Kalkaroo consists of stratabound replacement and vein style copper-gold mineralisation within Willyama Supergroup rocks of the Curnamona Craton.

The stratabound mineralization is uniformly distributed along more than 3 km of strike that follows an arc around the 35 degree dipping northern nose of the Kalkaroo south dome. It is hosted by an 80m -120m thick mineralised horizon that is sandwiched between psammitic footwall rocks and a thick pelitic hangingwall sequence.

In part, the mineralization is associated with near-vertical, mineralised quartz vein breccia fracture/fault fillings, which probably formed channel ways for the mineralising fluids. Interference folding resulted in dome structures which probably acted as structural traps for the rising mineralising fluids carried by these vertical structures.

The mineralising events were associated with iron-rich and sodium-rich alteration fronts, which are manifest as widespread fine-grained magnetite in the lower sandy formations and as pervasive albite alteration.

Erosion in the Mesozoic and Tertiary period exposed the Kalkaroo deposit to prolonged and deep weathering. Consequently, the deposit shows typical supergene enrichment features in its upper part, caused by oxidation of the primary sulphides in the weathering zone, forming a soft clay rich rock called saprolite. This is manifest in a subhorizontal stratification of the ore minerals from top to bottom:

1. Supergene free gold in saprolite, with generally minor copper, recoverable by gravity and cyanide leaching methods.

2. Native copper and gold in saprolite, largely recoverable by gravity methods.

3. Chalcocite dominant with gold, recoverable by conventional flotation.

4. Chalcopyrite dominant with gold and locally rich molybdenum, recoverable by conventional flotation.

The Kalkaroo mineralisation exists around an arcuate domal structure which has been drilled more than 3km along strike. Copper-gold mineralisation is continuous throughout this strike length and is open at depth along its entire length and is open at both ends.

The true width of mineralisation ranges from 40-80 metres thick, while the plan width of mineralisation above cutoff varies from 50 to 200 metres.

Mineralisation generally has an upper bound 50 metres below the topography and at its deepest has been intersected in a single drillhole 500 metres below the topographic surface.

The mining method is conventional open cut bulk mining using truck and excavator equipment. The PFS is based on an owner operated mining fleet.

The pit development is in a staged cutback to sequence extraction from generally high value to lower value and shallower to deeper ore over the life of the mine. The first year mining consists entirely of overburden pre-strip of the 50 or so metres of Tertiary sands and clays. The next three years are focused on mining the softer oxidized saprolite gold, native copper and chalcocite ore types at an annual production rate averaging around 4 million tonnes per annum, which is the nominal capacity of the oxide ore processing plant.

The ore mining rate almost triples in the fifth year peaking at approximately 12 million tonnes per annum and coinciding with the sulphide ore concentrator plant coming on stream in order to process the significant amounts of chalcocite ore being mined. The excess saprolite gold and native copper ore mined in this year will be stockpiled, with processing spread out over the next two years. With the bulk of the oxidized ore mined by the end of the fifth year, production in subsequent years is largely from deeper sulphide ores with a milling throughput rate of nominally 7 million tonnes per annum. As the mining operation moves deeper the proportion of chalcopyrite ore increases until it becomes the predominant ore type mined and processed in the later years.

Over the life of the mine the total waste material mined is 352 million tonnes while total ore is 100 million tonnes, giving an overall life of mine waste: ore ratio of 3.5:1.

After the initial ramp-up, and during the 13 year production period of continuous ore mining and processing, the Kalkaroo operation is anticipated to deliver on average 30,000 tonnes per year of copper metal and 72,000 ounces per year of gold (recovered metal).

Testwork supports the separate blending of the oxide (saprolite gold and native copper) and sulphide (chalcocite and chalcopyrite) ore types for co-processing in separate oxide and sulphide processing plants. Recovery of the various economic minerals employs conventional processing methods and is mainly dependent on the ability to separate the economic minerals from the gangue. For the oxide ores this means shearing, scrubbing and milling the oversize material, while for the more competent sulphide ores conventional crushing and milling can be used. Overall copper and gold recoveries vary by ore type.

Site water, which has Total Dissolved Solids (mostly sodium chloride) of around 22,000 ppm, was used for all metallurgical tests and did not adversely impact the recoveries, with the exception of saprolite gold ore.

The final saleable product produced by the conventional flotation processing circuit is copper concentrate containing average levels of 27.5% copper and 12.7 g/t gold.

The Oxide processing plant is primarily designed to treat blended Saprolite and Native Copper ores at a nominal 4 million tonnes per annum.

Blended oxide ores would be crushed with two stages of toothed roll crushers and scrubbed, with the oversize reporting to a ball mill in closed circuit with a hydrocyclone nest, and the overflow feeding a flotation circuit with two stages of cleaning. Within the milling circuit, gravity gold would be recovered by a Knelson concentrator while native copper would be captured through screening and upgraded by jigging. The final copper-gold flotation concentrate would thickened, and like the gravity gold and native copper concentrates, filtered. The flotation tailings would be thickened and the underflow would be discharged to Tailings Storage Facility

The Oxide processing plant would also have the ability to treat Chalcocite ores, additionally incorporating a jaw crusher and a SAG mill to prepare the Chalcocite ores for flotation. The flotation rougher concentrate would be reground and upgraded in three stages of cleaning.

The Sulphide processing plant is designed to treat a blend of Chalcocite and Chalcopyrite ores at a nominal 7 million tonnes per annum and would be a conventional hard rock processing facility. It would employ a SABC comminution circuit (gyratory crusher/SAG mill/Ball mill/pebble crusher in closed circuit with a hydrocyclone nest) feeding a flotation circuit with three stages of cleaning. The comminution circuit would include a Knelson concentrator for the recovery of gravity gold while the flotation rougher concentrate would be regrind prior to the production of a final concentrate. The final copper-gold flotation concentrate would thickened, and like the gravity gold concentrate, filtered. The flotation tailings would be thickened and the underflow would be discharged to Tailings Storage Facility.