scholarly journals Modification of the roof bolt support technology in the conditions of increasing coal mining intensity

2019 ◽  
Vol 109 ◽  
pp. 00042 ◽  
Author(s):  
Oleksandr Krukovskyi ◽  
Yurii Bulich ◽  
Yuliia Zemlianaia
Keyword(s):  
Coal Mining ◽  
Mine Working ◽  
Stable State ◽  
Roof Bolt ◽  
Suggested Approach ◽  
Roof Bolting ◽  
Working Face ◽  
The Face ◽  
Mine Workings ◽  
Host Rocks

The modification of the technology roof bolt supporting of mine workings in the conditions of increasing the coal mining intensity has been made. The technological schemes have been developed for the phased construction of roof bolting and frame support. This schemes make it possible to temporarily postpone the setting of frames in the mine working face, reduce the time and labour intensity for covering with a grid of the mine working arch and setting the bolts, as well as to increase the safety. The analysis of changes in the stress state of the border massif during the phased construction of roof bolting and frame support has been made. It is shown that the technology of phased construction of roof bolting and frame support ensures the maintaining a stable state of host rocks. In addition, the time between the extraction of the coal-rock mass and the setting of the primary support, as well as the distance between the face and the first row of roof bolts has been reduced to a minimum. The suggested approach makes possible to ensure the rate of preparatory mine workings development that are necessary for the intensification coal mining.

Water Probe in Coal Mine Working Face

2013 ◽  
Vol 734-737 ◽  
pp. 888-891
Author(s):  
Chen Shi
Keyword(s):  
Hydraulic Conductivity ◽  
Coal Mining ◽  
Coal Mine ◽  
Mine Working ◽  
Mine Water ◽  
Theoretical Calculations ◽  
Drainage System ◽  
Water Inflow ◽  
Interference Method ◽  
Working Face

Water probe in coal mine working face is an important part of the work of Mine Water. When the mine working face close to the aquifer hydraulic conductivity faults, underground rivers, caves and hydraulic conductivity collapse columns; extractive damaging effects, water probe should be done. However, the calculation of water inflow face probe has no feasible way. This paper discussed the theoretical calculations to explore water drilling inflow well group interference method and provides the basis for provision of drainage system for the coal mining enterprises.

scholarly journals Application of roof bolting to reduce water inflow into mine workings during the crossing of tectonic faults

2021 ◽  
Vol 280 ◽  
pp. 01006
Author(s):  
Oleksandr Krukovskyi ◽  
Viktoriia Krukovska ◽  
Yurii Vynohradov ◽  
Vladimir Dyomin
Keyword(s):  
Stress State ◽  
Mine Working ◽  
Numerical Study ◽  
Water Pressure ◽  
Stable State ◽  
Calculated Data ◽  
Water Inflow ◽  
Roof Bolting ◽  
Tectonic Disturbance ◽  
Hydrogeological Conditions

In this work, the problem of water inflow reduction in Ukrainian coal mines, which are distinguished by difficult hydrogeological conditions, was considered. A numerical study of the change in water inflow into a mine working when it crosses a tectonic fault was carried out. The cases when the permanent working was supported by frame supports and roof bolts were considered. The calculation of stress fields, zones with inelastic deformations and coefficients of permeability, which depend on the stress state and takes into account tectonic and natural permeability of the rocks, was performed. The results of calculating the water pressure and water inflow into the mine working in all considered cases are presented in the article. Analysis of the calculated data showed that a disturbed area, which covered water-bearing ricks, was formed in the roof of the mine working with the frame support. Within this area, water can move towards the contour of the mine working. The filtration permeability of the host rocks increases significantly when the mine face approaches the tectonic disturbance. The flow rate of water reaches critical values. The use of roof bolting restrains the unloading of the boundary rocks from the rock pressure and keeps them in a triaxially compressed stress state. The permeability value decreases by the value of its technological component. In different areas of the intersection of tectonic disturbance, the water inflow into the mine working with roof bolting is 3-8 times less than in the working, supported by frame supports. Therefore, the use of roof bolting allows not only to keep the mine working in a stable state, but also to significantly reduce water inflows at complicated hydrogeological conditions.

