Castillo Copper Ltd’s (ASX:CCZ) (LON:CCZ) (FRA:7OR) surged as much as 90% as assays for the 200 series and six drill-holes for the 300 series significantly extend known mineralisation at the high-grade Big One Deposit within the core Mt Oxide Project in northwest Queensland.
Best results are 40 metres at 1.64% copper from surface, including 1-metre at 16.65% from 29 metres, and 44 metres at 1.19% copper from surface.
The latest assays make the case for potential scaling at Big One Deposit more compelling, especially as they build materially on early high-grade findings.
Shares were as much as 90% higher to A$0.083, a new three-year high, and closed more than 47% higher than the previous close at A$0.065 with more than 141 million changing hands.
Development plans for the Big One Deposit are being actively accelerated, with a geophysics campaign being formulated and the modelling of a JORC-compliant resource has commenced.
Ramping up development work
Castillo Copper managing director Simon Paull said: “We are delighted to receive assays of this calibre, especially with global copper supplies tight.
"There is now compelling evidence Big One Deposit is a shallow, high-grade copper-cobalt system that can potentially scale further.
"The board is now ramping up forward development work and the modelling of a maiden JORC-compliant resource.”
The assays, which comprise final laboratory reporting for the 200 (complete) and 300 (partial) series, included potentially economic intercepts from surface:
➢ In hole 303RC the 40-metre result also included 11 metres at 4.40% from 24 metres and 5 metres at 7.34% from 28 metres.
➢ The 44-metre intersection in hole 301RC included 14 metres at 3.55% from 27 metres, 3 metres at 10.88% from 37 metres and 1-metre at 12.6% from 37 metres.
The latest assays significantly extend known mineralisation and build on high-grade historic potentially economic intercept, which produced stellar intercepts from supergene copper mineralisation up to 28.4% copper.
As a result of analysing the results in-depth, CCZ’s geology team made the following key interpretations:
➢ The full assay results, which included the entire seven drill-holes completed in the first tranche (201-213RC), confirm the presence of at least two mineralised lenses and a low-grade halo around the main ore body;
➢ For drill-holes 301RC, 303RC and 213RC the mineralisation is spread out which is significant given the trachyte to diorite dyke is generally 4-6 metres wide;
➢ There is likely secondary enrichment apparent within drill-holes 301RC and 303RC, as several 1-metre samples more than 10% copper possibly intersected mineralisation occurring in the transitional zone between the oxide and sulphide domains. This is consistent with earlier observations that confirmed visible malachite (oxide) and chalcocite (sulphide) in RC chips, though more data points are required;
➢ Surprisingly, ore grade cobalt readings were noted in 301RC – 12 metres at 912 ppm cobalt fermium 29 metres including 1-metre at 1,435 ppm cobalt. While further work is required to determine the extent of mineralisation, there is potential for significant cobalt credits; and
➢ Within the high-grade copper zone, there were anomalous readings for silver-arsenic-bismuth and very minor gold readings.
Still 15 holes to complete
One of the key insights observed from the recent assays is the extent of mineralisation within the halo zone and away from the main copper lode.
Holistically, this observation clearly extends the known mineralisation and upside potential for Big One Deposit.
Moreover, the prospects of intersecting incremental oxide, carbonate, shallow copper mineralisation in the next batch of the drilling campaign (307-14RC) is encouraging.
Beyond this, there are still 15 drill-holes to complete along the 600 metres strike, which delivers incremental exploration potential.
Modelling JORC resource
With a game-changing discovery of this nature at Big One Deposit, the board is now actively accelerating forward development plans
While there is a pause in drilling activities, due to the commencement of the wet season across northern Australia, a geophysics campaign is being formulated to identify new bedrock conductors and potential test-drill targets.
In addition, the board has instructed the geology team to begin modelling a JORC-compliant resource based on available historic and fresh data.
If the outcome of the geological modelling is positive, then the board expects to commence applying for a fresh mining lease.
The company will provide an update on the next batch of assay results (307-14RC), plans for a geophysics campaign at Big One Deposit and progress with modelling a maiden JORC resource.