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Australia

Beta Hunt Mine

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Overview

Mine TypeUnderground
StatusActive
Commodities
  • Gold
  • Nickel
Mining Method
  • Longhole stoping
  • Room-and-pillar
  • Cut & Fill
  • Longitudinal retreat
  • Airleg stoping
Backfill type
  • Unconsolidated rockfill
Production Start1974
Mine Life2028
SnapshotBeta Hunt is a gold producing underground operation with nickel by-product credits. Gold bearing ore from Beta Hunt is blended with Higginsville Gold Operations material for feed into the 1.6 Mtpa Higginsville processing plant. Concurrently, material from Beta Hunt is also treated at the 1.0 Mtpa Lakewood Mill.

All nickel ore from Beta Hunt is processed at BHP’s Kambalda Nickel Concentrator. BHP announced it will be placing the Kambalda Nickel Concentrator on care and maintenance from mid 2024 thereby impacting processing options for Beta Hunt’s nickel ore. Beta Hunt’s nickel ore has been successfully and economically processed through BHP’s Leinster Concentrator. The potential to process nickel ore through Leinster is currently being reviewed.

The expansion of Beta Hunt mining production rate to 2.0 Mtpa during 2024 include the completion of ventilation and other infrastructure that is required to support these areas, and an expanded mining equipment and trucking fleet.

Owners

SourceSource
CompanyInterestOwnership
Karora (Beta Hunt) Pty Ltd. (operator) 100 % Direct
Karora Resources Inc. 100 % Indirect
Karora owns 100% of the Beta Hunt mine through its wholly owned subsidiary Karora (Beta Hunt) Pty Ltd, which owns and operates the Beta Hunt mine.

April 7, 2024 - Karora Resources Inc. and Westgold Resources Limited have agreed to combine in a merger pursuant to which Westgold will acquire 100% of the issued and outstanding common shares of Karora by way of a statutory plan of arrangement under the Canada Business Corporations Act.

July 24, 2024 - Karora Resources Inc. has obtained the final court order from the Ontario Superior Court of Justice (Commercial List) approving the previously announced plan of arrangement under the Canada Business Corporations Act in respect of its merger with Westgold Resources Limited.

The Arrangement is expected to become effective on or about August 1, 2024.

Contractors

ContractorContractDescriptionRef. DateSource
DEVELOP Global Ltd. Mine Development DEVELOP Global Ltd. will see it undertake specialized underground development activities for Karora Resources at its Beta Hunt mine in the Kambalda/Southern Goldfields district of Western Australia. The work on the Fletcher & Western Flanks South Development at Beta Hunt is underway. Temporary surface infrastructure construction has also started with the contractor workshop and office buildings. Mar 21, 2024
unawarded or unknown Haulage Haulage of material from the mine to processing facilities. Sep 30, 2023

Deposit type

  • Vein / narrow vein
  • Magmatic
  • Mesothermal

Summary:

The sub-lease covers the lower stratigraphy of the Kambalda Dome sequence comprising the footwall Lunnon Basalt, overlain by the Silver Lake and Tripod Hill members of the Kambalda Komatiite. The stratigraphy is intruded by quartz-feldspar and intermediate porphyry sills and dykes.

The nickel deposits on the Beta Hunt sub-lease are examples of the Kambalda style komatiitehosted nickel sulphide deposits. The characteristics of the Western Flanks and A Zone gold lodes at Beta Hunt are consistent with the greenstone-hosted quartz-carbonate vein (mesothermal) gold deposit model.

Nickel Mineralization
Nickel mineralization is hosted by talc-carbonate and serpentine altered ultramafic rocks. The deposits are ribbon-like bodies of massive, matrix and disseminated sulphides varying from 0.5 m to 4.0 m in true thickness but averaging between 1.0 m and 2.0 m. Down dip widths range from 40 m to 100 m, and the grade of nickel ranges from below 1% to 20%. Major minerals in the massive and disseminated ores are pyrrhotite, pentlandite, pyrite, chalcopyrite, magnetite and chromite, with rare millerite and heazlewoodite generally confined to disseminated mineralization. The hangingwall mineralization tends to be higher tenor than the contact material. The range of massive ore grades in the hangingwall is between 10% Ni and 20% Ni while the range for contact ore is between 9% Ni and 12% Ni. The hangingwall mineralogy varies between an antigorite/chlorite to a talc/magnesite assemblage. The basalt mineralogy appears to conform to the amphibole, chlorite, plagioclase plus or minus biotite.

