The Project area is situated within the Mount Isa and North West Region of Queensland, Australia, an area that is one of the premier base metal-bearing areas of Australia, with mining activities having taken place since the discovery of copper and gold near Cloncurry in the 1860s. The Mount Isa area hosts numerous base metal copper, zinc, and lead deposits of global significance, including the Mount Isa, Ernest Henry, Century, Dugald River, Canington, and Selwyn deposits. The Eva Copper Project is hosted by Proterozoic-aged, metamorphosed and poly-deformed marine sedimentary and volcanic rocks of the Mary Kathleen domain of the Eastern Fold Belt Inlier. Deformation, metamorphism, and plutonic activity took place during the Isan Orogeny, approximately 1,600 to 1,500 million years (Ma) ago.

There are twelve known mineral deposits in the Project area, of which seven have been included in the current mine plan. Mineral deposits are grouped into two types: copper-gold, and copper only. There are five of the copper-gold deposits, all of which are in the mine plan. These deposits are classified as iron oxide copper-gold (IOCG) deposits, where mineralization is associated with regional-scale hematite and albite alteration (red-rock alteration), and localized magnetite alteration.

Copper sulphide mineralization, primarily chalcopyrite with lesser bornite, occurs as veins, breccias, fracture fill, and disseminations in mafic to intermediate volcanic or intrusive rocks. Gold is generally correlated with copper, and is recovered in the copper concentrate. Mineralization appears to be localized and/or bounded by faults and other deformation-related structures. The copper-only deposits are stratabound, locally stratiform, and most occur within metamorphosed calcareous metasedimentary rocks, forming an approximately linear trend stretching over 7 km. The origin of these deposits is uncertain; they may be deformed and metamorphosed versions of sedimentary or red-bed type copper deposits, or they could be more closely related to the IOCG deposits, but with enhanced stratigraphic controls related to the calcareous beds being particularly reactive with hydrothermal fluids.

All of the deposits have a 10 m to 25 m thick overlying zone of oxidation, where the rock is extensively weathered, and copper sulphide minerals have been leached or converted to various oxide minerals that cannot be recovered by flotation. The oxide zones are treated as waste, but tonnages and copper grades have been estimated. With the exception of the Turkey Creek deposit, the copper-only deposits commonly have a significant thickness of supergene material, where carbonate has been leached from the rock, reducing hardness and density, and the copper occurs as native-copper, chalcocite, and other low-sulphur copper species. The carbonate-leached zone is separated from the underlying sulphide zone by a thin transition zone. Each of these mineralogical zones has been modelled so that resources can be estimated for each and the appropriate metallurgical recoveries can be applied for reserve estimation.

Copper deposits of the Eva Copper Project are of two types. The most significant are those of the IOCG type, which are hydrothermal copper-gold deposits associated with relatively high contents of iron oxide minerals (magnetite or hematite), a general lack of quartz, and extensive sodic alteration. The hydrothermal fluids are believed to be sourced from, and/or driven by, magmatic systems with possible addition of basin brines; however, mineralization is commonly distal (or spatially distinct) from the causative plutonic rocks. Mineralization can take many forms, but the dominant ones are vein networks, breccias, dissemination, and replacement. Both structure (fault or fracture systems) and lithology (chemistry and rheology) are key features in localization of mineralization. The second type of copper deposit is termed copper-only; these deposits do not contain significant gold, and are typically hosted within deformed and metamorphosed calcareous sedimentary rocks as stratabound mineralization.

One deposit, Turkey Creek, is a stratabound copper-only deposit within volcanic rocks, and has processing characteristics similar to those for the copper-gold deposits. There are 12 defined deposits within the Eva Copper Project, ranging in size from 0.7 Mt to over 100 Mt, seven of which are included within the current mine plan. Four are copper-gold deposits, and three are copper-only deposits. Metallurgical recoveries for the copper-gold deposits are favourable, due to relatively coarse-grained chalcopyrite and lesser bornite. All of the deposits have a thin, 10 m to 40 m weathered or oxide zone at surface, for which tonnage and grades have been estimated, but which have been treated as waste within the mine plan.

The copper-only deposits hosted within calcareous metasedimentary rocks have additional zones of weathering and/or acid leaching, which has removed carbonate, reducing rock strength and density in addition to changing sulphide mineralogy. In the two such deposits, Blackard and Scanlan, a supergene zone termed native copper occurs below the oxide zone, and contains abundant native copper in addition to chalcocite, cuprite, and other low-sulphur copper species. Extensive metallurgical testing has been carried out on these deposits, with appropriate processing design and estimation of recoveries. Within these deposits a narrow transition zone occurs between the copper zone and underlying sulphide zone.

