The Yilgarn Craton contains a number of playas which are prospective for lithium enriched brines. In a review of Australian playas by Geoscience Australia, the Yilgarn Craton was identified as one of several regions ranked favourably to host lithium enriched brines. Lake Dundas (E63/1804) and Lake Cowan (E15/15320) were highlighted as having the highest lithium concentrations in Australia, with Lake Tay (E74/596) also noted to have elevated lithium levels
WML has six tenements located over Lakes Tay (lithium values 50x seawater), Sharpe (lithium values 50x seawater), Dundas (lithium values 90x seawater), Cowan (lithium values 90x seawater), Dumbleyung (surrounded by felsic rocks) and Binneringie (adjacent to Cowan).
Lake Tay and Sharpe (E74/596 and E74/598)
The Lake Tay and Lake Sharpe Project comprises two tenements totalling 152km2. Located north east of Mount Cattlin, there are abundant felsic volcanic source rocks surrounding this closed basin system, elevated salinity levels and good hydrogeological connectivity all favourable for lithium brine enrichment.
There is a strong K-U-Th anomaly in the northern part of Lake Tay which warrants further investigation (Figure 2). Previous exploration has been restricted to copper, nickel, gold and uranium.
Lake Dundas (E63/1804)
As part of the acquisition of the Lake Dundas Project (EL63/1804) on 5th March 2018, the Company acquired 10 tenements and tenement applications in Western Australia that are prospective for hard-rock lithium and lithium brines.
The Lake Dundas Project is located approximately 160 km south-south-east of Kalgoorlie in the Dundas Mineral Field in Western Australia. The tenement covers the north-eastern portion of Lake Dundas and is underlain by Archean granite, granitic gneiss and minor mafic intrusive rocks.
A recent review of open file information identified a significant lithium-beryllium anomaly (peak values of 71.4 ppm lithium and 4.4 ppm beryllium) adjacent to and within WML’s EL63/1804. The lithium-beryllium anomaly was identified from a comprehensive soil auger sampling program conducted by AngloGold Ashanti Australia in 2000 consisting of over 7,212 samples.
The presence of such a pronounced lithium and beryllium anomaly in the north-eastern portion of the tenement suggests that hard-rock lithium-pegmatites might be present on the edge and potentially under the lake.
Based on work previously conducted by Geoscience Australia that highlighted Lake Dundas as having one of the highest lithium concentrations (93-149ppm) in Australia, the Project demonstrates the potential to host lithium brines.
Lake Dundas has many of the elements that producing lithium brine deposits share, namely:
- occurs in an arid climate
- is part of a closed basin
- has experienced tectonically driven subsidence
- has associated igneous or geothermal activity
- has suitable lithium source rocks
- has one or more aquifers
- sufficient time to concentrate a brine
Lake Dumbleyung (E70/4870)
E70/4870 is located approximately 220km south east of Perth, covering approximately 86km2 over Lake Dumbleyung. Exploration to date has focused on gold with only recent interest in the lithium brine potential.
In 2007, Reward Minerals reported a composite brine sample from Lake Dumbleyung returning 530mg/l (530ppm) Lithium.
Lake Cowan (E15/1532)
E15/1532 lies on the boundary of Lake Cowan. Geoscience Australia has assigned the highest possible lithium prospectivity ranking to Lake Cowan with groundwater lithium levels being 90x that of sea water.
The tenement is also prospective hard rock lithium due to its proximity with the Bald Hill Lithium-Tantalum mine which has a reported Indicated and Inferred Mineral Resource estimate of 12.8Mt at 1.18% Li2O and 158ppm Ta2O5.
The Lake Cowan tenement is also prospective for gold and potash.
The Binneringie Project
In May, WML announced it had secured the Binneringie project, located along the northern shore of Lake Cowan and the western margin of a NNW trending Archaean Greenstone Belt (the Norseman-Wiluna Belt), in the Kambalda Domain of the Eastern Goldfields in Western Australia. Binneringie is located adjacent to WML’s existing Lake Cowan tenement and substantially increases the Company’s landholding in an area considered highly prospective for hard-rock lithium deposits.
On a regional scale the Kambalda Domain’s gold endowment is considerable, hosting the largest gold mines in the region, including the Golden Mile, New Celebration and the St Ives Gold Mines. The area is underlain by a sequence of strongly folded and faulted metamorphosed Archaean volcanics and intrusives, which have been intruded by Archaean granitoids and Proterozoic gabbro/dolerite dykes (the largest being the Binneringie Dyke which cuts through the project area).
The 50 km2 project area is under explored, and there is no record of systematic lithium focused exploration in the project area.
Pegmatite hosted mineralization at Bald Hill lithium-tantalum mine is located approximately 15km to the east of the proposed tenure and has a maiden Indicated and Inferred Mineral Resource estimate of 12.8Mt at 1.18% Li2O and 158ppm Ta2O5 at a 0.5% Li2O cut-off (Tawana website).
Based on proximity to Bald Hill and references by GSWA (2008) to the abundance of pegmatite dykes, WML considers that there is potential for hard rock pegmatite hosted mineralisation, warranting further investigation.