Application Of Very Low Frequency-Electromagnetic Method On Fluorite Mine Exploration In Shallow Covered Area Of Chi Feng, Inner Mongolia

The research area is located in the shallow covered area in Chi Feng, Inner Mongolia, where the metallogenetic condition and the favorable prospect of finding fluorite mine are both quite advantageous. In the area, the Quaternary cover is extensive, so it is hard for the fluorite mine exploration. The VLF-EM is a kind of geophysical exploration method which is convenient, shortcut and effective. The article selects the typical fluorite deposits in the area, taking the VLF-EM method efficacy trial and the dissemination. Here are the major acquaintanceships:1. The research area is widely covered by the Quaternary loess, but not deep. The electric resistivity and the magnetic susceptibility between ore body and wall rock are enormous differently. In the article, Saiboluogoumen deposit is accomplished as the trial deposit, and the result reflects that the VLF-EM abnormality and the orebody are dovetailed, and the abnormality also reflects the fault structure. Taking all factors into consideration, the method can be applied in the area.2. The VLF-EM has different reflects for the different geologic body:the abnormality value of the fault zone is higher than the value of the fault zone with fluorite orebody; the value of fault with fluorite is higher than the fault with the quartz vein. But the quartz vein has no obvious abnormality in Saiboluogoumen fluorite deposit.3. In the other deposits, the method also has good application effect:in Elimutai fluorite deposit, a strip of low resistance zone is newly found, and a small zone near it. The big one has almost SN trend, and mineralization alteration belt on the surface is corresponded with it, the length of the zone is about1km, indicating the favorable prospect of finding fluorite ore; in Madaigou fluorite deposit, the result reflects that the forecast lode may has more2.5km extend; in Xiaosijia fluorite deposit, the result shows that there are two fault zones distributed parallel. Their trend is nearly SN, and the length is longer than1km, showing the quite advantageous of fluorite prospect.