Method for optimizing the protecting pillars parameters in underground coal mining

A method for optimizing the protecting pillars parameters during the study of soft enclosing rocks (in Ukraine mines) is represented. The necessity of a differentiated approach has been substantiated when choosing the protecting pillar parameters based on the geomechanical factors analysis influencing the state of massif. Mining and geological situation was analysed. It has been studied a stress-strain state (SSS) along the protecting pillar width with account of the mined-out space on the basis of a computational experiment and is presented in the form of curves of vertical and horizontal stresses distribution, as well as stresses intensity distribution. The recommended engineering decisions have been substantiated and the SSS of fastening and security structures has been analysed. A certain reserve of the fastening structure loadbearing capacity as part of the frame support and the combined roof-bolting system has been revealed. An evidence base has been created for the measures development on conducting and maintaining mine workings in the zone of the stope works influence. The recommendations have been developed on the protecting pillar formation with a width of at least 40 – 45 m to exclude the stope works influence.

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Mathematical modeling of tight roof periodical falling

E3S Web of Conferences ◽

10.1051/e3sconf/20186000020 ◽

2018 ◽

Vol 60 ◽

pp. 00020 ◽

Cited By ~ 1

Author(s):

Vira Prykhodko ◽

Nataliia Ulanova ◽

Oleksandr Haidai ◽

Dina Klymenko

Keyword(s):

Mathematical Modeling ◽

Rock Mass ◽

Boundary Element Method ◽

Coal Seam ◽

Mine Working ◽

Strain State ◽

Stress And Strain ◽

Mine Workings ◽

Roof Falling ◽

Enclosing Rocks

The paper proposes a method to determine of a coal seam roof falling step basing upon the analysis of stress and strain state of the rock mass area with mine workings formed as a result of coal preparatory and extraction operations. A boundary element method has been applied to define stress and strain state (SSS). Fissuring of enclosing rocks was modeled by means of transversal-isotropic medium. Dependence of destructed rocks zone height within the roof of a seam being mined upon the weakening of the rock mass due to its fissuring and mine working geometry has been determined. Effect of fissility on the periodical roof falling step has been studied. Changes in support loads in the process of stope advance have been determined. A scheme of partial backfilling of the worked out area has been proposed to maintain the support in its working order.

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The Computational Experiment Substantiation and Stress-Strain State Analysis of Border Rocks, as Well as of the Basic Fastening System of Preparatory Mine Workings in the Zone of Stope Works Influence

Combined Roof-Bolting Systems of Mine Workings: Monograph ◽

10.1201/9781003081432-5 ◽

2020 ◽

pp. 37-53

Author(s):

V. Bondarenko ◽

I. Kovalevska ◽

H. Symanovych ◽

M. Barabash ◽

V. Chervatiuk ◽

...

Keyword(s):

Computational Experiment ◽

Strain State ◽

Stress Strain ◽

Stress Strain State ◽

Mine Workings ◽

State Analysis

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Numerical modeling of the stress-strain state of peripheral massif in the vicinity of mine workings

E3S Web of Conferences ◽

10.1051/e3sconf/202133001009 ◽

2021 ◽

Vol 330 ◽

pp. 01009

Author(s):

Anastasiya Nikitina ◽

Dmitriy Borzykh ◽

Sergey Rib ◽

Aleksandra Lesnykh ◽

Tonglin Zhao

Keyword(s):

Numerical Modeling ◽

Mine Working ◽

Strain State ◽

Stress Strain ◽

Roof Bolting ◽

Stress Strain State ◽

Numerical Studies ◽

Preparatory Working ◽

Mine Workings ◽

Maximum Exposure

In the process of numerical studies, the stress-strain state of the rock massif around the mine working driven at a depth of 600 m was determined. The article presents the analysis of the distribution of total vertical and horizontal stresses isolines in the working roof, as well as the ratio of the residual strength of rocks to the initial. The influence of the roof bolting on the displacement of working contour was established. Dangerous zones in the near-contour rocks of preparatory working were identified. The maximum exposure area of unsecured part of the roof during driving the workings in seam 3-3a was established.

