نتایج جستجو برای: longwall working

تعداد نتایج: 203882  

2017
Fangtian Wang Cun Zhang Ningning Liang

A thin coal seam mined as a protective coal seam above a gas outburst coal seam plays a central role in decreasing the degree of stress placed on a protected seam, thus increasing gas permeability levels and desorption capacities to dramatically eliminate gas outburst risk for the protected seam. However, when multiple layers of coal seams are present, stress-relieved gas from adjacent coal sea...

2003
David M. J. Tax Pavel Laskov

The paper presents two useful extensions of the incremental SVM in the context of online learning. An online support vector data description algorithm enables application of the online paradigm to unsupervised learning. Furthermore, online learning can be used in the large-scale classification problems to limit the memory requirements for storage of the kernel matrix. The proposed algorithms ar...

2017
Batchler Timothy

Pumpable roof supports are currently being used to provide a safe working environment for longwall mining. Because different pumpable supports are visually similar and installed fundamentally in the same manner as other supports, there is a tendency to believe they all perform the same way. However, there are several design parameters that can affect their performance, including the cementitiou...

2017
R. G. Jeffrey Z. Chen K. W. Mills S. Pegg

Narrabri Coal Operations is longwall mining coal directly below a 15 to 20 m thick conglom‐ erate sequence expected to be capable of producing a windblast upon first caving at longwall startup and producing periodic weighting during regular mining. Site characterisation and field trials were undertaken to evaluate hydraulic fracturing as a method to precondition the conglomerate strata sufficie...

Journal: :International Journal of Coal Science & Technology 2021

Abstract The breaking features and stress distribution of overlying strata in a steeply dipping coal seam (SDCS) differ significantly from those near-horizontal one. In this study, the laws governing evolution vertical release shear concentration seams with different dip angles are derived via numerical simulation, rock mechanics tests, acoustic emissions, field measurements. Thus, stress-drive...

Journal: :Energies 2021

Economic analysis allows for determining the required daily output under certain natural and mining conditions based on costs of production process in a particular mine infrastructure. Therefore, there is need to determine potential longwall using technical equipment at disposal mine. In case mines, when exploiting few longwalls simultaneously bumping hazards, it indispensable ensure safety. Du...

2008
C.Ö. Karacan

In longwall mining, premining prediction of methane emission rate depends on a number of geological factors, geographical factors, and operational factors. These same factors also can impact the selection of a specific degasification system. This study proposes a principle component analysis (PCA) and artificial neural network (ANN) approach to predict the ventilation methane emission rates of ...

Journal: :International Journal of Mining Science and Technology 2017

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