Ground movements due to longwall mining operations have the potential to damage the hydrological balance within as well as outside the mine permit area in the form of increased surface ponding and changes to hydrogeol...Ground movements due to longwall mining operations have the potential to damage the hydrological balance within as well as outside the mine permit area in the form of increased surface ponding and changes to hydrogeological properties. Recently, the Office of Surface Mining, Reclamation and Enforcement(OSMRE) in the USA, has completed a public comment period on a newly proposed rule for the protection of streams and groundwater from adverse impacts of surface and underground mining operations(80 FR 44435). With increased community and regulatory focus on mining operations and their potential to adversely affect streams and groundwater, now there is a greater need for better prediction of the possible effects mining has on both surface and subsurface bodies of water. With mining induced stress and strain within the overburden correlated to changes in the hydrogeological properties of rock and soil, this paper investigates the evaluation of the hydrogeological system within the vicinity of an underground mining operation based on strain values calculated through a surface deformation prediction model. Through accurate modeling of the pre- and post-mining hydrogeological system, industry personnel can better depict mining induced effects on surface and subsurface bodies of water aiding in the optimization of underground extraction sequences while maintaining the integrity of water resources.展开更多
This paper systematiedy expounds the history and present situation of tbe research &application of strip-parttal mining at home and abroad. Tbe prospect of using strip-parttal miningmcthod to mine under balldings ...This paper systematiedy expounds the history and present situation of tbe research &application of strip-parttal mining at home and abroad. Tbe prospect of using strip-parttal miningmcthod to mine under balldings (structures) at the present situation of market economy is also expounded here Strata & surface subsidence mechanism of atrip-partni mining the optimization ofthe width of unit goaf & coal pillar as well as the calculation method of surface subsidence pridictionbased on Holding-Ptate Control Theory and Coal Pillar Long-term Stability, which are our researchachivements in recent years about strata & surface subsidence control in strip-partial mining, arethe main points introdued bere.展开更多
Hard coal mining in the German Ruhr district has a tradition of more than 200 years. Starting in the south near the river Ruhr with mining of seams near to the surface, mining wandered to the north with coal seams dee...Hard coal mining in the German Ruhr district has a tradition of more than 200 years. Starting in the south near the river Ruhr with mining of seams near to the surface, mining wandered to the north with coal seams deeper and deeper. In the same way all environmental effects of mining wandered from south to north, as there are abandoned mining sites, contaminated areas, burning mining dumps, subsided areas and gas accesses at day ground. This all happened in a very high populated area with more than four million inhabitants. Therefore Germany has a long tradition in solving environmental problems of mining activities. The very good interaction of mine authority, mining companies and the mine workers’ union is the main reason why the problems of decreasing mining activities in Germany were solved without economic, environmental or social hazards.展开更多
Why do some room and pillar retreat panels encounter abnormal conditions？ What factors deserve the most consideration during the planning and execution phases of mining and what can be done to mitigate those abnormal...Why do some room and pillar retreat panels encounter abnormal conditions？ What factors deserve the most consideration during the planning and execution phases of mining and what can be done to mitigate those abnormal conditions when they are encountered7 To help answer these questions, and to determine some of the relevant factors influencing the conditions of room and pillar （R ＆ P） retreat min- ing entries, four consecutive R ＆ P retreat panels were evaluated. This evaluation was intended to rein- force the influence of topographic changes, depth of cover, multiple-seam interactions, geological conditions, and mining geometry. This paper details observations were made in four consecutive R ＆ P retreat panels and the data were collected from an instrumentation site during retreat mining. The pri- mary focus was on the differences observed among the four panels and within the panels themselves. The instrumentation study was initially planned to evaluate the interactions between primary and secondary support, but produced rather interesting results relating to the loading encountered under the current mining conditions. In addition to the obse^ation and ｜ll^trumentation, numerical modeling was per- formed to evaluate the stress condi~!ons. Both the LaModel 3.0 and Rocscience Phase 2 programs were used to evaluate these four panels, The results of both models indicated a drastic reduction in the vertical stresses experienced in these panels due to the full extraction mining in overlying seams when compared to the full overburden load. Both models showed a higher level of stress associated with the outside entries of the panels. These results agree quite well with the observations and instrumentation studies performed at the mine. These efforts provided two overarching conclusions concerning R ＆ P retreat mine planning and execution. The first was that there are four areas that should not be overlooked during R ＆ P retreat mining： topographic relief, multiple^seaPa stress relief, stress concentrations near the gob edge, and geologic changes in the immediate roof. The second is that in order to successfully retreat an R ＆ P panel, a three-phased approach to the design and analysis of the panel should be conducted： the planning phase, evaluation phase, and monitoring phase.展开更多
