Datong Coal Mine Group

Datong, China

Datong Coal Mine Group

Datong, China
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Qin T.,Heilongjiang University | Zhang K.Y.,Datong coal mine group | Liu H.L.,Heilongjiang University
Advanced Materials Research | Year: 2014

In order to study the mechanism of dynamic disaster on gassy coal and realize the monitoring and prediction, with the Didao mine as an example, this paper set up the thermal-fluid-solid three field couple mathematical models of driving face and comparative analyzed the mathematical models between couple and not couple by using the software comsol. The study result shows that it has a swift response, a close connection and a shorter time in the formation of o-ring, when it is the thermal-fluid-solid three field couple. © (2014) Trans Tech Publications, Switzerland.

Lin C.,Tsinghua University | Deng J.,Tsinghua University | Liu Y.,Tsinghua University | Yang Q.,Tsinghua University | Duan H.,Datong Coal Mine Group
Journal of Petroleum Science and Engineering | Year: 2016

Hydraulic fracture geometry is of paramount importance to enhance fracture effect in colliery hard roof control. Near wellbore complexity often resulted in low lateral dimension of induced fracture hence the fracking effect of the treatment. In the past, near wellbore fracture geometry is mainly believed to be controlled by the interaction between hydraulic fracture initiation and natural fracture infiltration/opening. Recently, lab experiments have proved that transverse notch plays a role in lowering breakdown pressure and also in reducing near wellbore complexity. Besides, colliery hard roofs are often over-pressured, therefore, with the increase of pore pressure, the influence caused by stress difference is weakened, and the role of notch becomes significant. In this paper, a series of lab experiments are conducted to gain in-depth understanding of the role transverse notch plays on near wellbore geometry and fracture reorientation. Hydraulic fracture process is physically simulated by injecting water (green dyed) at some certain rate into a pre-installed tube in a block (300×300×300 mm) under tectonic stress condition. Different notch parameters and fracturing regimes are used to make comparison. The notch changes the local stress and strain field in the blocks and affects the way blocks deform and fail. Post-mortem analysis and photo image of the block clearly show: (i) the length and angle of initial notch play a role in determining: near wellbore geometry and fracture reorientation; (ii) near wellbore fracture complexity may be reduced by making a longer initial notch and picking an appropriate notch angle; (iii) better understanding can be achieved by conducting further researches under normal stress condition and taking more factors into consideration. © 2015 Elsevier B.V.

Shan R.L.,China University of Mining and Technology | Zhang C.J.,China University of Mining and Technology | Zhang C.J.,Datong Coal Mine Group | Zhao X.,China University of Mining and Technology | Wu S.J.,China University of Mining and Technology
Applied Mechanics and Materials | Year: 2014

With the development of the economy, and investment structure is more complex, more investment direction is more diversified, capital investment efficiency is affected by more factors. Deep analysis and evaluation of the efficiency of investment and the objective and fair to find the factors that are critical for any investment or personal legal person. Based on the research of domestic and foreign scholars, this paper analyzed the influencing factors of coal mine construction investment efficiency from the theoretical level. © (2014) Trans Tech Publications, Switzerland.

Guo J.,China University of Mining and Technology | Guo J.,Energy and Chemical Research Institute of Zhong Ping Shen Ma Group | Xu G.,China University of Mining and Technology | Jing H.,China University of Mining and Technology | Kuang T.,Datong Coal Mine Group
International Journal of Mining Science and Technology | Year: 2013

To solve the problems of blindness and inefficiency existing in the determination of meso-level mechanical parameters of particle flow code (PFC) models, we firstly designed and numerically carried out orthogonal tests on rock samples to investigate the correlations between macro- and meso-level mechanical parameters of rock-like bonded granular materials. Then based on the artificial intelligent technology, the intelligent prediction systems for nine meso-level mechanical parameters of PFC models were obtained by creating, training and testing the prediction models with the set of data got from the orthogonal tests. Lastly the prediction systems were used to predict the meso-level mechanical parameters of one kind of sandy mudstone, and according to the predicted results the macroscopic properties of the rock were obtained by numerical tests. The maximum relative error between the numerical test results and real rock properties is 3.28% which satisfies the precision requirement in engineering. It shows that this paper provides a fast and accurate method for the determination of meso-level mechanical parameters of PFC models. © 2013 Published by Elsevier B.V. on behalf of China University of Mining & Technology.

Huang B.-X.,China University of Mining and Technology | Yu B.,China University of Mining and Technology | Yu B.,Datong Coal Mine Group | Feng F.,China University of Mining and Technology | And 3 more authors.
Journal of Coal Science and Engineering | Year: 2013

Research and development of safe and effective control technology of hard roof is an inevitable trend at present. Directional hydraulic fracturing technology is expected to become a safe and effective way to control and manage hard roof. In order to make hard roof fracture in a directional way, a hydraulic fracture field test has been conducted in the third panel district of Tashan Coal Mine in Datong. First, two hydraulic fracturing drilling holes and four observing drilling holes were arranged in the roof, followed by a wedge-shaped ring slot in each hydraulic fracturing drilling hole. The hydraulic fracturing holes were then sealed and, hydraulic fracturing was conducted. The results show that the hard roof is fractured directionally by the hydraulic fracturing function of the two fracturing drilling holes; the sudden drop, or the overall downward trend of hydraulic pressure from hydraulic monitoring is the proof that the rock in the hard roof has been fractured. The required hydraulic pressure to fracture the hard roof in Tashan coal mine, consisting of carboniferous sandstone layer, is 50.09 MPa, and the fracturing radius of a single drilling hole is not less than 10.5 m. The wedge-shaped ring slot made in the bottom of the hydraulic fracturing drilling hole plays a guiding role for crack propagation. After the hydraulic fracturing drill hole is cracked, the propagation of the resulting hydraulic crack, affected mainly by the regional stress field, will turn to other directions. © 2013 The Editorial Office of Journal of Coal Science and Engineering (China) and Springer-Verlag Berlin Heidelberg.

