Advanced Application of Electrical Survey Technology in Metal Ore Exploration

SUMMARY:

Electrical survey technology demonstrates favorable exploration effectiveness in locating concealed ore bodies and can be applied in areas heavily covered by vegetation. Moreover, compared to ordinary surrounding rocks, silicified rock formations exhibit significantly high resistivity anomalies, particularly in regions with quartz veins where electrical anomalies are pronounced.

CONCEPT:

After thousands of years of crustal movements, rock layers are formed through compression and tearing, giving rise to ore bodies and rock formations. These ore bodies and rock formations exhibit varying electromagnetic and electrochemical properties at different depths and structures, allowing for the inference of the geological structure and ore deposit locations in a region through the analysis of these attributes. Electrical survey technology is a common geophysical exploration method that primarily involves analyzing the electrochemical and electromagnetic properties of rocks and ore bodies within the strata to determine the structural characteristics and spatial distribution of ore bodies and rock formations, providing technical support for mineral resource development. Electrical survey technology is highly applicable in the exploration of metal ores, groundwater, and non-metallic minerals, playing a crucial role in mineral resource exploration. Particularly in the exploration of metal ores, this technology can be used to explore some concealed ore deposits. In general, the metal within a single ore body does not cause electrical anomalies, whereas sulfides and magnetic materials often accompany metals in gold ores, resulting in electrical anomalies. When conducting exploration using electrical survey technology, the position of ore deposits can be determined by detecting significant electrical field differences between gold-bearing minerals and rock formations, and estimating mineral resource reserves based on exploration data.

Investigation case of alteration rock type gold mine：

1.Case background

In 2019, a geological exploration research institute initiated mineral resource survey and exploration work in the northeastern region of China. Based on the actual survey results and mineral resource investigation, Area A was identified as a key exploration area for altered rock-type gold deposits. However, due to the extensive surface coverage in the area, including large areas of vegetation and farmland, conventional geological exploration and geochemical exploration techniques have struggled to achieve satisfactory exploration results. Therefore, the exploration team utilized induced polarization equipment and applied electrical survey technology to search for mineral veins during the exploration work.

2. Mineralization background

Area A is situated in the western slope region of the mid-section of a large mountain range in northeastern China. The geological structure of this area consists of Mesozoic volcanic rocks and belongs to the southeastern accretionary zone of the Siberian margin. The mineralization zone is located within the Yanshan period iron, zinc, tungsten, gold, and lead mineralization belt. 

3.Geological characteristics analysis

(1) Stratum characteristics:After preliminary exploration, the exposed strata in area A are mainly composed of gray siltstone and conglomerate sandstone, some of which are limonatized and yellow-brown. Individual areas are filled with fine quartz veins.

(2) Structural characteristics:There are two fault zones on the north side of area A, and the fault zones meet at one point. See Figure 1 for details.

  Figure 1: Schematic diagram of regional geological structure

Based on the information provided in the diagram, it can be understood that the region possesses well-developed fault structures and is influenced by crustal movements, indicating the potential for abundant mineral resources and ore-bearing space. Due to the influence of structural fractured zones on ore bodies in the area, the northern side features primary faults, with gold deposits located within silicified structural breccia layers. Following the examination of rock samples by technical personnel in the region, it was determined that the Au grade in the area reaches as high as 0.758g/t, further confirming the presence of rich gold ore bodies in the region.