Unlike other nickel deposits on the Kambalda Dome, the Beta Hunt system displays complex contact morphologies, which leads to irregular ore positions. The overall plunge of the deposits is shallow in a southeast direction, with an overall plunge length in excess of 1 km. The individual lode positions have a strike length averaging 40 m and a dip extent averaging 10 m. The geometry of these lode positions vary in dip from 10° to the west to 80° to the east. The mineralization within these lode positions is highly variable ranging from a completely barren contact to zones where the mineralization is in excess of 10 m in true thickness.

The Hunt and Lunnon shoots are separated from the Beta and East Alpha deposits by the Alpha Island Fault. Hunt and Beta both occur on the moderately dipping western limb of the Kambalda Dome and are thought to be analogous. Similarly, Lunnon and East Alpha occur on the steeply dipping eastern limb of the dome and also have similar characteristics.

Gold Mineralization
Gold mineralization is focused about the Kambalda Anticline and controlled by northwest trending, steep, west dipping shear zones associated with re-activated normal faults that previously controlled the komatiitic channel flow and associated nickel sulphide deposition. Gold mineralization is interpreted as a D3 extensional event associated with porphyry intrusives, the source of magmatic hydrothermal fluids carrying the gold.

Mineralization is hosted dominantly in Lunnon Basalt (below the ultramafic contact) with minor amounts associated with specific porphyry intrusives. Not all porphyries are mineralized; some are intruded post-mineralization. The basalt (and porphyries) are preferred mineralization hosts as a result of their susceptibility to hydraulic fracturing to form quartz veining, with the migrating ore fluids causing wall-rock alteration. The migrating ore fluids associated with shearing are interpreted to pass through the overlying ultramafic (because of its ductile nature), developing as mineralization only where the shear zone passes through more competent rock, e.g. porphyry and basalt.

Gold mineralization occurs in broad, steeply dipping, north-northwest striking quartz vein systems within biotite-albite-pyrite altered shear zones hosted by the Lunnon Basalt. Veining is dominated by shear parallel and extensional vein styles. In the Hunt Block, mineralized shears are represented by the A Zone, Western Flanks and Fletcher zones. The interpreted offset to the Western Flanks is represented by the Larkin shear zone to the south of the AIF in the Beta Block.

The East Alpha shear zone is interpreted by analogy to the known mineralized quartz vein systems; further drill testing is required to confirm its existence.

Coarse, specimen quality occurrences of gold can occasionally be found where the mineralized shears intersect the interflow sediment horizon and the overlying nickel-bearing basalt/ultramafic contact.

A Zone
Gold mineralization in A Zone is located below the A Zone nickel surface and is composed of a large, brecciated quartz vein that has a near vertical dip striking at 320°. A Zone varies in thickness from 2 m to 20 m wide with a low to medium grade distribution. The A Zone shear is mineralized over approximately 1.5 km of strike length with the northern portion containing the higher grade and greater thickness. Subparallel mineralized structures are found in both the hangingwall and footwall to the main A Zone shear. These structures appear to be of a similar nature to the main mineralized zone and are considered to be splays within a major anastomosing shear system.

Western Flanks
Mineralization comprises a main, northwest striking (320°), steep southwest dipping shear zone up to 20 m in width, over 1.2 km in strike length with a 500 m down dip extent and remains open to the north and down dip. Coarse ‘stockwork’ mineralization dominated by shallow, east-dipping extensional quartz veins occur in the hangingwall of the main shear. The combined main shear and hangingwall mineralization can, in places, be up to 50 m thick. The main shear zone consists of both shear and extensional veining associated with biotite-albite-pyrite alteration. Mineralization within the hangingwall is characterised by a lack of shearing and shear veins. Extensional veins in the hangingwall frequently contain specks of visible gold. The shear zone is dextrally offset to the south by the Alpha Island Fault. Felsic porphyries strike oblique to mineralization and zones of high grade are found along the margins where they are adjacent to or host mineralized structures.

Coarse, specimen quality gold similar to that found with the A Zone deposit is also found associated with the Lunnon interflow sediment within the main Western Flanks shear zone.

Coarse, Specimen Gold
Mining by Karora has intersected and recovered significant coarse, specimen grade gold mineralization (>1% Au) associated with the basalt/ultramafic contact and, more recently, with an interflow sediment within the Lunnon Basalt where it intersects the A Zone shear.

