Insights into the Relationships Among the Roof, Rib, Floor, and Pillars of Underground Coal Mines

Klemetti, Ted; Dyke, Mark A. Van; Evanek, Nicole; Compton, Craig C.; Tulu, Ihsan Berk

doi:10.1007/s42461-020-00313-7

Cited by 8 publications

(5 citation statements)

References 1 publication

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“…The dynamic pressure impacts the coal pillar and propagates to the entry ahead of the longwall face, leading to the surrounding rock's instability in the gateroad. Du et al, 7 Klemetti et al, 8 and Esterhuizen et al 9 observed that roadways with weak surrounding rock exhibit rapid early deformation, significant overall deformation, prolonged deformation duration, and comprehensive deformation of the surrounding rock. They attributed the extensive deformation and failure of roadways to high ground stress, the low soft strength of surrounding rock, significant section effect, and inadequate support.…”

Section: Introductionmentioning

confidence: 99%

Deformation mechanism of gob‐side entry at top coal caving mining face: A numerical study

Zhang,

Gao,

Yang

et al. 2024

Energy Science & Engineering

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To investigate the significant deformation of the surrounding rock within the dynamic pressure zone of the gateroad, this study utilized the tailgate of the 1506 longwall face in Anyang Coal Mine as the engineering context. A combined approach of field measurement and numerical analysis was employed to explore the deformation and failure mechanisms of the surrounding rock under dynamic pressure. The findings indicate that before the exploitation of the 1506 longwall face, there was a notable reduction in stress across the floor and immediate roof, with minimal stress concentration observed in the coal pillar and the entity rib side. The plastic zone surrounding the tailgate was limited, suggesting a high degree of stability in the entry's surrounding rock. However, during the extraction of the 1506 longwall face, the tailgate, extending 60 m ahead of the working face, was subjected to dynamic pressure, leading to a marked increase in stress within the floor, coal pillar, and immediate roof. Stress concentration was more pronounced on the entity rib side than on the pillar rib side. This resulted in significant fissuring and severe deformation of the entry's surrounding rock. The primary failure mechanism involved damage to both the roof and floor corners, with the severity of damage escalating alongside the stress in the surrounding rock. This culminated in the failure of roof corner bolts and anchor cables, thereby compromising the stability of the entry within the dynamic pressure zone.

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Section: Introductionmentioning

confidence: 99%

Deformation mechanism of gob‐side entry at top coal caving mining face: A numerical study

Zhang,

Gao,

Yang

et al. 2024

Energy Science & Engineering

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“…Therefore, multiple coal seams will appear in the same coal measure strata with a small distance between the adjacent multicoal seams. Different from the mining of a single coal seam, the mining activities of a close coal seam group can be influenced by each other's coal seams with the characteristics of mutual disturbance, stress concentration and severe damage to the mining roadway [1][2][3][4]. The roadway in the lower coal seam is significantly affected by the caving gangue generated after upper coal seam mining and the dynamic pressure due to the mining activities of the adjacent working face.…”

Section: Introductionmentioning

confidence: 99%

Study on Failure Characteristics and Control Technology of Roadway Surrounding Rock under Repeated Mining in Close-Distance Coal Seam

Shang

Kong

et al. 2022

Mathematics

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In this study, taking the Sheng’an coal mine as an engineering background, the failure characteristics of the surrounding rock of a roadway under repeated mining in a close-distance coal seam is comprehensively illustrated through field measurements (e.g., drilling imaging), theory analysis and numerical simulation (finite difference method (FDM)). The results show that although the return airway 10905 remains intact, the apparent failure of the roadway’s roof and the coal pillar can be observed. In addition, the expression of floor failure depth caused by upper coal seam mining is obtained through elastic-plastic theory. Meanwhile, the deformation of the surrounding rock of the roadway increases with the increase of repeated mining times, especially for the horizontal displacement of the roadway on the coal pillar side. Moreover, the cracks’ evolution of surrounding rock in the roadway can be observed as asymmetric characteristics. Finally, the stability control technology of “asymmetric anchor net cable + I-steel” is proposed to prevent potential mining disasters, and the feasibility of this support scheme is verified by numerical simulation and field practices. It can meet the requirement of safe mining and provide guidelines to effectively solve the failure of a roadway in close-distance coal seam mining.

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“…However, the ground pressure behavior is violent when mining deep buried and thick coal seams due to the large space for coal excavation and large extent of overburden damage. Therefore, the reasonable selection of shields plays an important role in safe and efficient production on the panel face (Qian and Xu, 2019;Xie, 2019;Xu, 2019;Zhang et al, 2020a;Li et al, 2020;Rajwa et al, 2020;Klemetti et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Research of the broken roof structure and supporting capacity of a shield in a deep and thick coal seam

Ren

et al. 2022

Front. Earth Sci.

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We determine the key issues of the reasonable supporting capacity of a shield and the shield selection in the panel face in a deep and thick coal seam. The No.232204 panel face of the Meihuajing mine in the Yuanyanghu mining area is taken as the research background. Using theoretical analysis, numerical simulation, and field measurement, the fracture characteristics and instability forms of roof structure of the panel face were studied. A mechanical model of roof fracture structure was established to calculate the reasonable supporting capacity of the shield, which guided the shield selection for the panel face. Also, a calculation and analysis system of the supporting capacity of the shield in a deep and thick coal seam was developed to realize the dynamic calculation and analysis of the supporting capacity of the shield. The results are as follows. 1) when the first weighting of the main roof appears, the broken rock block is hinged to form a “three-hinged arch” balanced structure. When the periodic weighting of the main roof appears, the broken rock block forms a “voussoir beam” balance structure. Also, the supporting capacity of the shield is stable between 8,900 and 9,600 kN. 2) The theoretical calculation showed that the supporting capacity of the shield in the No.232204 panel face was 9,581.04 kN, and the ZY10000/28/62D shield with supporting capacity of 10,000 kN is selected in the No.232204 panel face. 3) Through self-developed calculation software, the thickness and bulk density of the immediate roof had little influence on the supporting capacity of the shield, and the main roof thickness and bulk density have considerable influence on the supporting capacity of the shield. 4) The field measurement showed that the maximum supporting capacity of the shield in the panel face was distributed between 9,000 and 10,000 kN, which accounted for 77.58%. The loading utilization rate was more than 90%, and therefore the selected shield was reasonable. The research results provide a theoretical basis for the selection of shield supports for a deep buried and thick coal seam in the Yuanyanghu mining area.

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Insights into the Relationships Among the Roof, Rib, Floor, and Pillars of Underground Coal Mines

Cited by 8 publications

References 1 publication

Deformation mechanism of gob‐side entry at top coal caving mining face: A numerical study

Deformation mechanism of gob‐side entry at top coal caving mining face: A numerical study

Study on Failure Characteristics and Control Technology of Roadway Surrounding Rock under Repeated Mining in Close-Distance Coal Seam

Research of the broken roof structure and supporting capacity of a shield in a deep and thick coal seam

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