Exploration for unconformity uranium in Arnhem Land (NT)

Abstract

Since the mid nineties Cameco Australia Pty Ltd (Cameco) has been involved in exploration for unconformity-related uranium deposits in Arnhem Land, Australia. During this time the exploration model has evolved from the initial Athabasca Basin (Canadian) unconformity model. Physical property measurements and orientation programs have led to the current integrated exploration strategy that incorporates the disciplines of geology, geochemistry, and geophysics. Airborne radiometric surveys continue to be the primary tool for identifying near-surface uranium anomalies. However, other geophysical techniques are utilised to aid in mapping basement lithologies, alteration, and the depth of sandstone cover, which are all keys to Cameco's exploration objectives. With these aims in mind, hyperspectral, magnetic, and electromagnetic airborne geophysical techniques have been extensively utilised as efficient methods for quickly evaluating large areas, where rugged topography prevents effective use of ground techniques. Examples from Cameco's King River project, located in northwest Arnhem Land, show that integration of airborne electromagnetics, and hyperspectral surveys, is a significant factor in improving the exploration process.