The Warrawoona Project leases lie within the Warrawoona Group, one of the oldest greenstone belts within the Pilbara Craton. Composed largely of high-Mg basaltic lavas with lesser tholeiite, andesite, sodic dacite, potassic rhyolite, chert and banded iron formation (BIF), all metamorphosed to greenschist facies, the Warrawoona Group is sandwiched between the Mount Edgar batholith to the north and the Corunna Downs batholith to the south.

Gold occursin quartz veins and stringersin the Klondyke, Copenhagen and Fieldings Gully Shears and mineralisation is associated with quartz-carbonate-sericite-pyrite alteration. Quartz veins and stringers are generally approximately parallel to the predominant shear direction. The bulk of the gold mineralisation is hosted in strongly sericitised and sheared mafic units with thin chert bands marking probable stratigraphic breaks.

Over some abandoned workings gold mineralisation is associated with copper as indicated by the presence of malachite and other copper carbonates.

The Warrawoona Project is located within the East Pilbara Terrane of the Archean Pilbara Craton in Western Australia. The East Pilbara Terrane is characterised by large, dome-shaped composite granitic complexes wrapped by greenstone belts. The granite-greenstone terrane is unconformably overlain by little-deformed volcanic and sedimentary rocks of the Hamersley Province. The Klondyke deposit is hosted within the Warrawoona Group, a package of high-Mg basalt, komatiite and felsic volcanic units, that outcrops throughout much of the East Pilbara Terrane and is one of the more important hosts to Au mineralisation.

The Warrawoona Project mining leases lie within the Warrawoona greenstone belt, a highly tectonised package of rocks sandwiched between the Mount Edgar batholith to the north and the Corunna Downs batholith to the south. Episodic and long-lived diapirism during intrusion of the batholiths has resulted in pervasive deformation throughout the greenstone belt. In the eastern part of the tenement package between the batholiths, the greenstone belt is as narrow as 1.5km wide. To the west, the belt fans out to form a series of narrow, widely spaced mylonite zones with comparatively undeformed rocks between. Gold mineralisation is closely associated with the mylonite zones and with thin chert layers (such as Kopcke’s leader at Klondyke) which are interpreted to represent stratigraphic breaks and appear to have acted as a focus for mylonite development, hydrothermal alteration and gold mineralisation.

Klondyke Mineralisation
Gold mineralisation at Klondyke is concentrated around the Klondyke shear and is associated with quartz-carbonate- pyrite veins within sericite/fuchsite-carbonate-altered and intensely deformed mafic schists. The shear, and the veins, are sub-vertical or dip very steeply to the south-southwest and strike at about 110°. A 10–50cm-wide black chert band, referred to as Kopcke’s leader by the early miners, is exposed within the altered mafic schists. Kopcke's leader is persistent both laterally and at depth and provides a good indication as to the location of mineralisation along strike and down dip. Rock units and quartz-carbonate veins display strong egg-carton boudinage and are marked by a very strong sub-vertical mineral/intersection lineation.

One of the most prominent features of the sections through the ore zone is the profound asymmetry of the alteration, with fuchsite alteration in the footwall (northern side) and sericite alteration in the hangingwall. The alteration asymmetry implies that Kopcke’s leader is located at the contact between two different mafic units: a high-Cr (high-Mg) mafic unit below the chert in which fuchsite is developed and a low-Cr mafic unit above the chert in which sericite is developed. This contact marks an erosion surface with subsequent clastic deposition during a hiatus in volcanism. The Kopcke’s leader chert unit has a remarkable strike and depth continuity over the resource area, providing a strong marker unit to guide exploration and resource drilling.

Dimensions
Klondyke mineralisation has a sub-vertical dip as shown in diagrams in the body of this release, and ranges from 2m to 20m thick. The resource extends over approximately 5.1 km of strike and extends to a vertical depth of over 500 metres. The St George Trend mineralisation has a sub- vertical dip and ranges from approximately 1 m to 10 m thick with an approximate strike of 1.6 km extending to a vertical depth of approximately 200 m.

The resource is currently considered open along strike and down dip.

The lateral dimensions of the Copenhagen resources are shown in the diagrams in the body of this release. The mineralisation has a moderate to steep dip as shown in diagrams in the body of this release, and rangesfrom 2m to 10m thick. The resource extends over approximately 210m of strike and extends to a vertical depth of 190m.

The Fieldings Gully mineralisation has a steep dip and ranges from 2m to 10m thick. The resource extends over approximately 440m of strike and extends to a vertical depth of 140m.

Calidus has undertaken a conventional approach to the development of open pit and underground mine designs and schedules supporting this Feasibility Study. Resource models, key assumptions and inputs were provided to external consultants (Intermine Engineering Consultants for open pit studies, and Entech Pty Ltd for underground studies).

Intermine and Entech interrogated the block models generated by Optiro (Klondyke & St George Open Pit), Widenbar & Associates (Klondyke Underground) and Calidus (Copenhagen, Fielding’s Gully) undertaking detailed financial analysis utilising Whittle and Deswik MSO software for open pit and underground mining respectively.

A competitive tender process was undertaken for the Open Pit mining contract. Macmahon Holdings Limited (Macmahan) were awarded the preferred tender status for open pit mining (ASX release 17th September 2020 Construction underway at Warrawoona Gold Project).

