scholarly journals Coal Facies Characteristics and Coal Formation Mechanism of No. 38 Coal Seam in Cuipingshan Coal Mine

2018 ◽  
Vol 3 (5) ◽  
pp. 45
Author(s):  
Fumei Xu
Keyword(s):  
Coal Seam ◽  
Formation Mechanism ◽  
Coal Mine ◽  
Coal Facies

scholarly journals Formation Mechanism and the Height of the Water-Conducting Fractured Zone Induced by Middle Deep Coal Seam Mining in a Sandy Region: A Case Study from the Xiaobaodang Coal Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xiaoshen Xie ◽  
Enke Hou ◽  
Shuangming Wang ◽  
Xueyang Sun ◽  
Pengfei Hou ◽  
...  
Keyword(s):  
Coal Seam ◽  
Formation Mechanism ◽  
Coal Mine ◽  
Field Measurements ◽  
Development Stage ◽  
Mine Safety ◽  
Maximum Height ◽  
Fractured Zone ◽  
Seam Mining

The height of the water-conducting fractured zone (WCFZ) is a basic parameter related to water protection in coal mines and is also crucial for aquifer protection and mine safety. In order to accurately detect the height and shape and reveal the formation mechanism of the WCFZ, which is caused by middle-deep coal seam mining in a sandy region, the 112201 coalface at the 1# coal mine of Xiaobaodang was taken as a case study. Filed measurements including fluid leakage, borehole TV, and similar simulation were adopted to analyze the regularity of the WCFZ in this area. The detection results of field measurements showed that the maximum height of the WCFZ was 177.07 m in a borehole near the open-off cut, and the ratio of the height of the water-conducting fractured zone divided by the mining thickness was 30.53. The WCFZ acquired an inward-convergent saddle shape, which was inclined to the goaf. The saddle bridge was located at the boundary of the goaf, and the saddle ridge was located at the center of the goaf. Also, through analyzing the results of similar simulations, we found that, in the process of mining, separation cracks and the beam structure were the main forms of overburden disturbance transmitting upward and ahead of mining, respectively. The main cause of the increase in height of the WCFZ was the connection of the separation cracks and vertical cracks caused by fractures of beam structures. The development of the WCFZ was divided into five stages: incubation stage, development stage, rapidly increasing stage, slowly increasing stage, and stable stage. Moreover, the duration of each stage was related to the lithology and mining technology. This research can provide significant theoretical insights for the prediction of the WCFZ, enabling the prevention of water hazards on mine roofs and assisting with water resources protection.

Phosphorus minerals in tonstein; coal seam 405 at Sośnica-Makoszowy coal mine, Upper Silesia, southern Poland

2013 ◽  
Vol 63 (2) ◽  
pp. 271-281 ◽  
Author(s):  
Magdalena Kokowska-Pawłowska ◽  
Jacek Nowak
Keyword(s):  
Trace Elements ◽  
Coal Seam ◽  
Mineral Composition ◽  
Coal Mine ◽  
Chemical Compositions ◽  
Coal Basin ◽  
Upper Silesia ◽  
Southern Poland ◽  
Basin Area

Abstract Kokowska-Pawłowska, M. and Nowak, J. 2013. Phosphorus minerals in tonstein; coal seam 405 at Sośnica- Makoszowy coal mine, Upper Silesia, southern Poland. Acta Geologica Polonica, 63 (2), 271-281. Warszawa. The paper presents results of research on tonstein, which constitutes an interburden in coal seam 405 at the Sośnica- Makoszowy coal mine, Makoszowy field (mining level 600 m), Upper Silesia, southern Poland. The mineral and chemical compositions of the tonstein differ from the typical compositions described earlier for tonsteins from Upper Silesia Coal Basin area. Additionally, minerals present in the tonsteins include kaolinite, quartz, kaolinitised biotite and feldspars. The presence of the phosphatic minerals apatite and goyazite has been recognized. The presence of gorceixite and crandallite is also possible. The contents of CaO (5.66 wt%) and P2O5 (6.2 wt%) are remarkably high. Analysis of selected trace elements demonstrated high contents of Sr (4937 ppm) and Ba (4300 ppm), related to the phosphatic minerals. On the basis of mineral composition the tonstein has been identified as a crystalline tonstein, transitional to a multiplied one.

Reasonable Entry Layout of Lower Seam in Multi-Seam Mining Based on Numerical Simulation

2013 ◽  
Vol 295-298 ◽  
pp. 2980-2984
Author(s):  
Xiang Qian Wang ◽  
Da Fa Yin ◽  
Zhao Ning Gao ◽  
Qi Feng Zhao
Keyword(s):  
Numerical Simulation ◽  
Stress Distribution ◽  
Coal Seam ◽  
Coal Mine ◽  
Abutment Pressure ◽  
Surrounding Rock ◽  
Geological Conditions ◽  
Seam Mining

Based on the geological conditions of 6# coal seam and 8# coal seam in Xieqiao Coal Mine, to determine reasonable entry layout of lower seam in multi-seam mining, alternate internal entry layout, alternate exterior entry layout and overlapping entry layout were put forward and simulated by FLAC3D. Then stress distribution and displacement characteristics of surrounding rock were analyzed in the three ways of entry layout, leading to the conclusion that alternate internal entry layout is a better choice for multi-seam mining, for which makes the entry located in stress reduce zone and reduces the influence of abutment pressure of upper coal seam mining to a certain extent,. And the mining practice of Xieqiao Coal Mine tested the results, which will offer a beneficial reference for entry layout with similar geological conditions in multi-seam mining.

