At this stage, the coal mining is generally faced with many problems which are mainly caused by improper operation in the mining process, and in the mining of close coal seam slicing, can effectively find the residual...At this stage, the coal mining is generally faced with many problems which are mainly caused by improper operation in the mining process, and in the mining of close coal seam slicing, can effectively find the residual coal pillar, which will usually produce greater stress concentration on the lower coal seam, but the existence of this situation also has a lot of bad places, especially will lead to the changes of the working overburden structure of the lower strata to a certain extent, and the law of strata movement also changes to a certain extent. And the existence of these changes will create more problems for the lower coal mining work, especially for the layout of the coal mining face, and through the actual application and research investigation, it is found that the study on the pressure change of the overlying strata will also have a certain impact on the mining safety of the lower coal seam, so in order to better carry out the close coal seam mining, it is necessary to study the law and control of rock movement.展开更多
As mining depth becomes deeper and deeper,the possibility of undermining overburden aquifers is increasing.It is very important for coal miners to undertake studies on the height of fractured zone during longwall mini...As mining depth becomes deeper and deeper,the possibility of undermining overburden aquifers is increasing.It is very important for coal miners to undertake studies on the height of fractured zone during longwall mining and the effects of longwall mining on the underground water while mining under surface water bodies and underground aquifers.In order to study this problem,piezometers for monitoring underground water levels were installed above the longwall panels in an American coalmine.Large amounts of pre-mining,during mining and post-mining monitoring data were collected.Based on the data,the heights of fractured zones were obtained and the effects of longwall mining on the underground water were studied.The results demonstrate that when the piezometer monitoring wells had an interburden thickness of less than 72.7 m,the groundwater level decreased immediately to immeasurable levels and the wells went dry after undermining the face of longwall.The height of the fractured zone is 72.7-85.3 m in the geological and mining conditions.The results also show that the calculated values of fractured zones by the empirical formulae used in China are smaller than the actual results.Therefore,it is not always safe to use them for analyses while mining under water bodies.展开更多
文摘At this stage, the coal mining is generally faced with many problems which are mainly caused by improper operation in the mining process, and in the mining of close coal seam slicing, can effectively find the residual coal pillar, which will usually produce greater stress concentration on the lower coal seam, but the existence of this situation also has a lot of bad places, especially will lead to the changes of the working overburden structure of the lower strata to a certain extent, and the law of strata movement also changes to a certain extent. And the existence of these changes will create more problems for the lower coal mining work, especially for the layout of the coal mining face, and through the actual application and research investigation, it is found that the study on the pressure change of the overlying strata will also have a certain impact on the mining safety of the lower coal seam, so in order to better carry out the close coal seam mining, it is necessary to study the law and control of rock movement.
基金sponsored by the National Natural Science Foundation of China (No.50974053)Pennsylvania Service Corporation at Waynesburg,USA
文摘As mining depth becomes deeper and deeper,the possibility of undermining overburden aquifers is increasing.It is very important for coal miners to undertake studies on the height of fractured zone during longwall mining and the effects of longwall mining on the underground water while mining under surface water bodies and underground aquifers.In order to study this problem,piezometers for monitoring underground water levels were installed above the longwall panels in an American coalmine.Large amounts of pre-mining,during mining and post-mining monitoring data were collected.Based on the data,the heights of fractured zones were obtained and the effects of longwall mining on the underground water were studied.The results demonstrate that when the piezometer monitoring wells had an interburden thickness of less than 72.7 m,the groundwater level decreased immediately to immeasurable levels and the wells went dry after undermining the face of longwall.The height of the fractured zone is 72.7-85.3 m in the geological and mining conditions.The results also show that the calculated values of fractured zones by the empirical formulae used in China are smaller than the actual results.Therefore,it is not always safe to use them for analyses while mining under water bodies.
