When an extremely thick rock bed exists above a protected coal seam in the bending zone given the condition of a mining protective seam, this extremely thick rock bed controls the movement of the entire overlying stra...When an extremely thick rock bed exists above a protected coal seam in the bending zone given the condition of a mining protective seam, this extremely thick rock bed controls the movement of the entire overlying stratum. This extremely thick rock bed, called a ＂main key stratum＂, will not subside nor break for a long time, causing lower fractures and bed separations not to close and gas can migrate to the bed separation areas along the fractures. These bed separations become gas enrichment areas. By analyzing the rule of fracture evolution and gas migration under the main key stratum after the deep protective coal seam has been mined, we propose a new gas drainage method which uses bore holes, drilled through rock and coal seams at great depths for draining pressure relief gas. In this method, the bores are located at a high level suction roadway （we can also drill them in the drilling field located high in an air gateway）. Given the practice in the Haizi mine, the gas drainage rate can reach 73% in the middie coal group, with a gas drainage radius over 100 m.展开更多
Based on affirming the tremendous benefits that water resources of rivers can provide in their exploitation, main environmental problems and their countermeasures have been proposed and analyzed in this paper. It is a...Based on affirming the tremendous benefits that water resources of rivers can provide in their exploitation, main environmental problems and their countermeasures have been proposed and analyzed in this paper. It is argued that multiple measures should be applied to solving those problems by simultaneously carrying out engineering measures, scientific research and also programs to cultivate the society’s awareness, aimed at a sustainable development strategy for exploiting water resources.展开更多
Strengthening the environmental protection, deepening rural reform, increasing agricultural input, and promoting a more stable and higher-speed growth of peasants＇ income, all of these are playing a very important ro...Strengthening the environmental protection, deepening rural reform, increasing agricultural input, and promoting a more stable and higher-speed growth of peasants＇ income, all of these are playing a very important role in the sustainable development of agriculture. The environment problems are not only economic problems, but also important political problems. And they constitute an urgent and arduous task that we meet, and need a long time to be conquered. Under the present new historical circumstances, we should establish a scientific development philosophy, strengthen the environment protection, and build up a harmonious society in which urban and rural areas are progressing coordinately.展开更多
基金Projects 2005CB221503 supported by the National Basic Research Program of China70533050 and 50674089 by the National Natural Science Foundation of China2005BA813B-3-06 by the National Tenth 5-Year Key Scientific and Technological Project
文摘When an extremely thick rock bed exists above a protected coal seam in the bending zone given the condition of a mining protective seam, this extremely thick rock bed controls the movement of the entire overlying stratum. This extremely thick rock bed, called a ＂main key stratum＂, will not subside nor break for a long time, causing lower fractures and bed separations not to close and gas can migrate to the bed separation areas along the fractures. These bed separations become gas enrichment areas. By analyzing the rule of fracture evolution and gas migration under the main key stratum after the deep protective coal seam has been mined, we propose a new gas drainage method which uses bore holes, drilled through rock and coal seams at great depths for draining pressure relief gas. In this method, the bores are located at a high level suction roadway （we can also drill them in the drilling field located high in an air gateway）. Given the practice in the Haizi mine, the gas drainage rate can reach 73% in the middie coal group, with a gas drainage radius over 100 m.
文摘Based on affirming the tremendous benefits that water resources of rivers can provide in their exploitation, main environmental problems and their countermeasures have been proposed and analyzed in this paper. It is argued that multiple measures should be applied to solving those problems by simultaneously carrying out engineering measures, scientific research and also programs to cultivate the society’s awareness, aimed at a sustainable development strategy for exploiting water resources.
文摘Strengthening the environmental protection, deepening rural reform, increasing agricultural input, and promoting a more stable and higher-speed growth of peasants＇ income, all of these are playing a very important role in the sustainable development of agriculture. The environment problems are not only economic problems, but also important political problems. And they constitute an urgent and arduous task that we meet, and need a long time to be conquered. Under the present new historical circumstances, we should establish a scientific development philosophy, strengthen the environment protection, and build up a harmonious society in which urban and rural areas are progressing coordinately.
