Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was...Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.展开更多
The forms of roof break,roof fall,and effects of the region scope in a fully mechanizedtop-coal caving (FMTC) face of the 101 fully-mechanized top coal caving face ofthe Tingnan Coalmine were analyzed by UDEC and FLAC...The forms of roof break,roof fall,and effects of the region scope in a fully mechanizedtop-coal caving (FMTC) face of the 101 fully-mechanized top coal caving face ofthe Tingnan Coalmine were analyzed by UDEC and FLAC^(3D) software.The analysis resultconfirms the phenomenon of roof falling,roof-off-strata,roof breaking,first weighting,periodicweighting and stress concentration,redistributions of surrounding rock and so on.Itprovides the gist to analyze the law of roof movement,characteristic of confining pressure,and to determine the formative structure forms of the immediate roof and main roof duringthe caving process.These results and the underground pressure observation results are inagreement.展开更多
In view of the situation of excavation of should carry out simulation studies for the numerical open coal mine for the underground water disaster, we value of the water lowering project and improve the accuracy and th...In view of the situation of excavation of should carry out simulation studies for the numerical open coal mine for the underground water disaster, we value of the water lowering project and improve the accuracy and the level of the water lowering project. On the basis of the hydrological geological conditions of certain open mine digging, a more reasonable seepage numerical model was built according to MODFLOW. It was simulated in advance that the process of the confined water level descending with the time, and combining with the actual observations to test the correctness of the model. The calculation showed that the results coincided well with the results of actual measurement. Based on this, different water lowering numerical simulations were built for the open coal mine digging. It could be simulated and forecast that the changes of the groundwater level in drainage process within and outside the mine pit, and it was quantitatively assessed that the possible water lowering result of the opencast water drainage process, which provide an important basis for the actual water lowering project and the possible project disposal.展开更多
文摘Numerical simulation of the electrical field distribution helps in-depth understanding of the mechanisms behind the responses and the benefits of the high voltage pulse comminution. The COMSOL Multiphysics package was used to numerically simulate the effect of ore compositions in this study. Regarding phosphate ore particles shape and composition, the effects of mineral composition, particle size, particle shape and electrodes distance were investigated on the electrical field intensity and distribution. The results show that the induced electrical field is significantly dependent on the electrical properties of minerals,the feed particle size and the location of conductive minerals in ores. The angle of material contact surface with the discharge electrode is also an important factor in the intensity of electrical field. Moreover,it is found that the specific liberation effect at the disintegration of phosphate ore by electrical pulses is due to the locality of the electrical field at the interface of mineral components of the phosphate ore aggregates with different permittivities. However, the intensity of the electrical field increases with sharpening the contact angle. Besides, the electrical discharge in the samples is converted to the electrohydraulic discharge across the surrounding water by changing the distance between the discharge electrode and sample surface.
基金Supported by the National Natural Science Foundation of China (505740720,50874089)the National Natural Science Foundation of Shannxi Province(2006E203)
文摘The forms of roof break,roof fall,and effects of the region scope in a fully mechanizedtop-coal caving (FMTC) face of the 101 fully-mechanized top coal caving face ofthe Tingnan Coalmine were analyzed by UDEC and FLAC^(3D) software.The analysis resultconfirms the phenomenon of roof falling,roof-off-strata,roof breaking,first weighting,periodicweighting and stress concentration,redistributions of surrounding rock and so on.Itprovides the gist to analyze the law of roof movement,characteristic of confining pressure,and to determine the formative structure forms of the immediate roof and main roof duringthe caving process.These results and the underground pressure observation results are inagreement.
文摘In view of the situation of excavation of should carry out simulation studies for the numerical open coal mine for the underground water disaster, we value of the water lowering project and improve the accuracy and the level of the water lowering project. On the basis of the hydrological geological conditions of certain open mine digging, a more reasonable seepage numerical model was built according to MODFLOW. It was simulated in advance that the process of the confined water level descending with the time, and combining with the actual observations to test the correctness of the model. The calculation showed that the results coincided well with the results of actual measurement. Based on this, different water lowering numerical simulations were built for the open coal mine digging. It could be simulated and forecast that the changes of the groundwater level in drainage process within and outside the mine pit, and it was quantitatively assessed that the possible water lowering result of the opencast water drainage process, which provide an important basis for the actual water lowering project and the possible project disposal.
