- Initial assays for drill-holes BO_315-317RC verify up to 9.19% Cu and clearly extends known mineralisation – the best intercepts are summarised below:
9m @ 1.42% Cu from 88m including 4m @ 3.06% Cu from 92m & 1m @ 9.19% Cu from 92m (BO_317RC)
5m @ 1.06% Cu from 141m (BO_316RC)
3m @ 1.22% Cu from 65m (BO_315RC)
- Encouragingly, visual inspection shows new drill-holes have potentially intersected copper mineralisation up to 26m – the best intercepts are shown in Figure 1:
FIGURE 1: BEST INTERCEPTED MINERALISATION
| Borehole | From (m) | To (m) | Apparent Thickness (m) | ||||||||||||||||||||||||
| BO_322RC: | 57 | 73,5 | 16,5
| BO_323RC: |
82 | 97 | 15.0
| BO_324RC: |
41 | 53 | 12.0
| BO_326RC: |
134 | 160 | 26.0
| BO_327RC: |
60 | 68 | 8.0
| BO_327RC: |
81 | 90 | 8.0
| BO_327RC: |
90 | 99 | 9.0 |
|
- Assays for samples from priority drill-holes BO_318RC (1) & BO_326RC, which exhibited visual copper intercepts up to 34m & 26m respectively, should be back shortly as the laboratory is fast-tracking the analysis
- Holistically, a closer examination of the initial assay results by CCZ’s geology team, highlights the following interpretations:
- Factoring the new data points into the preliminary geological model for the Big One Deposit suggests the underlying system is larger than initially envisaged;
- There is now increasing evidence that copper mineralisation is potentially structural as it extends beyond the trachyte/dacite dyke; and
- Using geophysics has enabled significantly better targeting and, in turn, optimised the results of the drilling campaign so far
Castillo Copper’s Managing Director Simon Paull commented: “It is encouraging there is a strong correlation between visual mineralisation and the assays, as the Board optimistically looks forward to receiving further results. Otherwise, the progress of the drilling campaign is taking shape, especially verification the underlying copper system at the Big One Deposit is likely to be larger than our geology team’s initial expectations.”
Castillo Copper Limited (“CCZ”) is pleased to report the initial assays for drill-holes BO_315-317RC returned up to 9.19% Cu and verified extensions to known mineralisation at the Big One Deposit in Mt Isa’s copper-belt. In addition, visual inspection of samples from drill-holes BO_322-27RC identified further copper mineralisation, with the best intercept of 26m found in BO_326RC (refer to Figure 4 & Appendix A).
ASSAY RESULTS – MORE VISIBLE COPPER MINERALISATION
Encouraging initial assays
The initial assay results for drill-holes BO_315-317RC (Figure 2) are encouraging as up to 9.19% Cu was intersected, while the intercepts clearly extend known mineralisation.
A summary of the best intercepts is shown below:
9m @ 1.42% Cu from 88m including 4m @ 3.06% Cu from 92m & 1m @ 9.19% Cu from 92m(BO_317RC)
5m @ 1.06% Cu from 141m (BO_316RC)
3m @ 1.22% Cu from 65m (BO_315RC)
FIGURE 2: BIG ONE DEPOSIT – POSITION OF DRILL-HOLES 315RC-17RC
There are several interpreted takeaways the geology team has determined post-analysis of the initial
results, including:
- Incorporating the fresh data points into the preliminary geological model for the Big One Deposit suggests the underlying system is larger than initial expectations,
- There is now demonstrable evidence that Copper mineralisation is structural as there is increasing
evidence that it potentially extends beyond the trachyte/dacite dyke (refer Figure 3 – cross section for BO_315RC-316RC); and - The use of geophysics has enabled significantly better targeting and, in turn, delivered drilling and assay results higher than initially anticipated.
FIGURE 3: CROSS SECTION – DRILL-HOLES 315RC-316RC
Drilling down, the assay results verify there is a relatively strong correlation to the visual estimates of sulphides and alteration minerals. Notably, there were incremental zones outside these depths with 1-6m low tenor copper mineralisation ranging from 500–2,500ppm Cu coupled to elevated silver-cobalt levels.
However, consistent with the 2020 drilling campaign, there was no anomalous lead-zinc found at the Big One Deposit, while weak gold mineralisation (0.05–0.15 ppm) was apparent, it did not correlate with the copper zones, rather dolomitic siltstones and quartzites.
Visual copper mineralisation
Consistent with drill-holes BO_315RC-321RC, visual inspection shows that all new drill-holes have potentially intersected copper mineralisation. There are several significant intercepts ranging from 8m up to 26m (Figure 4 and Appendix A).
Assays for the priority drill-holes, BO_318RC and BO_326RC, with visual copper intercepts at 34m and 26m respectively, is being expedited. As such, the results of the analysis should be returned within the next few weeks.
FIGURE 4: BIG ONE DEPOSIT – QUALITATIVE ASSESSMENT OF DRILLHOLES 322RC-327RC
| Borehole | From (m) | To (m) | Apparent Thickness (m) | Comments | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| BO_322RC: | 57 | 73.5 | 16.5 | Dacitic
| BO_323RC: |
8 | 9 | 1.0 | Dacitic, pervasive orthoclase
| BO_323RC: |
82 | 97 | 15.0 | Dacitic, some orthoclase
| BO_324RC: |
3 | 6 | 3.0 | Quartzite
| BO_324RC: |
33 | 40 | 7.0 | Fractured quartzite
| BO_324RC: |
41 | 53 | 12.0 | Dacite
| BO_325RC: |
2 | 4 | 2.0 | Dacite
| BO_325RC: |
45 | 46 | 1.0 | Dacitic
| BO_326RC: |
5 | 9 | 4.0 | Dacite
| BO_326RC: |
27 | 28 | 1.0 | Quartzite with abundant pyrite
| BO_326RC: |
96 | 100 | 4.0 | Dacite
| BO_326RC: |
134 | 160 | 26.0 | Dacite
| BO_327RC: |
60 | 68 | 8.0 | Dacite
| BO_327RC: |
81 | 90 | 8.0 | Dacite
| BO_327RC: |
90 | 99 | 9.0 | Quartzite |
|
Notes:
- Samples have been taken at 1m intervals;
- Mineralisation estimated from field geologists rock-chip estimates;
- True vertical depths will be calculated by Minescape block model procedures;
- A zone of limited mineralisation inferred to be associated with the dyke was intersected in each deepened drill hole; and,
- In borehole BO_317RC, the dyke was intersected at a shallower depth than predicted; hence, there was no requirement to drill the bore to the estimated total depth of 150m.
Source: CCZ geology team
Next steps
There are several ongoing steps, including:
- Reporting of the assay results for BO_318-27RC which are due back from the laboratory; and
- Finalise logistics, access, cultural heritage, and targets for the drilling campaign at the Arya
Prospect.
References
- CCZ ASX Release – 15 July 2021