- All key logistics have been finalised to enable work to commence at the prime Arya Prospect during September 2021
- A re-interpretation of legacy data by CCZ’s geophysicist consultant (1),(5) – which enabled better targeting at the Big One Deposit – provides new insights and re-emphasises Arya Prospect’s merits as a major exploration target in Mt Isa’scopper-belt:
- Notably, re-processing data from AusAEM Survey, commissioned by Geoscience Australia (2), shows the EG01 anomaly – interpreted to be 130m thick, 1,500m long & 450m wide – is only around 100-200m deep (Figure 1)
FIGURE 1: RE-PROCESSED AUSAEM SURVEY DATA
- This is a significant finding, as it highlights EG01 is much shallower than the initial ~430m depth estimate based on analysing data from BHP, which discovered the Arya Prospect in the mid-1990s (3) and recommended it be drill-tested
- Incrementally, CCZ’s geophysicist re-processed aero-magnetic data generated by Mt Isa Mines in the mid-1990s (4),(5) which highlighted a significant electro- magnetic anomaly proximal to the Arya Prospect in an otherwise quiet magnetic terrain
- Reconciling known geochemical surface results (up to 1.84% Cu in rock-chips (4)), with newly interpreted magnetic and AEM results, makes the case for test-drilling the Arya Prospect even more compelling ahead of the campaign kicking-off
- CCZ will continue developing the Big One Deposit as numerous targets are yet to be drill-tested; furthermore, the Board’s strategic intent is to model up a JORC compliant resource and, if justified, apply for a mining lease
- Note, assays are still pending for the current Big One Deposit campaign as there is a backlog at the laboratory due to a significant volume of exploratory work in the Mt Isa region
Castillo Copper’s Managing Director Simon Paull commented: “We are on track to commence drilling the prime Arya Prospect during September. Encouragingly, recent work by our geophysicist consultant has uncovered new insights which make the case for drilling the Arya Prospect even more compelling, especially as interpretation of the sizeable EG01 anomaly shows it is materially shallower than previously estimated.”
Castillo Copper Limited (“CCZ”) is pleased to announce that all logistics are now in place for drilling to commence at the prime Arya Prospect during September 2021. In addition, CCZ’s geophysicist consultant has re-interpreted historical aero-electromagnetic (AEM) and electromagnetic (EM) data that verifies the Arya Prospect is a major target in Mt Isa’s copper-belt.
DRILL-TESTING PRIME ARYA PROSPECT
Logistics in place
CCZ’s logistic service providers have verified they are on track for drilling to commence at the prime Arya Prospect during September 2021. The key focus will be drill-testing several targets identified by BHP in the mid-1990s including EG01, EG02 and EG10 (Figure 2) (3).
FIGURE 2: EG01, EG02 & EG10 – ARYA PROSPECT
GEOPHYSICIST RE-INTERPRETATION
CCZ’s geophysicist consultant – instrumental in improving targeting at the Big One Deposit – has reviewed and re-interpreted legacy AEM and EM data for the Arya Prospect, concluding it is a major exploration target within the Mt Isa copper-belt.
Electromagnetics
To re-cap, the Arya Prospect was originally identified by the 1997 Alsace/Epsilon BHP AEM survey (3) as it was characterised by a strong AEM anomaly. At the time, BHP (3) classified the Arya Prospect a priority target which resulted in a follow up ground survey, but no test-drilling was ever undertaken.
In addition, BHP (3) identified several other prospective EM anomalies across the region (east of the Arya Prospect running north-east) attributable to steeply dipping thick carbonaceous pyritic shale horizons.
In March 2019, Geoscience Australia released the results of its AusAEM survey (2) which identified the anomaly at the Arya Prospect.
Reconciling BHP and Geoscience Australia’s AEM results with assayed rock chips at surface, up to 1.84% Cu (4) , resulted in the initial interpretation that EG01 was potentially a massive sulphide conductor 130m thick, 1,500m long, 450m wide and approximately 430m deep.
Figure 3 highlights BHP (red line) and Geoscience Australia’s (blue line) AEM surveys relative to surface geochemistry results in determining the prime target at the Arya Prospect.
FIGURE 3: ARYA PROSPECT COPPER GEOCHEMISTRY VS AEM SURVEY RESULTS
In re-processing Geoscience Australia’s AusAEM Survey data (Figure 1) (3) , CCZ’s geophysicist believes the EG01 anomaly is now only approximately 100-200m deep rather than ~430m as initially estimated.
This is a significant finding that enhances the exploration potential of the Arya Prospect.
Magnetics
In reviewing and re-processing historical aero-magnetics data generated by MIM (4) in the 1990s, CCZ’ geophysicist noted there is a significant magnetic anomaly proximal to the Arya Prospects otherwise quiet magnetic terrain (Figure 4).
FIGURE 4: ARYA PROSPECT – MAGNETIC DATA
Holistically, the cross-over of significant AEM and magnetic anomalies, aligning with elevated occurrences of copper at surface, make a compelling case for test-drilling the Arya Prospect.
BIG ONE DEPOSIT
As there are still multiple targets at the Big One Deposit which are yet to be drill-tested, development work will continue. Based on results to date, the Board remains committed to model up and estimate a resource to the standard of the 2012 JORC Code resource and, if justified, apply for a mining lease.
Next steps
There are several ongoing steps, including:
- Reporting of the assay results from the Big One Deposit drilling campaign and surface sampling along the IP survey lines; and
- Commence drilling campaign at the Arya Prospect.
References
- CCZ ASX Release – 20 May 2021
- CCZ ASX Release – 10 June 2020 and Brodie, R. C., & Ley-Cooper, A. Y. (2019). AusAEM Year 1 NT/QLD Airborne Electromagnetic Survey TEMPEST® airborne electromagnetic data and Em Flow®conductivity estimates. Geoscience Australia.
- CCZ ASX Releases – 4 September 2019 & 13 April 2021; BHP Minerals Pty Ltd, 1998. EPM 11383 (Alsace Camp), 11452 (Epsilon), Combined Annual/Final Report for the Period Ending 19/12/98. QDEX Report: 30750 and BHP Minerals Pty Ltd, 1997. EPM 11383 (Alsace Camp), 11452 (Epsilon), Combined Annual Report for the Period Ending 19/12/97. QDEX Report: 29762.
- Mt Isa Metals Ltd, 2010. EPM 15767, Myally Tenement, Annual Report for the Period 5/06/2009 to 4/6/2010. QDEX Report: 64491; M.I.M Exploration Pty Ltd, 1993, Exploration Permit for Minerals Nos. 7448 “Lagoon Creek”. Second Annual Report 18 May 1991 to 17 May 1992, Queensland Australia. QDEX Report: 24523; and M.I.M Exploration Pty Ltd, 1992, “Myally Creek” EPM 7338 and “Lagoon Creek” EPM 7448 Joint Twelve Month Report for Period 18 May 1990 to 18 May 1991 Queensland, Australia. QDEX Report: 23516.
- Nelson K., Review of open file EM and magnetic geophysical data at Ayra Prospect, GeoDiscovery Group, unpublished confidential report to Castillo Copper Limited, June 2021, 16pp