This style of mineralization is intermittently found associated with the A Zone, Western Flanks and Beta mineralization zones, where the mineralized shears intersect iron sulphide-rich contacts represented by the main basalt/ultramafic contact and pyritic interflow sediment (A Zone).

Beta Block
Mineralization in the Beta Block, which includes the Larkin deposit and new Mason deposit, is interpreted to be an offset extension to the Western Flanks and A Zone mineralization, with a dextral offset of between 100 m and 150 m. Beta is again characterised by a series of subvertical quartz veins within a sheared basalt. Mineralization at Beta has a more disjointed and erratic form, with narrow discontinuous lodes that have a strike extent of 20 m to 100 m. Lodes vary in thickness from 1 m to 5 m, commonly with high grades being present on the contacts of porphyries and ultramafic.

Fletcher Trend
The Fletcher Shear Zone is a parallel structural analogue to the Western Flanks and A Zone gold deposits occurring approximately 500 m west of the Western Flanks vein system. The Fletcher Shear Zone is interpreted to represent the offset continuation of the Beta nickel and gold mineralization across the Alpha Island Fault.

Reserves at September 30, 2023

The Mineral Reserve is reported at a 1.8g/t incremental cut-off grade.

The Gold Mineral Resource is reported using a 1.4 g/t Au cut-off grade.
The Nickel Mineral Resource is reported above a 1% Ni cut-off grade.

Mineral Resources are reported inclusive of Mineral Reserves.
CategoryTonnage CommodityGradeContained Metal
Proven 316 kt Gold 2.7 g/t 28 koz
Probable 6,260 kt Gold 2.7 g/t 545 koz
Proven & Probable 6,577 kt Gold 2.7 g/t 573 koz
Measured 1,278 kt Gold 2.8 g/t 116 koz
Indicated 16,855 kt Gold 2.7 g/t 1,484 koz
Indicated 776 kt Nickel 2.9 % 22,300 t
Measured & Indicated 18,133 kt Gold 2.7 g/t 1,600 koz
Inferred 12,865 kt Gold 2.6 g/t 1,086 koz
Inferred 500 kt Nickel 2.7 % 13,400 t

Mining Methods

  • Longhole stoping
  • Room-and-pillar
  • Cut & Fill
  • Longitudinal retreat
  • Airleg stoping

Summary:

At Beta Hunt gold is primarily mined by longhole stoping methods, while nickel is mined by airleg slot stoping and mechanized cut and fill.

Beta Hunt Gold Operation
Beta Hunt is a mechanised underground mine accessed from established portals and declines. The mine is producing at a rate of approximately 100,000 t/month ore. Gold mine production is processed at Karora’s 100% owned Higginsville and Lakewood processing facilities located 78 km by road to the south and 61 km by road to the north, respectively.

The mine is accessed via established portals and declines. Pumping, ventilation, power and mine service infrastructure is established and in use for current mining operations.

Underground gold mining currently takes place in two mining areas, the Western Flanks and the A Zone, with planned mining of the Larkin deposit within the next year. The strike of the A Zone and Western Flanks totals approximately 1,500 m, with stoping occurring over a total vertical extent of approximately 500 m. Western Flanks and A Zone employ a top down, longhole retreat mechanized mining method which suits the subvertical nature of the orebody. Mining at Larkin will also utilise the same mining method.

In situ rib and sill pillars are left at geotechnically specified positions, with sill pillars typically at 75 m vertical intervals.

The mine is accessed by portals and a series of declines throughout the mine. The declines are typically 5.5 mW x 5.8 mH, with a standard ore drive size of 5.0 mW x 5.0 mH. Lateral development profiles are well matched to the mobile fleet. Ore is hauled from the underground to surface via the decline where it is then transported via a separate surface haulage fleet to the processing facility.

The primary mining method used at Beta Hunt is top down, mechanised long hole retreat. Current stope design dimensions are typically 25 m high, vary in width from 5.0 m to 25 m and up to 50 m on strike. In situ rib and sill pillars are left at geotechnically specified positions, with sill pillars typically left at 75 m vertical intervals. Waste is used to backfill voids where possible. No other methods of backfilling stopes is employed in the mine plan.

