Application of EH4 in deep concealed rock (ore) body detection: A case study of the Donglufang copper-molybdenum polymetallic deposit, Shangri-la, China

Abstract

This study uses the method of Audio-frequency magnetotelluric sounding (EH4) to detect and analyze the deep geological structure in the Donglifang mining area. The underground spatial electricity and structural characteristics were effectively determined. We built an EH4-based indicator system for localizing ore bodies and summarized the relationship between the apparent resistivity anomalies and the ore bodies in the EH4 profile. The shallow veined or columnar low-resistance bodies may correspond to the low–medium temperature hydrothermal gold, lead, and zinc polymetallic ore bodies; the columnar medium-resistance or medium–low resistance bodies correspond to the silica or porphyry copper–molybdenum polymetallic ore bodies; the medium-resistance bodies correspond to the medium acidic magmatic rocks (porphyrites and porphyries). We identified eleven concealed ore bodies in the deep of the mine area, five of which are consistent with the drill holes, and the remaining six have an excellent prospect of finding ore bodies. It is further inferred that larger-scale porphyry copper–molybdenum ore bodies are formed in the deep rock body. This study proves that the EH4 is an effective geophysical method for finding concealed rock (ore) bodies in the Dongxuofang copper-molybdenum polymetallic mine or this type of deposit.

Keywords

• eh4
• donglufang deposit of yunnan province
• copper–molybdenum polymetallic deposit
• electrical property
• concealed rock (ore) body
• prospecting signs