Conventional open pit mining methods, which include drilling, blasting, loading, and hauling, will be employed at the Eva Copper Project open pits. The Eva Copper Project is estimated to have a two- year construction period, one of which is pre-production mining. Mining activities are based on open pit mining of the Little Eva deposit at a rate of 31,200 t/d of ore. This primary pit at Little Eva will be supplemented by progressively mining six satellite pit areas at Blackard, Scanlan, Turkey Creek, Bedford North and South, Lady Clayre, and Ivy Ann, to achieve a minimum 11.4 Mt/a mill feed rate.

The mining method involves a 13.4 Mt pre-strip of a starter pit at Little Eva, which includes 1.2 Mt of ore. To sustain a 31,200 t/d production rate during the mine life, stripping will continue at slightly elevated rates for several months after production commences. There will be three pushback pits in Little Eva, three pushbacks at Blackard, and two pushback pits in Turkey Creek, while Bedford, Scanlan, Lady Clayre, and Ivy Ann will have one phase of mining.

Drilling will be carried out using conventional drill and blast (D&B) blasthole drills with diesel-powered front shovel excavation, and off-highway dump truck haulage. The initial main mining fleet consists of two front shovels with 22-m3 buckets and an operating weight of 400-tonnes each, matched to fourteen (Year -2 and Year -1) 141-tonne off-highway rear dump trucks. This fleet is supplemented by the standard support equipment composed of, but not limited to, track dozers, water trucks, graders, front-end loaders (FELs), light vehicles, and service equipment. Ore haulage from the Scanlan and Lady Clayre satellite pits will be accomplished with the same mining fleet as discussed above.

Approximately 381 Mt of mine waste will be transported to dumps adjacent to each of the pits, or to the TSF for construction. The TSF is expected to require approximately 65 Mt of mine waste. Waste will also be used to construct an engineered creek diversion channel and flood protection bund around the Little Eva pit, known as the Cabbage Tree Creek (CTC) Bund. The channel and bund will redirect wet season water flows in Cabbage Tree Creek away from the Little Eva pit. Diversion bunds and ditches will also be built around the other open pits, where needed.

The ROM ore will be delivered to the ROM pad, where there will be the capability to direct feed from mine trucks to a gyratory crusher with 600 kW of installed power capable of accepting 1-m diameter rock at a rate of 1,733 t/h (75% crusher availability).

The current mining schedule then prioritizes the mining of ore sequentially from Little Eva, Blackard, Scanlan, and Turkey Creek. The other satellite deposits (Lady Clayre, Bedford, and Ivy Ann), which only account for 5% of the Mineral Reserves, will commence mining towards the middle to end of the mine life. The proximity of Turkey Creek to the mill makes it preferable to mine it early in the mining schedule. Further investigation and rescheduling will be carried out prior to project commencement.

Mining of ore from the Bedford pits (North and South) is scheduled to commence in Year 4 and Year 5. Lady Clayre pits are scheduled to be mined in years six to eight, and Ivy Ann in Year 5 through Year 6. As noted previously, three of the satellite pits are quite small compared to the Little Eva and Blackard pits.

Dewatering of the open pits will be required. A plan of dewatering wells, horizontal drains, and sumps is envisioned. A detailed plan will be developed during the Project’s development period. It has been estimated that the Little Eva pit dewatering will discharge approximately 4,000 m3/d, and the Blackard pit dewatering approximately 2,000 m3/d. This water is slated to be used as make-up water in the processing plant.

The Little Eva processing plant has been designed to produce a marketable copper concentrate withna grade of 28% Cu and containing about 3 g/t Au at a nominal throughput rate of 31,200 t/d. A key update in this feasibility study is the change from a SAG mill and pebble crushing circuit to a secondary crusher and HPGR design. The ball mill has also been upsized in order to support 31,200 t/d at a target grind of P80 of 165 µm.

The process plant flowsheet developed for processing copper ore from the Eva Copper Project is considered a relatively standard processing plant design for the treatment of copper-bearing sulphide mineral material. All the unit operations selected for the plant design are low risk and of proven technology.

