Based on the characteristics of the top coal thickness of the fully mechanized caving in special thick coal seam,the long distance of coal gangue caving,as well as the different sizes of the coal gangue broken fragmen...Based on the characteristics of the top coal thickness of the fully mechanized caving in special thick coal seam,the long distance of coal gangue caving,as well as the different sizes of the coal gangue broken fragment dimension and spatial variation of drop flow,this paper uses laboratory dispersion simulation experiment and theoretical analysis to study the arch structure effect and its influence rule on the top coal loss in the process of coal gangue flow.Research shows that in the process of coal gangue flow,arch structure can be formed in three types:the lower arch structure,middle arch structure,and upper arch structure.Moreover,the arch structure has the characteristics of dynamic random arch,the formation probability of dynamic random arch with different layers is not the same,dynamic random arch caused the reduction of the top coal fluency;analyzing the dynamic random arch formation mechanism,influencing factors,and the conditions of instability;the formation probability of the lower arch structure is the highest,the whole coal arch and the coal gangue arch structure has the greatest impact on top coal loss.Therefore,to prevent or reduce the formation of lower whole coal arch structure,the lower coal gangue arch structure and the middle whole coal arch structure is the key to reduce the top coal loss.The research conclusion provides theoretical basis for the further improvement of the top coal recovery rate of the fully mechanized caving in extra thick coal seam.展开更多
Aimed at determining the appropriate caving–mining ratio for fully mechanized mining of 20 m thick coal seam, this research investigated the effects of caving–mining ratio on the flow fields of coal and waste rocks,...Aimed at determining the appropriate caving–mining ratio for fully mechanized mining of 20 m thick coal seam, this research investigated the effects of caving–mining ratio on the flow fields of coal and waste rocks, amount of cyclically caved coal and top coal loss by means of numerical modeling. The research was based on the geological conditions of panel 8102 in Tashan coal mine. The results indicated the loose coal and waste rocks formed an elliptical zone around the drawpoint. The ellipse enlarged with decreasing caving–mining ratio. And its long axis inclined to the gob gradually became vertical and facilitating the caving and recovery of top coal. The top coal loss showed a cyclical variation; and the loss cycle was shortened with the decreasing in caving–mining ratio. Moreover, the mean squared error(MSE) of the amount of cyclically caved coal went up with increasing caving–mining ratio, indicating a growing imbalance of amount of cyclically caved coal, which could impede the coordinated mining and caving operations. Finally it was found that a caving–mining ratio of 1:2.51 should be reasonable for the conditions.展开更多
Based on the elastic plate theory, a mechanical model of thin plate for the first caving of overlying roof rock in steep mining face was established. The analytical solution of the deflection and stress distribution o...Based on the elastic plate theory, a mechanical model of thin plate for the first caving of overlying roof rock in steep mining face was established. The analytical solution of the deflection and stress distribution of roof rocks was obtained. According to the specific geological conditions of the 5-103 panel in Shanxi,the failure of roof rocks and the influence of seam dip on it during the exploitation were theoretically investigated. Meanwhile, the first caving characteristics of the overlying rock in the steep coal seam were investigated based on its stress contour. The results show that the dip angle has a distinct influence on the caving interval and the first caving interval for the 5-103 panel is 37 m in theory. Finally, a systematic monitoring on the behavior of rock pressures was conducted. The measured results agree well with the theoretical prediction, which provides a good reference for practical steep coal seam mining.展开更多
China＇s total coal reserves are enormous, in which recoverable reserves of coal seam thickness ofmineable coal reserves in China accounted for 43% of recoverable reserves When correctly using thick seam mining, minin...China＇s total coal reserves are enormous, in which recoverable reserves of coal seam thickness ofmineable coal reserves in China accounted for 43% of recoverable reserves When correctly using thick seam mining, mining methods can improve the proper thick seam mining rate and reduce coal loss. Using proper thick seam mining method can effectively reduce the thick seam mining costs. In mining safety, the use of appropriate thick seam mining methods can effectively prevent thick seam mining accidents. But in the process of development and current situation from the perspective of the Chinese coal mining, there are certain aspects of thick seam mining problems. These problems are mainly in the thick seam mining and the coal recovery rate is low, resulting in lots of waste coal. Besides, thick coal mining is less secure, safe and there are frequent accidents. These problems have seriously affected the thick seam mining. And a lot of thick coal seams of coal resources can not be effectively taken out. Now Chinese mining methods in thick seam mining areas are mainly open-pit mining and underground mining exploitation. Because of the open-pit coal burial depth has more stringent requirements, only used in shallow-depth areas. Underground mining is the primary way China is now using in thick seam mining. Underground mining methods include full-height slice mining and mechanized mining caving mining method once adopted. Research on these thick seam mining methods can provide theoretical and technical support for thick seam mining, thick seam mining techniques to enhance the level . I will combine the current situation of thick seam mining in Chinese study with thick seam mining methods, comments and suggestions for the current thick seam mining study展开更多
基金the Independent Research Subject of State Key Laboratory of Coal Resources and Mine Safety of China University of Mining and Technology (No.SKLCRSM12X03)the Scientific Research and Innovation Project for College Graduates in Jiangsu (No.CXZZ13_0947)+1 种基金Top-Notch Academic Programs of Jiangsu Higher Education Institutionsthe Priority Academic Development Program of Jiangsu Higher Education Institutions
文摘Based on the characteristics of the top coal thickness of the fully mechanized caving in special thick coal seam,the long distance of coal gangue caving,as well as the different sizes of the coal gangue broken fragment dimension and spatial variation of drop flow,this paper uses laboratory dispersion simulation experiment and theoretical analysis to study the arch structure effect and its influence rule on the top coal loss in the process of coal gangue flow.Research shows that in the process of coal gangue flow,arch structure can be formed in three types:the lower arch structure,middle arch structure,and upper arch structure.Moreover,the arch structure has the characteristics of dynamic random arch,the formation probability of dynamic random arch with different layers is not the same,dynamic random arch caused the reduction of the top coal fluency;analyzing the dynamic random arch formation mechanism,influencing factors,and the conditions of instability;the formation probability of the lower arch structure is the highest,the whole coal arch and the coal gangue arch structure has the greatest impact on top coal loss.Therefore,to prevent or reduce the formation of lower whole coal arch structure,the lower coal gangue arch structure and the middle whole coal arch structure is the key to reduce the top coal loss.The research conclusion provides theoretical basis for the further improvement of the top coal recovery rate of the fully mechanized caving in extra thick coal seam.