The typical stope ore cycle post ore drive development is:
• Drilling of blast holes using a longhole drilling rig;
• Charging and firing of blast holes;
• Bogging of ore from the stope using conventional and tele-remote loading techniques;
• Loading of trucks with a load-haul-dump (“LHD”) loader;
• Trucks haul ore to surface via the portal; and
• Surface trucks haul ore to the processing facility.

Lateral development drives are excavated using mechanised twin boom jumbos, with vertical development excavated using a raisebore drill rig.

Site performance has ramped up in recent months to 130 kt/month ore, made possible with an increase to the mining fleet size. Karora is targeting a 140 kt/month ore production rate which is underpinned by the 2023 Mineral Reserve estimate.

Beta Hunt Nikel Operation
The nickel operation extracts mineralization hosted in two distinctly different styles of mineralization:
• In the Gamma, Beta Central and parts of Beta Southwestzones, where nickel mineralization is narrow vein and flat lying, mineralization is mostly mined with handheld airleg drills, using the room-and-pillar method.
• In the East Alpha, Beta 40, and parts of Beta Southwest zones, where nickel mineralization is narrow vein and more steeply dipping, mineralization is mined with small scale mechanised equipment, using a cut-and-fill method.

The room-and-pillar method is mined conventionally, using handheld airleg drills. These drills are also used for installation of rock bolts. Holes are charged using ANFO and the target advance is 2.0 m per round. In the flat-lying room-and-pillar stopes, broken ground is scraped using winches to ore drives at the front of the stopes or into an orepass feeding a stockpile. Here, material is excavated using narrow vein (3 t payload) LHDs and trammed to re-muck stockpiles where it is rehandled by the large LHD onto 50 t trucks.

In the steeply dipping flat back stopes, the loading drives have been sized to allow immediate loading of broken material by narrow vein LHDs, eliminating the need for scrapers. Material is also excavated using narrow vein (3 t payload) LHDs and trammed to re-muck stockpiles where it is rehandled by the large LHD onto AD60 trucks.

Mine Design
Stopes are established with an initial 3.5 m by 3.5 m cleaning/bogging ore drive along the down-dip side of the stope, extending the entire strike length. This bogging drive allows sufficient operating space for a typical narrow vein LHD to load ore which ultimately gets scraped down from the roomand-pillar broken ore sections. Some areas aimed to reduce development by establishing a crosscut below the mining horizon and developing two separate rises to access the room-and-pillar sections. One rise is used for a travelling way, while the other serves as a short ore pass, cleaning ore via electrical winch to a Stockpile. Ore is scraped from rooms and holings into this ore drive or ore pass using electrical scraper winches, allowing these stopes to be developed at a low stope width which is the greater of either a 1.9 m minimum width cut (measured on true-width) or actual thickness of mineralization (note that the actual thickness of mineralization gets up to 3.0 m for single pass extraction). MSO runs included material up to a maximum height of 4 m, thus allowing up to a further 1 m footwall ripping on a retreat basis. A significant portion of the Gamma orebody allows for the additional maximum of 1 m footwall ripping, as shown in Figure 16.5. The control afforded by use of handheld drills (at the expense of productivity) results in no additional dilution beyond the minimum stoping height. The planned stoping width is 1.7 m, with planned overbreak equating to an additional 0.2 m, resulting in a finished excavation height at a minimum of 1.9 m high. With the resource being wider in places, room-and-pillar ore drives were designed utilising a shanty profile and were evaluated in the design. As such no additional dilution was allowed for within these drives but were reported as ore or waste according to their evaluated grades.

All cut-and-fill sections allowed for 10% unplanned dilution, similar to traditional development, but the split-fire ore less than 2.3 m resource width included an additional 0.15 m dilution between the ore and waste contact. Recovery was planned as a standard 90% recovery, as some of the ore may be left behind bogging on top of previous waste filled cuts. A further 10% ore loss can be applied to the <1 m resource cut-and-fill sections, but will impact recovered tonnes only marginally, as these tonnes equate only 3% of the cut-and-fill mined ore tonnes and only 0.5% of the total ore tonnes mined in the project.

A portion of the cut-and-fill tonnes (~19.3% of cut-and-fill mined ore tonnes) has widths in excess of 6.5 m up to a maximum of 15.4 m wide. In subsequent levels of study these areas can be investigated in more detail and possibly utilise an alternative mining method. Some of these stopes may be more conducive to mine with room-and-pillar as dip flattens in some places or alternatively opportune sections or in steeper dipping sections longhole open stoping may be considered, dependent on geotechnical recommendations.

