The majority of deposits of Chengmenshan Copper Mine, which is surrounded by lake on three sides, lie in the bottom of the lake and the geological condition of the formation is complicated. For the consideration of more efficient and safer exploitation, parts of lake have been backfilled on the second phase project. In order to figure out the geological structure of deep stratum as well as the thickness of backfilled soil and lake-bottom silt, EH-4 electromagnetic image system was used to investigate the geological condition of mining area near the lake. The distribution of the low resistance body was found out through data processing and interpretation. The engineering practice achieves the purpose of identifying the weak structure in the region and it is a foundation for safe mining in the future.


Based on the fact tha affected by geomagnetic field, magnetic reflected waves of the formations with different properties are different (Chen 2009).1t is possible to invert the geological magnetic characteristics difference between different formation lithology through the measurement of reflected magnetic fields of different depth formation underground. Electric magnetic image system can collect magnetotelluric waves to calculate resistivity or conductivity and the abnormal body in the formation underground can then be identified through processing and analysis. Based on the magnetotelluric theory, this system belongs to magnetotelluric system combining artificial magnetic field with natural magnetic field and it is currently the most advanced method of electromagnetic prospecting methods (Wang & Wang 2003). Soft formations include geological structures such as fault fracture zone, karst cave, weak zone and water-rich zone etc. In the highly weathered zone, the underground soft structure would threaten the stability of slope engineering and underground engineering. It is significant for project's stability analysis and management to identify the geological condition of unknown soft structure in neighboring zone of lake using EH-4 electromagnetic image system.

This content is only available via PDF.
You can access this article if you purchase or spend a download.