scholarly journals Application of Comprehensive Geophysical Prospecting Method in Water Accumulation Exploration of Multilayer Goaf in Integrated Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lei Zhang ◽  
Lin Xu ◽  
Yong Xiao ◽  
NingBo Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Comprehensive Analysis ◽  
High Density ◽  
Electromagnetic Method ◽  
Mine Safety ◽  
Practical Significance ◽  
Time Base ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic

A coal mine in Datong is an integrated mine. At present, there is goaf in the upper and lower part of the mining coal seam. There is a lot of ponding in the goaf, which has great potential safety hazards for production. In order to find out the scope and location of ponding in goaf, the comprehensive geophysical exploration method combining transient electromagnetic method and high-density resistivity method is used to carry out the research. Firstly, the time-base, turn-off time, receiving delay, current, superposition times, and other parameters of the instrument are tested on the surface of known goaf to obtain the best instrument parameters, and the parameters are used to verify the feasibility of the research scheme; then, the transient electromagnetic method is used for large-area exploration on the surface of the mine, the suspected goaf ponding area is found through comprehensive analysis, and the high-density resistivity exploration is arranged in the suspected goaf ponding area. According to the obtained results, the scope and location of the goaf ponding area are accurately located through comprehensive analysis. The results show that there are two goaf ponding areas in the exploration area, which are located above the 8# coal seam currently mined; the range and location of goaf ponding area can be accurately obtained by using the comprehensive geophysical method of high-density electrical method and transient electromagnetic method. This method can provide reference for mine water prevention and control in Datong area and has great practical significance to ensure coal mine safety production.

scholarly journals Prediction Model for Spontaneous Combustion of Coal around Boreholes Using Bedding Gas Drainage

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Youxin Zhao ◽  
Qingjie Qi ◽  
Xinlei Jia
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Negative Pressure ◽  
Spontaneous Combustion ◽  
Orthogonal Test ◽  
Gas Drainage ◽  
Positive Linear Correlation ◽  
Drainage Hole ◽  
Spontaneous Combustion Of Coal ◽  
Fractured Coal

To accurately and reliably predict the time of spontaneous combustion of fractured coal around a borehole induced by gas drainage along the seam, this study performed an orthogonal test taking the No. 10 Coal Mine of Pingdingshan as the research object, in terms of the suction negative pressure and coal seam buried depth. COMSOL Multiphysics was used to model the orthogonal test results, and a multielement statistical analysis of four factors and their relationships with the spontaneous combustion of coal around the borehole and a single-factor analysis in line with the site conditions were performed on the modeling results through multiple regression. The results showed a nonlinear regression relationship between the sealing hole length, sealing hole depth, negative pressure, and coal seam depth and the spontaneous combustion of the coal around the gas drainage borehole; the prediction regression model is significant. Taking the field gas drainage in the No. 10 Coal Mine of Pingdingshan as an example, the relationship between the time of spontaneous combustion of gas drainage and the drainage pressure follows a power of two. When the drainage negative pressure is less than 45 kPa, the coal around the borehole is more likely to undergo spontaneous combustion with increasing pressure, and the sealing hole length has a positive linear correlation with the time of spontaneous combustion of the coal around the borehole. When the sealing hole length is 23 m, the time of spontaneous combustion of the coal around the gas drainage hole is >500 days, and the coal around the borehole does not easily undergo spontaneous combustion. When the sealing depth is 15 m, the time of spontaneous combustion of the coal around the gas drainage hole is 76 days, which is most likely to cause spontaneous combustion.

scholarly journals Study on Roof-Coal Caving Characteristics with Complicated Structure by Fully Mechanized Caving Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Yunpei Liang ◽  
Lei Li ◽  
Xuelong Li ◽  
Kequan Wang ◽  
Jinhua Chen ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Research Work ◽  
Maximum Principal Stress ◽  
Complicated Structure ◽  
Mining Technology ◽  
Thick Coal Seam ◽  
Soft Coal ◽  
Mining Depth ◽  
Arch Forms

With mining technology and mechanization degree being improving, fully mechanized caving mining technology (FCM) has become a main method for thick coal seam extraction in China. However, roof-coal caving characteristics in turn restrict its recovery efficiency, especially for the coal seam with complicated structure (CCS), that is, the coal seam comprises hard or soft coal and gangue. In order to explore the key factors influencing the roof-coal caving and recovery characteristics, related research work has been conducted as follows: firstly, a mechanical model of CCS has been established, which indicates the strength of the coal and gangue will directly affect the roof-coal recovery. Meanwhile, based on the geological settings of Qinyuan coal mine, numerical simulation on roof-coal caving law under different thicknesses of hard or soft coal and gangue has been performed using UDEC software. The results show that the maximum principal stress will increase with the increase of mining depth, making the roof-coal to break easily. Furthermore, the range of the plastic zone of the top coal and the damage degree of the top coal increase with the increase of mining depth. Physical modeling results show that when an extraction-caving ratio is 1, the number of times the coal arch forms is 0.43 at every caving, up to a maximum of 3; the number of times coal arch forms with an extraction-caving ratio of 2 is 4.65 times larger than that with an extraction-caving ratio of 1. The probability of coal arch formation with an extraction-caving ratio of 3 is minimal, about 0.4, which is due to that the arch span is large and the curvature is small, so it is difficult to form a stable arch structure. According to the mechanical characteristics of roof-coal in Qinyuan coal mine, deep-hole blasting technique has been used to reduce the fragments of roof-coal crushed. The results show that this technique can effectively improve the recovery of roof-coal.

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