BALI COPPER

On 2 June 2021 Norwest announced the commencement of drill planning at its highly prospective, 100% owned, Bali Copper Project located 75 kilometres west of Paraburdoo in Western Australia. The Bali Project hosts the 8km long Bali shear being a major faulted zone proven to host copper, lead, zinc and silver mineralisation.

Norwest holds 100% of the Bali Copper Project located in Western Australia, 250 kilometres west of Newman. The project covers 41km² with five prospects identified along the 8-kilometre northwest trending Bali shear zone. The complex history of the Bali Shear combined with interaction of earlier structures has resulted in mineralisation within and adjacent to the Bali Shear[1]. Small-scale mining occurred in the 1950s and 1960s.

Bali project location map showing key copper prospects along the Bali shear zone.

Bali project location map showing key copper prospects along the Bali shear zone.  

The prospects have been lightly drill tested with most holes being less than 30 metres deep and returning intersections up to 6m @ 7.2% copper. Drilling was last undertaken by Barrack in 1989. The potential for the shear zone to host copper and/or other base metals at depth has not been tested.

In 2018, exploration included mapping along the Bali Shear Zone and the collection of 87 rock chip samples from the Bali Hi, Bali Lo and Bali East prospects. Along the surface, the potential for high-grade copper mineralisation was evidenced by visual copper associated with gossans. Assaying of the rock chips resulted in 33 samples reporting above 5% copper, 17 samples returning an impressive 10% copper or greater and a best recorded sample assaying at 36.8% copper. The copper grades of all 86 rock chip samples averaged 6.3%.

Map showing the locations of 17 copper rock chip samples grading above 10%. These samples were part of a suite of 86 rock chips collected in mid-2018

Map showing the locations of 17 copper rock chip samples grading above 10%.
These samples were part of a suite of 86 rock chips collected in mid-2018. 

Visual copper associated with gossan in rock chip samples collected along the Bali Shear Zone.
Visual copper associated with gossan in rock chip samples collected along the Bali Shear Zone.

Visual copper associated with gossan in rock chip samples collected along the Bali Shear Zone.

Historic drilling work along the Bali Shear Zone targeted copper, lead, zinc and silver mineralisation at Bali Lo and Bali High. No drilling was carried out at Bali East. The drilling was undertaken by groups including PMI (2 diamond holes in 1968), Esso (20 percussion holes in 1977) and Barrack (16 RC holes in 1984 and 21 RAB holes in 1989); a total of 59 holes for just 2,379m. Drill intercepts include:

  • 9 metres @ 1.8% Copper and 9 g/t silver from 8 metres downhole (Drill hole CL4),
  • 12 metres @ 3.6% Copper and 16 g/t silver from 0 metres downhole (Drill hole CL1B),
  • 6 metres @ 7.2% Copper and 27 g/t silver from 17 metres downhole (Drill hole CL1A).

Historic channel sampling of the Bali East prospect returned encouraging results, with assays ranging up to 20.6% copper. Sampling of the Bali South prospect similarly returned promising assays that ranged from 0.98% up to 11.3% copper[2].

The majority of holes from past drilling on the Bali shear only tested for mineralisation down to 30 metres.  As well, additional structures mapped in the project area trending adjacent to the mineralised Bali Shear Zone were not tested by historic exploration work.

An airborne electromagnetic (AEM) and magnetic survey was flown across the Bali project tenement at the end of 2018 by Norwest. The survey was designed to highlight conductors representing potential primary copper mineralisation that may be present within the project area.

The processing of the data failed to show discrete EM anomalies that present as walk-up drill targets. It was noted, however, that the profile is highly weathered and the sulphides oxidized, thus the lack of a conductive AEM response is not surprising

In May of 2021, the full Bali surface sampling and historical drill dataset was analysed by independent geochemist Dr Nigel Brand. His work confirmed the strong prospectivity for copper mineralisation in the areas previously sampled as well as many untested zones along and away from the main Bali shear.

Of the 302 rock chip samples collected over the entire Bali Project tenement, the mean value is 2.9% Cu and of the 106 (top 33% of population) the mean value is 8.7% Cu. Statistical work also shows that the Copper is dominant with only a minor association with Lead or Zinc. Observations based on the rock chip samples are set out on the ‘copper dot plot’ map below.

Summary map of May 2021 rock chip analysis by Dr Brand.

Summary map of May 2021 rock chip analysis by Dr Brand.   

Dr Brand’s work has also shown that stream sediment sampling serves as an effective low-cost exploration tool. The historical sediment samples clearly identify:

  • the Bali shear zone copper mineralisation
  • the historical Stockyard Creek copper prospect south of the Bali tenement
  • the mineralisation associated with the D2 to D3 shears and
  • a significant anomalous zinc region in the northern Bali project area (not shown).

Dr Brands analysed the historical drilling which was undertaken in 1968 (PMI), 1977 (Esso), 1984 and 1989 (Barrack) at the Bali Hi and/or Bali Lo prospects. His initial results are shown below with recommendations to drill target the extensions of the modelled grade shells.

Bali Lo drilling element shells showing elevated copper (>1%) plunging north and remains open and untested.
Maximum depth of drilling is 75m in hole CRC2 which ended in 1.35% copper mineralisation.

Bali Hi drilling element shells showing elevated (>1000ppm) Cu, Zn & Pb and indicates
a north plunging mineralised system which remains open.

Norwest is using the recent analytical results to drill-target the more prospective copper areas at Bali including the Bali Hi, Bali Lo and the Bali East prospect. Mapping, stream sediment and rock chip sampling will also be undertaken to across areas including the D2 to D3 shears and the untested ridges that run parallel to the Bali Shear zone.  

[1] Painter, M, 2006, Bali Hi Prospect – Reconnaissance Mapping and Geology of the Bali Hi Exploration Tenement: RSG Global Consulting on behalf of Globe Uranium Ltd/span>
[2] Norwest Minerals Limited Prospectus, Independent Geologist’s Report, Section 3.4

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Email

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