Combined Magnetic and Transient Electromagnetic Methods to Locate and Predict the Dislocated Concealed Orebody at the Deep Edge of Yanqianshan Iron Deposit in Anshan-Benxi Area
It's becoming more and more challenging to find iron ores with economic values since all iron mines on the surface have been explored.The main directions of iron prospecting turn to the concealed orebodies.In particular,locating and identification of the concealed orebodies in deep(or periphery)parts of the existing mines have become the focus and main challenges of current geophysical exploration projects.With this view,we focus our study on locating and identifying the concealed orebodies in deep(or periphery)structural faults of the existing mines by taking the concealed iron orebodies in Yanqianshan,Anshan-Benxi area as a study case.Based on the previous geology and geophysical studies,we conducted the joint detection application studies by using the ground-based high-precision magnetic method and the transient electromagnetic method,which is based on large fixed source central loop devices and multi-turn overlapping loop devices.The research findings indicate that high-precision ground magnetic methods can delineate the planar boundaries of concealed iron ore bodies,thereby narrowing down prospective mining areas.In the eastern and southwestern sectors of the Yan-qianshan Mountain iron ore deposit,two mineralization prediction zones have been identified.In the eastern a-nomaly zone,transient electromagnetic methods were employed to locate and identify the depth and morphology of concealed iron ore bodies.Through drilling verification,a substantial concealed magnetic iron ore body with a depth of 320 to 410 meters was discovered,exhibiting a stable eastward extension and a gradual thickening trend.Based on these findings,it is inferred that the southwestern anomaly zone,exhibiting similar anomalous characteristics,holds significant exploration potential.The multi-turn overlapping loop device of the transient electromagnetic method has higher resolution than the center loop device and is more suitable for detecting and locating concealed metal ore bodies under the cap layer.
concealed ore bodiesYanqianshan Iron Mineconstruction errorhigh-precision magnetic me-thodtransient electromagnetism
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