Tomographic processing of the measurement results allows obtaining an image of changes in various geoelectric parameters in the cross-hole
space. Such images can be useful when laying additional boreholes for drilling, help identifying potentially dangerous sites for development at an early
stage, and promptly determine the economic efficiency of the mining projects at the planning stage.
Historically, the method of radiofrequency survey was applied for the detection of inhomogeneities in coal seams. In addition, the method served to increase
safety during production, by pointing to the occurrence of water or gas pockets near coal seams. Later, the method was used at ore deposits, where the
survey targets are characterized by a low resistivity and are surrounded by the high-resistivity rocks. The method was successfully applied at the major ore
deposits in Russia, Europe, North America, South America and Australia.
The method of Radio Imaging (RIM) is applied to study the
geological structures between boreholes using a high-frequency
The Radio Imaging method is based on different degrees of
absorption of electromagnetic energy during radio waves passage
through rocks. In most cases, the absorption degree of radio waves
is determined by the electrical conductivity of rocks, since other
parameters - dielectric and magnetic permeability - vary within a
small range. Absorption of electrical energy increases with
increasing electrical conductivity of rocks. Ore bodies with a high
electrical conductivity, and other high-conductivity bodies, act as
screens for the passing radio waves creating an anomalous effect
which shows up as a decreasing electromagnetic field intensity.
The greatest attenuation occurs when electromagnetic energy
passes through massive ores composed of sulphides, magnetite
and other high-conductivity minerals. The anomalous effect depends
not only on the electromagnetic properties of rocks and ores, but
also on the thickness and linear dimensions of the bodies, the
applied sounding frequency and the distance between the
transmitter and the receiver.