Overview

Deposit type

• IOCG
• Hydrothermal
• Vein / narrow vein
• Stratabound

Summary:

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 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 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.

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.

Little Eva
The Little Eva deposit is a significant hydrothermal iron-oxidecopper gold (IOCG) deposit within the Eva Copper Project area, and is the largest single copper deposit in the project, sharing similarities with the Ernest Henry copper-gold deposit nearby. Spanning 1.4km in length, varying from 20m to 370m in width, the deposit's mineralisation is open below 350m (165mRL) vertically and extends beyond the current drilling extents, with additional potential both to the north and south.

The mineralisation is hosted by faulted subvolcanic porphyritic and amygdaloidal intermediate volcanic or intrusive rocks within intercalated folded calc-silicate, marble, quartzite, and biotitescapolite schists. The mineralisation is structurally controlled, occurring within breccias, fracture fill, and veinlet stock works.

Turkey Creek
The Turkey Creek deposit is located 1.5km east of the Little Eva deposit. The deposit is sub-cropping in a relatively flat, gently undulating area with thin (<0.5m) in-situ soils and alluvium cover. The deposit is over 1.8km in length, with mineralisation is open at depth extending from surface to drilled depths of 150m. The deposit displays excellent continuity along strike and down-dip with true widths varying from 10m to 30m at the southern end, to 30m to 50m at the northern end. The main part of the deposit strikes north and dips 60 degrees to the east. At the northern end, the mineralisation and host stratigraphy are folded sharply eastwards into a curved synform that dips steeply south. The northern zone is slightly offset by faulting from the main southern zone.

Blackard and Scanlan
The Blackard and Scanlan deposits are located approximately 5km and 17km, respectively, south of the Eva deposit and form a 7km long trend of mineralisation that follows the stratigraphy as it curves around the east side of the Knapdale Quartzite. The Blackard deposit morphology is a function of folded stratigraphy and/or faulting having a strike length of 3.5km, a maximum plan width of 350m, and a stratigraphic width of only 60m to 90m. A series of parasitic folds and/or fault repetitions result in a much wider deposit. The Scanlan deposit has a strike length of 1 500m and a maximum width in plan of 500m. Scanlan comprises a 10m to 50m thick horizon in the southern half, with the thicker part folded into a ‘V’ shaped synform on the eastern side and the thinner part forming a nearly flat antiform to the east.

Mining Methods

• Truck & Shovel / Loader

Summary:

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.

Comminution

Crushers and Mills

Summary:

Primary and Secondary Crushing
The primary and secondary crushing areas of the plant will include the following:

- ROM will be delivered using 141-tonne haul trucks that will feed directly into the crusher dump pocket, with a live capacity of 440 tonnes, and will feed the primary gyratory crusher via apron feeder. The ROM bin live capacity of three truck volumes is larger than typical, and a Copper Mountain Mining Corp. (CMMC) requirement to reduce truck wait times.

- FELs will re-handle ROM ore on the ROM pad as required to ensure crushing circuit availability is achieved.

- The primary crusher will be a gyratory crusher (42 in x 65 in), and will process 1,733 t/h of ROM ore. The gyratory crusher has a feed opening of 1,066 mm, with a closed side setting (CSS) of 130 mm, and with a 450-kW installed power motor.

- Primary crushed ore will feed a double-deck banana screen (4.2 m by 8.5 m) of the same size as the downstream HPGR screens. The secondary screen will be fitted with two screening decks, the first (75 mm) to relieve the load to the lower deck, and the second deck (50 mm) to separate the material that is smaller than the crusher closed side setting and does not require further crushing.

- Oversize material from the secondary screen will feed into the secondary crusher feed bin. The bin capacity is equivalent to 15 minutes residence time. The secondary crusher will be a cone crusher fitted with a 933-kW motor. The cone crusher will operate with a CSS of 50 mm. The secondary crusher product will be returned to the secondary screen, closing the circuit.

