Lake Surprise Uranium Project

South Australia – Australia

The Lake Surprise Project Area is located in South Australia, 550km north of Adelaide, and 70km East of Marree. The company holds 3 tenements, EL5892, EL5893, and EL5644 with a total area of 396 km2.

Exploration Licence IDArea (km2)Project Location
EL 589292Lake Arthur East, South Australia
EL 5893167Lake Arthur, South Australia
EL 5644137Canegrass Swamp, South Australia
Adavale Resources Tenements
Map of Lake Surprise Project Locality
Lake Surprise Project Locality

The Lake Surprise tenements cover an area that is prospective for sandstone hosted roll-front uranium mineralization. Strong radiometric anomalies occur in the Project area and uranium minerals have been found in outcrop. Adavale explored the original tenements in this area between 2007 and 2011 with 486 holes drilled in that period. Several geophysical and geochemical anomalies were identified, and two large and continuous geochemical anomalies have been defined by this work. The current tenement holding reflects what the company believes are the best areas that have been explored, and the areas that have the best potential to host additional deposits within geological structures.

Known uranium orebodies on the eastern side of the Flinders Ranges include Beverley, Honeymoon, Goulds Dam and Yarramba, and the Mt Gee project. Several of these projects lie in the northern Flinders Ranges about 60 Km from the Lake Surprise Project area. The Lake Surprise Project area was identified in 2015 by a Geoscience Australia EM survey as an area that potentially hosts similar orebodies to the ones closer to the Flinders Ranges. Rocks of the Flinders Ranges and surrounding areas are highly enriched in uranium due to geological processes and it is amongst the world’s most prolific uranium provinces.

Map of Adavale Resources company prospects
Location of Company Prospects

Targets within the Lake Surprise tenements are within thirty metres of the surface. Several of the sites within the tenements have uranium hosting rocks outcropping as a result of silicification of stream sediments during uranium deposition from artesian water. The standard roll front model only considers reducing-oxidation (redox) conditions in relation to the deposition of uranium. The proposed model for Lake Surprise incorporates additional input of uranium and other chemical species from artesian springs.

The Jubilee Prospect

The Jubilee Prospect lies in the northern part of EL5893 and contains zones of strong uranium enrichment that lie within a north-trending paleochannel system. The main features of the paleochannel system are as follows:

  • It is a continuous geochemical anomaly of 1900m length x 50m width at approximately 200ppm eU3O8. This is predominantly based on gamma logging with limited geochemical analysis from handheld equipment.
Map of Jubilee gamma anomaly
Location of Jubilee Downhole Gamma Anomaly
  • The system contains an equivalent U3O8 concentration downhole up to 611 ppm (0.06%) calculated by calibration of gamma logs against Handheld XRF analysis of diamond drill core.
  • Drill logs, downhole gamma and geochemistry indicate the uranium is locked in silcrete and sandstone up to 2m thick.
  • Additional infill drilling, downhole logging and geochemical analysis is required to confirm the current findings.
  • An overlying gamma anomaly is present in airborne data, indicating the system is within 1m of the surface – this is the smaller and weaker of two gamma anomalies in the area.
  • Larger gamma anomaly to the south is approximately 8km in length and 1.5km at its widest point.
  • Southern anomaly is to be better constrained by ground gamma survey and rock chip analysis with the aim of developing a targeted drilling program to define a previously unrecognised portion of the system.
  • Previous rock chip analysis returned values up to 7000 ppm uranium using hand-held XRF on silcrete samples with visible carnotite mineralisation.
Map of surface anomalies in Jubilee and Jubilee South
Jubilee and Jubilee South Surface Anomalies

The Mookwarinna Prospect

The Mookwarinna Prospect is in the south-central part of EL5893 and has widely spaced drill-holes defining a broad anomalous zone of uranium enrichment. Downhole gamma is recorded in five drill-holes within a zone about 9km in strike length. This zone appears to wrap around the southern margin of a local structural downwarp within the Clayton Basin sequence. Work so far on the prospect has identified:

  • A geochemical and geophysical anomaly between adjacent drill holes, with downhole uranium estimated up to 500ppm equivalent uranium.
  • A potential zone of enrichment with a depth of less than 35m that could be ideal for open pit mining and heap leach extraction.
  • Additional uranium is likely present in a state of disequilibrium, so the potential contained uranium is probably underestimated from the downhole gamma. Future infill drilling and chemical analysis along with downhole logging will confirm this.

Canegrass Swamp Prospect

The Canegrass Swamp prospect was identified as a potential host for uranium that is underlying recently transported sediments to the south of the Jubilee and Mookwarinna Prospects. This prospect lies under the southern portion of EL5892 and completely underlies EL5644. The characteristics of the tenement that make it a good exploration target are:

  • Shallow down-warped fold system is present acting as a potential host for the recent transport of uranium in groundwater or uranium transported from the primary source in the Flinders Ranges when the quartz sands forming the Jubilee Deposit and Mookwarinna Deposit were emplaced.
  • Deposits present in this structure will likely share similarities with Mookwarinna and be buried to approximately 35m.
  • Small surface gamma anomalies around the edge of the fold system that indicate uranium is present in outcropping silcrete and sediment in small quantities.
  • Recent sediments that have been transported to cover the basin in the last 2 million years will mask stronger gamma anomalies, meaning gamma surveys are less desirable as target generation for drilling.
  • The area is a good geophysical target that could use an EM survey to generate potential drill targets.
  • Potential host structure is 18km in strike length.
Map of Canegrass Swamp surface geology
Canegrass Swamp Surface Geology and Gamma Anomalies

Note: that the alignment of the boundaries on the above maps is not North – South or East-West. This is to do with the conversion from geographic coordinates to GDA2020 UTM zone 54. These tenements are near the boundary between zone 53 and 54 so the boundaries appear to rotate a little and is a distortion related to projection.