GEOPHYSICAL MODEL OF IRON DEPOSITS IN FUSHUN REGION OF LIAONING PROVINCE: A Case Study of Maogongpu Iron Mine

Fushun region of Liaoning Province is rich in iron deposits, which belongs to the eastern Liaoning-southern Jilin metallogenic belt with the famous Anshan-Benxi iron deposits. The ore-forming strata of both are Anshan Group, belonging to sedimentary-metamorphic type and obviously controlled by the stratified metamorphic rock series. The Anshan-Benxi area is developed with Cigou and Yingtaoyuan complexes of Anshan Group, while the Fushun-Qingyuan area with Shipeng and Tongshicun complexes of Anshan Group, and both share similar lithologic compositions and geophysical characteristics. Based on the research project of exploration technology for deep blind orebodies, taking Maogongpu iron mine in Fushun as an example, the paper analyzes the gravity-magnetic-electrical characteristics of iron ores, and establishes the geophysical model. The research shows that the gravity-magnetic-electric integrated exploration is feasible and effective other than the traditional exploration by single magnetic survey. Gravity method has unique advantages in horizontal positioning, while electrical/magnetic sounding works well in vertical. The polarization of magnetite is obvious, presented as low resistance and high polarization. The gravity-magnetic-electrical characteristics of iron ores are high magnetic, high density, high polarization and low resistance. The higher the grade is, the greater the polarizability is. The resistivity should not be higher than 2 000 Ωm, polarizability no less than 6%, magnetic susceptibility no less than 100 000×10^-6 SI, and the density higher than 3.00×10³ kg/m³.