Coal pillar strength estimation from failed and stable cases

Sheorey, P.R.; Das, M.N.; Barat, D.; Prasad, Reshma; Singh, B.

doi:10.1016/0148-9062(88)90013-7

Cited by 4 publications

(5 citation statements)

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“…This process involves drilling and blasting technology for the extraction of coal and LHD/SDL for conveyance/transport of blasted coal, followed by the installation of supports, which slows the rate of extraction and also becomes a source for adverse strata conditions in case of delay in the extraction of exposed pillar during the depillaring [13,14]. A rib-and-slice method is commonly practiced in conventional depillaring [15,16]. A rib/snook is left against the goaf along with breaker-line support in openings at the goaf edge [12,17].…”

Section: Conventional Miningmentioning

confidence: 99%

Underground Coal Mining Methods and Their Impact on Safety

Vinay¹,

Bhattacharjee²,

Ghosh³

2023

Natural Hazards - New Insights

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In underground coal mining, the working environment is completely enclosed by the geologic medium, which consists of the coal seam and overlying and underlying strata. Depillaring is one of the most dangerous phases of underground coal mining. Even after centuries of experience in underground coal mining, there is no well-established depillaring method w.r.t existing geo-mining method. As far as fatal accidents are concerned, most of the fatal accidents occur mostly during depillaring operations. Method of extraction is one of the keys and underrated parameters, which plays an eminent role in successful depillaring in underground coal mining. This chapter highlights the underground coal mining methods and their impact on safety.

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Section: Conventional Miningmentioning

confidence: 99%

Underground Coal Mining Methods and Their Impact on Safety

Vinay¹,

Bhattacharjee²,

Ghosh³

2023

Natural Hazards - New Insights

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“…After many simulation trials, these values were chosen intuitively. Several researchers have adopted a similar approach for roof caving in longwall panels [3,25,[32][33][34][35][36][37]. When a zone qualifies to be caved, it nulled (Figure 8).…”

Section: Constitutive Models For Simulating the Behaviour Rockmentioning

confidence: 99%

“…The multivariate regression statistical method has been widely used for the assessment of mining engineering problems [32,40,41,[43][44][45][46][47]. Therefore, the multiple linear regression approach was used to develop empirical models for MSD and LFSpI prediction.…”

Section: Multiple Regressionmentioning

confidence: 99%

Study on the Mechanism, Prediction, and Control of Coal Wall Spalling in Deep Longwall Panels Utilizing Advanced Numerical Simulation Methodology

Murmu

Budi

2022

Geofluids

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This research looked at the occurrence of coal wall spalling, a type of longwall face failure, during the main weighing period (MWP) for panels greater than 300 m depth. FLAC3D software was exploited to simulate the ground condition of longwall panel 1 of Adriyala Longwall Project mine. The extent and severity of coal wall spalling were quantified using evaluation criteria based on the concepts of vertical stress distribution and maximum shear strain. Subsequently, a parametric analysis of thirteen factors influencing the coal wall spalling was carried out. Empirical equations for predicting coal wall spalling were suggested. Based on the parametric analysis, a coal wall spalling classification system (CWSC) chart is presented to predict spalling characteristics of coal wall that may occur at the MWP. The empirical models depicted good predictive ability with R 2 values greater than 0.9. Parametric analysis revealed that coal wall spalling is highly sensitive to seam compressive strength, mining-induced stress, extraction height, and immediate roof characteristics. The CWSC system’s applicability to the five panels was in good agreement with field observations.

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“…Martin 20 carried out pillar case studies, and found that the pillar strength is directly related to the pillar width-to-height ratio. Sheorey 21 improved the calculation formula of coal pillar strength by introducing buried depth and width-to-height ratio. Ebrahim 22 reported that weathering and moisture greatly reduce the strength of coal pillars.…”

Section: Experimental Study On Granite Acoustic Emission and Micro-frmentioning

confidence: 99%

Experimental study on granite acoustic emission and micro-fracture behavior with combined compression and shear loading: phenomenon and mechanism

Cao

Chen

et al. 2020

Sci Rep

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One element that is essential to consider in underground mining engineering applications is the possibility of pillar failure, which can result in deadly geological disasters, including earthquakes and surface subsidence. Pillars are commonly present under an inclined state and are significantly dependent upon combined compression and shear loading. However, many scholars regard the pure uniaxial compression strength (UCS) of rock as the main evaluation index of pillar strength, which is inconsistent with the field practice. Hence, the present study developed a novel combined compression and shear test (C-CAST) system, which was applied in the investigative acoustic emission (AE) experiments to characterize the failure mechanism and micro-fracture behavior of granite specimens at different inclination angles. The experimental results presented the exponential decrease of UCS of inclined specimens with increase in the shear stress component. Changes in the inclination angle with a range of 0°–10° produced a splitting-shear failure fracture mode from the initial splitting failure. In comparison, an increase in the inclination angle from 10° to 20° produced a single shear failure fracture mode from the initial combined splitting-shear failure. The specimens exhibited nonlinearly reduced microcrack initiation (CI) and damage (CD) thresholds following an increase in the inclination angle, suggesting the dependence of the microcrack initiation and propagation on the shear stress component. The ratio of CI and CD thresholds to inclined UCS varies within a certain range, indicating that the ratio may be an inherent property of granite specimens and is not affected by external load conditions. Additionally, the rock fracture behavior was largely dependent upon the mechanism of shear stress component, as validated by the microcrack initiation and growth. Finally, a modified empirical formula for pillar strength is proposed to investigate the actual strength of inclined pillar. Results of a case study show that the modified formula can be better used to evaluate the stability of inclined pillars.

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Coal pillar strength estimation from failed and stable cases

Cited by 4 publications

References 0 publications

Underground Coal Mining Methods and Their Impact on Safety

Underground Coal Mining Methods and Their Impact on Safety

Study on the Mechanism, Prediction, and Control of Coal Wall Spalling in Deep Longwall Panels Utilizing Advanced Numerical Simulation Methodology

Experimental study on granite acoustic emission and micro-fracture behavior with combined compression and shear loading: phenomenon and mechanism

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