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

Bondarenko, Volodymyr; Kovalevska, Iryna; Symanovych, H.; Barabash, Mykhailo; Snihur, V.

doi:10.1051/e3sconf/20186603001

Cited by 14 publications

(10 citation statements)

References 3 publications

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“…Thus, it is planned to use the experimental method of mine instrumental observations of the development of mine working contour displacements and deformations of its support in combination with the methods of correlation-dispersive analysis of the experimental data results [21]- [23].…”

Section: Basic Research Materialsmentioning

confidence: 99%

Technical and technological aspects of the coal mine closure based on the geomechanical component assessment

Barabash¹,

Salieiev²,

Symanovych³

2021

Min. miner. depos.

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Purpose.Development of a comprehensive methodology for assessing the state of mine workings based on the analysis of their contour displacement patterns when solving the problem of minimizing the risks during the closure of coal mines in Ukraine. Methods. Based on an integrated analysis of international and domestic trends when assessing the consequences of mine closure, the main provisions of using the method of instrumental mine observations have been substantiated. When solving the problem, the approaches of regulatory documents are taken into account to identify the geomechanical situation according to two conditions: the structure and strength properties of the lithotypes in the adjacent coal-bearing stratum and the peculiarities of the rheological processes manifestation during the development of its displacements. Findings. The geomechanical, technological and hydrogeological factors have been distinguished that are required to take into account when closing the coal mines. Fundamental methodological provisions have been substantiated for the most reliable assessment of the mine workings state, taking into account the long period of their operation. A criterion for making a decision on the decommissioning of mine workings or their further maintenance is presented. Originality.A series of generalizing dependences of the mine working contour displacement development has been obtained, which can be divided into four main groups according to the criteria of the structural and strength properties of lithotypes in the adjacent mass, as well as the type of their rheological manifestations: decaying and persistent deformation creep. For each group, using the methods of correlation-dispersive analysis, empirical formulas have been determined for calculating the convergence of the roof and bottom of mine workings, as well as their sides, depending on the geomechanical criterion H/R of the maintenance conditions and the duration t of this period. Practical implications.The obtained correlation ratios make it possible to predict the residual section of mine working at any time of its maintenance. They are a geomechanical component of its operational state assessment. The result of this research is the development of a new methodology for assessing the mine working state according to the patterns for predicting its contour displacement.

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Section: Basic Research Materialsmentioning

confidence: 99%

Technical and technological aspects of the coal mine closure based on the geomechanical component assessment

Barabash¹,

Salieiev²,

Symanovych³

2021

Min. miner. depos.

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“…Groundwater is the second very important factor that affects rocks deformation. In general, Bondarenko et al [35] floor stability criterion considers after division of the floor beds on three types, depending on their saturation and thickness. Groundwater can cause rocks slaking and swelling, which results in the loss of rock strength around the excavation and additionally promotes deformation of the rocks around the excavation.…”

Section: The Mechanism Of the Floor Upheaval In Roadwaysmentioning

confidence: 99%

The Effect of Selected Factors on Floor Upheaval in Roadways—In Situ Testing

2020

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The phenomenon of the floor upheaval occurs in virtually every type of rock mass and at every depth, accompanying the process of excavation of tunnels and headings. Despite its inconvenience, it is rarely studied because of the complexity of the process and the multiplicity of the factors causing deformations in floor rocks. To quantify the effect of the selected factors on floor upheaval, this article presents an analysis of results of in situ measurements carried out in three coal mine roadways at 15 measuring stations. These measurements were taken over varying periods of time, between 129 and 758 days. Groundwater and fault zones intersecting the excavations were considered as the key factors that affect floor upheavals. Therefore, the measurement bases were located at local faults and sites of water inflow. To compare the results, the stations were also located where the rock mass was not exposed to any factors other than stresses resulting from the depth of the excavation. The excavations were driven in various rocks and were located at different depths from 750 to 1010 m. The analyses of the study results show that the floor upheaval always depends on time and can be described in polynomial form: ufl = a·t2 + b·t + c or by a power function: ufl = a·tb. However, the further regression analyses show that roadway’s floor upheaval can be expressed by a complex form using the key parameters determining the phenomena. In the absence of an impact of geological factors on the stability of the excavation, the floor upheaval depends on floor rocks compressive strength σc and Young’s modulus E: ln(ufl)=a·ln(tσc)−bE−c; in the case of rock mass condition affected by water depends on the rock compressive strength reduction after submerging rock in water σcs 6h: ufl=a·t0.5−bσcs 6hσc+c and in the case of fault depends on the fault’s throw f: ufl=a·t0.8+b·f1.2−c. Statistical analysis has shown that the matching of the models to the measurement data is high and amounts to r = 0.841–0.895. Hence, in general, the analysis shows that the floor upheaval in underground excavation in any geological conditions may grow indefinitely.

