The Que River TEM case-study

Abstract

Several years after the combined geophysical-geochemical discovery of the Que River gold-silver base-metal deposit in the Mt Read Volcanics of Tasmania, experimental SIROTEM and UTEM surveys were completed with the aim of determining their effectiveness in the search for similar volcanogenic ore types. Of the two main mineralized ore lenses at Que River, only the subcropping, copper-rich S lens was clearly detected by both surveys. This lens had previously been detected by AEM and FEM surveys during the discovery program. On the other hand, the deeper lead-zinc-rich P lens, not previously detected by AEM and FEM surveys, nor recognized in the SIROTEM data, appears to have been detected by the UTEM survey. Furthermore an interpretation of the decay character of the P lens UTEM anomaly suggests that this lens has a greater conductance than the shallow S lens. Possible explanations for the lack of a distinctive SIROTEM response over the P lens are in-adequate spatial resolution and poor coupling of the coincident loop geometry with the deeper, more steeply dipping mineralization.