Pilbara region, Western Australia

Overview

Lithium Australia NL (‘LIT’) has established a regional footprint in Western Australia’s rapidly emerging, world-class lithium province in the Pilbara (see Figure 1), as follows.

  • LIT and Pilbara Minerals Limited (‘PLS’) have entered into an agreement to establish the SiLeach® joint venture on a 50:50 basis, with the aim of producing lithium carbonate or lithium hydroxide from a SiLeach® processing plant fed by PLS’s spodumene concentrate.
  • LIT and Venus Metals Corporation (‘VMC’) have entered into an agreement to jointly explore certain exploration licences (and current applications). LIT will undertake exploration activities primarily to evaluate the lithium mica potential of the area controlled by VMC.
  • LIT has made application for four exploration licences in prospective geological terrain – the Hillside project.

Figure 1: Pilbara regional projects and alliances.

LIT/PLS technology alliance

Summary

Worldwide, the Pilgangoora lithium-tantalum project of PLS is one of the larger of the new lithium ore (spodumene) deposits, with a globally significant hard-rock spodumene resource. It has long been recognised that lithium micas, principally lepidolite, are associated with the spodumene mineralisation at Pilgangoora. Lithium hosted by lepidolite is largely ignored through the conventional spodumene treatment process and reports to the waste stream. LIT’s memorandum of understanding (‘MoU’) with PLS allows LIT to evaluate the Pilgangoora deposit for lepidolite mineralisation and its potential as a value-add opportunity to the project.

Using technologies developed in-house for detecting lithium in soils, LIT has delineated a large lithium anomalous area – the Triple Creek anomaly – separate to the main zone of spodumene mineralisation at Pilgangoora. LIT plans to further define the extent of the anomaly and its mineralogy.

Terms of the MoU

In November 2014, LIT announced the execution of an MoU with PLS to test the lepidolite potential of the PLS-owned Pilgangoora project, located in the Pilbara region of Western Australia, which is southeast of Port Hedland. The aim of the collaboration was to evaluate the potential of lithium mica mineralisation at Pilgangoora to produce high-grade lithium carbonate for use in advanced hi-tech batteries.

Under the terms of the agreement, LIT will report on the ways in which the combined expertise of both companies can be optimised. The aim is to enable more complete exploitation of Pilgangoora’s lepidolite mineralised areas by providing feed to produce lithium carbonate for the rapidly expanding global lithium battery industry.

Pilgangoora project

PLS’s 100%-owned Pilgangoora lithium-tantalum project is located 120 kilometres (‘km’) from Port Hedland in the resource-rich Pilbara region. As noted, it is one of the largest new lithium ore (spodumene) deposits in the world, with a globally significant hard-rock spodumene resource.

The most recent Mineral Resource update – published in July 2016 and incorporating the results of successful in-fill drilling completed from February to June 2016 – comprises a Measured, Indicated and Inferred Resource of 128.6 million tonnes (‘Mt’) grading 1.22% lithium oxide (‘Li2O’ – spodumene) and 138 parts per million (‘ppm’) tantalum pentoxide (‘Ta2O5‘ – tantalum) containing 1.57 Mt of Li2O and 39 million pounds of Ta2O5.

PLS commenced construction at Pilgangoora at the end of 2016, with commissioning targeted from March 2018.

Exploration by LIT

In January 2016, LIT announced the results from a high-resolution, soil geochemical survey targeting the pathfinder elements indicative of lithium micas, or their derivatives, present in the soil profile. A significant geochemical anomaly defined in the northwest of the project area had a chemical signature typical of lithium micas (see Figure 2). Importantly, the anomaly is separate to the spodumene-bearing lithium mineralisation.

Known as the Triple Creek Zone, this unique high response is more indicative of lithium micas than the more generalised geochemical response over the main pegmatite zone. It is now a major target for further evaluation. In general, such occurrences are close to the lithium pegmatites and have resulted from weathering and dispersion in the soil profile. LIT will now focus on determining the mineralogy and extent of these deposits.

Figure 2 shows the outcropping pegmatites (blue) and their relationship with lithium mica geochemical pathfinders. The very large anomaly in the northwest is interpreted as a concealed greisenised granite, the geochemical signature of which separates it from the main pegmatite swarm.

SiLeach® development programme

LIT developed SiLeach® – a universal process for the recovery of metals from silicates – with the assistance of Australian federal government grants and a Western Australian government grant, as well as the technical assistance of ANSTO Minerals (‘ANSTO’), a division of the Australian Nuclear Science and Technology Organisation.

Pilot testing of spodumene concentrates from PLS’s Pilgangoora deposit was completed in early 2017 at ANSTO. The test run produced the following outcomes.

  • Pilot SiLeach® operations successfully recovered lithium from Pilgangoora spodumene concentrates without the requirement for roasting.
  • Despite operations suffering mechanical disruptions, lithium extractions into pregnant liquor solution of up to 73% were achieved.
  • Sufficient pregnant liquor was recovered to continue with lithium carbonate refining tests.
  • Data valuable for improving plant viability was generated.

