Depth estimation with PEM ? a cautionary note

Abstract

The method advocated by Crone (1977) for determining the position of a "current axis" for a conducting ore body will give a positive result even if there is no ore body. The depth, l, to this axis in a uniform ground of conductivity s and permeability m0 is given by: [see full text for equation]. In this expression t is time and consequently the result can be used to determine the conductivity profile of a nearly uniform ground.