Application Of 3D Geophysical Prospecting Technology In Concealed Mineral Exploration

With the development of the economy,China's increasing demand for polymetallic minerals has gradually shifted the focus of exploration from shallow layers to concealed deposits in the middle and deep parts,and the ensuing difficulty in prospecting is increasing.With the increasing difficulty of geological prospecting,China's geological work is gradually entering a three-dimensional model.As an important means of prospecting in the middle and deep parts,geophysical three-dimensional exploration plays an increasingly important role.Based on the comprehensive collection of comprehensive data on the upper leadzinc mine area of Xiagalai Aoyi River,Bishui lead-zinc mine area and Boli Shuangxing copper-gold mine area,three key areas were selected as the research objects.Firstly,carry out three-dimensional direct current method numerical simulation,establish a single anomaly body,two anomaly bodies,Y-type anomaly body models,perform a three-dimensional resistivity forward model,then invert the obtained forward data,compare the inversion model with the theoretical model,and analyze the theoretical model reverse simulation effect.Then,the three-dimensional inversion is performed on the collected measured data to establish a three-dimensional geophysical model of the study area,which include density,susceptibility,resistivity and polarizability.Combined with the geological conditions of the study area,some hidden ore bodies and deep ore bodies are predicted.Finally,the application effect of the comprehensive geophysical prospecting method adopted in three typical mining areas is analyzed,and the three-dimensional geophysical prospecting method is evaluated.The results show that the comprehensive geophysical method adopted in this paper has a good application effect in the skarn orebody in the upper reaches of the Xiagalai Aoyi River,because the skarn deposit is formed by intermediate acid intrusions and carbonate in and near the contact zone.The medium-acid intrusive body has obvious high magnetic susceptibility in terms of magnetic susceptibility.Therefore,granite and granodiorite intrusive bodies can be encircled by high-precision magnetic method measurement;three-dimensional IP measurements are used to obtain high polarizability anomaly,presumably caused by altered marble;in terms of resistivity,both marble and granite are high-resistance,but after mineralization occurs,the metallogenic part becomes low-resistance,so in terms of resistivity corresponding to low resistance.The inversion results of skarn minerals correspond to low resistance,high polarization,and high magnetic susceptibility.According to this feature,a new prediction area is delineated in the upper mining area of Xiagalai Aoyi River.In the Boli Shuangxing porphyry deposit,by analyzing the three-dimensional inversion results of gravity,magnetism and electricity,there is no polarization anomaly in the polarizability in the area where the surface sees the ore,and it is predicted that there is no large porphyry body in the deep part;The anomaly can identify the fault zone,and the low-resistance and high-polarization anomalies in the northeast of the work area can be further studied.In the Bishui hydrothermal metamorphic deposit,the pyrite mineralization in the mining area is relatively strong,and pyrite mineralization can be seen in various rocks in the mining area,but the pyrite mineralization often causes a high polarization rate of more than 7%,and the anomaly of the polarization rate caused by the lead-zinc ore body is between 3% and 7%,the inversion result of the highly polarized area in the Bishui lead-zinc mine area is between 3% and 5.5%,so it is predicted to be caused by the lead-zinc ore body,and this low resistance and high polarization region can be further verified.