ANALYTIC MODELS FOR THE INTERPRETATION OF ELECTRICAL SURVEYS USING BURIED CURRENT ELECTRODES

Abstract

The IP response and the apparent resistivity resulting from a buried current pole in the presence of a stratigraphic target and a three‐dimensional target have been studied. The targets were modeled using a layered model to simulate the stratigraphic target and a buried sphere model to simulate the three‐dimensional target. The results show that there is a substantial increase in the response of the target measured at the surface for current electrode depths of greater than half the depth to the top of the target. A larger anomalous response is of particular importance when dealing with deeply buried targets from which little or no response is measured using conventional surface electrode methods. Furthermore, the results indicate that a survey around a drill hole containing a current electrode can be used to outline mineralization in the immediate vicinity of the drill hole. Some empirical observations resulting from our study are presented which relate the lateral offset of the target from the drill hole and its depth to characteristics of the anomaly pattern as measured on the surface.