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Geomechanics of overworked mine working support resistance in the laminal massif of soft rocks

E3S Web of Conferences ◽

10.1051/e3sconf/202020101003 ◽

2020 ◽

Vol 201 ◽

pp. 01003

Author(s):

Iryna Kovalevska ◽

Hennadii Symanovych ◽

Jacek Jarosz ◽

Mykhailo Barabash ◽

Oleksandr Husiev

Keyword(s):

Mine Working ◽

Computational Experiment ◽

Strain State ◽

The Finite Element Method ◽

Mining Operations ◽

Soft Rocks ◽

Second Stage ◽

Support Resistance ◽

Complicating Factors ◽

Water Cut

The relevant issues of ensuring trouble-free mining operations on the underlying horizons, which are partially or fully overworked are studied in this paper. The problem has been solved using the example of a laminal massif of the Western Donbas soft rocks; complicating factors were taken into account: water-cut, fracturing, and the rheological properties manifestation. The model, proposed for calculation, has been substantiated in view of geomechanics, as well as the finite element method has been chosen to obtain the stress-strain state of the adjacent massif and support. At the first stage, mine observations of the state of mine working planned for overworking have been conducted and analysed. At the second stage, a computational experiment has been conducted in the most difficult areas. The stresses fields have been analysed according to vertical, horizontal and stresses intensity components of the soft rocks laminal massif, as well as their distribution curves for the recommended and basic fastening options. It has been proved that the recommended parameters of the fastening structure provide repair-free mine working maintenance for the entire exploitation period with account of overworking. Recommendations have been developed for mining the seam C6 in M.I. Stashkova Mine, DTEK Pavlohradvuhillia PJSC.

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The results of monitoring of hydroimpulsive disintegration of outburst-prone coal seams using ZUA-98 system

E3S Web of Conferences ◽

10.1051/e3sconf/202016800068 ◽

2020 ◽

Vol 168 ◽

pp. 00068

Author(s):

Vasyl Zberovskyi ◽

Kostiantyn Sofiiskyi ◽

Rishard Stasevych ◽

Artem Pazynych ◽

Jan Pinka ◽

...

Keyword(s):

Acoustic Emission ◽

Rock Mass ◽

Coal Seam ◽

High Frequency ◽

Strain State ◽

Monitoring And Evaluation ◽

Dynamic State ◽

Coal Seams ◽

Gas Dynamic ◽

Mine Workings

The paper represents the results of monitoring and evaluation of the efficiency of hydroimpulsive disintegration of outburst-prone coal seams in the stopes of development mine workings using a system of sound detecting facilities. Methods of acoustic emission control have been considered as well as the monitoring tasks to evaluate rock mass conditions before the procedure and after it inclusive of the results of sound accompaniment of hydraulic disintegration of the coal seam. It has been determined that the higher concentration of stresses within the rock mass is, the more efficient action of high frequency self-oscillations of cavitation transmitter is on both the fissuring and changes in gas-dynamic state of the coal seam. It has been recommended to apply a mode of impulsive fluid pumping under the conditions where coal seam is in the stress-strain state.

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Assessment of the mutual influence of deformation-strength characteristics of the fastening system elements

E3S Web of Conferences ◽

10.1051/e3sconf/201912301006 ◽

2019 ◽

Vol 123 ◽

pp. 01006 ◽

Cited By ~ 2

Author(s):

Iryna Kovalevska ◽

Zenon Pilecki ◽

Oleksandr Husiev ◽

Vasyl Snihur

Keyword(s):

Mine Working ◽

Strain State ◽

Mutual Influence ◽

Strength Characteristics ◽

Stress Strain ◽

Load Bearing ◽

Stress Strain State ◽

Operation Modes ◽

Mine Workings ◽

Rigid Element

The degree of influence has been determined of diversified deformation-strength characteristics of load-bearing elements in the fastening system of the preparatory mine workings, while maintaining them in a laminal massif of soft rocks. The analysis has been performed of multivariate computational experiments of the stress-strain state of the load-bearing elements of the fastening system in the preparatory mine workings from the position of the mutual influence of their deformation-strength characteristics and the support loading as a whole. An analysis is represented of the mutual influence of the operation modes of the mine working support elements between themselves and the fastening system as a whole; it has been studied the stress-strain state of the mine working fastening system with a central hydraulic prop stay, as well as a significant increase in reliability of the support performance has been analysed and determined. The tendency has been substantiated of minimizing the load on the mine working fastening system – increasing the coherence of the diversified operation modes of fastening elements by enhancing preferentially the yielding property of the rigid element. The application has been substantiated of the central yielding prop stays of the strengthening support of a frame in case of intensive rock pressure manifestation in the zone of the stope works active influence.

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