Comminution

Crushers and Mills

Milling equipment has not been reported.

Summary:

Higginsville Processing Facility
Crushing
Mill feed is trucked to the ROM pad from open pits in the immediate Higginsville area together with underground ore from the Beta Hunt Mine located 73 km to the north. The mill feed is classified and stockpiled according to gold grade to blend an optimal feed mix to the processing facility. Oversize mill feed is sorted from stockpiles and broken on the ROM pad using a loader or excavator. Any oversize that cannot pass through the primary crusher grizzly is broken by a rock breaker.

The crushing circuit has a nameplate capacity of 1.0 Mtpa and consists of four stages of crushing:
• A 36 x 48 Trio primary single-toggle jaw crusher;
• A 1.68 m Trio Turbocone TC66 (standard configuration) secondary cone crusher;
• A 1.68 m Trio Turbocone TC66 (short head configuration) tertiary cone crusher; and
• A 1.29 m Trio Turbocone T51 quaternary cone crusher.

There are also separate surge bins that operate in closed circuit with a 2.4 m wide by 7.3 m long Oreflow double deck vibrating screen.

Crushed material exits the product screen with a P80 of 10 mm and is stored in the fine ore bin, which has a live capacity of 1,500 t.

The crushing circuit contains one Ramsey belt scale for measuring mass of circuit ore.

Grinding
Crushed mill feed is withdrawn from the fine ore bin via a belt feeder, which transfers the crushed product onto the mill feed conveyor that feeds into the ball mill. Mill feed can also be fed via an emergency feeder, which is fed from the fine ore stockpile via FEL.

The grinding circuit consists of an overflow ball mill, hydrocyclone cluster classifier and gravity recovery circuit. The ball mill is a 4.90 m diameter by 6.77 m effective grinding length (EGL) LMMP/CITIC-HMC overflow ball mill.

The crushed mill feed is conveyed to the ball mill feed chute and combined with process water and recirculating cyclone underflow slurry. The ball mill operates in closed circuit with the mill discharge slurry classified by a cluster of hydrocyclones.

Oversize ore particles and reject grinding balls are removed from the ball mill discharge slurry by a 16 mm aperture trommel screen connected to the discharge trunnion of the mill. The oversize material (mill scats) is removed from the circuit to protect the cyclone feed slurry pumps and reduce wear rate on cyclone liners and the slurry handling equipment. Mill scats are rejected to a scats bin for removal by FEL.

Slurry from the grinding and classification circuit is passed over a trash screen to ensure that no oversize particles enter the leaching circuit and to remove plastic and other containments from the slurry. The trash screen is a 1.5 m wide by 3.6 m long horizontal vibrating screen with an aperture size of 0.80 mm. Undersize from the trash screen is directed to the leach feed distributor ahead of the 1,000 m3 leach tank.

Lakewood Gold Processing Facility
Crushing
Mill feed is trucked to the ROM pad from the underground Beta Hunt Mine located 56 km by road to the south. The mill feed is classified and stockpiled according to gold grade and is not typically blended. Oversize mill feed is sorted from stockpiles and broken on the ROM pad using a loader or excavator. Any oversize that cannot pass through the primary crusher grizzly is broken by a rock breaker.

The crushing is provided by a contract crushing provider who uses a variety of mobile crushing equipment, including jaw and cone crushers plus screens, to achieve a final crushed product with a P80 of 10 mm. This product is then stockpiled by a radial stacker onto the ground.

The crushing circuit contains one Ramsey belt scale for measuring mass of circuit ore.

Grinding
Crushed mill feed is fed by a loader via a belt feeder, which transfers the crushed product onto the mill feed conveyor that feeds into the ball mill.

The grinding circuit consists of a grate discharge ball mill, hydrocyclone cluster classifier and gravity recovery circuit.

The crushed mill feed is conveyed to the ball mill feed chute and combined with process water and recirculating cyclone underflow slurry. The ball mill operates in closed circuit with the mill discharge slurry classified by a cluster of hydrocyclones.

Oversize ore particles and reject grinding balls are removed from the ball mill discharge slurry by a 16 mm aperture trommel screen connected to the discharge trunnion of the mill. The oversize material (mill scats) is removed from the circuit to protect the cyclone feed slurry pumps and reduce wear rate on cyclone liners and the slurry handling equipment. Mill scats are rejected to a scats bin for removal by wheel loader.

