Ground pulse EM ? examples of survey results in the search for massive sulphides and new equipment developments

Abstract

Currently ground pulse EM surveys using the Crone PEM system are being used throughout the world in the search for massive sulphide deposits. Survey results from Canada, Arizona, the Sultantate of Oman and Australia demonstrate the ability of the PEM method to delineate in detail a buried conductive target. A detailed PEM survey method using vertical loops has also been developed. This method permits accurate determination of the depth, dip and the location of the edge of a conductive target. The vertical loop PEM method has been found particularly useful when checking and defining deep conductors which produce only marginal anomalies. Under construction at present is a borehole PEM system with a depth capability of 1000 metres. An analog model study of this system has also been recently completed. Examples from this study show how the responses of the borehole PEM system change as the borehole moves from intersection with a conductive target to well outside the target.