LOCATION
NSW, Australia
YEAR
Since July 2017
POTENTIAL
3 Targets
MINERALISATION
IOCG
Overview
The historic Cangai Copper Mine was one of the most successful mining operations in NSW during the early 1900s
Discovery of supergene ore, rich in azurite and malachite, implies the presence of an enriched copper resource
Full extent of orebody remains undetermined. It remains open to the east, south-east and down dip
JORC MRE: 4.4Mt @ 2.5% Cu inferred and 0.2Mt @ 1.35% Cu indicated for ~114kt contained copper
Location
The Cangai Copper Project area is located approximately 40kms west of Grafton, in north-east New South Wales.
Geology
Castillo Copper Limited’s Cangai Copper Project consists of three exploration tenures: EL 8625, EL 8635 and EL 8601.
The Cangai Copper Project is classified as a structurally controlled, hydrothermal deposit, hosted near to a steeply dipping shear zone within hornfelsed volcanoclastic sequences, including dacitic volcanics and tuffaceous sediments of the Willowie Creek Beds.
This sequence is intersected by two generations of steeply dipping dykes: an older hydrothermally altered micro-tonalite and younger crosscutting lamprophyre dyke. It is possible that the interaction of the dykes and shears created weak areas for fluid flow and mineral deposition.
Cangai features a high-grade supergene zone, dominated by malachite and azurite. Below the base of complete oxidisation, the fresh mineralised rock is dominated by chalcopyrite, bornite and minor sphalerite.
Veins composed of late stage, chlorite-carbonate quartz-pyrite are widespread and appear to be associated with mineralisation. The occurrence of pyrite disseminations and fracture fill is commonly observed.
Beyond the Cangai Copper Project, previous explorers have documented multiple instances of mineral occurrences and mapped additional mineralised dykes.
Exploration
The Cangai Copper Project, first discovered in 1901, operated during two periods (1904-17 and 1934-37), yielding over 5,000 tonnes of copper.
Following the closure of the mine, various companies have engaged in exploration activities, with Castillo Copper leading the way with the most extensive efforts to date.
Since 2017, Castillo Copper has actively engaged in exploration activities relating to the closed Cangai Copper Mine and its associated dump and slag piles.
Between 2017 and 2018, thirty-four reverse circulation (RC) and two diamond core drill-holes totalling 5,222m were drilled.
The best intercepts from these campaigns comprised:
- 11m at 5.94% Cu; 2.45% Zn & 19.13g/t Ag from 40m including:
- 3m at 8.1% Cu; 2.84% Zn & 23.42g/t Ag from 41m
- 1m at 10.25% Cu; 1.68% Zn & 32.50g/t Ag from 48m
- 1m at 7.53% Cu; 6.04% Zn & 30.60g/t Ag from 50m (CC0023R)
- 5m @ 1.56% Cu, 4.43g/t Ag & 0.4% Zn from 92m including:
- 3m @ 2.22% Cu, 6.38g/t Ag & 0.60% Zn (CC004RC)
- 4 4.39m @ 5.06% Cu, 2.56% Zn and 20.1 g/t Ag from 49.9m (CC0036D)
Findings from Drillhole Electromagnetics (DHEM) reveal sizeable conductors at greater depths, whilst fixed Loop Electromagnetic (FLEM) results identify promising drilling opportunities both beyond and beneath established historical mining areas.
2023 Mineral Resource Estimate
Castillo Copper’s geological team, collaborating with a specialised geological consultancy, has generated a revised Mineral Resource Estimate (MRE) for the Cangai Copper Mine.
The estimate, compliant with the JORC (2012) standards, indicates 4.4Mt at 2.5% Cu as inferred in situ, along with 0.2Mt at 1.35% Cu indicated from historical stockpiles. This amounts to approximately 114,000 tonnes of contained copper metal, enhanced by additional credits for zinc, gold, and silver.
When updating the maiden 2017 MRE (3.3Mt at 3.35% Cu for 108,000t) the geological team included data from reverse circulation and diamond core drilling conducted between 2017 and 2018 and incorporated more cautious assumptions to enhance confidence in the updated 2023 MRE.
The Mineral Resource wireframes were generated using a 0.1% Cu wireframe threshold and reported using a reporting cut-off grade of 0.2% Cu.
Exploration Upside
The geology team note encouraging observations that underpins significant exploration potential for Cangai Copper Mine, including:
- The underlying orebody, which commences from surface, is not fully defined, as it remains open to the east, south-east and down dip.
- There are several sizeable electromagnetic conductors, proximal to the line of lode, that can potentially extend known mineralisation along strike.
With the revised 2023 MRE enhancing Cangai Copper Mine’s robust fundamentals, the Board is highly optimistic Castillio Copper can align with a strategic partner to fully develop the project’s copper potential.