Goldfields region, Western Australia
Lithium Australia NL (‘LIT’) has agreements with Focus Minerals Limited (the Coolgardie Rare Metals Venture) and Cazaly Resources Limited (Goldfields Lithium Alliance) to explore lithium prospective holdings in the southern Goldfields of Western Australia (see Figure 1). The area contains extensive pegmatite swarms and has a long history of tantalum mining.
Coolgardie Rare Metals Venture
In September 2014, LIT announced the commencement of the Coolgardie Rare Metals Venture (‘CRMV’), a joint initiative with Focus Minerals Limited. The initiative will evaluate lithium and rare metals (cesium, rubidium, gallium, tantalum, niobium) within 20 prospecting licences and two mining leases located to the south of Coolgardie.
Under the terms of the venture, LIT will sole fund exploration to the point of committing to a definitive feasibility study within five years of the commencement date, at which time the CRMV will be replaced by a contributing joint venture (80% LIT, 20% Focus Minerals Limited).
The CRMV tenure covers pegmatite swarms known to contain lepidolite (lithium mica), petalite (lithium aluminum silicate), tantalite (an oxide of iron, manganese and tantalum), pollucite (cesium zeolite), beryl (beryllium silicate) and other minerals that may be of commercial importance. The lepidolite is most abundant at Lepidolite Hill, where, in addition to lithium, the mica contains high concentrations of rubidium. The CRMV also covers Tantalum Hill, a well-documented tantalite occurrence.
Exploration and evaluation
Fieldwork commenced in September 2014, the focus being Lepidolite Hill, where mining during the period 1971-73 resulted in an open pit 150 metres (‘m’) long, 60 m wide and 15 m deep. Spoil from the pit is dumped nearby. It contains abundant lithium minerals, bulk samples of which were collected and dispatched to Perth for evaluation of lithium and rare metals (cesium, rubidium, gallium, tantalum and niobium).
In order to determine the lithium, rubidium and potassium grades in material rejected by prior mining operations, the samples were crushed, homogenised and subjected to flotation to produce a lepidolite concentrate. Initial indicative test work produced encouraging results, in that the flotation concentrate contained the following.
- Li2O 3.34%
- Rb2O 2.34%
- K2O 8.21%
In August 2015, lepidolite from the dumps at Lepidolite Hill was used as feed material in a 10-day continuous mini-plant processing trial completed at a Perth laboratory. The trial was conducted using processing technology licensed to LIT. It led to the production of a total of 7.7 kilograms (‘kg’) of high-purity lithium carbonate (99.57% pure), with 94% recovery from leach liquor.
In September and October 2016, LIT announced that ANSTO Minerals (a division of the Australian Nuclear Science and Technology Organisation) had successfully applied the Sileach™ process to extract lithium from lepidolite ore from Lepidolite Hill. The pilot plant operated robustly, producing 6 kg of ~99% purity lithium carbonate concentrate (see Figure 2). It also provided further engineering design data for the Sileach™ process.
Soil geochemistry was undertaken in areas around the Lepidolite Hill workings in the latter part of 2015. Using a Niton field-portable X-ray fluorescence device (XL3T), pathfinder elements were successfully trialled to indicate prospectivity (lithium cannot be detected by field-portable XRF). Highly anomalous indicators are strongly suggestive of the potential for repetitions of lithium-rich pegmatite mineralisation well beyond the historical boundaries of the mine and the dumps (see Figure 3).
In early 2016, LIT submitted a Programme of Works (‘PoW’) for approval by the Western Australian Department of Mines and Petroleum. The PoW is the first stage in recovering about 1,500 tonnes (‘t’) of lepidolite from the Lepidolite Hill workings for further metallurgical testing.
Goldfields Lithium Alliance
In May 2016, LIT and Cazaly Resources Limited (‘Cazaly’) announced the formation of the Goldfields Lithium Alliance (‘GLiA’), which combines their present and future lithium mineral interests within a 100-km radius of Kalgoorlie for an initial period of 5 years (see Figure 1 above). The GLiA significantly enhances the technical and land management resources available to advance lithium projects within the Goldfields region.
Equity in the GLiA will be 50% LIT and 50% Cazaly. By incorporating all Cazaly and LIT interests within the designated area, the GLiA provides LIT with immediate access to further prospective ground, including the following projects.
- Coolgardie project – the GLiA includes Cazaly’s Kangaroo Hill tenements, which adjoin the CRMV. Cazaly’s recently completed reconnaissance fieldwork over the project confirmed the presence of pegmatites within the tenements. However, surficial cover in the area prevents any clear indication of their true size and extent. Evaluation of these pegmatite bodies can be challenging, due to their mineral zonation and variation in mineral assemblages. LIT plans to complete more detailed work over the project when access is finalised and all data from previous exploration has been collated.
- Widgiemooltha project – in July 2016, LIT and Cazaly announced their acquisition of the rights to ‘pegmatite minerals’ in the Widgiemooltha pegmatite field, located ~45 km southeast of Coolgardie in the eastern Goldfields and 25 km south of the globally significant Mount Marion lithium project, jointly owned by Mineral Resources Limited, Neometals Ltd and Chinese lithium producer Jiangxi Ganfeng Lithium Co., Ltd.
Covering approximately 81 km2, the project area has not been explored for lithium to date, despite hosting extensive pegmatites (identified by the Geological Survey of Western Australia). The pegmatites are part of a significant regional dyke swarm.
The GLiA has implemented data searches and desktop studies and is undertaking initial fieldwork to test the potential of the several mapped pegmatite occurrences at the project. Early investigations confirm that the exposed pegmatites extend for ~1.8 km. Aerial photography suggests the area has potential for several other pegmatite bodies not mapped so far. Further fieldwork – including geological mapping, geochemical surveys and rock-chip sampling, to help determine the extent of the pegmatites and their potential to host significant lithium minerals – is planned, with a view to commencing drilling as soon as possible.