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Wu K.,China University of Mining and Technology | Cheng G.-L.,Huainan Mining Industry Group Co. | Zhou D.-W.,China University of Mining and Technology
Arabian Journal of Geosciences

Dynamic movement within strata overlying coal mines and the distribution of the movement boundary are keenly investigated topics but are hampered by the difficulties of obtaining reliable monitoring data of movement within rock masses. The work presented in this paper combines physical experiments with a digital photogrammetry method to investigate these two topics. Two similar material model experiments were conducted, and a high-precision, close-range digital photogrammetry method was employed to observe movement in the model. The results, including dynamic movement tracking of targeted points, indicate the presence of six different movement areas in the overlying strata in the model. Based on motion vector directions determined for the model, the overlying strata were divided into three zones: (1) a zone with the movement vector oriented vertically downward, (2) a zone with the movement vector oriented towards the goaf center, and (3) a zone with the movement vector oriented towards the coal pillar. Dynamic movement tracking shows that all zones experienced an initial, active, and decline stage, but the timing, duration, and movement tracks are different for each zone. The overall analysis reveals that the movement boundary in the strata overlying the rock mass is not a straight line, but an S-shaped curve, in contrast to the traditional findings with respect to the movement boundary. These findings may prove significance in guiding better prediction of movement and deformation inside a given rock mass and related improvements in protecting engineered infrastructure. © 2014, Saudi Society for Geosciences. Source

Zhou D.-W.,China University of Mining and Technology | Wu K.,China University of Mining and Technology | Cheng G.-L.,Huainan Mining Industry Group Co. | Li L.,China University of Mining and Technology
Arabian Journal of Geosciences

Based on a wealth of measured data and the special occurrence condition of coal seam in the Huainan coal mining area of China, this paper proposes a new idea, which is to first separate the overlying bedrock and quaternary alluvium upon coal seam, then study regularities of mining subsidence, respectively, and finally, make a comprehensive research. A method of combining the physical simulation, theoretical analysis, and experimental data is adopted; the internal mechanism behavior and the characteristics of the surface subsidence in coal mining areas with thick alluvium are investigated. The results show that the subsidence in thick alluvium coal mining areas consists of four parts: the subsidence of alluvium soil following the bedrock subsidence caused by coal mining; the synergy subsidence between alluvium soil and bedrock; the subsidence due to groundwater loss and consolidation of the alluvium soil in coal mining area; and the compacting subsidence of shallow soil under the disturbance of coal mining. This theory can be used to completely explain the particularity of surface subsidence in coal mining areas with thick alluvium and provide the basis for establishing the prediction model. © 2014, Saudi Society for Geosciences. Source

Liu H.,Anhui University of Science and Technology | Sang S.,China University of Mining and Technology | Wang G.G.X.,University of Queensland | Li M.,Shanxi Coalbed Methane Branch of Huabei Oilfield Company | And 7 more authors.
Journal of Petroleum Science and Engineering

This study performs a block scale investigation on gas content of a coal reservoir in Zhengzhuang Block of the southern Qinshui basin in China. The gas content of Coal Seam No. 3 in this coal reservoir was measured in field and laboratory in conjunction with tests on coal properties such as adsorption isotherm, maximum vitrinite reflectance, coal composition and maceral component etc. Total 36 coal cores collected from 3 adjacent coalmines in the southern Qinshui basin were investigated, including analysis of logging data from the drilling wells. The investigations provided experimental data for block scale modeling and visualization analyses on the correlation between gas content and the key factors such as coal properties and geological conditions of the coal reservoir. Data obtained by field and lab tests were analyzed by statistical models in order to correlate gas content and individual type of coal properties and geological variables. The statistical model was then used to map the gas content of the target coal seam in the studied area, resulting in a flood map of gas content at a 1:50000 scale. The flood map was further visualized with other variables in terms of the properties of coal and coal reservoir and its geological conditions. These visualized maps provide useful geological interpretation for block scale investigation of the comprehensive relationships between the gas content and the coal properties and regional structure in the given coal reservoir. The results show that gas content has little correlation with coal rank, maceral composition, coal thickness, cap and bottom lithology, while it is highly related to the structural properties such as burial depth and effective cover thickness. A stagnant hydrodynamic condition is favorable to the higher gas content on the whole but does not contribute to gas lateral and local variation. Canonical correlation and principal component analysis on the statistical model reveal the key factors that control the gas content are burial depth, effective thickness of overlying strata, groundwater level and moisture content in coal seam. © 2013 Elsevier B.V. Source

Cao X.-C.,Hefei University of Technology | Qian J.-Z.,Hefei University of Technology | Sun X.-P.,Huainan Mining Industry Group Co.
Meitan Xuebao/Journal of the China Coal Society

Chose hydrochemical data of 46 water samples in Quaternary and Coal in Guqiao Mine, took use of multivariate statistical analysis methods to classify and identify the groundwater. Based on the results obtained by the principal component analysis and cluster analysis, used Bayes discriminant analysis method to establish the discriminant model of mining groundwater chemical in each aquifer(discriminant function), and then discriminated forecast water samples. Finally compared with Artificial Neural Network, Degree of Grey Incidence method, Bayes Discriminant Analysis and Fuzzy Comprehensive method, it has a higher accurance than the former two methods and the same as the latter two methods. The results show that it is an effective and practical way in classifying and identifying of groundwater or gushing water sources with high stability. Source

Yang K.,Anhui University of Science and Technology | Lu W.,Anhui University of Science and Technology | Pan G.,Huainan Mining Industry Group Co. | Sun L.,Anhui University of Science and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering

Aimed at complicated geological conditions of large inclined angle seam with soft coal, soft roof, and soft floor and difficulties for ground control in rotary and full-mechanized longwall mining with high height in Panbei coal mine, field observation and numerical simulation have been used to investigation into strata behaviors of No. 12124. Based on strata behaviors analyzing, the ground pressure mechanism have been opened out with longwall and high height rotation mining in complicated geological and technical conditions. During the process of rotary mining, with the mining-induced stress affected after No. 12125 longwall panel mined, the co-action of abutment pressure concentration developing and powered support periodical supporting is the key factor to result in roof fracturing, roof falling, coal collapsing in working face, and large deformation of entries' surrounding rocks. Some technique have been implemented and practiced, which mainly includes as follows: to pave network and use steel beams to strengthen the roof salability; to apply anti-skid jack to connect hydraulic support to conveyor and advancing jack to control the decline of conveyor; to use bolting-wire-mesh to control stability of entries surrounding rock in rotation areas; to reinforce timbers to control stability of entries advanced about 10 m to working face. Engineering practice show that research plays an important role in safely mining and provides technologies for rotation mining in complicated geological conditions. ©, 2015, China University of Mining and Technology. All right reserved. Source

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