◽

Close Distance Coal Seams

Mining in close distance coal seams (CDCSs) is frequently associated with engineering disasters because of the complicated nature of stress distribution within CDCSs. In order to establish a layout of a roadway to minimize the occurrence of disasters associated with mining CDCS, here the spatial and temporal evolution of stress distribution during the multiworking face mining of a CDCS was explored through numerical simulation based on the engineering and geological conditions of the Nantun Coal Mine. The numerical simulation results indicate that, after the extraction of adjacent multiple working faces, the spatial distribution of stress can be characterized with areas of increased, reduced, and intact stress. The superposed stress of inclined seams that are very close to each other propagates through coal pillars in the bottom floor, and this propagation follows neither the line along the axis of the coal pillar nor the line perpendicular to the direction of the floor. It instead propagates along a line angled with the axis of the coal pillar. The roadway can be arranged in the area with reduced stress, to improve its the stability. Based on the computed spatial and temporal evolution of stress, an optimized layout of roadway was proposed. This layout features a reasonable interval between the mining roadway and a minimal proportion of increased stress areas along the mining roadway and is aligned with geological structures.

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