Lithium was successfully recovered from refractory alpha-spodumene (that is, unroasted spodumene) throughout the pilot run. This resulted in extractions – based on pregnant liquor solution analyses – that ranged from 62% up to 73%. It is expected that elimination of mechanical and material handling interruptions to plant throughput will have a significant positive impact on future lithium recoveries. LIT and ANSTO will now review pilot plant designs ahead of follow-up pilot studies of SiLeach® on spodumene later in 2017.

LIT/VMC MoU

Summary

The broader objective of this partnership will be to determine if there is potential for the provision of enough feedstock to feed a Pilbara-based lithium processing facility and produce high-grade lithium carbonate and/or hydroxide for use in advanced hi-tech applications, including lithium batteries.

Terms

The terms of the MoU require that LIT report on the ways in which the combined expertise of VMC and LIT can be optimised. In particular, LIT will provide a plan for cogeneration of revenue from both lithium micas and spodumene (where spodumene occurs in association with the other minerals), using LIT’s exclusive licence for mica and its intellectual property for spodumene.

LIT will pay VMC a fee for exclusive access to the latter’s ground and will sole-fund exploration over the project tenements in the first year following tenement grant. VMC will retain 100% ownership of its Pilgangoora tenements.

Exploration

The area covered by VMC’s tenement applications contains many known pegmatites, so has the potential to add significant quantities of lithium silicates (including lithium mica and spodumene) to the regional inventory. LIT’s testwork programme will include field inspections, data and observations across the project area and in the laboratory, to confirm the suitability of the lithium mica, spodumene and clay materials within the MoU area as a source for battery-grade lithium carbonate and lithium hydroxide.

Reconnaissance exploration, consisting of mapping and sampling, commenced in August 2017.

Minerals Research Institute of Western Australia project

In November 2016, LIT advised that the Minerals Research Institute of Western Australia (‘MRIWA’) had officially confirmed commencement of its collaboration with LIT and others on an innovative project to enhance lithium recoveries and maximise the potential of valuable by-products recoverable from the processing of pegmatites.

The full title of the project is MRIWA Project M479 – Solution purification and valuable by-products formation during the production of battery-grade lithium. MRIWA and LIT aside, other collaborators in the project include VMC and, importantly, Western Australia’s Murdoch University, which is renowned for world-class research with real-world impact.

In April 2017, LIT announced the commencement of phase 2 of the research project, the focus being on the potential added value of optimisation, or additions, to the SiLeach® circuit as it currently stands. This programme will also be undertaken at Murdoch University, using the same personnel and facilities as those in phase 1.

Hillside

The Hillside project comprises four contiguous exploration licence applications with a combined area of 102 km2, located 80 km southwest of Marble Bar (see Figure 3). There, tin and tantalite minerals were mined previously from pegmatites reported to contain the lithium micas lepidolite and zinnwaldite.

Figure 3: Hillside project geological plan.

Geology

Regionally, the project is located within the East Pilbara granite-greenstone terrain, which is characterised by granitic rocks of the Shaw Batholith. Metamorphosed granitic rocks of the Archean Tambina, Split Rock and Callina Supersuites in the centre and southeast of the project area dominate the local geology The granites have intruded older Archean rocks of the Pilbara Supergroup, composed of mafic and felsic volcanic rocks, with minor sedimentary and intrusive rocks. These units underlie much of the western and northern parts of the tenure. The granitic rocks contain extensive swarms of late-stage pegmatites, the source of the tin and tantalum mineralisation in the area.

The Hillside tenure is located adjacent to several tin and tantalum deposits known collectively as the Shaw River mining area. Historically, one of the larger historical operations was the Cooglegong mining centre. Mining commenced in the Shaw River field in 1893, with sporadic operations producing from alluvial and elluvial deposits. Later, Greenbushes Tin Ltd consolidated the area’s holdings, undertaking extensive sampling programmes from 1978 to ’82. However, uncertainty and fluctuations in metal prices prevented further development of the tin occurrences in the area.

In 1980-81, workings at Trigg Hill – located in the centre of the Hillside project area – were exploited in a small-scale alluvial operation that produced tantalite and cassiterite concentrates. The mineralisation there is associated with pegmatite intrusions, which in some cases form up to 5% of the outcrop pattern. The pegmatites at Trigg Hill are reported to contain not only tin and tantalum but also the lithium minerals lepidolite, zinnwaldite and spodumene. Despite this, no focused exploration to evaluate the lithium potential of the ground has ever been undertaken.

Proposed exploration

LIT will begin by undertaking desktop studies and compiling a database using open-file data and company reports. On grant of the tenure, LIT will commence field mapping and sampling, to evaluate the lithium potential of the numerous pegmatites in the area. Soil geochemical surveys will be undertaken, using cutting-edge technology (laser-induced breakdown spectroscopy or LIBS), to provide real-time lithium assays that will help delineate concealed mineralisation. Open-file geophysical surveys will also be acquired and processed, to provide a better understanding of structural controls on pegmatite emplacement.