In order to study the effect of Iongwall mining on surface stream water, monitoring stations of water flow rate was established. A lot of water flowing data were collected before, during and after Iongwall mining. Bas...In order to study the effect of Iongwall mining on surface stream water, monitoring stations of water flow rate was established. A lot of water flowing data were collected before, during and after Iongwall mining. Based on monitoring data, the effects of Iongwall mining on surface stream water were analyzed. The results demonstrate that Iongwall mining has effects on the surface stream water; and the stream water would be lost and decrease due to Iongwall mining but never go into underground through fractured zone. Also, the mechanism of water loss due to Iongwall mining was presented. The stream water can go into the surface cracks in the intersection of stream and surface cracks, longwall mining subsidence can change the surface stream slope and the downstream water flowing status. The results also show the effects of Iongwall mining on stream water are temporary and about one or two years later, surface stream water can be recovered.展开更多
The results of experimentaI studies about the characteristics of broken rock expansion and reconsolidation were briefly introduced in this paper, and the surface subsidence coefficient under critical mining conditions...The results of experimentaI studies about the characteristics of broken rock expansion and reconsolidation were briefly introduced in this paper, and the surface subsidence coefficient under critical mining conditions was also analysed based on the principle of expansion and reconsolidation of the broken rock strata, a equation to calculate the corresponding surface subsidence was finally produced. This calculation method can be used to calculate more accurately the convergence quantity of consolidated rocks in the broken zone of the working face. In addition, case analyses by using the introduced calculation method were conducted and satisfactory results were obtained.展开更多
The Wongawilli strip pillar mining technique,which combines the strip pillar mining layout and Wongawilli mining technology,is a new high efficient mining technology for mining under surface structures. The Wongawilli...The Wongawilli strip pillar mining technique,which combines the strip pillar mining layout and Wongawilli mining technology,is a new high efficient mining technology for mining under surface structures. The Wongawilli strip pillar mining technique was studied in this paper using theoretical analysis and numerical simulation. As an example,the geological and mining conditions of a coal mine were used to design the Wongawilli strip pillar plans,including the support parameters of the entries and the mining technology. In order to control the surrounding rocks and manage the roof effectively during coal mining,the stress fields,displacement fields and plastic zones were studied by numerical simulation. The stress fields,displacement fields,and plastic zones generated by Wongawilli strip pillar mining were obtained. And the surface movement and deformation were also determined after mining was completed and its effects on surface structures were analyzed and evaluated. The results demonstrate that it is feasible to mine under surface structures with the Wongawilli strip pillar mining technique. This mining method can protect the surface structures from damages.展开更多
Six main influencing factors： slope, aspect, distance, angle, angle of coal seam, and the ratio of depth and thickness, were selected by Grey correlation theory and Grey relational analysis procedure programmed by th...Six main influencing factors： slope, aspect, distance, angle, angle of coal seam, and the ratio of depth and thickness, were selected by Grey correlation theory and Grey relational analysis procedure programmed by the MATLAB software package to select the surface movement and deformation parameters. On this basis, the paper built a BP neural network model that takes the six main influencing factors as input data and corresponding value of ground subsidence as output data. Ground subsidence of the 3406 mining face in Haoyu Coal was predicted by the trained BP neural network. By comparing the prediction and the practices, the research shows that it is feasible to use the 13P neural network to predict mountain mining subsidence.展开更多
基金sponsored by the Appalachian Research Initiative for Environmental Science(ARIES)
文摘Ground movements due to longwall mining operations have the potential to damage the hydrological balance within as well as outside the mine permit area in the form of increased surface ponding and changes to hydrogeological properties. Recently, the Office of Surface Mining, Reclamation and Enforcement(OSMRE) in the USA, has completed a public comment period on a newly proposed rule for the protection of streams and groundwater from adverse impacts of surface and underground mining operations(80 FR 44435). With increased community and regulatory focus on mining operations and their potential to adversely affect streams and groundwater, now there is a greater need for better prediction of the possible effects mining has on both surface and subsurface bodies of water. With mining induced stress and strain within the overburden correlated to changes in the hydrogeological properties of rock and soil, this paper investigates the evaluation of the hydrogeological system within the vicinity of an underground mining operation based on strain values calculated through a surface deformation prediction model. Through accurate modeling of the pre- and post-mining hydrogeological system, industry personnel can better depict mining induced effects on surface and subsurface bodies of water aiding in the optimization of underground extraction sequences while maintaining the integrity of water resources.
文摘This paper systematiedy expounds the history and present situation of tbe research &application of strip-parttal mining at home and abroad. Tbe prospect of using strip-parttal miningmcthod to mine under balldings (structures) at the present situation of market economy is also expounded here Strata & surface subsidence mechanism of atrip-partni mining the optimization ofthe width of unit goaf & coal pillar as well as the calculation method of surface subsidence pridictionbased on Holding-Ptate Control Theory and Coal Pillar Long-term Stability, which are our researchachivements in recent years about strata & surface subsidence control in strip-partial mining, arethe main points introdued bere.