Slurry from the grinding and classification circuit is passed over a trash screen to ensure that no oversize particles enter the leaching circuit and to remove plastic and other containments from the slurry. The trash screen is a 1.5 m wide by 3.6 m long horizontal vibrating screen with an aperture size of 0.80 mm. Undersize from the trash screen is directed to the leach feed distributor ahead of the 1,546 m3 leach tank.

Processing

  • Gravity separation
  • Consep Acacia Reactor
  • Centrifugal concentrator
  • Smelting
  • Crush & Screen plant
  • Intensive Cyanidation Reactor (ICR)
  • Carbon re-activation kiln
  • Flotation
  • Agitated tank (VAT) leaching
  • Concentrate leach
  • Carbon in leach (CIL)
  • Elution
  • Carbon adsorption-desorption-recovery (ADR)
  • Solvent Extraction & Electrowinning
  • Cyanide (reagent)

Summary:

Gold mine production from Beta Hunt is processed at both the 100% owned Higginsville and Lakewood processing facilities. Nickel mine production is processed at BHP’s Kambalda Concentrator.

Higginsville Mill
Gravity and Intensive Cyanidation
A gravity separation circuit is included in the design to improve the gold recovery from the hydrocyclone underflow stream.

A 100 t/h bleed of the hydrocyclone underflow stream is classified by the gravity feed screen, which is a 1.2 m wide by 2.4 m long horizontal vibrating screen with an aperture size of 3.25 mm.

Oversize from this screen returns to the ball mill feed chute for further grinding. Undersize material reports to a centrifugal concentrator to extract the gold. The gravity concentrator is a XD40 Knelson Concentrator.

The resulting concentrate is subjected to intensive cyanidation in a CS1000DM ConSep Acacia dissolution module to recover the gold. Pregnant solution from the intensive cyanidation process is pumped to the gold room for electrowinning in a CS1000EW ConSep electrowinning module.

Leaching and Adsorption
The leach and adsorption circuit consists of one 1,000 m3 leach tank and six 1,000 m3 CIL carbon adsorption tanks.

All tanks are mechanically agitated with dual, open, down-pumping impellor systems powered by 55 kW drives. Facilities are currently available to inject oxygen into Tanks 1, 2 and 3 with a high shear oxygen injector pump recirculating into Tank 1.

Leach Tank 1 is the initial oxidation (oxygen sparged) tank and receives the initial dosing of cyanide. Slurry flows from this tank into the carbon adsorption circuit.

Dissolved gold in the cyanide leach solution is recovered and concentrated by adsorption onto activated carbon (Haycarb) in the adsorption tanks.

Cyanide solution at 30% strength by weight is added to the leach tank feed distributor box and/or the first CIL tank via a flow meter and automatic control valve. The design leaching residence time is 5 hours.

Discharge from the leach tank overflows into the first of six 1,000 m3 CIL tanks, each with an average effective working volume of 984 m3 . The combined adsorption residence time is 30 hours.

In the CIL tanks, the carbon is advanced counter-current to the slurry flow, with new and regenerated carbon added to the last tank and advanced to the first tank while the slurry flows from CIL Tank 1 to Tank 6. Loaded carbon is periodically pumped from Adsorption Tank 1 to the gold room elution circuit for stripping of the gold.

The target pH in the leach circuit is 8.6, and the target cyanide concentration is up to 300 ppm. An on-line free cyanide analyser is used to control the cyanide addition. Cyanide can be added to Tank 1 and Tank 3. Dissolved oxygen probes are installed in Tanks 1 and 2.

Carbon Stripping, Electrowinning, Refining, and Carbon Regeneration
Gold is recovered from the loaded carbon by a Pressure Zadra electrowinning circuit. Gold is deposited onto steel wool cathodes by the electrowinning cells. The cathodes are subsequently washed to remove the gold concentrate which is then dried and smelted in the gold room furnace to produce gold bullion for shipment.

The gold from the gravity circuit is leached in the Acacia reactor, and it is then electroplated by the Acacia electrowinning circuit onto steel wool cathodes in the Acacia cell. The gold is recovered and smelted in a similar manner to the gold produced by the Pressure Zadra circuit.

Barren carbon is reactivated using a liquified natural gas (LNG) fired horizontal kiln at around 700°C and is returned to the adsorption circuit for reuse.

