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Abstract: The hydro-fracturing technology is the depressurization antireflection elimination outburst technology for the low permeability outburst coal seam with high methane. At present, the mechanism of the depressurization antireflection elimination outburst is sufficiently mastered and the application effectiveness of field engineering also is well, but how to determine hydro-fracturing parameters is not systematically described, especially the reasonable water pressure. Based on the hydro-fracturing mechanism and process, the reasonable water pressure is theoretically analyzed, and then the pressure parameter of hydro-fracturing applicated in the low permeability outburst coal seam with high methane is obtained, finally the reasonable pressure formula of water injection is obtained. The application test results of field engineering shows that there is the difference between the theoretical analysis result and the pressure in field engineering test, namely, the theoretical analysis pressure is lower than the pressure in field engineering test. [Copyright &y& Elsevier]

Abstract: The purpose of the paper is to solve gas limitation of the upper corner of working face of the protective seam. According to the actual situation of the 12nd Mine of the Ping Dingshan Mining Group Corporation (hereinafter referred to 12nd Mine), the technology of progressive and large diameter buried drainage pipe by crossing-hole was put forward, by the way of numerical simulation and field tests. The best reasonable distance and drainage hole diameter of the buried drainage pipe was obtained through the FLUENT simulation, and in accordance with the actual site, the protective seam Ji 14-31010 and Ji 15-31010 have implemented the buried drainage pipe in the site layout, and effective analysis was carried out. It''s known by the actual performance that the technology can solve the problem of the gas limitation in the upper corner effectively. [Copyright &y& Elsevier]

Abstract: In order to research the influence between air return tunnel and dedicated gas emission tunnel to arrange the tunnels properly, numerical experimental model is established according to the exploitation technical conditions and mechanical properties of rocks of 32020 working face in Pingmei NO.5 mine. FLAC3D is used to analysis the stress distribution among air return tunnel and dedicated gas emission tunnel with different interval thus confirm the most appropriate interval. By simulating the impact of gob to the tunnels, fully caving of the gob is helpful to reduce the outburst risk of coal and rock can be obtained. Variation of vertical stresses in two situations (dedicated gas emission tunnel driving along and air return tunnel driving first) is simulated respectively, thus obtain the safe distance of air return tunnel driving ahead. Research results can provide theoretical basis to control stress concentration, ensure emission efficiency and reduce tunnel construction so as to make safe and fast driving come true. [Copyright &y& Elsevier]

Abstract: View of the high stress, high gas coal seam characteristics and the current process of regional gas control problems, regional gas control method, based on drilling-blasting-fracturing-extracting integration technology were investigated by theoretical research, numerical simulation and field testing. Composite sealing technology has been carried out in the domestic relevant mine. The application results show that the technique obviously enhance the drill effective range, reduced the quantity of drills, shortened the gas extraction time and eliminated the outburst risk of coal mines which implied a broad industrial application prospect. [Copyright &y& Elsevier]

Abstract: In recent times, with the development of protection stratum, it is more and more important to investigate its effects. In this paper, in view of this situation, similar simulation experiment and site test are used to investigate the real-time effects at a certain mine of Pingdingshan Coal Group Company. The results of similar simulation experiment and site test show the stress and displacement variation of overlying rock and protected seam; define the max relative deformation and Roof Falling Interval; and determine the Protected Zone and Pressure Relief Angle. So, the result of research has great significance in directing the production of the mine and in developing the technology of protection stratum mining. [Copyright &y& Elsevier]

Abstract: There are so many fuzzy factors that affect the safety of mine ventilation system, and the data acquired from onitoring systems was so large that it is very difficult to evaluate the ventilation system accurately while using raditional methods. In order to solve the problem, a safety evaluation model was established based on fuzzy neural networks and rough set theory. It can not only complete a multi-level and multi-factor evaluation system also have self-learning capabilities, the verification of the evaluation model shows that the model has a high accuracy, and the total error is only 0.037, so that the model can be applied to the safety evaluation of complex dynamic network. [Copyright &y& Elsevier]