The following summary of the unit process descriptions is based on the nominal ore throughput rate of 31,200 t/d:

-The ROM ore primary crushing circuit will use a gyratory crusher with a nominal crushing rate of 1,733 t/h (1,925 t/h design) at the availability of 75%. The crusher is a Metso model Mk III 42/65. The crusher will be supplied using haul trucks dumping into a 3-truck capacity dump pocket, equipped with an apron feeder transferring ROM to the primary crusher feed. The primary crusher product size is designed as a P80 of 137 mm.

-A MP1250 or equivalent secondary crusher will operate in a closed loop with a double deck vibrating screen to produce a product size P80 of 35 mm. The screen undersize will be transferred to the fine ore stockpile.

-The fine ore stockpile has a live capacity of 30,086 tonnes. The crushed ore stockpile reclaim system will be equipped with two reclaim apron feeders each capable of supplying 100% of downstream tonnage.

-A 2.4 m by 1.65 m HPGR supplied with two 5.4 MW drives will operate in a closed loop with two 4.2 m by 8.5 m double deck vibrating screens. The target transfer size to the ball mill circuit is a P80 of 4 mm. A nominal and design circulating load has been set at 85% and 130% for the conveyors, respectively.

-The ball mill is a 24-ft diameter by 40-ft EGL with 2 x 7 MW motors. The throughput rate of the grinding circuit will be 1,413 t/h (nominal) and 1,700 t/h (design) at an availability of 92%. The Ball Mill grind product size will have a P80 value of 165 µm. Two roughers, a cleaner, and re-cleaner Jigs operating on a bleed of the ball mill cyclone feed will generate a coarse, high grade gravity concentrate to be sent to final concentrate.

-The rougher flotation circuit will consist of six 300 m3 flotation cells. The circuit has an overall nominal residence time of 35 minutes. Provision is designed for sulphidization in the final two stages of rougher flotations. Rougher concentrate will be reground in the regrind circuit. Rougher tailings will be discharged to the 50 m diameter tailings thickener.

-The rougher concentrate regrinding circuit incorporates a Vertimill® (model VTM1500) and cyclones for classification. The regrind circuit product size will have a P80 value of 53 µm. A partial underflow stream will be directed to a flash flotation unit producing a final grade copper concentrate with the tailings returned to the regrind mill. A bowl concentrator will operate on a bleed of cyclone underflow, concentrating free native copper collecting within the regrind cyclone loop. This product will be sent to final concentrate.

-The regrind cyclone overflow will feed two 18 m3 DFR first cleaners, producing a >28% concentrate sent to the final concentrate thickener. Six 18 m3 first cleaner scavengers will send concentrate to three 6 m3 second cleaners. The second cleaner concentrate will join the first cleaners concentrate as final concentrate. Tailings from the second cleaners will be recycled to the regrind mill. Tails from the cleaner scavengers will be sent to final tailings.

-The concentrate thickener will collect the concentrate products from the cleaner and recleaner DFR cells. The thickened concentrate will be delivered to the concentrate storage tank, and this will feed the concentrate filter press. The filtered copper concentrate will have a moisture value of 8.5%. The dewatered final concentrate will be loaded onto trucks for despatch to smelters.

-A separate dewatering cone and drying paddock is included for dewatering of gravity concentrates.

-Under nominal design conditions, the copper concentrate production can be 194 kt/a inclusive of gravity and flotation concentrates.

-The concentrate thickener overflow solution will be recovered and used in the grinding and flotation circuit.

-The tailings thickener will combine the rougher and cleaner scavenger tailings for discharging to the TSF as final tailings. Process water will be recovered from the tailings thickener and the TSF for re-use in the plant.

-The process water circuit will provide process water to the grinding circuit and other parts of the plant.

-A fresh water circuit will provide water for reagent make-up, gland service, mill lube systems cooling water, filter press cloth wash, and process water make-up.

-The reagent preparation section will prepare the flotation collector reagent (PAX) and the frother reagent for distribution to the slurry streams. A liquid sodium hydrosulphide circuit will supply sulphidizer to the final stages of rougher recovery. The flocculant required for the tailings and concentrate thickeners will also be prepared in this section. A “test reagent” circuit is included for the testing of additional reagents.

-Various process streams will be sampled automatically on an on-line basis and analyzed for copper to provide the necessary information for process control and a metallurgical balance.

-An assay and metallurgical laboratory will be included in the design.

-Site services, power supply, air supply, and water supply will be included in the design.