Interpretation of airborne geophysical data over the OK Tedi porphyry copper?gold ore body using image processing techniques

Abstract

In December 1984 a helicopter-borne magnetic/radiometric survey was carried out over a 30 ´ 40 km area surrounding the Ok Tedi porphyry copper?gold deposit (Fig. 1). The aim of the survey was to map the geology utilizing the magnetic and radiometric physical property contrasts between rock types and more specifically to explore for unmapped or buried igneous intrusives, skarns and zones of hydrorhermal alteration which might host gold mineralisation at shallow depth. Two previous helicopter magnetic surveys over the deposit provided limited information due to flight path recovery problems, but did indicate that the igneous intrusives and skarns associated with the deposit were significantly magnetic. No previous radiometric surveys had been carried out.