- The secondary screen undersize (with P80 at 35 mm) will be collected by the fine ore stockpile feed conveyor, which will feed a single, conical fine ore stockpile.

HPGR
The HPGR area of the plant will include the following:

- Fine ore will be reclaimed from the fine ore stockpile and transferred to the HPGR feed bin. Feed to the HPGR will be controlled to ensure that the HPGR is choke fed. The HPGR roll dimensions will be 2.4 m diameter by 1.65 m length, with 5.4 MW installed power.

- The HPGR circuit will be closed linked with the grinding circuit, with an availability of 92%, and the nominal crushing rate will be 1,413 t/h.

- The HPGR product will pass to the HPGR screen feed bin, where ore will be fed to two HPGR wet screens (4.2 m by 8.5 m). The top and bottom deck apertures will be 10 mm and 6 mm, respectively. Water will be added to each of the HPGR screen feed boxes and HPGR screens to ensure optimum separation efficiency and ball mill density.

- Screen undersize (with P80 of 4 mm) will gravitate to the cyclone feed pump box, while the oversize will return to the HPGR feed bin via the HPGR screen oversize transfer conveyor.

- To prevent damage to the HPGR rolls, metal detectors will be located on the HPGR feeder and on the HPGR screen oversize transfer conveyor that will activate diverter gates to tramp metal bunkers.

Grinding
The grinding area of the plant will include the following:

- A ball mill operating in closed circuit with a cyclone cluster, producing a cyclone overflow particle size of P80 165 µm. A particle size analyzer will be installed to facilitate the production of ground slurry at the required particle size.

- The HPGR screen undersize gravitates to the cyclone feed pump box, where it is combined with the discharge from the ball mill. Slurry from the cyclone feed pump box is pumped to the ball mill cyclone cluster, with a portion of the flow reporting to the jig circuit. CMMC advised that they preferred an installed standby variable-speed cyclone feed pump, and this has been incorporated into the design.

- CMMC has sourced a competitively priced new ball mill with 7.3 m diameter by 12.2 m effective grinding length, and it will be fitted with a 14.0 MW dual pinion, variable frequency drive. Ausenco has confirmed that this mill will be suitable for the required throughput and grinding duty, and that the ball mill power draw can be controlled using mill speed control should a coarser or finer grind be more economically favourable for certain ore blends.

Regrinding
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.

Processing

• Jig plant
• Gravity separation
• Crush & Screen plant
• Centrifugal concentrator
• Flotation
• Dewatering
• Filter press

Summary:

The Eva Copper Project, comprising Little Eva, Blackard, and other satellite deposits, has been developed based on the mine plan for a nominal combined mining rate of approximately 31,200 t/d copper ore, equivalent to 11.4 Mt/a, with direct feeding of the ore to the processing plant. The processing plant was designed to produce a marketable concentrate with a grade of 28% Cu (and 3 g/t Au when treating gold-bearing ores) using conventional recovery methods, including crushing, grinding, gravity concentration, flotation, and tailings disposal.

The throughput of 31,200 t/d of copper ore was developed for a feed blend consisting of 75% sulphide ores and 25% native copper ores.

The process description that follows is based on the nominal throughput of 31,200 t/d. The key
process units are the following:
- Primary, secondary and tertiary crushing.
- Ball milling in closed-circuit with cyclones, which includes a jigging circuit.
- Rougher flotation circuit.
- Rougher concentrate regrind mill in closed circuit with cyclones and a gravity circuit
- Cleaner, recleaner, and cleaner-scavenger DFR circuit.
- Gravity concentrate dewatering and sun-drying paddock.
- Flotation concentrate thickening, filtration, and storage.
- Gravity and flotation concentrate dispatch.
- Tailings thickening and disposal.
- Process and fresh water circuits.

