Influence of canopy ratio of powered roof support on longwall working stability – A case study

Rajwa, S.; Janoszek, Tomasz; Prusek, S.

doi:10.1016/j.ijmst.2019.06.002

Cited by 37 publications

(29 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The hydraulic shocks in the safety elements of a hydraulic leg are characterized by vibration frequencies of several hundred Hertz (Hz) and amplitudes significantly exceeding the operating values. The effect of the hydraulic shocks is a loss of tightness in the safety elements of the powered roof support, and reduction or loss of the load bearing capacity of the powered roof support, which consequently may lead to the uncontrolled lowering of the shield height [10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Simulations for Investigation of the Damage Causes in Safety Elements of Powered Roof Supports—A Case Study

et al. 2021

Self Cite

View full text Add to dashboard Cite

The paper describes a case study of the safety hydraulic system damage in the working of a longwall in a Polish coal mine. The safety elements are a component of the powered roof supports which secure the shield against damage during rock burst incidents. The damage event, which occurred in the hydraulic system during the mining process, caused the uncontrolled lowering of the powered roof support height during the mining process. The uncontrolled lowering of a shield may cause the danger of the loss of the stability along the longwall working in the form of a rock burst and collapses and may represent a serious and immediate danger to the safety and health of employees. Based on the results of the computational fluid dynamics methods (CFD) analysis of the safety elements in the hydraulic system of longwall 2-leg shield, the causes of damage were diagnosed and presented. The CFD and the strength analysis by the finite element method (FEM) were used for numerical modeling. The diagrams and maps of changes of parameters having an impact on the damage mechanism in safety elements of the hydraulic leg were developed based on the results of model tests. The forecasted values of stress distributions in the safety system of the hydraulic leg have made it possible to identify the reasons of the damage causes, verified by real observations.

show abstract

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics Simulations for Investigation of the Damage Causes in Safety Elements of Powered Roof Supports—A Case Study

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…erefore, the material constitutive relation selected in the simulation scheme is the Mohr-Coulomb model. Discrete element numerical software UDEC is used for simulation analysis, the rock mass constitutive model is the Mohr-Coulomb plastic model, and the model of calculation parameters includes bulk (K), shear (G), cohesion (C), friction (Φ), and density (ρ) [15,16].…”

Section: Establishment Of the Numerical Simulation Modelmentioning

confidence: 99%

Influence Factors’ Analysis of the Face‐End Roof Leaks Exposed to Repeated Mining Based on Multiple Linear Regression

Kong

et al. 2021

Advances in Materials Science and Engineering

View full text Add to dashboard Cite

In view of the fact that the face-end roof fall under repeated mining of close-distance coal seams seriously affects the normal production of the working face, this paper takes working face 17101 as the background, different influencing factors of face-end roof caving exposed to repeated mining are analyzed through field observation of mine pressure data, different calculation schemes are obtained by using the orthogonal experiment, the subsidence of the face-end roof is taken as the judgment index, UDEC simulation software is used to calculate the subsidence of the face-end roof when different influencing factors change, and the application of SPSS statistical software is used for various parameters of multivariate linear regression analysis. The research results show that the influence degree of different factors from large to small is, respectively, mining height > tip-to-face distance > advancing speed > distance of coal seams > surrounding rock strength > support setting load. It is necessary to strengthen the coordination of all influencing factors and comprehensively control the stability of the face-end roof exposed to repeated mining. Through the analysis of the regression model, it is found that there is no collinearity among the influencing factors, which has a significant influence on the regression equation and regression coefficient, and the multiple linear regression equation has a good fitting effect. The model can predict the stability of the face-end roof exposed to repeated mining, which provides a basis for controlling the face-end roof exposed to repeated mining.

show abstract

“…In order for the support to perform its functions properly, it is important to select it correctly, taking into account the mining and geological conditions and parameters of the wall. Recent research in the development of supports is presented in the works [48][49][50][51][52][53][54][55][56][57]. Currently, leg and protection supports with a lemniscate canopy guiding mechanism are commonly used.…”

Section: Introductionmentioning

confidence: 99%

Development of a Hydraulic System for the Automatic Expansion of Powered Roof Support

Szurgacz

Borska²,

Diederichs³

et al. 2022

Energies

View full text Add to dashboard Cite

A mechanical support in a longwall complex requires proper supervision and control of operating parameters because it is responsible for the safety of machines and workers. Its main functions are to protect the excavation against the adverse effects of rock mass and to move it along with the operational progress of the shearer and the scraper conveyor. In the era of Industry 4.0 as well as green economy and sustainable development, the development of machines and devices included in the longwall complex is an important area of invention. When it comes to the mechanical support included in the longwall complex, the authors propose changes to the hydraulic control system. The main purpose of the work was to develop a system that can automatically expand the legs of the powered support. Tests were carried out under real conditions while equipping the support section with a prototypical hydraulic system and with a system monitoring the correct operation of the prototype. This article presents the development of a prototypical installation under real conditions for testing on a longwall. The innovative solution proposed by the authors consisted of introducing a prototypical double valve block into the hydraulic system of the housing, which enables the function of automatic section expansion. The authors proposed a solution aimed at shortening the work time of the powered-support-section operator. The research results made it possible to evaluate the usefulness of the proposed solution. This type of solution can be considered technical support in the process of coal mining in an underground mine. Analysis presented in this paper, along with results from research conducted and its conclusions, can be of practical help to enclosure users to improve reliability and achieve optimal performance.

show abstract

Influence of canopy ratio of powered roof support on longwall working stability – A case study

Cited by 37 publications

References 8 publications

Computational Fluid Dynamics Simulations for Investigation of the Damage Causes in Safety Elements of Powered Roof Supports—A Case Study

Computational Fluid Dynamics Simulations for Investigation of the Damage Causes in Safety Elements of Powered Roof Supports—A Case Study

Influence Factors’ Analysis of the Face‐End Roof Leaks Exposed to Repeated Mining Based on Multiple Linear Regression

Development of a Hydraulic System for the Automatic Expansion of Powered Roof Support

Contact Info

Product

Resources

About