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“…When considering the trends of the main geomechanics factors influence on the state of fastening and security systems of the preparatory mine workings in the zone of the stope works influence (Bondarenko, Kovalevska, Symanovych, Barabash, & Snihur, 2018;Kovalevska, Barabash, Husiev, & Snihur, 2018), a certain impact have been constantly observed on each other all of the load-bearing elements constituting the diagram for maintaining the mine working. And the degree of this impact largely depended on how different their operation modes are in the process of resistance to the rock pressure manifestations (Majcherczyk, Niedbalski, & Malkowski, 2007).…”

Section: Introductionmentioning

confidence: 99%

“…For example, if rigid and pliable elements interact with each other, then usually in the area of their contact in the pliable element, the significant perturbations of stresses components occur, which often reach the destructive values (Kulczycka, Hałasik, Nowaczek, Whirt, & Szkop, 2017). Therefore, it is a very important issue of matching between the deformation-strength characteristics of the elements included into the fastening system of mine working, against their total adaptation to the nature of rock pressure, conditioned by the action of geome-chanics factors combination (Kovalevska, Barabash, Husiev, & Snihur, 2018;Bondarenko, Kovalevska, Symanovych, Barabash, & Snihur, 2018), including the rigidity of the collapsed rocks and the rocks of immediate and main roof being consolidated in the mined-out space of the longwall face (Kovalevska, Vivcharenko, & Snigur, 2013;Symanovych, Demydov, & Chervatuk, 2013).…”

Section: Introductionmentioning

confidence: 99%

The influence of rigidity of the collapsed roof rocks in the mined-out space on the state of the preparatory mine workings

Bondarenko¹,

Symanovych²,

Kicki³

et al. 2019

Min. miner. depos.

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Purpose. The substantiation of accounting the deformation-strength characteristics of the collapsed rocks and the rocks consolidating near the reusable preparatory mine working of the mined-out space to optimize the loading parameters of its fastening and security systems. Improving the research adequacy and recommendations reliability.Methods. By means of computational experiments based on the finite-element method, the influence has been studied of rigidity of the collapsed rocks and consolidating rocks in the mined-out space on the level of intensity of the load-bearing elements of the fastening and security systems of mine working. The analysis has been performed of the stress-strain state of the geomechanical system load-bearing elements, as well as comparative mine research.Findings. The research results and analysis are represented of the stress-strain state of the fastening and security systems elements in the preparatory mine workings with different degree of rigidity of the collapsed and consolidated rocks of the mined-out space. The patterns of the rigidity influence of the collapsed roof rocks on the stable state of preparatory mine workings have been assessed. Originality.A different-valued relation has been established between the deformation-strength characteristics of the collapsed rocks in the mined-out space and the elements of fastening and security systems of mine working, which should be considered when optimizing the modes of their operation. It has been revealed that the increased loading on the combined roof-bolting system elements protects the frame support from the increased rock pressure, which contributes to reducing the section losses of mine working. Practical implications.The research performed is the basis for the parameters optimization when maintaining the preparatory mine workings for their repeated use and also for the rational parameters search of the combined roof-bolting system in order to develop a method for choosing its parameters depending on mining and geological conditions.

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

Cited by 14 publications

References 3 publications

Technical and technological aspects of the coal mine closure based on the geomechanical component assessment

Technical and technological aspects of the coal mine closure based on the geomechanical component assessment

The Effect of Selected Factors on Floor Upheaval in Roadways—In Situ Testing

The influence of rigidity of the collapsed roof rocks in the mined-out space on the state of the preparatory mine workings

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