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According to the special form of water occurrence and migration in No.2 coal seam of Balasu Coal Mine in northern Yuheng Mining Area of Jurassic Coal Field in northern Shaanxi province, through theoretical analysis, calculation and prediction, simulation experiment and other methods, the water resources volume, water-rich zoning and mine water inflow are studied, and the water characteristics of No.2 coal seam water in the study area are preliminarily explored. According to the five main control indexes of coal seam thickness, coal core extraction rate, coal seam porosity, seam roof aquifer thickness and bottom water-insulating layer thickness affecting the water-rich coal seam, ArcGIS software and analytic hierarchy process (AHP) were combined to make water-rich prediction zoning for the No.2 coal seam in the study area. The water inflow of underground driving (including shaft, roadway) and stoping face under different working conditions is predicted. The results show that the estimated hydrostatic reserves of No.2 coal seam in the study area are about 0.665 billion m3, the dynamic recharge water is about 362 m3/h, and the coal seam water shows an overall decaying trend. The water-rich zone of No.2 coal seam is divided into 5 types: relatively strong, strong, medium, weak and weak.

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The electricity consumption of mine multi-level relay drainage system is very large, in order to improve economy of drainage system operation, it is necessary to optimize drainage system control, but current optimal control methods of mine multi-level relay drainage system have some problems such as easy overflow of sump and frequent start and stop of water pump. For the above problems, an optimal control strategy of mine multi-level relay drainage system was proposed. The optimal control model of mine multi-level relay drainage system was established which took water level of each level sump must be between the lowest and highest level and displacement of each level sump should not be less than inflow as constraint conditions, and the lowest sum of electricity costs of each level within one drainage period as objective function. By introducing margin into flow constraint condition, frequent start and stop of water pump is avoided. Gray model is used to predict water inflow, so as to obtain accurate water level of sump and avoid overflow accident. The application results show that the optimal control strategy can reduce electricity cost of drainage system under premise of ensuring safety of drainage.

The prediction of water inflow from coal mining face is the basis for the prevention and control of water in the production process of coal mines. Through the generalization of hydro-geological conditions in coal mine goaf, combined with the analysis of hydro-geological models of various sources and sink items in groundwater numerical simulation software Visual MODFLOW, it is proposed that the water gushing in goaf should be generalized into the boundary conditions of the drainage ditch with the characteristics of planar drainage in the process of numerical simulation. Using the boundary of the drainage ditch and the analysis of the local water balance, the amount of water in the goaf after the mining of the working face can be calculated. Based on the generalized method of goaf in this study, the numerical simulation of water inflow in 303 working face of Tingnan Coal Mine in Huanglong Coalfield is carried out. The results show that the method is reasonable and reliable, and the flow field characterization and water prediction results are better than that from the model of a hole pumping well.

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.)

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.)

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office 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.)

In view of the uncertainty and randomness in the process of risk assessment of water inrush, 10 factors of hydrogeological conditions were considered to construct evaluation index system, and a cloud model for water inrush risk assessment in coastal gold mine was established. Based On the evaluation resultst the phase space reconstruction of the water inrush time series is carried out. The evolution law of the influx phase distance is analyzed, and the early warning mechanism of water inrush is established. Combined with the reconstructed phase space, the RBF neural network prediction model is established. The results show that the evaluation results of the cloud model are accurate and reliable. The phase space reconstruction reveals the chaotic characteristics of the system. The nearest neighbor phase evolution magnifies the subtle characteristics of the water inflow change, which provides a basis for the establishment of the early warning mechanism of the water inrush. The chaotic RBF nerve network short-term accurate predictions of water inflow and provides technical support for safe underground mining. [ABSTRACT FROM AUTHOR]