GPR Characteristics of Ore-Bearing Layered Igneous Bodies

For many geological materials, the magnetic properties of the constituent parts are often considered unimportant when compared to their ‘dielectric’ characteristics (i.e., the permittivity and conductivity). However, if significant amounts of iron sulphide and/or magnetic minerals exist (such as magnetite, pyrrhotite, etc|) then the EM relaxation phenomena of these minerals can have a noticeable effect on the GPR wave’s attenuation and propagation velocity. Both surface and borehole-based GPRs have been successfully used to delineate and map layered igneous ore bodies but subtle, natural, variations in magnetite/ore mineral composition, grain size and mineral fabric can all have an effect on the nature of the GPR responses. In this paper, we present the latest findings of a measurement and analysis study on the GPR-related apparent permittivity, attenuation and propagation velocity characteristics of a range of natural occurring, magnetite/ore-rich igneous samples collected from the Bushveld complex, South Africa.