The Duke rare earth project is located 50 km north-west of Tennant Creek, 25 km west of the Stuart Highway, and on the Darwin-Adelaide rail line. It comprises two exploration licences EL33101 and EL33194 covering a combined area of 255 km2 on the Phillip Creek pastoral lease.
Outcrop on the project comprises faulted metasedimentary rocks of the Tomkinson and Warramunga provinces of the Tennant Region, separated by an unconformity, and the Warrego Granite.
The Duke area has been worked for ironstone-hosted gold-copper-bismuth, IOCG and unconformity-related uranium, but not for rare earths.
The project is being explored by HRE for heavy rare earths (HREE) in unconformity-related hydrothermally-altered breccias and quartz veins as at Browns Range in Western Australia (Browns Range mineral resources: 9.24 Mt @ 0.67% TREO). A secondary target for exploration is HREE-enriched ion-adsorption clay-type mineralisation hosted in regolith developed on the extensive but poorly outcropping Warrego Granite.
A reconnaissance visit to the project area by HRE in April 2023 yielded promising rare earth assays of up to 732 ppm TREO in historic drill core samples from the Warrego Granite and in rock chips. Encouraged by these results, a 470-sample soil survey was completed in August 2023 over a 23 km2 area of airborne thorium anomalism and a Cu-Bi-Au soil anomaly identified in previous exploration but never drilled.
Assays from the soil program reveal a sizeable area of rare earth anomalism that is contiguous with rare earths in saprolitic Warrego Granite intersected in historic percussion drilling (e.g. 42 m @ 770 ppm TREO from 8 m depth). The new soil data also confirm and extend the Cu-Bi-Au soil anomaly.
For more information about the Duke project, see here.