Castillo Copper Ltd (ASX:CCZ) (LON:CCZ) (FRA:7OR) has further extended the large copper discovery at Big One Deposit within the Mt Oxide Project in Queensland’s Mt Isa copper-belt following the final results from its 2020 program and recently found historical assays.
Factoring in the extensive data points from the three drilling campaigns, which highlights mineralisation is open in all directions, a regional induced polarisation (IP) survey, covering around 3,000-line metres, can now be finalised.
In addition, as part of the JORC-compliant resource modelling, legacy stockpiles have now been digitalised, with average grades ranging from 0.5-2% copper.
Volume calculations still require an on-site visit and drone survey to be fully determined.
High-grade copper system
Castillo Copper managing director Simon Paull said: “All systems are go as we accelerate developing Big One Deposit, especially aiming to extend known mineralisation further and identify new test-drill targets.
“Our two new initiatives are now taking shape, with an upcoming IP survey being planned and JORC modelling now underway.
“Discovering FME’s assays was a windfall, as we can now optimistically assert that Big One Deposit is a high-grade copper system.”
Castillo’s geology consultant, ROM Resources, who were appointed to model a JORC-compliant inferred resource, uncovered comprehensive historical assays from a drilling campaign undertaken by previously-listed Forsayth Minerals Exploration NL (FME).
Combining these findings from FME, with the final assay results from Castillo’s 2020 campaign, clearly extends known mineralisation at Big One Deposit.
The best economic intercepts below, include the standout FME_B0017 with up to 9.4% copper:
- 34 metres at 1.51% from surface including 21 metres at 2.25% from surface, 12 metres at 3.44% from 3 metres, 6 metres at 4.79% from 3 metres and 1-metre at 9.4% from 9 metres;
- 18 metres at 0.86% from 11 metres including 6 metres at 1.85% from 20 metres, 3 metres at 2.98% from 20 metres and 1-metre at 8% from 20 metres; and
- 12 metres at 0.40% from 14 metres including 2 metres at 0.84% from 22 metres & 1-metre at 1.23% from 23 metres.
FME’s 22 shallow drill-hole campaign was aimed at testing the primary orebody constrained within the dyke for high-grade copper mineralisation.
To this extent, FME’s drilling campaign was successful, especially as the high-grade historical assays build significantly on the insights garnered from reviewing comparable results from WME and Castillo.
There is now clear evidence the high-grade mineralisation zone at Big One Deposit is constrained within the dyke, dips more vertically than initial expectations and has the potential to scale.
More extensive halo mineralisation
Reviewing the drill-hole assays confirmed there is more extensive copper mineralisation contained within the halo than initially expected.
Notably, the result from 307RC demonstrates this fact and, moreover, verifies the deposit is open to the northeast.
The upshot of assessing these results is there are now sufficient data points to re-configure a second stage infill drilling campaign to test for extended mineralisation at greater depths.
IP survey/resource modelling
Leveraging the insights from the extensive data points thrown up by the three drilling campaigns, a regional IP survey – covering 3,000-line metres – is set to be finalised.
The inaugural geophysical campaign is aimed at investigating several known anomalies and mapped gossanous outcrops northeast of the line of lode.
These dumps and stockpiles have been extensively sampled, both historically and recently.
However, to complete the volume calculations an on-site visit and drone survey are now being planned.
Update on planned site visit to collect key data to further the JORC-compliant resource modelling and IP survey roll-out.