Jigging
The two blanks are dedicated to feed the rougher jigs (1 blank per rougher jig). A portion of the cyclone cluster feed (typically 15%) gravitates to the rougher jigs, which consist of two IPJ3500 inline pressure jigs. The rougher jigs produce a concentrate that requires further upgrading, and reports to the cleaner jig. The cleaner jig is a single IPJ2400 inline pressure jig. The cleaner gravity concentrate gravitates to the recleaner jig. Both rougher and cleaner jig tailings gravitate to the cyclone feed pump box.

The recleaner jig consists of a single IPJ1000 inline pressure jig. Tailings from the recleaner jig report to the recleaner jig tailings tank, from where they are pumped and recirculated to the cleaner jig. Concentrate from the recleaner jig reports to the gravity concentrate dewatering cone.

Flotation and Flotation Concentrate Regrind Circuits
The flotation circuit consists of conventional rougher flotation followed by rougher concentrate regrind, and a cleaner, recleaner, and cleaner-scavenger DFR circuit to produce a final flotation concentrate. The flotation area of the plant will include the following:
- Conventional rougher flotation followed by rougher concentrate regrind, and a cleaner, recleaner, and cleaner-scavenger DFR circuit to produce a final flotation concentrate.
- Six conventional forced-air addition 300 m3 rougher flotation tank cells. The rougher concentrate flows by gravity to the regrind circuit, and the rougher tailings reports to the tailings thickener via a metallurgical sampler.
- Rougher concentrate is directed to a regrind tower mill operating with circulating load of 150% in closed circuit with a cyclone cluster.
- The regrind cyclone cluster has six ports, with four 400 mm diameter operating cyclones and two in standby. The cyclones operate at 80 kPa, producing a cyclone overflow particle size of P80 48 µm. The regrind cyclone overflow reports to the cleaner flotation head tank.
- A continuous gravity concentrator has been included in the rougher concentrate regrind circuit. The gravity concentrator, treating 25 t/h of solids, has been sized for this application, and processes approximately 16% of the regrind cyclone underflow stream. The resulting concentrate reports directly to the gravity concentrate dewatering cone.
- The cleaner circuit consists of two 18 m3 DFRs. The cleaner DFRs produce a high-grade concentrate that reports to the final flotation concentrate pump box, while the tailings flow to the cleaner-scavenger DFRs.
- The cleaner-scavenger circuit consists of six 18 m3 DFRs. Concentrate from the cleaner-scavenger DFRs is pumped to the recleaner DFRs, while the tailings are pumped to the tailings thickener via a metallurgical sampler.
- The recleaner circuit consists of three 6 m3 DFRs. The recleaner concentrate reports to the final flotation concentrate pump box, and tailings are pumped to the regrind cyclone feed pump box.
- An on-stream analyzer (OSA) and associated multiplexer is included for online process control and sampling.
- Flotation collector (PAX) is added to the ball mill and rougher and cleaner flotation. Frother (MIBC or Polyfroth H27) is added to the rougher, cleaner, and cleaner-scavenger flotation as required. Sulphidizer (NaHS) is added to the two last rougher flotation cells.

Gravity Concentrate Handling
The gravity concentrate handling area of the plant is summarized as follows:
- A 1.8 m diameter gravity concentrate dewatering cone receives the concentrate from the recleaner jig and Knelson concentrator. The dewatering cone overflow solution is recovered and sent to the flotation concentrate thickener. Gravity concentrate solids settle for collection at the underflow cone at a density of 70% solids.
- The dewatering cone underflow gravity flows to the gravity concentrate paddock, where the remaining moisture will evaporate.

Flotation Concentrate Handling
The flotation concentrate handling area of the plant is summarized as follows:
- A 16 m diameter high-rate concentrate thickener, including a Frothbuster system to minimize foam and concentrate loss, is included in the design. The concentrate thickener underflow density has been specified as 65% solids. Flocculant is added to facilitate settling and limit suspended solids in the supernatant solution. Overflow solution from the concentrate thickener is recycled as process water to the primary cyclone pump box to utilize the presence of residual flotation reagents.
- The design specification is for an automatic pressure filter (horizontal filter press) with a filtration area of 140 m2 (using sixty-two 1.5 x 1.5 m plates) and air drying, to achieve a concentrate filter cake with 9% moisture, operating at an availability of 65%, with a cycle time of 12.5 minutes.

