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.
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Summary:
The Whim Creek Project comprises four deposits - Whim Creek, Mons Cupri, Salt Creek and Evelyn.
The Mons Cupri, Whim Creek, Evelyn and Salt Creek deposits are interpreted to be VMS-style deposits. VMS-style deposits are classed under the general heading of “exhalative” deposits, which also include sedimentary exhalative type deposits and form at or near the seafloor through the circulation of hot, metal-rich hydrothermal fluids. These hydrothermal fluids undergo rapid cooling as they come into contact with the ocean floor, resulting in the precipitation and accumulation of metals, similar to present-day black smokers.
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.
Whim Creek
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).
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.
Dimensions
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.
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).
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).
Production
Gold(Precious Metal) Concentrate: Along with 39 g/t Au and 146 g/t Ag, the precious metals concentrate also contains 6% Cu and 2.8% bismuth.
| Commodity | Units | LOM |
|
Copper
|
kt
| 251 |
|
Zinc
|
kt
| 152 |
|
Lead
|
kt
| 39 |
|
Gold
|
kt
| 5.9 |
All production numbers are expressed as concentrate.