Westar Resources Ltd (ASX:WSR) has identified prospective geology for gold and base metals following targeting work and first-pass mapping at the Opaline Well Project in Western Australia’s Pilbara region.
A detailed litho-structural interpretation and targeting exercise completed by geophysical specialists, PGN geoscience, has provided encouragement.
Adding to this has been a reconnaissance exploration program consisting of first-pass geological prospect mapping from two areas of interest.
Samples gathered
There were 63 rock chip samples collected that confirmed gold anomalism and the potential to host base metals mineralisation (VMS), including copper, cobalt, nickel and zinc.
In addition, prospective geology including ironstone outcrop (potential gossans), chert horizons and quartz veining, has been noted along strike and parallel to the zones of interest and these areas are assigned for follow up rock chip sampling and mapping.
"Very active Pilbara region"
Westar managing director Karl Jupp said: ”Opaline Well is based in the very active Pilbara region and has demonstrated prospectivity for both gold and base metal targets from our initial fieldwork program.
"We look forward to following up on these preliminary and historic results with additional geophysics, further expanded mapping and sampling programs.”
DMIRS regional gravity with historic rock chips and MINDEX locations.
PGN was engaged to complete a litho-structural interpretation and high-level targeting exercise using a combination of Westar geophysical datasets collected during quarter four of 2020 and DMIRS open file datasets.
Priority areas
This work resulted in identification of three priority areas of interest:
Area 1 (Triberton Creek) - historical gold in rock chip samples from Triberton Creek workings were reported to include 6.32 g/t, 7.95 g/t, 13.7 g/t, 13.22 g/t, 17.0 g/t, 20.5 g/t, 44.6 g/t and 200 g/t gold. Assays are interpreted to correlate with thrust faulting and late reactivation of earlier formed structures.
Area 2 (Opaline Well) - contains two gravity anomalies and is based on potential gold-VMS mineralisation around the historical Opaline Well 1 and 2 workings. Historical rock-chip samples are up to 1.15% copper, 1.85% zinc, 155 g/t silver and 0.41 g/t gold.
Area 3 - based on historic cobalt anomalies that are likely related to a discrete interval, such as a layered magmatic nickel-copper-cobalt intrusive, or alternatively, ultramafic hosted copper (cobalt, nickel, gold) VMS mineralisation.
Mapping consultants were engaged by Westar to complete reconnaissance mapping and rock chip sampling over priority areas 1 and 2 with 63 samples collected.
Gold in samples
In Area 1 rock chip samples confirm the presence of gold mineralisation to a maximum of 1.3 g/t and this area is assigned for further mapping and investigation.
A separate prospect for follow up investigation, around 4.3 kilometres SSE of the Triberton Creek shafts, shows silver, barium, copper and zinc anomalism and in particular, 0.3 g/t silver and 218 ppm copper.
Base metals in samples
Area 2’s historical workings are proximal to rock chips collected by Great Southern Mines in 1995 that returned assays of 0.35 ppm gold, 155 ppm silver, 1.15% copper and 1.85% zinc.
Field mapping identified numerous, generally ridge forming, chert units and in some cases paired ridges that are interpreted to form paired fold-limbs of a single unit.
Opaline Well chert ridges and ironstone outcrops.
The chert units and surrounding stratigraphy indicate that a considerable portion of the recognised Pilbara greenstone stratigraphic sequence is absent, which is inferred to signify a major unconformity or fault with the potential to be a mineralisation locus.
Additionally, the presence of felsic volcanic rocks adjacent to the cherts, in conjunction with anomalous rock chips such as one that assayed at 343 ppm lead, 1,080 ppm zinc and 508 ppm copper, highlights the potential for VMS base-metal mineralisation.
Pronounced arsenic enrichment in one sample of 189 ppm is also of interest, although no relationship is yet established with potential mineralisation.
Opaline Well Project location and significant gold operations in the Pilbara region of Western Australia.
Prospective for cobalt
Westar considers the Opaline Well Project to be highly prospective for cobalt and under-explored.
Historical stream sediment sampling by Anglo American in the 1970s, delineated above average and coherent corridors of elevated cobalt tenor.
The Opaline Well Project adjoins Greatland Gold PLC (AIM:GGP, OTC:GRLGF, FRA:G8G)’s Panorama Project, of which Geatland states “… known gold mineralisation and potentially the largest coherent cobalt-in streams anomaly in Western Australia” (source: https://greatlandgold.com/projects/panorama/).
Next steps
Westar intends to progress exploration at Opaline Well to advance the gold and base metals targets and is preparing further field activities.
These include additional soil and rock-chip sampling, detailed mapping over target areas 1 and 2 and an airborne electromagnetic (AEM) survey over the lease.
Once complete, the AEM data will be used, together with the mapping and surface geochemistry results and interpretations, to generate plate models of electromagnetic anomalies for drill targeting.