Three-Dimensional Analysis of Gate-Entry Stability in Multiple Seams Longwall Coal Mine Under Weak Rock Conditions

Mao, Pisith; Sasaoka, Takashi; Shimada, Hideki; Hamanaka, Akihiro; Wahyudi, Sugeng; Oya, Jiro; Naung, Naung

doi:10.5539/esr.v9n1p72

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…At the same time, this area is also the throat of transportation, pedestrians, and ventilation [8,9]. So, it is the key point of roadway-surrounding rock maintenance [10][11][12], but its failure mechanism is not yet clear [13]. At present, a single hydraulic prop and advance hydraulic support are mostly used for ASSoMF [14,15].…”

Section: Introductionmentioning

confidence: 99%

Failure Mechanism and Stability Control of Soft Roof in Advance Support Section of Mining Face

Ren

et al. 2023

Minerals

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There is a great risk of roof falls in the advance support section of the mining face (ASSoMF), and it is difficult to control the roof. Based on the soft roof of Lijiahao coal mine, this paper studies the stress distribution of the ASSoMF and the space-time evolution of the surrounding rock plastic zone by using theoretical analysis and numerical simulation, and reveals its failure mechanism. Based on the control effect of support resistance on plastic zone, it is proposed that the advance support should mainly adapt to the roadway deformation. Advance equipment without repeated support for mechanized movement has been developed, and the support timing analysis and strength check have been carried out. Results show that the roadway at ASSoMF is in a non-uniform stress field, the confining pressure ratio reaches 1.5~7, and the surrounding rock forms asymmetric failure; the principal stress direction deflects, the angle between it and the vertical direction is about 10°~25°, and the plastic zone of the surrounding rock also rotates to the roadway roof. The proposed equipment can adapt to the characteristics of an unsymmetrical large deformation of a soft roof, and can effectively bear the roof load and maintain the stability of the roadway.

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Section: Introductionmentioning

confidence: 99%

Failure Mechanism and Stability Control of Soft Roof in Advance Support Section of Mining Face

Ren

et al. 2023

Minerals

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“…Weak geological conditions have proven to impose many challenges in the development of longwall mining [20][21][22]. The lack of rock strength competence requires its own investigation of its rock mass, strata behavior, stress distribution, deformation, and exclusive support design during mine development and operation [21][22][23][24][25]. A big portion of the global coal reserves is located in weak geological conditions [26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Roof Stability in Longwall Face Developed in Shallow Depth under Weak Geological Conditions

et al. 2022

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Developing longwall mining under weak geological conditions imposes a substantial challenge with regard to the higher risk of falling roofs. Maintaining the stability of the longwall face in this aforementioned condition is crucial for smooth operation. Investigating roof conditions in longwall requires detailed study of rock behavior in response to a few key influences. This paper presents the outcome of a numerical analysis of roof stability in shallow depth longwall face under weak geological conditions. A series of validated FLAC3D models was developed to examine the roof condition of the longwall face under the influence of shield canopy ratio, shield resistance force, and stress ratio. The results show that these three key factors have a significant impact on longwall roof conditions, which can be used to optimize its stability. Two distinct mechanisms of the roof caving behavior can be observed under the influence of stress ratio. The countermeasures of reducing face-to-tip distance and cutting width are proposed to improve the roof condition of longwall face under weak rock. The outcomes show a substantial improvement in roof conditions after adopting the proposed method.

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Block Caving Mining Method: Transformation and Its Potency in Indonesia

et al. 2022

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The block caving mining method has become increasingly popular in the last two decades. Meanwhile, Indonesia has several potential ore bodies which have not yet determined suitable mining methods. The references to block caving mining projects worldwide and the potency of metal deposits in Indonesia were reviewed to determine the requirements of ore bodies suitable for mining using the transformed block caving method. This method can be applied on a blocky ore body with a thickness of 200–800 m, various rock mass strengths until 300 MPa, from low to high (from 0.3% Cu until more than 1.0% Cu), but of uniform grade and at a depth from 500 to 2200 m. The technical specifications for running block caving mines have been synthesized, including preparation methods, undercutting strategy, mine design, mining equipment and monitoring. Considering the requirements and the successful practice of the block caving project in the Grasberg Caving Complex as a role model, the Indonesian government should concentrate on the detailed exploration of porphyry deposits and feasibility studies on applying the method to the prospective ore bodies, i.e., Onto, Tambulilato, Tumpangpitu and Randu Kuning. In addition, the exploration method, cost, operation, environment, mining policy and social geology are important aspects worth noting.

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Three-Dimensional Analysis of Gate-Entry Stability in Multiple Seams Longwall Coal Mine Under Weak Rock Conditions

Cited by 3 publications

References 9 publications

Failure Mechanism and Stability Control of Soft Roof in Advance Support Section of Mining Face

Failure Mechanism and Stability Control of Soft Roof in Advance Support Section of Mining Face

Numerical Investigation of Roof Stability in Longwall Face Developed in Shallow Depth under Weak Geological Conditions

Block Caving Mining Method: Transformation and Its Potency in Indonesia

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