scholarly journals Principles for certain geomechanics problems solution during overworking of mine workings

2021 ◽  
Vol 280 ◽  
pp. 01007
Author(s):  
Volodymyr Bondarenko ◽  
Iryna Kovalevska ◽  
Hennadii Symanovych ◽  
Mykhailo Barabash ◽  
Ildar Salieiev
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Mine Working ◽  
Mining Activity ◽  
Mining Engineering ◽  
Real Representation ◽  
Resource Saving ◽  
Mining Operations ◽  
Complete Extraction ◽  
Mine Workings

This paper deals with two relevant and interrelated directions of coal mining development. Firstly, the resource-saving complete extraction of reserves, and secondly, the intensification of mining activity through mining operations conducted on several seams. The objective of overworking of mine workings with a real representation of mining-and-geological and mining-engineering conditions has been formulated. Five peculiarities of the geomechanical models construction for overworking of mine works have been revealed and substantiated. The technology for performing a series of computational experiments is proposed. The task of the protecting pillar influence, which is located in overlying coal seam, on the state of mine working placed in the underlying coal seam has been solved. An optimal scheme for its maintenance is proposed.

scholarly journals DETERMINING THE PATTERNS OF STABILITY OF MINE WORKINGS FOR CALCULATION ROOF BOLTING PARAMETERS

2021 ◽  
pp. 9-16
Author(s):  
S. Barsukov ◽  
А.Т. Batyrkhanova ◽  
Vladimir Dyomin
Keyword(s):  
Coal Seam ◽  
Longwall Mining ◽  
Practical Significance ◽  
Roof Bolting ◽  
Pull Out ◽  
Deformation Processes ◽  
Mine Workings ◽  
The Stability ◽  
Host Rocks ◽  
Roof Rocks

Purpose.  The published studies are aimed at determining the mechanism of deformation of the rocks of the contour around the workings in terms of the parameters of the emerging fracturing and their dependence on the indicators of the strength of the rocks and the depth of occurrence in the massif. The tasks of the study include the installation of fracture indicators, the determination of the parameters of the development of the deformation process around the working, including the effect of longwall mining and taking into account the possibility of reuse of the workings. Methodology. To solve the set tasks, the method of field observations was used together with the use of regression dependencies to determine the dependences of the parameters on the influencing factors. In addition, the method of full-scale pull-out tests of anchor support was used, which made it possible to determine the clamping forces of the anchors. Originality. In the course of the research, the dependences of stresses and deformation along the K7 coal seam in the conditions of the mine named after Kuzembaev CD JSC "ArcelorMittal Temirtau" for the massif around the mine with fastening. Rational parameters for the use of roof bolting in preparatory mine workings have been established. This type of fastening provides direct contact between rocks and lining. Analysis of the results of calculating the parameters of the roof bolting showed that to maintain the roof in the development workings, it is necessary to take into account the parameters of the roof bolting. The main parameters include the length of the anchors, the total resistance of the roof bolting and the density of the anchors. Anchor support forms laminated rock beams in the roof rocks, which ensure the stability of the workings. Conclusions and practical significance. The results of studies devoted to the establishment of the influence of mining-geological and mining-technical factors on the formation of zones of inelastic deformation in the host rocks were considered. Significant dependences of the deformation processes of rocks in the massif around the workings were obtained, and the parabolic zone of destruction of rocks was determined. The practical significance of the research consists in determining the actual indicators of the required bearing capacity of the anchorage at two levels in the conditions of the development of the coal seam k7 of the Kuzembaev mine.  

scholarly journals Water stability influence of host rocks on the process of water filtration into mine working with frame and roof-bolting support

2019 ◽  
Vol 109 ◽  
pp. 00041 ◽  
Author(s):  
Viktoriia Krukovska ◽  
Yurii Vynohradov
Keyword(s):  
Mine Working ◽  
Water Pressure ◽  
Water Inflow ◽  
Water Filtration ◽  
Water Stability ◽  
The Finite Element Method ◽  
Mining Operations ◽  
Roof Bolting ◽  
Host Rocks ◽  
Roof Rocks

