Three-dimensional analysis of coal barrier pillars in tailgate area adjacent to the fully mechanized top caving mining face

Cheng, Yung Ming; Wang, J. A.; Xie, Guangxiang; Wei, W. B.

doi:10.1016/j.ijrmms.2010.08.008

Cited by 67 publications

(31 citation statements)

References 12 publications

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“…In the process of mining advance, the goaf area is filled by a soft elastic material to simulate the support capability of the fallen rock from the roof. Young's modulus for this material is set at 470 MPa, and Poisson's ratio is 0.25 [32]. The physical properties (or coring recovery rate) at different sections of the X1 are different (Figure 3), leading to the differences of the mechanical and hydraulic properties.…”

Section: Materials Parameters and Calculation Resultsmentioning

confidence: 99%

A Cascade Disaster Caused by Geological and Coupled Hydro-Mechanical Factors—Water Inrush Mechanism from Karst Collapse Column under Confining Pressure

Bai

et al. 2017

Energies

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Abstract:The water inrush from karst collapse column (KCC) is a cascading, vicious cycle disaster caused by geological and mining activities, that can cause serious casualties and property losses. The key to preventing this risk is to study the mechanism of water inrush under confining pressure. Aiming at the investigationg the characteristics of the KCC named X1 in Chensilou mine, a series of methods, including connectivity experiments, water pressure monitoring tests in two side-walls, and numerical simulations based on plastic damage-seepage (PD-S) theory have been developed. The methods are used to test the security of the 2519 mining area, the damage thickness, pore water pressure, and seepage vector in the X1. The results indicate that the X1 has a certain water blocking capacity. In addition, with the decrease of confining pressure and increase of shear stress, deviatoric stress could cause the increase of permeability, the reduction of strength, and the reduction of pore water pressure in KCC. Therefore the increased effective stress in the rock will force the rock to become more fractured. Conversely, the broken rock could cause the change of stress, and further initiate new plastic strains, damage and pore water pressure until a new equilibrium is reached. This cascading water inrush mechanism will contribute to the exploitation of deep coal resources in complex geological and hydrogeological conditions.

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Section: Materials Parameters and Calculation Resultsmentioning

confidence: 99%

A Cascade Disaster Caused by Geological and Coupled Hydro-Mechanical Factors—Water Inrush Mechanism from Karst Collapse Column under Confining Pressure

Bai

et al. 2017

Energies

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show abstract

“…In this study, the excavation was performed by changing the mechanical properties of the coal seam in the caved area to a very soft elastic material, in which case, the bearing capacities of the caved rock could be fully considered. This analogy method of the excavation process has also been used by other researchers [20,21].…”

Section: Numerical Modelmentioning

confidence: 99%

Analysis and Optimization of Entry Stability in Underground Longwall Mining

et al. 2017

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For sustainable utilization of limited coal resources, it is important to increase the coal recovery rate and reduce mine accidents, especially those occurring in the entry (gateroad). Entry stabilities are vital for ventilation, transportation and other essential services in underground coal mining. In the present study, a finite difference model was built to investigate stress evolutions around the entry, and true triaxial tests were carried out at the laboratory to explore entry wall stabilities under different mining conditions. The modeling and experimental results indicated that a wide coal pillar was favorable for entry stabilities, but oversize pillars caused a serious waste of coal resources. As the width of the entry wall decreased, the integrated vertical stress, induced by two adjacent mining panels, coupled with each other and experienced an increase on the entry wall, which inevitably weakened the stability of the entry. Therefore, mining with coal pillars always involves a tradeoff between economy and safety. To address this problem, an innovative non-pillar mining technique by optimizing the entry surrounding structures was proposed. Numerical simulation showed that the deformation of the entry roof decreased by approximately 66% after adopting the new approach, compared with that using the conventional mining method. Field monitoring indicated that the stress condition of the entry was significantly improved and the average roof pressure decreased by appropriately 60.33% after adopting the new technique. This work provides an economical and effective approach to achieve sustainable exploitation of underground coal resources.

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“…The goaf is mainly made of broken rock pieces, hence it was modeled as aggregate of fractured rocks [11]. To simulate the goaf in longwall mining, both the coal seam and immediate caved roof were excavated, and then the caved area was filled with a very soft material [12]. Since the measurement of deformations in the goaf is difficult due to the inaccessibility, there is still no standard method for modeling the goaf.…”

Section: Modeling Of Goafmentioning

confidence: 99%

Numerical Study on Effect of Longwall Mining on Stability of Main Roadway under Weak Ground Conditions in Indonesia

Pongpanya¹,

Sasaoka²,

Shimada³

et al. 2017

JGRE

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Abstract:The purpose of this research is to study the effect of longwall mining on the stability of main roadway in the underground coal mine. The PT GDM (Gerbang Daya Mandiri) underground coal mine in Indonesia, where the rocks are weak, was selected as a representative study site. To accomplish the objective of the research, the finite difference code software FLAC3D was used as a tool for the numerical simulations. The longwall mining of several panel and barrier pillar widths at various depths was simulated and discussed. Based on the simulation results, it indicates that the effect of coal panel extraction on the main roadway stability depends on the width of panel and barrier pillar. The greatest effect occurs when the large panel width and the small barrier pillar width are applied, whereas the smallest effect happens when the narrow panel width and the large barrier pillar width are adopted. In this paper, therefore, to maintain the stability of the main roadway with the aim of maximizing the coal recovery, the appropriate size of panel and barrier pillar width is proposed for each mining depth for this underground coal mine.

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Three-dimensional analysis of coal barrier pillars in tailgate area adjacent to the fully mechanized top caving mining face

Cited by 67 publications

References 12 publications

A Cascade Disaster Caused by Geological and Coupled Hydro-Mechanical Factors—Water Inrush Mechanism from Karst Collapse Column under Confining Pressure

A Cascade Disaster Caused by Geological and Coupled Hydro-Mechanical Factors—Water Inrush Mechanism from Karst Collapse Column under Confining Pressure

Analysis and Optimization of Entry Stability in Underground Longwall Mining

Numerical Study on Effect of Longwall Mining on Stability of Main Roadway under Weak Ground Conditions in Indonesia

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