基金provided by the independent research subject of State Key Laboratory of Coal Resources and Mine Safety of China University of Mining and Technology (No. SKLCRSM12X03)the Scientific Research and Innovation Project for College Graduates in Jiangsu (No. CXZZ13_0947)
文摘Aimed at determining the appropriate caving–mining ratio for fully mechanized mining of 20 m thick coal seam, this research investigated the effects of caving–mining ratio on the flow fields of coal and waste rocks, amount of cyclically caved coal and top coal loss by means of numerical modeling. The research was based on the geological conditions of panel 8102 in Tashan coal mine. The results indicated the loose coal and waste rocks formed an elliptical zone around the drawpoint. The ellipse enlarged with decreasing caving–mining ratio. And its long axis inclined to the gob gradually became vertical and facilitating the caving and recovery of top coal. The top coal loss showed a cyclical variation; and the loss cycle was shortened with the decreasing in caving–mining ratio. Moreover, the mean squared error(MSE) of the amount of cyclically caved coal went up with increasing caving–mining ratio, indicating a growing imbalance of amount of cyclically caved coal, which could impede the coordinated mining and caving operations. Finally it was found that a caving–mining ratio of 1:2.51 should be reasonable for the conditions.
基金financially supported by the National Natural Science Foundation of China (Nos. 51374197 and 50774078)the National Basic Research Program of China (No. 2015CB251600)+1 种基金the University Discipline Construction Project of Jiangsu Province, Blue Project of Jiangsu Provincethe Open Foundation of State Key Laboratory of Coal Resources and Sage Mining (No. SKLCRSM12X06)
文摘Based on the elastic plate theory, a mechanical model of thin plate for the first caving of overlying roof rock in steep mining face was established. The analytical solution of the deflection and stress distribution of roof rocks was obtained. According to the specific geological conditions of the 5-103 panel in Shanxi,the failure of roof rocks and the influence of seam dip on it during the exploitation were theoretically investigated. Meanwhile, the first caving characteristics of the overlying rock in the steep coal seam were investigated based on its stress contour. The results show that the dip angle has a distinct influence on the caving interval and the first caving interval for the 5-103 panel is 37 m in theory. Finally, a systematic monitoring on the behavior of rock pressures was conducted. The measured results agree well with the theoretical prediction, which provides a good reference for practical steep coal seam mining.
文摘China＇s total coal reserves are enormous, in which recoverable reserves of coal seam thickness ofmineable coal reserves in China accounted for 43% of recoverable reserves When correctly using thick seam mining, mining methods can improve the proper thick seam mining rate and reduce coal loss. Using proper thick seam mining method can effectively reduce the thick seam mining costs. In mining safety, the use of appropriate thick seam mining methods can effectively prevent thick seam mining accidents. But in the process of development and current situation from the perspective of the Chinese coal mining, there are certain aspects of thick seam mining problems. These problems are mainly in the thick seam mining and the coal recovery rate is low, resulting in lots of waste coal. Besides, thick coal mining is less secure, safe and there are frequent accidents. These problems have seriously affected the thick seam mining. And a lot of thick coal seams of coal resources can not be effectively taken out. Now Chinese mining methods in thick seam mining areas are mainly open-pit mining and underground mining exploitation. Because of the open-pit coal burial depth has more stringent requirements, only used in shallow-depth areas. Underground mining is the primary way China is now using in thick seam mining. Underground mining methods include full-height slice mining and mechanized mining caving mining method once adopted. Research on these thick seam mining methods can provide theoretical and technical support for thick seam mining, thick seam mining techniques to enhance the level . I will combine the current situation of thick seam mining in Chinese study with thick seam mining methods, comments and suggestions for the current thick seam mining study