Lakewood Mill
Gravity and Intensive Cyanidation
A gravity separation circuit is included in the design to improve the gold recovery from the hydrocyclone underflow stream.

The hydrocyclone underflow stream is classified by to two gravity feed with an aperture size of 3.25 mm.

Oversize from these screens returns to the cyclone feed hopper for reintroduction back into the milling circuit. Undersize material reports to two centrifugal concentrators to extract the gold. The gravity concentrators are two XD30 Knelson Concentrator, which are always in operation.

The resulting concentrate is subjected to intensive cyanidation in a CS1000DM ConSep Acacia dissolution module to recover the gold. Pregnant solution from the intensive cyanidation process is pumped to the gold room for electrowinning in a CS1000EW ConSep electrowinning module.

Leaching and Adsorption
The leach and adsorption circuit consists of one 1,546 m3 leach tank and seven CIL carbon adsorption tanks, with total capacity of 2,337 m3 .

All tanks are mechanically agitated with dual, open, down-pumping impellor systems powered by 55 kW drives. Facilities are currently available to inject oxygen into Tanks 1, 2 and 3 with a high shear oxygen injector pump recirculating into Tank 1.

Leach Tank 1 is the initial oxidation (oxygen shear pump) tank and receives the initial dosing of cyanide. Slurry flows from this tank into the carbon adsorption circuit.

Dissolved gold is recovered from the cyanide leach solution and concentrated by adsorption onto activated carbon (Haycarb) in the adsorption tanks.

Cyanide solution at 30% strength by weight is added to the leach tank feed distributor box and/or the first CIL tank via a flow meter and automatic control valve. The design leaching residence time is 12.8 hours.

Discharge from the leach tank overflows into the first of seven CIL tanks (Tanks 11 to 17) with a combined adsorption residence time of 20 hours.

In the CIL tanks, the carbon is advanced counter-current to the slurry flow, with new and regenerated carbon added to the last tank and advanced to the first tank as the slurry flows from Tank 11 to Tank 17. Loaded carbon is pumped from adsorption Tank 11 to the gold room elution circuit periodically for stripping of the gold.

The target pH in the leach circuit is 9.6 and the target cyanide concentration is up to260 ppm. Cyanide can be added to Tank 11 and Tank 13.

Carbon Stripping, Electrowinning, Refining, and Carbon Regeneration
Gold is recovered from the loaded carbon by a Pressure Zadra electrowinning circuit. Gold is deposited onto steel wool cathodes by the electrowinning cells. The cathodes are subsequently washed to remove the gold concentrate, which is then dried and smelted in the gold room furnace to produce gold bullion for shipment.

The gold from the gravity circuit is leached in the Acacia reactor, and it is then electroplated by the Acacia electrowinning circuit onto steel wool cathodes in the Acacia cell. The gold is recovered and smelted in a similar manner to the gold produced by the Pressure Zadra circuit.

Barren carbon is reactivated using a LNG fired horizontal kiln at around 700°C and returned to the adsorption circuit for reuse.

Nickel
Processing of Beta Hunt mineralization is performed offsite, by BHP under a tolling contract.

Nickel mineralization is processed by BHP at the Kambalda Nickel Concentrator and more recently at the Leinster Nickel Concentrator, both are flotation-style nickel concentrators.

Mineralization is blended with mill feed from other mines and the recovery credited to Beta Hunt is based on the grade of feed. Concentrate produced from Beta Hunt mineralization is treated and refined by BHP under standard commercial terms.

Recoveries & Grades:

CommodityParameter20232022202120202019201820172016
Gold Head Grade, g/t 2.712.42.952.773.114.482.172.3
Gold Recovery Rate, % 949493919391
Nickel Head Grade, % 2.312.732.72

Water Supply

Summary:

Beta Hunt mine
Service water that is sourced from groundwater stored in what is effectively an aquifer created by the mined-out Silver Lake deposit. Storage tanks have been added to provide surge capacity.

Potable water is supplied by St Ives Gold Mining Company Pty Ltd and BHP.

Lakewood Gold Processing Facility
Process water stored in the process water tanks is made up of bore water, tailings return water from Lakewood, and offtake from Kalgoorlie Consolidated Gold Mines (KCGM).

Potable water trucked in from the WA Water Corporation in Kalgoorlie is utilised in the process plant, administration building, workshop and stores.