Xie Q.,China University of Mining and Technology | Yao X.,China University of Mining and Technology | Yang C.,China University of Mining and Technology | Jiang Y.,China University of Mining and Technology | And 2 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2015

A series of granular activated carbons (GACs) were prepared by briquetting method from five typical Chinese coals of different coalification degrees (Shengli lignite, three subbituminous coals including Lingwu coal, Shenmu coal and Datong coal, and Taixi anthracite). The effects of coalification degree on the pore structure development of activated carbon were investigated with the aids of the mineral constitution and content of the coal and the crystalline parameters of the char. The results show that: (1) layer thickness (Lc) and graphitization degree (G) increase with the increase of the coalification degree (Cdaf), which leads to larger BET specific surface area (SBET) and smaller average diameter (da) of the activated carbon; (2) Mineral matters in the coal also affect the pore structure of activated carbon significantly: high mineral content means less organic carbons available for pores shaping while Fe-and Ca-containing minerals in the char catalyze the gasification reaction, promoting pore structure development. The pore structure of activated carbon prepared by briquetting method is highly affected by coalification degree because chars with different crystalline sizes and mineral constitutions are formed after carbonization. ©, 2015, China Coal Society. All right reserved.

Guo W.-B.,China University of Mining and Technology | Liu C.-Y.,China University of Mining and Technology | Wu F.-F.,China University of Mining and Technology | Yang P.-J.,China University of Mining and Technology | Wu S.-F.,Datong Coal Mine Group
Meitan Xuebao/Journal of the China Coal Society | Year: 2014

According to the support crushing accident in the large mining height fully-mechanized face with hard roof condition in Jinhuagong Mine, the type and cause of the accident was given by thorough analyses. Based on the structure of overlying strata, the calculating method for hanging length of the key strata in immediate roof and its influencing factors were put forward with theoretical analyses. The load-estimate-method was modified to obtain the reasonable support working resistance in the large mining height fully-mechanized face with hard roof condition. In accordance with the method and the geological condition of 402 panel, the reasonable working resistance of support is 12184 kN, the supporting strength is 1.22 MPa and the support type was determined. With these results, the large mining height fully-mechanized face in 402 panel achieved safety and high efficiency mining, which shows that the theoretical analyses and the selected support type are reasonable.

Wang J.-R.,LIAONING Technical University | Zhang X.,LIAONING Technical University | Wang Y.-B.,LIAONING Technical University | Wang Y.-B.,Datong Coal Mine Group | And 3 more authors.
Meitan Xuebao/Journal of the China Coal Society | Year: 2014

When mining the close coal seams with risk of spontaneous combustion, the working face interconnected with upper multilayer goaf and earth's surface, and then stereoscopic cross air leakage network was formed. In order to prevent spontaneous mine fire caused by multi-source air leakage, the method of dynamic pressure regulation was analyzed for multi-face, and theory of multipoint pressure balance in multilayer goaf was put forward by pressure feedback and compensation. By identifying model of regulatory regions connected state, pressure gain coefficient was used to describe the connected state of various regulatory regions. With the dynamics equation of pressure distribution in dynamic multi-point regulation system, judging method was put forward for system stability. Through the pressure control method of feedback and compensation for various regulatory regions, multi-face pressure system would realize overall dynamic balance.

Jin W.,University of Sichuan | Gao M.,University of Sichuan | Yu B.,Datong Coal Mine Group | Zhang R.,University of Sichuan | And 2 more authors.
Environmental Earth Sciences | Year: 2015

Roof-coal recovery rate and the performance of gas extraction are essentially controlled by the fractures within coal-rock mass. Thus, it is important to generate the accurate fracture network ahead of mining face. In this study, ten boreholes located differently from the 8212 working face of Tashan Mine in Datong coal mining group, China, were drilled. With the help of borehole video instruments, the location, orientation of each fracture and the fracture number of different intersection type on each borehole wall were mapped with the advancing of mining face. These data were analyzed using the Matlab Toolbox RJNS3D and Dips to determine structural homogeneity zone, to find the number of fracture sets that exist in the coal-rock mass, volume density frequency for each set and the probability distributions of orientation, fracture size in 3-D. Sampling biases associated with orientation, spacing were corrected during the process. The constructed fracture networks were validated by comparing the observed mean spacing along normal vector of mean orientation for each set and the predict value on similar scanlines. © 2015, Springer-Verlag Berlin Heidelberg.

Yu B.,Datong Coal Mine Group | Zhang R.,University of Sichuan | Gao M.-Z.,University of Sichuan | Li G.,University of Sichuan | And 2 more authors.
Thermal Science | Year: 2015

Numerical study of mining-induced stress evolution of coal during the top coal caving process under different coal seam thicknesses is carried out, and the numerical prediction agrees well with the field test data. Main characters on stress distribution and dangerous area are elucidated. For the same coal quality, coal layers under 7 m thick fail earlier than thicker coal layers; correspondingly, the internal fracture networks of thin layers are more easily developed. During the mining of a coal layer less than 7 m thick, stress monitoring of the "dangerous area" in the middle of the top coal should be emphasized, whereas during the mining of coal layers less than 11 m thick, stress monitoring of the "dangerous area" at the bottom of the top coal should be highlighted. The research is to optimize caving technique and extraction process.

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