Abstract:

Anshan-Benxi Area of Liaoning Province is one of the most important iron resource bases in Northern China. There are various iron-rich orebodies distributed in this area. The studies on the iron-rich ore metallogeny are fruitful for the past decades but the prospecting technology for iron-rich ores is relatively lacking. Based on the discrepancy of physical parameters between the iron-poor and -rich orebodies, we selected surface high-precision magnetic and high-density resistivity methods to perform the comprehensive geophysical exploration of the iron-rich orebodies in the Qidashan iron mine area in Anshan, Liaoning Province. The study results show that the high-precision magnetic method is able to delineate the spatial distribution range of the magnetic anomalies caused by the enriched iron bodies in the magnetic anomaly field with a poor iron grade through limiting the magnetic field intensity at >16,000 nT. The high-density resistivity method can accurately characterize the shape and scale of iron-rich bodies in the high magnetic anomaly field by limiting the resistivity at <2200 Ω·m. This can be considered as a constraint threshold to build a forward and inverse models for the ground magnetic method as to identify and locate the iron-rich bodies in iron-poor ore layers. We also found that the intersection area of the NNW strike and NEE lateral fault in Qidashan iron mine area has a higher potential to form thick and enriched iron orebodies.

Key words: Anshan-Benxi Area, iron-rich mine, high-precision magnetic method, high-density resistivity method, ore identification and location