| Tielukan Cu deposit,located in Jiujiang City,Jiangxi Province,is a typical skarn deposit with 599900 tons of Cu resources.The mining of the mining area will provide a great mount copper for industrial development and bring great social benefits to the region.Open-pit mining will apply to the Tielukan deposit.However,the engineering geological conditions are still poor constrained,and its mining technical conditions still need to be further evaluated.The regional geological background and geological characteristics of the Tielukan ore deposit are well summarized in this study.Combined with field investigation,hydraulic environment test and sample detection,the mining technical conditions of hydrology,engineering and environment in the mining area are studied in detail.The water filling factor analysis of the deposit and the calculation of the mine water inflow are completed.In addition,not only the stability of ore body and surrounding rock is evaluated,but also the engineering geological rock group is divided.Finally,the environmental status of the mining area is investigated and analyzed,and the possible environmental geological problems in the future mining are predicted.It is determined that the deposit is a complex deposit with hydrogeological conditions,engineering geological conditions and environmental geological conditions.Field investigation shows that the main water-filled layer of the ore deposit is Permian Carboniferous limestone cave fissure aquifer,which is directly filled with karst groundwater.The water filling of the deposit is generally controlled by karst aquifer of Permian Carboniferous limestone and structural fracture zone(mainly F1 and F20).In addition,the constant expansion of the bulky drawdown dewatering and drainage funnel will lead to shallow subsidence or cracking in the lake area,and the lake water may directly fill in the deposit.The prediction of mine water inflow shows that the calculated maximum,minimum and average of atmospheric precipitation catchment in open pit are 3102m3/d,374m3/d and 1623.6m3/d,respectively.The water inflow of open pit was calculated by the water cut-off section system at one side of corridor according to three middle sections of-46 m,-130 m and-322 m(final mining bottom boundary),and the results are 17091 m3/d,29303 m3/d and 59033 m3/d,respectively.Fault analysis shows that the main fault fracture zones in the mining area are F1 and F20.Since the fault has certain destructive effect on the integrity of rock stratum,it is considered that both of them have relatively great impact on the engineering geology of the mining area.Geological survey shows that the depth of weathered fracture zone can reach-250 m.The engineering geological analysis shows that the weathering material has low strength,weak and loose structure,which is easy to disintegrate when encountering water,which seriously affects the slope stability.It should be noted that the stability of the deep part of orebody and wall rocks are better than that of the shallow part.However,there are also some engineering geological bodies with poor and complex hydrogeological conditions in the deep part,which may affect the stability of the ore body and wall rock.Based on systematic field investigation and data analysis,it is shown that both of the eastern and southern slope areas of the open pit slope hold poor engineering geological conditions.Especially for the eastern slope,due to the loose Quaternary accumulation structure,robust weathering of rock mass,wrecked rock mass in the contact zone and other adverse engineering geological conditions,the slope is easy to produce circular and broken line sliding failure.This study confirmed that the content of conventional chemical components in the water quality of the mining area falls within the scope of the natural environment background state,and is not affected by the mining of Chengmenshan copper deposit.There is no radioactive anomaly on the ground of the mining area.The measured annual effective dose equivalent of radioactive radiation is less than 1 m Sv.The mining area belongs to the high temperature area with normal geothermal gradient background.According to the classification standard of thermal damage assessment degree,it belongs to medium heat damage level.In addition,local ground deformation,cracking and ground subsidence are the main environmental geological problems in the area affected by the depression of groundwater level.It is worth noting that the west side of Tielukan mining area in the study area is adjacent to the mining pit of Chengmenshan Copper Mine,which has been included in the third phase expansion mining plan of Chengmenshan copper mine.The research results may provide an important reference for the mine development and deep mining. |
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