辽宁省鞍山-本溪地区深部磁铁矿多尺度勘探技术应用研究OA

This study aims to locate deep concealed magnetite ore bodies in the Xiaolingzi iron mine of the Anshan-Benxi area,Liaoning Province,through integrated geophysical exploration techniques.Addressing challenges such as weak aeromagnetic anomalies,great burial depth of ore bodies,and difficulties in detection using traditional methods in this area,this paper systematically integrates multi-scale exploration approaches,and focuses on the identification of the spatial morphology of deep ore bodies and the precise determination of their occurrence location,thereby providing a technical demonstration for the exploration of similar concealed iron ore deposits in the eastern Liaoning region.Methodologically,the study employed aeromagnetic weak anomaly extraction technology to identify key target areas,and combined with ground high-precision magnetic surveys and gravity measurements to construct a regional field characteristic model.Borehole three-component magnetic survey data were used to invert ore body parameters such as burial depth(approximately 700 m),distance and azimuth from the drillhole(300 m south),and occurrence elements.Magnetic anomaly upward continuation(50～1000 m)was utilized to analyze the variation patterns in the dip of magnetic bodies.The audio-frequency magnetotelluric(AMT)method was introduced for stratigraphic interface identification and structural delineation.Finally,based on constraints from drill core occurrence data(chlorite schist dip angle of 70°),joint gravity-magnetic inversion was performed,and established a parameterized model for density(iron ore body 3.4 g/cm³)and magnetization intensity(50,000 A/m).Three magnetite ore bodies were prospected at depths of 901～1066 m,with a cumulative true thickness of 164 m;Inferred resources of 6097.26 thousand tons were submitted,with predicted prospective resource reserves reaching 115159 thousand tons.A three-dimensional metallogenic model of"basement dome controlling mineralization-faults channeling ore-overlying strata shielding"was established,indicating that the ore bodies occur within the Cigou Formation at the top of the granite basement.The correspondence between high-resistivity anomalies in the AMT profile and the ore-bearing formation was verified.Limitations include a weak gravity anomaly response,insufficient resolution for kilometer-deep ore bodies,and the fact that drillhole ZK1 did not intersect the ore body due to its depth design.The study demonstrates that a multi-technology integrated"borehole-ground-air"collaborative exploration system can effectively overcome the detection bottleneck for concealed iron ore deposits shallower than 1200 m.The combination of aeromagnetic weak anomalies and AMT high-resistivity anomalies serves as an important prospecting indicator for deep Anshan-type iron deposits.Joint gravity-magnetic inversion combined with borehole constraints enables detailed three-dimensional modeling of deep ore bodies.This technical combination holds promotion value within the tectonic belt at the margin of the Eastern Liaoning Craton,which provides a complete technical pathway for similar deep mineral exploration domestically.