In-situ stress measurements and stress distribution characteristics in underground coal mines in China

Kang, Huan; Zhang, X.; Si, Lina; Wu, Yan; Gao, Fuqiang

doi:10.1016/j.enggeo.2010.09.015

Cited by 218 publications

(114 citation statements)

References 24 publications

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“…6). The pressure measuring sensor can observe Generally, the breakdown pressure is determined according to the peak pressure during the first injection cycle, and the reopening pressure is interpreted as the pressure at which the borehole pressurization curve deviates from its sub-linear increasing trend during an injection cycle and can be taken from the average value following several cycles (Kang et al, 2010).…”

Section: Test Methodsmentioning

confidence: 99%

Analytical and experimental study of water seepage propagation behavior in the fault

Huang¹

2014

Acta Geodynamica Et Geomaterialia

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Coal mine water inrush has an impartible relationship with the fracture zone such as faults, which deeply threaten the safety production in China. In order to study the water seepage behavior in the fault and the impermeability of the fault when water inrush through fault occurs, some water inrush cases through faults were analyzed, and water injection tests which drilled one injection borehole and one observation borehole into the fault zone were carried out at one coal mine. The breakdown pressure, reopening pressure, as well as the initial water seepage pressure, impermeability and the initial hydraulic conductivity of Puzizhier fault, were obtained from the result of the water injection tests. The study shows that water seepage in faults goes through three stages which consist of pore flow, fracture flow and pipe flow. It shows a process of the fine particulates and existing in-fill in the fault zone washing out and original and newborn cracks expanding and connecting. The results of water injection tests can be thought to show the fault healing effect under the underground pressure. In addition, the risk of water inrush through faults owes a great deal to the characteristic of water source. ARTICLE INFO

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Section: Test Methodsmentioning

confidence: 99%

Analytical and experimental study of water seepage propagation behavior in the fault

Huang¹

2014

Acta Geodynamica Et Geomaterialia

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“…The mining depth is about 450 m. A 9.75 MPa compressive stress boundary condition is applied to the top surface of the numerical model to simulate the overburden stress (assuming the density of the overburden strata is 2500 kg/m 3 ). The horizontal in situ stresses are 8.25 MPa and 10.17 MPa respectively with the maximum horizontal in situ stress being perpendicular to the panel retreating direction (i.e., the Y axis in Figure 4) [41].…”

Section: Thickness Descriptionmentioning

confidence: 99%

A New Gob-Side Entry Layout Method for Two-Entry Longwall Systems

et al. 2018

Energies

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Abstract:The gob-side entry layout is popular at two-entry longwall mine sites in China for the benefit of improving the coal recovery rate. Currently, two methods have been widely used to develop gob-side entries, including gob-side entry retaining and gob-side entry driving. Gob-side entry retaining maximizes the recovery rate by pillarless mining but increases the difficulty in gob-side entry support. Also, this method has limited applications in hard roof conditions. The gob-side entry driving mine site uses the rib pillar to separate the gob entry and the gob area of the previous panel, which leads to additional coal losses. The waste is more intolerable in large-cutting-height panels and longwall top coal caving panels as the Chinese government limits the minimum recovery rate of longwall panels using these mining methods. In this paper, a new gob-side entry layout method, termed gob-side pre-backfill driving, is established to overcome the shortcomings of the existing methods. The new method eliminates rib pillar losses and enhances gob-side entry stability. The feasibility of gob-side pre-backfill driving is studied by numerical modelling and a field trial at Changcun Mine in China. The results indicate that gob-side pre-backfill driving is an alternative for gob-side entry development. This method is practical and also has the potential to bring significant economic benefits to the mining industry.

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“…However, the mining depth increased rapidly in China as the shallow coal resources gradually exhausted in the past few years. The mining depths of some coal mines in central and east China now reach between 800 m and 1200 m. The deep mining conditions are characterized by high in-situ stress, high methane gas pressure and content, low strength and low permeability [5].…”

Section: Introductionmentioning

confidence: 99%

“…However, the CMM capture (drainage) engineering faces many challenges from the deep mining conditions. Borehole stability problem in-duced by high in-situ stress and low coal strength is one of the main challenges that influences the CMM capture effectiveness [6][7][8]. The stability analysis of drainage borehole and protection technology have drawn a lot of attention [9][10][11][12], and recently protecting borehole with screen pipes has been developed to solve the stability problem [6].…”

Section: Introductionmentioning

confidence: 99%

Deep Coal Mine Methane Drainage in China with Lower Greenhouse Gas Emissions: Insights of Borehole Protection Technology

Liu¹,

Kong²,

Wang³

2017

JRST

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Climate warming has currently been one of the most important global environmental issues. Coal mine methane (CMM) is a typical greenhouse gas with higher global warming potential and ozone depletion potential than CO 2 . Unfortunately, it should be noted that the CMM emission increases rapidly with the increasing coal consumption in China. Fast and whole protection technology of borehole is a recently developed method to maintain the drainage efficiency in deep mining level. However, the potential negative impact of screen pipes on CMM drainage efficiency has not been well studied. To investigate this impact, an innovative coal permeability model from elastic to post-failure state was deduced to develop our previous gas migration model. Then redistributed stress, coal permeability and gas pressure around a borehole were studied by implementing the mathematical model into Comsol Multiphysics. Numerical results indicate that the negative impact of screen pipes on drainage subpressure do not affect the drainage efficiency due to the stress redistribution. Engineering application shows that comparing to the traditional borehole protection technology, the gas concentration increases about 120% and the gas flux increases about 110% by using the fast and whole protection technology. The research will provide theoretical foundation of CMM capture and borehole protect technology and is of great significance for the CMM utilization and the global environment.

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In-situ stress measurements and stress distribution characteristics in underground coal mines in China

Cited by 218 publications

References 24 publications

Analytical and experimental study of water seepage propagation behavior in the fault

Analytical and experimental study of water seepage propagation behavior in the fault

A New Gob-Side Entry Layout Method for Two-Entry Longwall Systems

Deep Coal Mine Methane Drainage in China with Lower Greenhouse Gas Emissions: Insights of Borehole Protection Technology

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