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Australia

Whim Creek Heap Leach Project

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Overview

Mine TypeOpen Pit & Underground
StagePermitting
Commodities
  • Copper
  • Zinc
  • Lead
  • Silver
  • Gold
Mining Method
  • Truck & Shovel / Loader
  • Longitudinal retreat
  • Avoca
  • Longhole open stoping
Backfill type ... Lock
Mine Life... Lock
SnapshotThe Whim Creek Heap Leach Scoping study, released in September 2023, considers processing of oxide, transitional and low-grade sulphide ore using the existing recently refurbished and fully permitted heap leach infrastructure located at Whim Creek. The heap leach is proposed to operate in parallel with the proposed 400 ktpa concentrator considered in the April 2023 Definitive Feasibility Study of the Whim Creek project. The heap leach is assumed to commence production in the third year of operation.
Related AssetWhim Creek Project

Owners

SourceSource
CompanyInterestOwnership
DEVELOP Global Ltd. 20 % Indirect
Anax Metals Ltd. 80 % Indirect
The Whim Creek Project is jointly held by Anax Metals Ltd. (80%) through its wholly owned subsidiary, Whim Creek Metals Pty Ltd, and Develop (20%) through wholly owned subsidiaries, Venturex Pilbara Pty Ltd and Jutt Resources Pty Ltd.

Contractors

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Deposit type

  • VMS

Summary:

The Whim Creek Project comprises four deposits: Mons Cupri, Whim Creek, Evelyn and Salt Creek deposits, which are interpreted to be VMS-style deposits.

The base metal deposits that comprise the Project all occur within the Whim Creek Greenstone Belt, a granite-greenstone terrane that formed between 3,600 Ma and 2,800 Ma, part of the Archaean-aged Pilbara Craton.

The Whim Creek volcanics crop out as a continuous arcuate belt some 85 km long and 5-10 km wide, that extends around the southern, eastern and northern flanks of the ovoid Caines Well batholith. The western limit of the southern arm of the volcanic arc is blanketed by Late Archaean rocks, although it may extend further west and overly the Sholl belt. The northern flank is wedged out between the Caines Well batholith and the Scholl Shear. All stratabound VMS deposits in the Whim Creek belt (i.e., Mons Cupri, Salt Creek and Whim Creek) are at the same or equivalent stratigraphic level within the Mons Cupri Volcanics or Rushall Slate and their distribution indicates widespread volcanogenic hydrothermal activity during accumulation of the volcanic pile.

The Whim Creek Deposit mineralisation occurs at a stratigraphic position some 150 to 200 m above the base of the Rushall Slate. Mineralisation occurs as either higher-grade rhyolite-hosted zinc or copper rich lenses, or as stratiform bedding-parallel mineralised lenses within sericite-chlorite altered argillite and siltstone units of the Rushall Slate. The mineralisation dips moderately to the north and can be traced along strike for over 600 metres. It extends down dip below the base of the current pit for approximately 120 m and has a thickness of between 5 to 8 metres. Transform faults displace mineralisation at the western and eastern margins of the main mine horizon.

Dimensions
The main modelled mineralized domains have a total dimension of 1000m (east-west), and 250m (north-south) in stacked lenses and ranging between -150m and 100m RL (AMSL).

Salt Creek
The Salt Creek copper-zinc-lead-silver(-gold) deposit consists of two mineralised zones hosted towards the top of a sequence of volcaniclastic siltstones overlain by basaltic andesite flows and tuffs. The deposit is closely associated with a thick underlying rhyolitic pile containing a welldeveloped coarse pyroclastic unit towards the top within the north–easterly trending Whim Creek belt in the western Pilbara Craton. The deposit is an example of an Archaean volcanogenic massive sulphide (VMS) style deposit that has undergone post-mineralisation deformation and mineralisation remobilisation.

The known mineralisation is hosted in tuffaceous siltstones and is overlain by andesite flows and tuffs. Massive sulphides at Salt Creek occur as two separate lenses approximately 200 m apart along strike. The western lens is interpreted to extend to a depth of approximately 250 m below surface, while the eastern lens extends to at least 420 m below surface and remains open at depth.

These deposits are interpreted to form in close association with submarine volcanism through the circulation of hydrothermal fluids and subsequent exhalation of sulphide mineralisation on the ancient seafloor similar to present-day black smokers. VMS mineralisation typically forms concordant or strata-bound lenses of polymetallic semi-massive to massive sulphides, which are underlain by discordant feeder-type vein-systems and associated alteration.