文摘Hard coal mining in the German Ruhr district has a tradition of more than 200 years. Starting in the south near the river Ruhr with mining of seams near to the surface, mining wandered to the north with coal seams deeper and deeper. In the same way all environmental effects of mining wandered from south to north, as there are abandoned mining sites, contaminated areas, burning mining dumps, subsided areas and gas accesses at day ground. This all happened in a very high populated area with more than four million inhabitants. Therefore Germany has a long tradition in solving environmental problems of mining activities. The very good interaction of mine authority, mining companies and the mine workers’ union is the main reason why the problems of decreasing mining activities in Germany were solved without economic, environmental or social hazards.
文摘Why do some room and pillar retreat panels encounter abnormal conditions？ What factors deserve the most consideration during the planning and execution phases of mining and what can be done to mitigate those abnormal conditions when they are encountered7 To help answer these questions, and to determine some of the relevant factors influencing the conditions of room and pillar （R ＆ P） retreat min- ing entries, four consecutive R ＆ P retreat panels were evaluated. This evaluation was intended to rein- force the influence of topographic changes, depth of cover, multiple-seam interactions, geological conditions, and mining geometry. This paper details observations were made in four consecutive R ＆ P retreat panels and the data were collected from an instrumentation site during retreat mining. The pri- mary focus was on the differences observed among the four panels and within the panels themselves. The instrumentation study was initially planned to evaluate the interactions between primary and secondary support, but produced rather interesting results relating to the loading encountered under the current mining conditions. In addition to the obse^ation and ｜ll^trumentation, numerical modeling was per- formed to evaluate the stress condi~!ons. Both the LaModel 3.0 and Rocscience Phase 2 programs were used to evaluate these four panels, The results of both models indicated a drastic reduction in the vertical stresses experienced in these panels due to the full extraction mining in overlying seams when compared to the full overburden load. Both models showed a higher level of stress associated with the outside entries of the panels. These results agree quite well with the observations and instrumentation studies performed at the mine. These efforts provided two overarching conclusions concerning R ＆ P retreat mine planning and execution. The first was that there are four areas that should not be overlooked during R ＆ P retreat mining： topographic relief, multiple^seaPa stress relief, stress concentrations near the gob edge, and geologic changes in the immediate roof. The second is that in order to successfully retreat an R ＆ P panel, a three-phased approach to the design and analysis of the panel should be conducted： the planning phase, evaluation phase, and monitoring phase.
基金Supported by Pennsylvania Service Corporation at Waynesburg, Pennsylvania, USA the 0utstanding Youth Science Foundation of Henan Province （0612002100）, China.
文摘In order to study the effect of Iongwall mining on surface stream water, monitoring stations of water flow rate was established. A lot of water flowing data were collected before, during and after Iongwall mining. Based on monitoring data, the effects of Iongwall mining on surface stream water were analyzed. The results demonstrate that Iongwall mining has effects on the surface stream water; and the stream water would be lost and decrease due to Iongwall mining but never go into underground through fractured zone. Also, the mechanism of water loss due to Iongwall mining was presented. The stream water can go into the surface cracks in the intersection of stream and surface cracks, longwall mining subsidence can change the surface stream slope and the downstream water flowing status. The results also show the effects of Iongwall mining on stream water are temporary and about one or two years later, surface stream water can be recovered.
文摘The results of experimentaI studies about the characteristics of broken rock expansion and reconsolidation were briefly introduced in this paper, and the surface subsidence coefficient under critical mining conditions was also analysed based on the principle of expansion and reconsolidation of the broken rock strata, a equation to calculate the corresponding surface subsidence was finally produced. This calculation method can be used to calculate more accurately the convergence quantity of consolidated rocks in the broken zone of the working face. In addition, case analyses by using the introduced calculation method were conducted and satisfactory results were obtained.
基金sponsored by the National Natural Science Foundation of China (No.51374092)
文摘The Wongawilli strip pillar mining technique,which combines the strip pillar mining layout and Wongawilli mining technology,is a new high efficient mining technology for mining under surface structures. The Wongawilli strip pillar mining technique was studied in this paper using theoretical analysis and numerical simulation. As an example,the geological and mining conditions of a coal mine were used to design the Wongawilli strip pillar plans,including the support parameters of the entries and the mining technology. In order to control the surrounding rocks and manage the roof effectively during coal mining,the stress fields,displacement fields and plastic zones were studied by numerical simulation. The stress fields,displacement fields,and plastic zones generated by Wongawilli strip pillar mining were obtained. And the surface movement and deformation were also determined after mining was completed and its effects on surface structures were analyzed and evaluated. The results demonstrate that it is feasible to mine under surface structures with the Wongawilli strip pillar mining technique. This mining method can protect the surface structures from damages.
文摘Six main influencing factors： slope, aspect, distance, angle, angle of coal seam, and the ratio of depth and thickness, were selected by Grey correlation theory and Grey relational analysis procedure programmed by the MATLAB software package to select the surface movement and deformation parameters. On this basis, the paper built a BP neural network model that takes the six main influencing factors as input data and corresponding value of ground subsidence as output data. Ground subsidence of the 3406 mining face in Haoyu Coal was predicted by the trained BP neural network. By comparing the prediction and the practices, the research shows that it is feasible to use the 13P neural network to predict mountain mining subsidence.