Higginsville Gold Processing Facility
Raw water is sourced from the main production source at the disused Chalice open pit 16 km to the west. Process water is stored for use in a 5,000 m3 process water dam. Process water is made up of raw water from the Chalice production source and tailings return water. Incoming raw water from Chalice reports to the disused Aphrodite pit before it is pumped to the 2,000 m3 site raw water dam.

Potable water is sourced from the WA Water Corporation supply line from Kalgoorlie to Norseman. Potable water is utilised in the process plant, administration building, workshop, stores, main camp and mining offices.

Karora holds two Licences to Take Water GWL 203328(2) and GWL 203329(2) for a combined abstraction of 900,000 kL at Lakewood for water supply. Lakewood also has an agreement with KCGM for the supply of process water from their Fimiston mining operations.

Production

CommodityProductUnits20232022202120202019201820172016
Gold Metal in doré oz 108,69879,12578,47666,47947,64262,23335,30723,002
Nickel Metal in concentrate kt 0.30.81.8

Operational metrics

Metrics202420232022202120202019201820172016
Ore tonnes mined 1,600,000 t ^1,320,355 t1,106,104 t886 kt747 kt512 kt531 kt371 kt
Tonnes milled 1,314 kt1,084 kt884 kt745 kt475 kt493 kt552,531 t354 kt
Annual ore mining rate 1 Mt
Waste 367,335 t153,045 t163,620 t
^ Guidance / Forecast.

Production Costs

CommodityUnits2023202220212020201920182017
Credits (by-product) Gold USD -24 / oz   -40 / oz  
Total cash costs (sold) Nickel USD 4.29 / lb   2.98 / lb  
Total cash costs Gold USD 1,554 / oz  
Total cash costs (sold) Gold USD 1,088 / oz **   1,045 / oz **   840 / oz **   943 / oz **   958 / oz **   924 / oz **   1,520 / oz **  
All-in sustaining costs (sold) Nickel USD 4.33 / lb   3.27 / lb  
All-in sustaining costs (sold) Gold USD 1,049 / oz   1,641 / oz  
All-in sustaining costs (sold) Gold USD 1,617 / lb **  
** Net of By-Product.

Financials

Units2023202220212020201920182017
Sustaining costs M CAD 8.8   3.4  
Revenue M CAD 278.5  190.8  185.4  160.9   94.6   101.9   35  
Operating Income M CAD 76.6  53.8  73.9  96.1   24.5   13.8   -65  

Heavy Mobile Equipment

HME TypeModelSizeQuantityStatusRef. DateSource
Drill 2 Existing Sep 30, 2023
Drill jumbo (single boom) 1 Existing Jun 30, 2022
Drill jumbo (single boom) 1 Required Jun 30, 2022
Drill jumbo (two boom) 3 Existing Sep 30, 2023
Drill jumbo (two boom) 1 Existing Jun 30, 2022
Explosives Charger 1 Required Jun 30, 2022
Loader - Tool Carrier 5 Existing Sep 30, 2023
Load-Haul-Dump (LHD) 3 t 1 Existing Jun 30, 2022
Load-Haul-Dump (LHD) 3 t 1 Required Jun 30, 2022
Load-Haul-Dump (LHD) Caterpillar R2900 17 t 7 Existing Sep 30, 2023
Load-Haul-Dump (LHD) Caterpillar R1700 14 t 1 Existing Sep 30, 2023
Truck (underground) Caterpillar AD60 60 t 6 Existing Sep 30, 2023
Truck (underground) Caterpillar AD63 63 t 6 Existing Sep 30, 2023
Truck (underground) 55 t 1 Existing Sep 30, 2023
Truck (underground) Caterpillar AD60 60 t 1 Existing Jun 30, 2022
Truck (underground) Caterpillar AD60 60 t 2 Required Jun 30, 2022

Personnel

Mine Management

Job TitleNamePhoneEmailProfileRef. Date
Chief Operating Officer Peter Ganza LinkedIn Jul 23, 2024
Environmental Manager Alex Ruschmann (08)-9278-6503 alex.ruschmann@KaroraResources.com.au LinkedIn Jul 23, 2024
General Manager Ben McAllister LinkedIn Jul 25, 2024
Mine General Manager Stasi Capsanis LinkedIn Jul 23, 2024
Mining Manager Wayne Gough LinkedIn Jul 25, 2024
Processing Manager Mark Atta-Danso LinkedIn Jul 25, 2024

Total WorkforceYear
245 2023
160 2022
100 2020

Aerial view: