Under fully mechanized, large mining height top coal caving conditions, the shield beam slope angle of the support increases due to the enlargement of the top coal breaking and caving space. This results in a change o...Under fully mechanized, large mining height top coal caving conditions, the shield beam slope angle of the support increases due to the enlargement of the top coal breaking and caving space. This results in a change of the caving window location and dimensions and, therefore, the granular coal-gangue movement and flows provide new characteristics during top coal caving. The main inferences we draw are as follows. Firstly, after shifting the supports, the caved top coal layer line and the coal gangue boundary line become steeper and are clearly larger than those under common mining heights. Secondly, during the top coal caving procedure, the speed of the coal-gangue flow increases and at the same drawing interval, the distance between the coal-gangue boundary line and the top beam end is reduced. Thirdly, affected by the drawing ratio, the slope angle of the shield beam and the dimensions of the caving window, it is easy to mix the gangue. A rational drawing interval will cause the coal-gangue boundary line to be slightly behind the down tail boom lower boundary. This rational drawing interval under conditions of large mining heights has been analyzed and determined.展开更多
The room and pillar method is usually used to extract coal from shallowly buried seams with thin bedrock. This results in a very low production efficiency and in a low degree of extraction. In recent years short-wall ...The room and pillar method is usually used to extract coal from shallowly buried seams with thin bedrock. This results in a very low production efficiency and in a low degree of extraction. In recent years short-wall continuous mechanical mining has been extensively used in many situations except shallowly buried coal seams with thin bedrock. The principles governing movement of the overlying strata above the 2-2 coal seam were deduced from in-situ experience, laboratory data, calculations and computer simulations. The thicknesses of the bedrock in the Shendong Coal Field where the coal is shallowly buried are classified into 5 types: <10 m, 10–15 m, 15–25 m, 25–35 m and >35 m, which was done using fuzzy clustering results. A series of reasonable, relative parameters in each category have been calculated and analyzed. One proposed way to perform short-wall continuous mechanical mining in shallowly buried coal seams is given. This is significant for coal mines with similar geological conditions.展开更多
基金Project 50774079 supported by the National Natural Science Foundation of China
文摘Under fully mechanized, large mining height top coal caving conditions, the shield beam slope angle of the support increases due to the enlargement of the top coal breaking and caving space. This results in a change of the caving window location and dimensions and, therefore, the granular coal-gangue movement and flows provide new characteristics during top coal caving. The main inferences we draw are as follows. Firstly, after shifting the supports, the caved top coal layer line and the coal gangue boundary line become steeper and are clearly larger than those under common mining heights. Secondly, during the top coal caving procedure, the speed of the coal-gangue flow increases and at the same drawing interval, the distance between the coal-gangue boundary line and the top beam end is reduced. Thirdly, affected by the drawing ratio, the slope angle of the shield beam and the dimensions of the caving window, it is easy to mix the gangue. A rational drawing interval will cause the coal-gangue boundary line to be slightly behind the down tail boom lower boundary. This rational drawing interval under conditions of large mining heights has been analyzed and determined.
基金Projects NCET-05-0480 supported by the Program for New Century Excellent Talents in University07KF09 by the 2007 Research Fund of the State Key Laboratory of Coal Resources and Mine Safety
文摘The room and pillar method is usually used to extract coal from shallowly buried seams with thin bedrock. This results in a very low production efficiency and in a low degree of extraction. In recent years short-wall continuous mechanical mining has been extensively used in many situations except shallowly buried coal seams with thin bedrock. The principles governing movement of the overlying strata above the 2-2 coal seam were deduced from in-situ experience, laboratory data, calculations and computer simulations. The thicknesses of the bedrock in the Shendong Coal Field where the coal is shallowly buried are classified into 5 types: <10 m, 10–15 m, 15–25 m, 25–35 m and >35 m, which was done using fuzzy clustering results. A series of reasonable, relative parameters in each category have been calculated and analyzed. One proposed way to perform short-wall continuous mechanical mining in shallowly buried coal seams is given. This is significant for coal mines with similar geological conditions.
