Location: Wudinna region, central-northern Eyre Peninsula and south east of Kimba Geological Province: Gawler Craton Commodity: Uranium (Base Metals) Ground Holding: 9 ELs totalling ~4770 square kilometres Status: Adelaide Resources 100%; EL 3564 90%, with option for 100%
Project Summary
The Wudinna Basement Uranium Project is targeting uranium in the Archaean-Proterozoic basement rocks in the tenements outside the Quasar Joint Venture. It is a 100% (90%)-owned initiative by Adelaide Resources, and is building on the previous gold-copper exploration conducted by the company in the district since 1997.
The uranium exploration potential of the basement rocks of this region have received very little attention in the past, and has resulted in only scattered analytical data as a by-product of previous work. The most useful result was a limited data set that showed that some phases of the Hiltaba Granite intrusives in this region were unusually enriched in uranium, (up to 20 ppm U).
In 2004, detailed airborne magnetic and radiometric surveys were flown over a portion of the project area as part a previous joint venture targeting gold in the basement. This delineated several subtle uranium channel anomalies in areas with regolith and sand cover over deeply weathered basement granite and gneiss. These have been targeted as potential surface expressions of underlying uranium mineralisation.
The Ulysses and KO11 South targets have undergone initial drill testing. The first phase of RAB drilling conducted in 2007 intersected anomalous uranium at both localities, disposed as relatively flat lying secondary plumes in the lower saprolite weathering zone. Additional drill testing as carried out early in 2008, returning further highly anomalous values, up to 6 metres at 342 ppm U3O8 (including 1 metre at 488 ppm U3O8) from Ulysses, and 3 metres at 341 ppm U3O8 (including 1 metre at 613 ppm U3O8) from KO11 South. Both of these targets are associated with nearby Hiltaba Granite intrusives, and the second drilling phase at Ulysses has expanded the anomaly ‘footprint’ to an area of approximately 1.5 x 1.0 kms, still open to the east and south. At Ulysses, the anomalous values observed are interpreted to represent both weathered primary mineralisation, as well as secondary remobilised uranium in the weathering zone.
These promising results are believed to be convincing evidence that there is potential for significant bedrock-hosted uranium mineralisation in this region, possibly representing the uranium-rich end member of the IOCG(U) family of deposits known elsewhere in the Gawler Craton. The company is continuing its exploration of these two prospects, and plans to extend the program to investigate several additional radiometric anomalies of similar character in the region.
The Yalanda Hill project (EL 3473) is located around 90 km south west of Whyalla, and 28 km south east of Kimba township. The main exploration target is uranium mineralisation in the Proterozoic basement rocks of the Gawler Craton in this region.
From 1991 to 1996 exploration in the region by Pasminco targeted base metals associated with the Hutchison Group, including airborne magnetic and radiometric surveys carried out in 1991. Little attention was paid to the radiometric data at the time, and in due course it was filed in PIRSA’s Open File data repository. In early 2006 the company retrieved and re-processed this data, and identified several radiometric anomalies within EL 3473 for follow up investigation.
The Ethiopia Target was defined by a strong combined uranium (U) and thorium (Th) signature, with follow up surface sampling returning 36 ppm U and 220 ppm Th associated with the unconformity between the basal Warrow Quartzite of the Hutchison Group and the underlying Miltalie Gneiss. An initial RAB drill test was supported by PACE funding, with anomalous uranium up to 42 ppm U and thorium up to 120 ppm Th from fresh and weathered bedrock.
Follow up of other combined U and Th anomalies has identified several other localised zones with a high radiometric signature. Sample assays returned uranium values up to 0.23% U (2300 ppm U), believed to be associated with local concentrations of monazite and xenotime (U and Th-bearing resistate minerals) in the host gneisses. Further investigation is planned into the potential for accompanying discrete uranium-bearing mineral phases in this environment.
Potential target styles in this terrain include:
Vein style or shear zone hosted uranium, associated with active faulting and shearing during granite emplacement, similar to the primary pitchblende mineralisation in Lincoln Complex gneisses on southern Eyre Peninsula near Port Lincoln.
Disseminated uranium associated with pegmatitic bodies and sheet-like intrusives, similar to ‘Rössing-style’ deposits in Namibia.
