The Peranbye Project is approximately 300km north of Perth close to the agricultural towns of Morawa and Perenjori and covers the drainage and tributaries that drain south and westwards through Lakes Moore, Monger and Weelhamby, terminating in the Yarra Yarra Lakes near Three Springs.
The Project comprises four granted Exploration Licences and three EL applications, covering an area of 1,442km2. The area is extensively covered by alluvial, colluvial, calcrete, and lacustrine deposits associated with the Moore, Monger and Weelhamby drainage systems. The depth of the cover sediments generally ranges from a few metres up to an estimated 80m.
Following public release of the airborne geophysical survey data covering the Murgoo, Yalgoo and Perenjori mapsheets in February 2012 by the Geological Survey of Western Australian, Enterprise Metals Limited identified uranium anomalies in the data which were related to the major drainage systems and were often associated with mapped calcrete.
The EL applications were lodged and selected airborne radiometric anomalies were prioritised for follow-up with ground radiometrics and bulk soil sampling. The highest and most consistent spectrometer results were found at anomaly YG1 and eight bulk soil samples returned laboratory assays of up to 504 ppm U. The anomalous samples were associated with either gypsiferous clay, clay with calcrete nodules, or calcrete rubble.
Significant anomalous U responses in spectrometer readings were also found at the PJ3 anomaly. The highest laboratory assay from bulk soil samples was 555 ppm U, with other strongly anomalous samples, including 406 ppm U. All the anomalous samples were associated with gypsiferous lacustrine clay.
The lowest assay result of the soil sampling of 2 ppm U was collected from the shoreline of Mongers Lake.
The extensive surface U anomalism confirms the movement of significant amounts of U through the palaeodrainage systems and suggests that with the appropriate trap site a significant deposit might be formed. An AEM survey completed in June 2012 confirmed the presence of extensive and deep palaeochannels below the present day lake and river systems. In several cases these directly correlate with uranium anomalies detected from the airborne radiometric survey data.
Figure 1: Peranbye Project local geology dominated by drainage areas.