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Qin W.,State Key Laboratory of Coal Resources and Safety Mining | Qin W.,China University of Mining and Technology | Xu J.-L.,State Key Laboratory of Coal Resources and Safety Mining | Xu J.-L.,China University of Mining and Technology
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

The limitations of key stratum distinguishing method based on the thin slab theory and the relationship between the width of working face and the key stratum distinguish were analyzed. The result shows that the breaking order of hard strata is decided by the span criterion of hard strata and it is not relate to the width of working face in general case. So using the thin slab model or clamped-clamped beam model has no effect to the distinguishing results of the key stratum. The geometry size of hard strata is not always accord with the definition of the thin slab model. And the key stratum distinguishing method based on the thin slab theory should consider the width of working face. If the width of working face is less than the span criterion of the overlying hard strata, hard strata will not break, the interval of roofing breaking of hard strata can not be obtained, the position of key stratum can not be determined by comparing the interval of roofing breaking of hard strata. Source


Tian Z.-J.,China University of Mining and Technology | Tian Z.-J.,State Key Laboratory of Coal Resources and Safety Mining | Tian Z.-J.,Hunan University of Science and Technology | Wang D.-M.,China University of Mining and Technology | And 5 more authors.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2010

Foamed gel was studied as a new type of material for mitigating coal mine fires and gas accidents. The Ross-Miles method was used to identify a surfactant capable of creating at least 22 cm high foam at a relatively low dose. The parameters of the foam were studied. The foamed gel has perfect stability and holds water for ten days at normal temperatures and pressures. The gel is able to hold back coal gas and form a plug. Inhibition experiments showed that the rise in coal temperature was controlled by the foam. The inhibition rate was 62.23%, which effectively reduces coal oxidation rate and controls the release of CO. Source


Qin Y.-P.,China University of Mining and Technology | Qin Y.-P.,State Key Laboratory of Coal Resources and Safety Mining | Liu W.,China University of Mining and Technology | Liu W.,State Key Laboratory of Coal Resources and Safety Mining | And 3 more authors.
Procedia Engineering | Year: 2011

In order to study the influence of non-Darcy seepage on spontaneous combustion in goaf, seepage tests were conducted in three groups of broken rocks which were different average particle sizes, and then the test data were processed by non-Darcy seepage equation. So that the equations of non-Darcy permeability coefficient K with porosity n and particle size d, non-Darcy flow factor β with the n and the d were achieved. On the basis of these equations, the paper analyzed the influential factors of the spontaneous combustion in goaf, and then established the spontaneous combustion mathematical model on the coupling of air flow field, oxygen concentration field and temperature field on moving coordinates. According to the model, the calculating software was programmed by VB6.0 to obtain the oxygen concentration distribution map and the residual coal temperature distribution map in goaf. The results are of theoretical and practical significance to prevent spontaneous combustion in goaf. © 2011 Published by Elsevier Ltd. Source


Yang J.,China University of Mining and Technology | Yang J.,State Key Laboratory of Coal Resources and Safety Mining | Hao S.,China University of Mining and Technology | Hao S.,State Key Laboratory of Coal Resources and Safety Mining | And 2 more authors.
Electronic Journal of Geotechnical Engineering | Year: 2015

Application of bolt-cable anchor support has been extended in most of the coal mine in China, and the support theory and technology are becoming more mature. When the roadway is in the special geologic condition, in order to put forward the corresponding supporting measures, we need to understand the roadway stress environment and failure rule. The study in this paper shows that a large number of separation gap is generated in the roof and the influence of the stress concentration to coal pillar is serious and the coal pillar will be crushed and instability when the roadway is influenced by the adjacent gob. So, in this case, the strengthening support of roof and coal pillar used bolt-cable anchor is key to ensure the roadway stability. © 2015 ejge. Source


Qin Y.,China University of Mining and Technology | Qin Y.,State Key Laboratory of Coal Resources and Safety Mining | Liu W.,China University of Mining and Technology | Liu W.,State Key Laboratory of Coal Resources and Safety Mining | And 8 more authors.
Safety Science | Year: 2012

In order to research the actual oxygen consumption rate of residual coal in goaf, the heating and oxidizing experiment was conducted respectively on five types of single particle size of coal samples and one hybrid particle size of coal samples by using self-developed CSC-B2 test system. This study measured inlet and outlet oxygen concentration of the oxidation tank, and calculated the oxygen consumption rate of each coal sample at different temperatures. For the residual coal in the same goaf, which is regarded as a hybrid particle size of coal consisting of a variety of single granularity of coal, its oxygen consumption rate is the mass weighted average of the rate of each particle size of coal. Accordingly, this paper established the equation of oxygen consumption rate of hybrid particle size of coal samples, taking into account temperature, granularity and oxygen concentration. Then comparison between the calculated value and the actually measured value of oxygen consumption rate of hybrid particle size of coal samples at different temperatures was conducted. And the results reveal that the calculated value basically coincide with the actually measured one. Moreover, the results prove that the established calculation formula for oxygen consumption rate can be used to accurately calculate the actual oxygen consumption rate of residual coal samples. The achievement of this research is of theoretical and practical significance for learning about the characteristics of coal spontaneous combustion and forecasting the self-ignition of residual coal in goaf. © 2011 Elsevier Ltd. Source

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