The mineralised domain interpretations were based upon a combination of geology, mineralisation (sulphide) logging, supporting multi-element lithochemistry (where available) and a lower cut-off grade of 0.4% Cu (for the lower-grade boundary of the Cu zones) and 1% Zn (for the lower-grade boundary of the Zn zones). Distinct internal high-grade massive sulphide Zn zones were also modelled correlating to an approximate 8-10% Zn cut-off. Domains were constrained by drilling along strike and extrapolated down plunge roughly to approximately 50m where appropriate. Domains were extrapolated below the deepest drill intercept based on the geological model and interpreted continuity, although the deeper blocks with limited drill support were not necessarily classified according to the JORC (2012) Code.

Dimensions
The combined modelled mineralized domains are present over a total dimension of 500m (eastwest), and 500m (vertically) in numerous lenses up to 200-300m long down-plunge and ranging between 10m and -490m RL (AMSL).

Mons Cupri
The Mons Cupri copper-zinc-lead deposit is hosted by the Mons Cupri Volcanics (Fitton et al., 1975), which is a complex sequence of felsic volcanic, volcanoclastic and epiclastic sedimentary rock and felsic intrusive bodies within the north-north easterly trending Whim Creek belt in the western Pilbara Craton. The deposit is an example of an Archaean volcanogenic massive sulphide (VMS) style deposit in a low-grade metamorphic terrain.

The Mineral Resource covers the strata bound, massive sulphide and underlying stringer mineralisation identified by drilling. The Main Mons Cupri zone measures ~300 metres (NW) by 160 metres (NE). It is approximately 5-20 metres thick and dips to the west at 30 degrees. Its stringer zone measures 350metres (EW), 150 metres (down dip) and is generally 30 metres thick.

Evelyn
The Evelyn copper-zinc-lead-silver-gold deposit comprises two high-grade shoots which are hosted within an altered volcaniclastic turbiditic sediment.

Evelyn occurs within the Archaean-aged Pilbara Craton, a granite-greenstone terrane formed between 3,600 Ma and 2,800 Ma.

The Evelyn prospect, located 25 km south of the major Mons Cupri and Whim Creek prospects, occurs along the contact between mafic-ultramafic units of the De Grey Group and sediments of the Constantine Sandstone which forms part of the north-plunging Croydon Anticline of the Mallina Basin. The sequence is considered a lateral equivalent of the Whim Creek Greenstone Belt. The mineralisation has been interpreted to have formed in a volcanogenic massive sulphide (VMS) setting.

Drilling has revealed that copper-zinc mineralisation is hosted in a sequence of volcaniclastic turbiditic sediments along the western limb of the steeply plunging Croydon Anticline. The mineralisation dips steeply to the northwest. The dimensions of the mineralisation extend for approximately 390 m along strike and down dip for 250 m. The maximum true width of the mineralisation is ~16 m. It is characterised by high-grade copper and zinc cores with gold grades exceeding 1 g/t. The mineralisation style is somewhat enigmatic and interpreted to be either VMS or hydrothermal.

The mineralised domain interpretations were based upon a combination of geology, mineralisation (sulphide) logging, supporting multi-element lithochemistry (where available) and a lower cut-off grade of 0.3% Cu for the lower-grade boundary. A distinct internal high-grade massive sulphide zone was also modelled correlating to an approximate 2% Cu cut-off. Domains were constrained by drilling along strike and extrapolated down plunge roughly to approximately 30m.

Dimensions
The main modelled mineralized domains have a total dimension of 10m (east-west), and 300m (north-south) in three key lenses 70-100m long and ranging between -170m and 95m RL (AMSL).

Reserves

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Mining Methods

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Comminution

Crushers and Mills

Milling equipment has not been reported.

Processing

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Production

CommodityProductUnitsLOM
Copper Cathode t 8,875
Zinc Sulphate t 13,325

Operational metrics

Metrics
Annual processing capacity  ....  Subscribe
Tonnes processed, LOM  ....  Subscribe
* According to 2023 study.

Production Costs

CommodityUnitsAverage
Assumed price Zinc USD  ....  Subscribe
Assumed price Copper USD  ....  Subscribe
* According to 2023 study / presentation.

Operating Costs

Currency2023
Processing costs ($/t milled) AUD  ....  Subscribe
* According to 2023 study.

Project Costs

MetricsUnitsLOM Total
Pre-Production capital costs $M AUD  ......  Subscribe
Total OpEx $M AUD  ......  Subscribe
Pre-tax Cash Flow (LOM) $M AUD  ......  Subscribe

Heavy Mobile Equipment

Fleet data has not been reported.

Personnel

Mine Management

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Jan 12, 2024
....................... Subscription required ....................... Subscription required Subscription required Nov 16, 2023
....................... Subscription required ....................... Subscription required Subscription required Nov 16, 2023
....................... Subscription required ....................... Subscription required Subscription required Nov 16, 2023

Aerial view:

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