The Mt. Cattlin Project lies within the Ravensthorpe Terrane, with host rocks comprising both the Annabelle Volcanics to the west, and the Manyutup Tonalite to the east. The contact between these rock types extends through the Project area.

The Annabelle Volcanics at Mt. Cattlin consist of intermediate to mafic volcanic rocks, comprising both pyroclastic material and lavas.

Both the Annabelle Volcanics and the Manyutup Tonalite are intruded by numerous fine to coarse-grained metamorphosed dolerite dykes. A NNW trending gabbro (termed pyroxenite in earlier reports) occurs at the eastern edge of the Mt. Cattlin pegmatite ore body.

The pegmatites which comprise the ore body occur as a series of sub-horizontal dykes, hosted by both volcanic and intrusive rocks. Several dolerite or quartz gabbro dykes trending roughly ENE and north-south cut all lithologies including the pegmatite dykes and are believed to be Proterozoic in age.

Mineralisation.
Lithium and tantalum mineralisation occurs in pegmatites, which have intruded both the Annabelle Volcanics and the Manyutup Tonalite, close to the contact between these two sequences.

The pegmatite dykes occur as a series of sub horizontal to gently-dipping horizons. In places they occur as stacked horizons which overlap in section. Pegmatite mineralisation defined to date covers an area of around 1.6 km east-west and 1 km north-south. The main pegmatite units drilled to date generally lie between 30 m and 60 m below the surface, and outcrop in some locations. However, deeper zones of lithium-mineralised pegmatites occur over 140 m below the surface to the northwest of the main ore body and may have potential to be mined from underground.

The pegmatites have a diverse mineralogy with major minerals comprising quartz, albite, cleavelandite (platy albite), microcline, perthite, spodumene, muscovite and lepidolite. Minor minerals include tourmaline, schorlite, elbaite, beryl, microlite, columbite-tantalite, sphalerite, amblygonite-montebrasite, triphylite, apatite, spessartite and fluorite. Spodumene is the predominant lithium ore mineral, and several types of spodumene are recognised, including light green and white varieties. Tantalum occurs as the manganese-rich end members of the columbite-tantalite series including Ta-rich manganotantalite, and as microlite.

The lithium minerals within the pegmatites are shown below:
- Spodumene LiAl(SiO3)2 contains 4 to 8 % lithium oxide (lithia).
- Amblygonite, LiAl(F,OH)PO4, contains 8 to 10 % lithia.
- Lepidolite, (lithium mica) contains 2 to 4 % lithia.
- Cookeite, (lithium chlorite).

The mineralogy of the pegmatites varies laterally, and can also be crudely zoned in a sub-vertical manner (perpendicular to margins), with zones differentiated by mineralogy and grain size.

Part of the northeast of the deposit contains the lithium-bearing mica lepidolite, which does not occur in the rest of the deposit. The lepidolite-rich zones contain higher tantalum (mainly microlite) grades. Zones include an aplitic rock comprising mainly quartzalbite- muscovite near contacts with country rocks, and zones of predominantly light green, and predominantly white spodumene. Lepidolite is generally associated with the white spodumene. Quartz-tourmaline veins are associated with the pegmatites and occur in places in the country rocks up to 10s of metres away from the pegmatites.

The Mt Cattlin mine currently operates using a conventional open pit mining method to deliver ore to the processing plant from a series of open pits adjacent to the plant facility. The mining method is industry standard involving drilling and blasting of all material before loading and hauling using backhoe excavators and rear dump rigid trucks. The ore and waste rock is drilled and blasted with 10 m high benches, and mined on 2 m to 2.5 m flitches.

The ore is delivered to a conventional crushing and dense medium separation (DMS) circuit. During mining operations, a portion of the mined ore is diluted with basalt which is considered a contaminant. The processing plant includes a separate circuit during crushing and screening that utilises optical sorters to remove basalt material from the process stream.

Earthmoving operations use a mining contractor to conduct all drilling, blasting, load, haul and ancillary work for the open-cut mining operation. The planned pit designs, which encompass the remaining mineral reserves, include two discrete open pits comprising the Northeast (NE) Pit and the Northwest (NW) Pit. The original main Dowling Pit, as well as the Southwest (SW) Pit and Southeast (SE) Pit have been mined out and are used for waste backfill. The SW Pit incorporates in-pit tailings disposal.

The current mining strategy will be to mine the NE Pit in two stages and NW Pit in three stages in order to defer the waste stripping requirements and maintain continuous ore delivery to the processing plant. In early 2021 the initial mining of part one of NE Pit was well advanced and delivering ore while mining of the pre-strip waste in part two progresses. Ore delivery from part two of the NE Pit is planned for Q1 2022 when ore is being exhausted in part one of the NE Pit.

Mining of the NW Pit is planned to start in mid-2021 with part one planned to reach the ore by Q2 2022 as the ore is depleted from NE Pit. This approach of staged mining is planned to continue into parts two and three of the NW Pit, a strategy that will provide a continuous supply of ore as mining operations shift between the two pit locations.

Crushing and Wet Plant Feed Preparation
Ore from the mine is stockpiled on the Run of Mine (ROM) stockpile. Ore is reclaimed from the ROM stockpile by Front End Loader and fed into the ROM Bin, from where it passes over a grizzly feeder into a single toggle jaw crusher. Material more than 125 mm passes into the crusher where it is broken down to progress to the secondary cone crusher. Any material smaller in size to fit through the grizzly is passed around the jaw directly onto a triple-deck sizing screen with respective deck layer apertures at 50 mm, 22 mm and 14 mm. The +50 mm particles feed the secondary cone crusher, -50 to +14 mm meets the secondary crusher discharge, -14 mm reports to Fine Ore Stockpile (FOS) or the Fine Ore Bin (FOB).

When feeding contaminated ore, material which comes from the secondary cone and the first sizing screen combine and are directed towards two parallel triple-deck sizing screens that feed the optical sorters and tertiary crushers.

The secondary screening, tertiary crushers and optical sorters are arranged to sit back-to-back in a mirroring arrangement so that the feed makes its way down the centre of the network and is recirculated back up the outside of the network. The two individual triple-deck sizing screens, which are set up with 40 mm, 22 mm, and 14 mm apertures respectively, separate the feed to the optical sorters to achieve the required size distribution for optimum contaminant rejection. The +40 mm reports to the Optical Sorters where contaminant basalt is removed. The +40 mm optical sorter product and the -40 +14 mm progress to the tertiary crusher, -14 mm reports to the FOS. The tertiary crusher product is recirculated to the secondary screening feed conveyor creating a closed loop with a -15 mm exit path. Once the crushed ore meets this size, it reports to the FOS at -15 mm. Material that has made its way to the FOS is either stockpiled for reclamation, or directly fed into the FOB.

Beginning in 2019, several additional improvements were made to the flowsheet as part of the Yield Optimisation Project (YOP), designed to improve yield and increase throughput of ROM ore to 1.8 million tonnes per annum. These changes included:
- Further optimisation of size fractions for Wet Plant feed and feed to the DMS Plant;
- Reliberation circuit for the Secondary DMS rejects to recover spodumene composited with gangue material;
- Replacement of the Vacuum Belt Filter with Wet High Intensity Magnetic Separation and an Ultrafine DMS circuit for recovery of spodumene from the Wet Screen undersize;
- Introduction of a Product Quality Upgrade (PQU) circuit containing a Wet Belt Magnetic Separator and an Optical Sorter for removal of basalt to improve product grade.

In early 2019, two in-series optical sorters were introduced in the crushing circuit to utilise ongoing and previous material classed as contaminated and not suitable for plant feed. The sort ........