Application of Very Low Frequency (VLF) Electromagnetic method to mineral exploration (Mining Geophysics) with case study review.

Thesis Abstract

The Very Low Frequency Electromagnetic (VLF-EM) method, which enables surveying without contact with the ground, is suitable for ground surveys in a wide area and has been used in mapping geology and in mineral exploration for decades. The technique makes use of signal radiation from military navigation radio transmitters operating in the frequency range of 15-30 kHz. When the electromagnetic wave impinges on the surface it is both reflected back into the air and refracted into the earth. By measuring the shifted reflected magnetic field relative to the primary field, subsurface structures can be constrained. Freely and readily available primary signals anywhere around the earth make the VLF method very convenient and efficient for field data collection. Further, VLF data processing using digital linear filtering is quite accurate and very efficient in depicting the qualitative information about subsurface conductors, even though quantitative interpretation of VLF data is as complex as other EM data interpretation. In this study, various aspect of VLF-EM method such as basic theory, worldwide VLF transmitters, and quantities measured and a case study review of the integrated geophysical exploration for sulphide minerals In the Wadi Sa'al area, south Sinai in Egypt (only the VLF-EM method used in this study were review).