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The first and currently only Jurassic coal seam mining floor Baotashan sandstone water inrush and well flooding accident occurred in the New Shanghai No. 1 Coal Mine in Shanghai Miao Mining Area, Inner Mongolia. This paper researched the water inrush risk assessment method and prevention and control technology of the Baotashan sandstone in the Jurassic coal seam mining floor, which is highly water-rich. Firstly, it is clear that the water inrush source of the "11.25" accident is the Baotashan sandstone aquifer in the lower part of the Jurassic Yan'an formation, and the water barrier between the coal seam and the floor Baotashan sandstone has the characteristics of low strength, low softening coefficient and poor cementation, so it belongs to geological soft rock. Secondly, a water inrush evaluation system was established using “aquifer thickness, aquifer water richness, aquifer permeability, aquifer water pressure and the effective thickness of the 18 coal floor aquifer” as the main indicators, and the water inrush of the Baotashan sandstone aquifer was the dangerous zones are divided into three types: safety zone (32.21%), threat zone (37.53%) and dangerous zone (30.26%), and the accuracy of the evaluation model was verified through the “11.25” water inrush accident. Finally, combined with the engineering geological characteristics of the floor aquifer, the method of “fault grouting to form a local restricted boundary+group hole water release” was used to prevent and control Baotashan sandstone water inrush. It was set that “Water drainage begins until drilling site #1 exits work, the 2#, 3#, and 4# drilling fields continue the water drainage work until 3# exits work, and the 2# and 4# drilling sites continue to drain water until the model is replenished and balanced.” According to the specification, the maximum curtain permeability coefficient after grouting is 2×10−2 m/d, When the curtain permeability coefficient after fault grouting is 2×10−2 − 2×10−8 m/d, the drainage volume is 4.02×10−4 m3 − 3.478×10−4 m3. The proportion of safe areas in the mining area is 43.34%−67.37% respectively. Combining the grouting cost, drained water volume and safe area, when the curtain permeability coefficient is not greater than 2×10−4 m/d, can effectively ensure the safety and technical and economic benefits of the mine. The combined technology of fault grouting local restriction boundary+water drainage can effectively prevent and control sandstone water damage in Baotashan. The research work in this paper is of great significance and engineering practice value for the prevention and control of floor water in the Jurassic Coalfield development in western China.

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To solve the water hazard problem of Jurassic coal seam roof sandstone in Yinxing No.1 Coal Mine of Ningxia Province, the direct relationship between the sedimentary environment of Jurassic coal seam roof sandstone and water abundance was analyzed and the water abundance of sandstone aquifer was evaluated on the basis of combing the geological and hydro-geological conditions of the mine. The mechanism and characteristics of water disaster in Jurassic coal seam roof sandstone were analyzed based on the study of the mechanical properties, mineral composition, water stability characteristics and water-conducting fracture development law of coal seam roof strata. In this paper, we propose the idea of comprehensively applying various measures of “exploration, drainage, discharge, interception and monitoring”, and focusing on the basic exploration work, using hydrophobic and depressurizing technology to control water damage. The water damage control effect of 110301 working face show that it was feasible to control the sandstone water damage on the roof of Jurassic coal seam through hydrophobic depressurization.

For problems of existing discrimination methods of water inrush source based on hydrochemical characteristics such as complex process, difficulty to distinguish single water inrush point, neglecting the correlation among hydrochemical characteristics, large calculation amount and so on, a discrimination method of mine water inrush source based on Bayes-extension discrimination method was proposed combining with Bayes discrimination method and extension discrimination method. Twenty-six groups of water samples from different aquifers and four groups of water samples to be judged in Pa'er Coal Mine are obtained, the content of SO2-4, Cl-, HCO-3, K++Na+, Mg2+, Ca2+ in the water samples is taken as hydrochemical characteristic indexes, and thus matter-element models of the water samples are established. The correlation degrees between the water samples to be judged and the known water samples are obtained by use of extension discriminant method. The miscalculation loss of Bayes discriminant method and density function of the water samples to be judged with the known water samples are combined to get Bayes-extension solutions. The type of water inrush sample is discriminated according to the minimum value of Bayes-extension solutions. Piper trilinear diagram, extension discriminant method and Bayes-extension discriminant method are adopted separately to discriminate the type of mine water inrush samples. The results show that Piper trilinear diagram is difficult to accurately discriminate a certain type of water samples, extension discriminant method has misjudgment, while Bayes-extension discriminant method can accurately discriminate the type of water inrush sample.

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The purpose of this article is to use the microscope image method to analyze the prediction of the amount of water inflow from the working face of the coal mine field during the production process, and explore the measures for the prevention and control of water damage. On the basis of collecting and summarizing similar research results at home and abroad, the mine water inflow prediction equipment and water hazard prevention methods were constructed using microscopic image technology. For the outline of the mine, the motion history image method is introduced to map the motion in the image sequence to a static image, and the complex shape dynamic change problem is converted into a relatively simple static shape description problem, and then the image description method is used to obtain the characteristics of this image. Describe the size, direction and dynamic shape of mine outline movement. On the basis of identifying the water filling factors of the pit and obtaining reliable calculation parameters, the large well method is used to predict and analyze the water inflow and the prevention of water damage in the mining area, which is of great significance for the design of the mine water inrush prediction equipment and the design of water damage prevention. According to the analysis, the prediction result of the big well method is 166.10m3 / h as the most suitable basis for the prevention and control of water in the mining area. Based on this, the ground and underground water damage prevention measures are proposed. For the first 10 sets of data (within the theoretical prediction time), the average prediction error is 3.63%, The maximum prediction error is 7.42%; for the last 10 sets of data, the average prediction error is 5.14%, the maximum prediction error is 14.11%, and the comparison of microscopic images shows that the accuracy of the comparison of the traditional mine water inflow is increased by 23%, Which can effectively improve the prediction of water inflow and provide a strong guarantee for the prevention of equipment and water damage. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)