Early contract engagement with Macmahon has given Macmahon the opportunity to have input into the final open pit mining schedule for the Feasibility Study. Mining rates used in the Feasibility Study are the tendered rates from Macmahon.

Given that the underground does not commence until Year 3 of the Project, the underground schedule was provided to underground mining contractors with a request to provide budget pricing. Macmahon underground rates were also utilised for the Feasibility Study.

Open Pit
The Klondyke deposit will be mined utilising conventional open pit mining methods comprising:
- Clearing, stripping and stockpiling of near surface material in the areas of the pit and proposed waste storage facility;
- Initial pioneering work in pit areas with high topographic relief to establish suitable sized (>35m width) working bench areas for the proposed mine fleet as well as provide material for the TSF embankment construction;
- RC grade control programs to further delineate ore boundaries;
- Load and haul using 100 t – 200t excavators and 100 t rigid trucks using 2.5 m flitch heights;
- Haulage of ore to the ROM pad stockpiles to be fed to the crusher, and haulage of waste to nearby WRDs or in-pit backfilling.

Open Pit Design
Due to the variancesin topography in the Klondyke & St George project area, it was decided to conduct mining operations in two distinct phases, namely pioneer and production mining.

Pioneer mining will proceed until a 35m mining width is achieved which will allow the full turning circle of a 140-t class truck. Topographical highs within the pit crest were reviewed and natural topography utilised to generate 1:10 ramps to a 35m turnaround bay. Areas above this mining horizon would be selectively drilled & blasted and sequentially mined, commencing at the turnaround bay and advancing to the extremities of the horizon to facilitate safe extraction.

Once Pioneer benches exceeded 35m width, these were demarcated as production areas with normal mining assumptions and productivities applied for scheduling purposes.

The Klondyke Open Pit has been separated into four areas, being King, Cuban, Kopcke and Criterion. The naming convention is based on historic underground mines in the area.

In addition to the Pioneer mining outlined above, the intent of the discrete areasis to mine all oxide/transitional material during the early years of the Project. The Process Design throughput is based on 2mtpa whilst treating fresh and 2.4mtpa whilst treating oxide/transitional.

The final pit at Klondyke has a strike length of 2.4km and width of 240m.

Underground
The underground mine will be accessed via a box cut location adjacent to the mining contractor facilities near the main Processing Plant area and is located beneath the main Klondyke Open Pit.

The mining method selected was top-down longhole bench open stoping leaving in-situ pillars for support, based onorebody spatial characteristics and geotechnical recommendations

The layout has designed for the following reasons:
- The boxcut is located south of the pit close to surface infrastructure;
- The boxcut allows for the underground to be fully independent of the Open Pit, meaning the timing of commencement of the underground can be optimised in subsequent years;
- Capital development is located in the footwall providing better geotechnical conditions;
- Three declines provide adequate coverage along orebody (maximum strike per decline ~700m); and
- The decline develops between the Klondyke and St George Shear Zones to allow positioning for diamond drill Grade Control Drilling ahead of production.

The Klondyke underground mine is accessed via a portal in the boxcut as per above. A single heading access decline will be developed northwards towards the orebody before branching off to develop three decline systems in the Footwall as shown above.

At month 6 of the underground mining schedule, when the initial two declines are established, an initial 3 month close spaced diamond drill programme is planned (Grade Control drilling) to de-risk the central “core” of the underground production. The diamond drill programme utilises the established development as a drill platform, negating the need for additional development to establish dedicated drill positions. This is achievable due to the almost vertical nature of the orebody. During this period, there is no development scheduled which recommences at the completion of the grade control programme.

Development was subsequently designed to access the stoping blocks. The following describes the underground mine development design approach:
- The planned mining method is top-down longhole open stoping with in-situ pillars retained for support, retreating to a central crosscut. The orebody will be accessed from three declines located to provide maximum ore drive lengths of 400m;
- The mine is planned to be developed using conventional twin boom jumbos;
- Access is by a 5.5 mW x 5.7 mH Decline, commencing from a dedicated box cut adjacent to the processing plant, administration area and workshops;
- A floor to floor level interval of 25 m with a Decline standoff at least 30 m from the orebody has been used as recommended by POA;
- Second means of egress will be via raise bored escape ways collared at surface on the South side of open pit;
- Fresh air will intake through the main decline and several fresh air raises to surface. Return air will be exhausted via dedicated return air raises to surface. All ventilation raise bores from surface are designed at 4.0 m diameter and will collar on the southern side of the open pit; and
- Ground support patterns are as per geotechnical guidance from POA.

- subscription is required.

Process Plant
The process plant design has been developed from the outcomes of the metallurgical test work conducted during the FS and all previous study phases. The comminution circuit was sized the basis of processing 100% open pit fresh ore at a rate of 2.0 Mtpa. The transitional ore is softer and as such theoretically a higher throughput is achievable with the selected comminution circuit but to prevent over capitalising the downstream circuit the design feed rate has been limited to 2.4 Mtpa. Design of the conveyors, leaching circuit, thickener and tailings pumps are driven by the transitional ore throughput rate.

The plant design is simple and robust and comprises the following elements:
- Single stage crushing circuit, crushing to a P80 of 105 mm.
- Surge bin, reclaim feeder and crushed ore stockpile;
- Single stage SAG mill grinding circuit to produce leach feed slurry with a P80 of 150 microns;
- Gravity recovery;
- Leaching and adsorpt ........