The Company’s namesake Pioneer Dome Project is a highly prospective, multicommodity project located approximately 130 km south of Kalgoorlie and 200 km north of the port of Esperance. Access is excellent with the Goldfields Highway and Esperance railway, and water and gas pipelines passing through the Project.
The Company has now accumulated approximately 341 km² of tenements along the 20 km strike length of the eastern periphery of the Pioneer Dome. The Project was recognised as having potential for lithium mineralisation following a review of historic exploration reports which recorded numerous pegmatite intersections in nickel or gold‐focussed drilling completed since the 1960s. The prospectivity model was further enhanced by colloquial records of lepidolite, tantalite and tourmaline in prospector scale workings, which are some of the characteristic minerals of a zoned pegmatites complex. The Project is comprised of six exploration licences plus a mining lease which has been pegged over the Sinclair Caesium Zone. Pioneer Dome is highly prospective for a traditional LCT system - at least 13 clusters of pegmatites have been identified along a 20 km strike length.
LCT pegmatites, thought to be late time intrusions related to s-type granite intrusions, exhibit characteristic zonation of a range of economically important rare-element minerals such as lithium (in spodumene), tantalum, niobium and tin. This same type of pegmatite that hosts the Greenbushes mine, is similar to that intersected in drilling at the Company’s optioned Mavis and Raleigh Lithium Projects (Ontario, Canada); and that which Pioneer is targeting at its 100% held Phillips River, Donnelly and Pioneer Dome Lithium Projects.
The Sinclair Caesium discovery within the project area, has resulted in the Company transitioning to miner December 2018 to January 2019. Sinclair is Australia’s first commercial caesium mine - and one of only three in the world.
The Company’s primary focus at this Project is the Sinclair Pegmatite – where the Sinclair Caesium Mine was completed in January 2019 and the export of Pollucite is underway. The Sinclair Pegmatite is one of 13 targets that occur within a 20km north-south “pegmatite corridor”.
The Sinclair Pegmatite is classed as a complex Lithium-Caesium-Tantalum (LCT) pegmatite due to its mineral assemblage and degree of mineral fractionation, which is extreme. This has resulted in the formation of a suite of mono-mineralic phases that include pollucite (Cs) as well as petalite and lepidolite (Li), feldspar (K) and silica (Si). The commercialisation of these other minerals is being investigated concurrently.
Sinclair Caesium Mine
Pioneer achieved a major milestone with the completion of the Stage 1 Pit of the Sinclair Caesium Mine (ASX announcement 22 January 2019). This is Australia’s first commercial caesium mine - and one of only three in the world.
Pioneer reported the discovery of the Sinclair Zone caesium deposit in September 2016 and mining operations commenced two years later (ASX announcement 13 September 2018). Project funding was provided through an Offtake and Loan Facility Agreement with Cabot Specialty Fluids Limited, a company associated with the Cabot Corporation (Cabot) (NYSE:CBT) (ASX announcement 20 June 2018).
The first block of Pollucite was extracted in December (ASX announcement 12 December 2018) and exporting commenced during January 2019.
Stage 1 Mining at Sinclair Caesium Mine at a Glance
- Approximately 484,100 BCM of material was excavated
- Combining run of mine (“ROM”) Pollucite and lower grade stocks, the mine produced approximately 19,000t1 of Pollucite with an average grade of approximately 9.1% Cs2O, which exceeds the minimum grade specification under the Cabot Offtake and Loan Facility Agreement (ASX announcement 22 January 2019). These figures are expected to change slightly once crushing of all Pollucite has occurred and shipment grade reconciliations are complete.
- The contained caesium (“Cs”) within the ROM stockpiles, being 1,640 tonnes, has outperformed the start-up Mineral Resource Estimate in the Measured category of 1,047 tonnes of contained Cs by 593 tonnes or 57%.
- By blending ROM Pollucite and lower grade stocks to achieve a grade of approximately 9% Cs the Company plans to export approximately 1,800t of contained Cs. As the sale price is effectively based on the contained Cs above a minimum grade for a consignment, this will greatly improve the revenue received by Pioneer, while maximising the metal content delivered to Cabot.
First Pollucite Shipment Delivered to Cabot
The first shipment of crushed Pollucite was containerised in Esperance and is currently in transit to Cabot from the Port of Esperance. Shipments are expected to continue throughout the calendar year and conclude by December 2019 (dependent on shipping schedules and quantities per shipment).
Note 1: by Loadright-style weightometer at the crushing circuit, or truck count with truck factors applied.
Note 2: based on grade control and stockpile sampling. Samples pulped and analysed on site using a Bruiker CTX XRF analyser.
Mineral Resource (Prior to Mining)
Prior to the commencement of mining, the Company provided a Mineral Resource Estimate (ASX 8 November 2018) of 7,110t of the caesium ore ‘pollucite’ with a grade of 16.4% Cs₂O for a contained 1,100 tonnes of Cs, as summarised by category in Table 1 below.
|Classification||Tonnes (t)||Cs₂O (%)||Contained Cs (Tonnes)|
Note: Appropriate rounding applied
Cs₂O (%): Assays by fusion XRF are reported by Intertek Genalysis, a commercial laboratory, as the element oxide.
Contained Cs (Tonnes): Stoichiometric element oxide to element conversion uses a factor of 1.0602. Pioneer has added this column.
The Sinclair Pegmatite
The host “Sinclair Pegmatite” is a complex lithium-caesiumtantalum (LCT) pegmatite characterised by a suite of monomineralic phases of pollucite (caesium), petalite and lepidolite (lithium), feldspar (potassium) and silica (silicon) in the pegmatite core zone.
The caesium mineral pollucite is a high value, high demand commodity and global supply is very constrained. The primary use of caesium is in the manufacture of Caesium Formate brine, a heavy fluid used in high temperature/high pressure oil and gas drilling.
Other Pegmatite Minerals
While operations at the Sinclair Mine are based on the extraction of pollucite only, the Company will also extract and stockpile petalite, lepidolite, potassium feldspar and silica while markets are established. Potassium feldspar is used in the manufacture of ceramics and glassware, especially in glazes for hard-wearing tableware and floor tiles, and as a key component of advanced high-tolerance insulators and electro-ceramics.
Lepidolite Development Strategy
Pioneer has a Farm-in Agreement with Lepidico Ltd (ASX: LPD) to advance the PEG009 Lepidolite target at Pioneer Dome. The Farm-in provides Pioneer with a solution to unlock the Project’s significant potential Lepidolite value. Lepidolite mineralisation from Pioneer Dome has been assessed as being suitable for extraction via Lepidico’s L-Max® process, which produces lithium carbonate directly from lepidolite.
- Pioneer Dome Lepidolite mineralisation produced a high specification battery-grade lithium carbonate grading 99.7% using L-Max® technology
- L-Max® achieved 93.9% lithium extraction and 93.3% caesium extraction from a flotation concentrate
- estimated lithium recovery to the final lithium carbonate product of 90%
- PDRC070: 12m at 2.22% Li₂O from 44m
- PDRCD072: 8.65m at 3.01% Li₂O from 40m
- PDRC073: 13m at 2.13% Li₂O from 39m
- PDRC079: 14m at 2.32% Li₂O from 46m
- PDRC090: 8m at 2.62% Li₂O from 51m
- PDRC091: 13m at 2.03% Li₂O from 55m
- PDRC095: 6m at 2.95% Li₂O from 49m