The Whundo Project is located approximately 40 km south-southwest of Karratha in the West Pilbara Region of Western Australia and is approximately 12.5 km southeast of the Radio Hill nickel plant (Figure 1).
The known copper and zinc deposits at Whundo are confined to a single stratigraphic horizon as a series of NW to NNW plunging shoots that outcropped as a sinuous line of discontinuous goethite- hematite gossans that can be traced for some 500 metres along strike. Individual ore shoots have a restricted strike length and are commonly 1-5 metres thick but reach a maximum thickness of 20 metres in the hinge zone of two small upright synclines in the axis of the major synclinal structure where they form the Whundo deposits.
The stratigraphic sequence at Whundo has undergone upper greenschist to lower amphibolite grade metamorphism, and is overprinted, in part, by hornblende hornfels contact metamorphism. These units have been folded about a moderately north plunging (25°-45°) synformal structure.
The West Whundo deposit outcropped as a gossan folded around a synclinal nose. The gossan was about 135 metres in length and up to 10 metres wide in the core of the syncline which plunges shallowly to the north. The gossan was surrounded by chloritic and sericitic schists, and with volcanic rocks present in the sequence.
Secondary copper mineralisation at West Whundo is present in two zones within the syncline; a southern zone centred about 75 metres to the north of the gossan, and a northern zone centred a further 90 metres to the NNE. The southern zone has a diameter of about 60 metres and the northern about 30 metres.
Figure 1: West Pilbara regional geology (Source GSWA 1:500,000 digital geological map with units modified to simplify legend. MGA94 Zone 50 coordinates)
2022 Drilling Program
In early 2022, GreenTech undertook a maiden 4,974m RC drill program at Whundo and Ayshia to test multiple drill-ready targets aimed at growing the existing JORC 2012 compliant resources at Whundo, as well as lateral and deeper extensions to the eastern and western lobes of the Whundo resource.
At Whundo, the Company drilled 25 holes for 3,838m, with significant intersections returning:
- 32m @ 2.43% Cu from 75m, including 17m @ 4.37% Cu and 0.46% Zn from 90m, including 7m @ 7.83% Cu, 0.64% Zn and 0.26g/t Au from 95m in RC0051
- 62m @ 1.12% Cu, 1.36% Zn and 0.36g/t Au, including 19m @ 1.6% Cu, 2.27% Zn and 0.51g/t Au from 21m in RC0071
- 45m @ 1.15% Cu and 2.6% Zn from 23m, including 12m @ 9.17% Zn, 2.34% Cu and 0.62g/t Au from 52m in hole 22GTRC0081
- 8m @ 2.65% Cu, 0.64% Zn and 0.11g/t Au from 141m in hole 22GTRC017
- 10m @ 2.85% Cu and 0.96% Zn from 162m in hole 22GTRC023
Figure 2: Whundo Project Area showing VTEM anomaly outlines from late-time VTEM data.
Combined Whundo Project Resources
The combined Whundo and Ayshia resources are shown in Table 1 below (refer ASX announcement dated 11 May 2022 for full details).
Table 1: Combined Whundo and Ayshia JORC 2012 Mineral Resource Estimate
|Ore Type||Grade Range||Tonnes (kt)||Cu (%)||Zn (%)||Cu Eq (%)||Cu Metal (t)||Zn Metal (t)||Total
*Whundo deposit resource reported in 2018 using LME metal prices Cu US$6,058/t, Zn US$2,457/t and using 0.5% CuEq cut-off grade
**Ayshia deposit resource reported using LME metal prices for 6/5/2022; Cu US$9,428/t, Zn US$3,828/t, Au US$1,833/oz, Ag US$22.38/oz and using a 0.5% CuEq cut-off grade
Figure 3: Projected Cross Section A-B showing broad zones of high-grade copper, zinc and gold intercepts at Whundo
Downhole electromagnetics (DHEM)
Concurrently with the 2022 RC drilling program, GreenTech carried out DHEM surveys on three drill holes at Whundo. Strong DHTEM anomalies were defined in each of the three surveyed drill holes (22GTRC011, 22GTRC019 and 22GTRC024). The strongest “off-hole” anomaly is located to the north of hole 22GTRC024 which also reported a local “in-hole” response at approximately the same depth (Figure 4). The smaller local EM response in hole 22GTRC024 coincides with a 2m thick mineralised interval which returned an assay of 1.5% Cu from 209m depth located within a broader mineralised zone of 12m @ 0.25% Cu also from 209m depth. This intercept could represent a peripheral intercept to the larger conductor target. Five historic drill holes, three of which were collared over the target, did not test the conductor due to their inclination and depth.
The larger strong conductor (~6,000 to >10,000 siemens) in drill hole 22GTRC024 has not been previously drill tested and represents a high priority for testing with a target depth of ~200-250m. The modelled areal size of the conductor plate which has a northerly dip of ~200 -300 is considered significant with a 200m plus strike and down plunge extent of at least 40-60m. The vertical extent of the conductor is not known as it cannot be determined from the survey data. However, as the target has similar dip and width as the Whundo deposit, it may represent an extension or deeper repetition of the Whundo deposit.
Figure 4: Whundo Section Showing Location of Austin Conductor Plate