Uranium – Lake Surprise, South Australia

Lake Surprise

South Australia — Australia

The Project Area is in South Australia, is situated 550 Km north of Adelaide, 70 Km East of Marree and covers 2705 Km2 on the northern flank of the Flinders Ranges.

Map of Adavale's South Australia tenements
Adavale Resources Tenement Locations

The Lake Surprise tenements cover an area that is prospective for surficial and sandstone style uranium mineralization. Strong radiometric anomalies occur in the Project area and uranium minerals have been found.

Known uranium orebodies on the eastern side of the Flinders Ranges include Beverley, Honeymoon, Goulds Dam and Yarramba and the Mt Gee project lies in the northern Flinders Ranges about 60 Km from the Lake Surprise Project area.

Rocks of the Flinders Ranges and surrounding areas are highly uraniferous and it is amongst the world’s most prolific uranium provinces.

The targets are surficial uranium ore bodies in a number of suitable host rocks, and roll front style orebodies developed in both Tertiary and Mesozoic host rocks.

A model similar to that being used by Eromanga Uranium is applicable to the Project area. The standard roll front model only considers reducing-oxidation (redox) conditions in relation to the solubilisation and the precipitation of uranium. The proposed model incorporates additional physicochemical processes that influence the equilibrium between soluble and precipitated uranium. It also incorporates the input of uranium and other chemical species from artesian springs.

The Jubilee Prospect

The Jubilee Prospect contains fourteen potentially economic ore blocks that lie within a north-trending, sinuous, quartzose palaeochannel system. These blocks have eU3O8 concentrations of greater than 100ppm reaching a maximum of 611ppm and have thicknesses greater than 0.5m. The deposits comprise a mixture of unconformity, sheet-like or roll-front style deposits that in places crop out and extend to depths to about 25m below the ground surface and lie within a sinuous palaeochannel that is more than 2km in length. This channel has tributary branches and segments that are undrilled and in places are open in several directions. The palaeochannel system contains fine to coarse grained quartzose sandstone and minor siltstone. Most of the uranium, including occurrences of visible carnotite, is held within hardened silicified sandstone and silcrete layers. Adavale has made a preliminary assessment as to the quantity of uranium present from a study estimating equivalent uranium present through analyses of gamma ray logs of drill-holes. This assessment cannot be accurately completed due to relatively few geochemical analyses that were undertaken and because some uranium may not have responded as radioactive anomalies in the gamma ray logs, due to the probable disequilibrium state of recently groundwater-precipitated uranium. The Board recognises the potential economic significance of this area and has received a report recommending an infill drilling plan to further explore and upgrade knowledge of the uranium resources of this prospect.

The Mookwarinna Prospect

The Mookwarinna Prospect lies in the south-central part of EL 5893 and has widely spaced drill-holes on an approximate 1km grid spacing. A broad anomalous zone of uranium enrichment is recorded in five drill-holes within a zone about 6km in strike length which appears to wrap around the southern margin of a local, structural downwarp within the Clayton Basin sequence. An area of about 300 X 400m was subjected to a ground spectrometer survey and infill drilling of six gamma-ray logged holes and contains anomalous uranium above the 100ppm cut-off grade in layers up to 3.25m in thickness. The deposits are shallow and in places lie just below the surficial sand cover to depths of about 20m. It is likely that the uraniferous granites in the Flinders Range is the likely source and the proximity to this terrain may indicate that the uranium deposits could be more extensive than those located further north in the Jubilee Prospect. A programme of closer-spaced drilling, gamma-ray logging, XRF and geochemical analyses of core and cuttings, has been designed for this area.