Study of deformation manifestations in the excavation working floor when it is supported by roof bolting

Purpose. The research aims to substantiate the technological solutions to ensure the rock mass stability through a rational approach to strengthening the zones of increased rock pressure behind the longwall face. Methods. To achieve the purpose set, a complex research method is used, which includes an analysis of practical experience in mining medium-thickness flat-lying coal seams, a study of the stress-strain state of rocks above the coal mass marginal area, and mine research into the influence of mining-technical factors on the state of zonal preparatory workings. Findings. The patterns of stress influence on the mine working stability have been determined depending on the mining-technological parameters of mining operations. Empirical dependences of the stress influence on the mine working stability have been revealed. The parameters of stress influence on the mine working stability have been found depending on the mining-technological parameters of mining operations. Originality. The conducted research made it possible to determine the degree of influence of mining-technical conditions of mining operations on deformations in border rocks with various types of support in extraction workings, which helps to understand the dynamics of deformation processes occurring in the coal-rock mass surrounding mine workings maintained behind the longwall face. Practical implications. The revealed deformation patterns can be used in calculating the rock pressure manifestations when conducting mine workings on deep levels under various mining-technical conditions of mining operations, which has practical significance for ensuring the stability and safety of maintaining mine workings at the stage of mining operations. The use of roof-bolt support is proposed as an effective means not only to ensure stability, but also to maintain safe operating conditions in mine workings.

Section: Study Areamentioning

confidence: 99%

Research into mine working fastening technology in the zones of increased rock pressure behind the longwall face to ensure safe mining operations

Demin,

Khalikova,

Rabatuly

et al. 2024

“…The latter can be achieved by using protection methods that are aimed at including the border rock mass in the joint work with fastening element. One of the types of fastening elements that imple-ment this is the roof-bolt support [42]. The main task in this case is the correct choice of its parameters [43]- [45].…”

Section: Mining-geological Operating Conditionsmentioning

confidence: 99%

Ensuring a safe geomechanical state of the rock mass surrounding the mine workings in the Karaganda coal basin, Kazakhstan

ZHOLMAGAMBETOV¹,

Khalikova²,

Demin³

et al. 2023

Purpose. The research purpose is to determine the instability zones in the host rocks and the dynamics of propagation of active fracturing zones to ensure the stability of the rock mass surrounding the mine workings. Methods. The research uses a set of analytical and experimental studies to determine the dynamics of the deformation process development in the coal-rock mass surrounding the mine workings. Mathematical modeling of the stress-strain state of the rock mass surrounding the active extraction workings is performed using the numerical method of finite elements in modern AN-SYS, Mergel and KMS-III software products. Findings. The influence has been studied of the mine working section shape and the coal seam dip angle on the value of the maximum stresses that arise in the rock mass when the mine working is fastened with the roof-bolt support. The instability zones in the host rocks and the dynamics of propagation of active fracturing zones have been determined both ahead of the front of the conducted mine working and on its sides for rocks of different strength. Originality. For the conditions of the Karaganda coal basin, the dependence of a change in the development of conventional inelastic deformation zones (CIDZ) on the host rock strength has been revealed. The influence of the coal seam dip angle on the dynamics of stratifications around preparatory working has also been substantiated. In addition, new data have been obtained on the influence of the roof rock strength on the stratification of the rock mass surrounding the mine working. Practical implications. By determining instability zones in the host rocks and the dynamics of propagation of active fracturing zones, it is possible to control geomechanical processes in the border rock mass of a mine working and influence it in order to prevent the occurrence of negative rock pressure manifestations. The data obtained are the basis for the development of recommendations on the use of roof-bolting technology for fastening extraction workings to ensure their stability and reduce the cost of their operation.

“…In addition, they may complicate processes of draining, rock caving, and making mine working stable. Large empty fractures as well as those filled with minerals may result in deformations and instability of mine workings [46], [47]. Slickensides with clay gouge may also influence mechanical characteristics of rocks and the formation behaviour while mining.…”

Section: Introductionmentioning

confidence: 99%

Assessing a natural field of rock mass stress by means of in-situ measurements within Vostochnaya Sary-Oba deposit in Kazakhstan

Akpanbayeva,

Issabekv

2023

Purpose is to assess a natural field of rock mass stress within Vostochnaya Sary-Oba deposit using in-situ measurements. It will help identify stress distribution as well as high-stress areas that may be dangerous for mining operations. Methods. The research has applied a technique of well hydraulic fracturing to study parameters of the initial stress field within the deposit. For the purpose, two metering points in two measuring (horizontal and vertical) wells were used. Hydraulic fracturing has been tested at each installation location. Findings. The in-situ measurement results have helped obtain quantitative parameters of stress-strain state of the rock mass. It has been understood that the available tectonic disturbances may result from the shape of structural folds as well as from tectonic fissility. Operating azimuth of the maximum horizontal stress within the points coincides, it is equal to 70° ± 10. Originality is the use of a new approach to assess the stress rock mass state within Vostochnaya Sary-Oba deposit while applying in-situ measurements and well hydraulic fracturing. The abovementioned favours more accurate and reliable assessment of rock stress state at the field being quite important for mining safety and for the development of the efficient supporting procedures and ore extraction procedures. Practical implications. The research results are applicable to adapt project documents for the deposit mining, a supporting technique selection, and ore extracting. Moreover, they will help make the substantiated choice of a structure and geotechnical parameters taking into consideration safety of operations as well as quality of ore mining. In addition, the results help develop measures to prevent rock mass outburst and fall in mine workings.