Concentrate Storage and Load-Out
Gravity and flotation concentrates will be stored and transported separately:
- A covered building provides storage for up to 2,400 tonnes of flotation concentrate (equivalent to three to four days of production at design rates) and a FEL is used to optimize concentrate storage within the building. Flotation concentrate is loaded into trucks by FELs. Trucks are positioned on a scale prior to loading. The scale provides feedback to the FEL operators as the trucks are filled. When trucks are full, they drive through a wheel wash, and then the concentrate is transported to an off-site facility in half-height sealed containers.
- The gravity concentrate paddock provides storage of up to 200 tonnes of gravity concentrate. The gravity concentrate paddock has two compartments, each with capacity of 100 tonnes. While concentrate fills one compartment during a period of 11 days, the gravity concentrate in the other compartment dries out and is loaded into a truck by a FEL, similarly to the procedure described for the flotation concentrate. The proportion of copper production as gravity concentrate is anticipated to vary significantly over the life of mine; therefore, the residence time provided by the drying paddocks is estimated based on the nominal mill feed blend composition and corresponding testwork results.

Pipelines and Water Supply

Summary:

Raw water for the Project will be supplied from a borefield to be established at Cabbage Tree Creek, located approximately 2 km north of the Little Eva pit. CMMPL completed a hydrogeological investigation to define the borefield capabilities. Following the successful exploration program, two test bores and a monitoring bore were constructed (CTPB01 through CTPB03), which will eventually be expanded to form the Cabbage Tree Creek borefield. Test pumping conducted at two of the three test bores (CTPB02 and CTPB03) confirmed supply at a rate of 25 m³/h to 50 m³/h each. An additional 12 wells will be added for a total of 15 wells in the Cabbage Tree Creek borefield. The wells will be powered by an 11 kV distribution line. Each well has been calculated to produce an average of 6.5 L/sec for a total of 351 m³/h. The water then will be pumped into a 1,575 m3 nominal capacity collection tank at the western side of the Little Eva pit on elevation, which will be pumped via centrifugal transfer pumps, as and when required, to the fresh water/firewater tank, which is 14.8 m in diameter with a height of 9.2 m (capacity 1,575 m3) located in the processing plant.

Mine dewatering of the Little Eva pit will be accomplished by ten dewatering well holes equipped with submersible pumps, strategically located around the pit to ensure that mining remains as dry as practical. It is calculated that the pit dewatering wells and pit dewatering pumps will produce a total of 180 m3/h of raw water. The wells will each be designed for a capacity of 18.0 m³/h, and will each pump through a dedicated 180 mm OD HDPE DR13 pipeline into the collection tank at the western side of the Eva Pit. The wells will be powered by an 11 kV distribution line. The individual pipelines from the wells to the common water tank will be run above ground, except at road crossings.

Return water from the TSF will also be used to supply process water. A system has been designed using three 75 kW submersible pumps, each capable of pumping 5,443 m3 of reclaim water per day, to a maximum of 17,136 m3/d using from one to three pumps. The reclaim water will be transferred by a 2 km long HDPE pipeline to the process water tank. It will also be possible to source water from the Lake Julius to Ernest Henry pipeline owned by SunWater. Potable water for the accommodation village will be supplied from a water well to a tank, then to a water treatment plant. Potable water for the plant site will be treated prior to plant entry in a reverse osmosis (RO) water treatment plant. The safety showers will be supplied from a 23 m³ chilled water tank, and distributed around the plant site using duty or standby pumps via a ring main.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Consultant - Costs	Alistair Kent		May 7, 2020
Consultant - Recovery Methods	Paul Staples		May 7, 2020
Environmental Manager	Sarah Watson		Nov 14, 2024
Project Executive	Bryan Bailie		Nov 14, 2024