Lake Barlee Project

The Lake Barlee Project covers a portion of the Cainozoic Lake Raeside - Lake Barlee palaeo-drainage system near Gum Well, south west of Ida Valley Homestead in the North Coolgardie Goldfield of Western Australia.

Between 1979 and 1981, previous explorers identified potential uranium targets within the Lake Raeside - Lake Barlee palaeo-drainage. Reconnaissance drilling located anomalous uranium and vanadium assays in groundwater in the drainage system. Values of up to 3,400ppb U and 240ppb V were recorded. Samples of calcareous material from these drill holes assayed between 104 and 194ppm U3O8.

Follow up shallow drilling at 1km spacings confirmed the reconnaissance results with groundwater assays of up to 860ppb U, 400ppb V and 123ppb Mo. Radioactive samples from these drill holes assayed up to 500 ppm U3O8 and outcrops in the same area, some with visible carnotite, a hydrated calcium uranium phosphate, assayed up to 1,600ppm U3O8.

Reverse circulation drilling of a line of six holes at a spacing of 1km south west of Gum Well showed a sequence of Cainozoic sediments, up to 80 metres thick, in the palaeo-drainage channel. Radiometric logging of these sediments confirmed uranium mineralization, and defined anomalous calcareous, ferruginous and carbonaceous horizons. Assays up to 310ppm U3O8 were obtained from calcareous samples and one carbonaceous horizon assayed 121ppm U3O8. Ferruginous zones were not assayed.

A statistical reassessment of the 1980 analytical data shows that chemical disequilibrium is widespread confirming that uranium, vanadium and molybdenum are being actively leached and are migrating through the drainage channel. However, south west of Ida Valley Homestead, where the drainage channel has been restricted by the ridge of Achaean rocks forming Dead Camel Hill, the chemistry approaches equilibrium suggesting a relatively stable environment.

Processed radiometric data outlines uranium anomalies in the Cainozoic sediments and the Achaean granites. The highest responses in the Cainozoic sediments occur north and south west of Gum Well. One peak is coincident with an exposure of calcrete which assayed 1600ppm, but other high responses, covering an area of 1.5 square km north and south of Gum Well, 2.5km south southwest and 4.5km south east of Gum Well are untested. Many spot anomalies occur throughout the sand and talus covered areas suggesting the radiometric response from the underlying Cainozoic sediments is partially masked by Recent cover.