The water stability influence of host rocks on water filtration process from the undermined aquifer to the mine working, depending on the way of its fastening has been studied in the paper. When solving the problem of water filtration in a deformable massif, the finite element method was used. The results of calculations are presented of the filtration permeability of the coal-bearing massif, the water pressure and the value of the water inflow into mine working in the cases of mining operations in sandstone and argillite. It is shown that the use of roof-bolting support prevents the development of the fractures formation process in the mine working roof, preserving the rocks in a natural, monolithic state. As a result, the process of water filtration from water bearing rock layers is constrained, which prevents or significantly reduces the soaking of border roof rocks. The use of roof-bolting fastening several times reduces the water inflow into mine working, located even in water-permeable rocks. The application of the roof-bolting support as a technological method for reducing the water inflow into mine workings has been substantiated.

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

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.

scholarly journals Study on the Law of Earth’s Surface Movement on Ultra-long Working Face

2021 ◽  
Author(s):  
Rui Peng ◽  
Fang Meiling ◽  
Ren Ruile ◽  
Zhu Jianming ◽  
Qifeng Zhao ◽  
...  
Keyword(s):  
Coal Mining ◽  
Simulation Software ◽  
Coal Bed ◽  
Length Effect ◽  
Surface Movement ◽  
Working Face ◽  
Face Length ◽  
The Face ◽  
The Law ◽  
Rock Strata

Abstract The problem of stoping on ultra-long working face is one of challenges for making coal mining safe and efficient. The strong mining effect of surrounding rock induced by long working face mining causes a number of coal or rock dynamic disasters to safe and efficient coal mining. For the purpose of in-depth study of the law of earth’s surface movement on ultra-long working face, this paper, with FLAC3D (numerical simulation software) used to build a numerical model of ultra-long working face, analyzes the law of roof-to-floor strata behaviors in coal bed during mining, and studies the weakening of roof-to-floor parameters in coal bed, bearing pressure and the law of roof caving and rock strata movement; Analyzes the face length effect resulted from the difference in face lengths. It has been recognized that the sphere of influence of bearing pressure changes from small to large and then to small, and changes in distribution of arch bottom and arch height at the plastic failure zone are further intensified over advancing of the working face, moreover, the movement of rock strata is subject to the cumulative influence of the advancing direction of the working face and the face length effect. The above-mentioned research results can serve as a theoretical basis for practical engineering.

scholarly journals Directional Hydraulic Fracturing (DHF) of the Roof, as an Element of Rock Burst Prevention in the Light of Underground Observations and Numerical Modelling

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 562
Author(s):  
Marek Jendryś ◽  
Andrzej Hadam ◽  
Mateusz Ćwiękała
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
Coal Mining ◽  
Rock Burst ◽  
Coal Mine ◽  
Seismic Activity ◽  
Black Coal ◽  
Directional Hydraulic Fracturing ◽  
Before And After ◽  
The Face

The following article analyzes the effectiveness of directional hydraulic fracturing (DHF) as a method of rock burst prevention, used in black coal mining with a longwall system. In order to define changes in seismic activity due to DHF at the “Rydułtowy” Black Coal Mine (Upper Silesia, Poland), observations were made regarding the seismic activity of the rock mass during coal mining with a longwall system using roof layers collapse. The seismic activity was recorded in the area of the longwall itself, where, on a part of the runway, the rock mass was expanded before the face of the wall by interrupting the continuity of the rock layers using DHF. The following article presents measurements in the form of the number and the shock energy in the area of the observed longwall, which took place before and after the use of DHF. The second part of the article unveils the results of numerical modeling using the discrete element method, allowing to track the formation of goafs for the variant that does not take DHF into consideration, as well as with modeled fractures tracing DHF carried out in accordance with the technology used at “Rydułtowy” coal mine.

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