Australian copper explorer Castillo Copper (ASX:CCZ) has been active in drilling throughout the year and has been rewarded in kind with a series of positive results.
Much of its focus during 2022 remained on developing the East Zone, BHA Project in Broken Hill and Big One Deposit, NWQ Copper Project in the Mt Isa copper belt in north-west Queensland.
As the year progressed, Castillo had identified several prime rare earth element (REE) targets for drill testing following reconciling of geophysical and geochemical data at its Broken Hill Zn-Ag-Pb-IOCG Project in New South Wales.
H1 2022 was a ‘Big One’ for Castillo
During 1Q 2022, most of the focus for the company remained on developing the East Zone, BHA Project in Broken Hill and Big One Deposit, NWQ Copper Project in the Mt Isa copper belt in north-west Queensland.
On 28 February 2022, Castillo announced that modelling the 2020-21 reverse circulation and diamond core drilling campaigns at the Big One Deposit produced a maiden JORC 2012 t MRE of 2.1Mt @ 1.1% Cu for 21,886t contained metal. The underlying orebody – which commences from surface – at the time had not fully defined, as it remained open to the east, north and down dip.
Towards the end of Q1 2022, Castillo encountered ‘high-grade’ cobalt-zinc mineralisation following re-testing of diamond drill core from The Sisters prospect within its Broken Hill Project in New South Wales
Towards the end of Q1 2022, Castillo encountered ‘high-grade’ cobalt-zinc mineralisation following re-testing of diamond drill core from The Sisters prospect within its Broken Hill Project in New South Wales.
The results were generated from re-testing using pXRF analysers, and returned readings up to 1,705ppm Co and 9.63% Zn.
The company also noted that several wide pXRF intervals were delineated with ‘high-grade’ cobalt-zinc readings at the Reefs Tank and Tors Tank Prospects, which returned cobalt grades up to 1,600ppm.
During the June quarter, most of the focus remained on developing the cobalt potential at the East Zone, BHA Project in Broken Hill and successfully negotiating an option to sell the Zambia Projects.
On 1 June 2022, the company announced the maiden MRE to the JORC (2012) Code for BHA’s Project’s East Zone totaled 64Mt @ 318 ppm Co for 21,556t contained cobalt metal at relatively shallow depths (0-80m). Furthermore, the global MRE has 44,260t (64Mt @ 0.07% Cu) of contained copper metal that enhances the overall result.
2H 2022 off to a flying start
In August, Castillo had finalised targets for an upcoming drilling campaign at the Broken Hill Alliance (BHA) Project’s East Zone across four prospects in New South Wales. Castillo reported at the time that the campaign comprises one diamond core and 17 reverse circulation (RC) drillholes for 2,100m with depths ranging from 100m to 160m.
The objective of the campaign is to extend known mineralisation primarily for cobalt then copper, rare earth elements, and gold. In turn, the geology team began targeting to use fresh assay data to refine the geological model which should facilitate updating the current global Mineral Resource Estimate (MRE) – 21,556t cobalt (64Mt @ 318 ppm Co) and 44,260t copper (63Mt @ 0.07% Cu).
A key goal during this period has been to increase the confidence of the current MRE and enhance the cobalt grade. To potentially achieve this objective, the drilling at Fence Gossan, Reefs, and Tors Tanks prospects has been designed to penetrate deep enough to intersect 2 lower cobalt-rich zones.
By October, Castillo Copper reported it had identified several prime REE targets for drill testing following reconciling of geophysical and geochemical data at its Broken Hill Zn-Ag-Pb-IOCG Project in New South Wales.
The results, generated by reconciling data from historical drilling campaigns in 2000, 2001, and 2017 at the project’s Iron Blow prospect, have identified several ‘significant’ bedrock conductors that have the potential to host REE mineralisation.
In particular, diamond drillhole DD90_1B3 (sourced from the core library) returned positive readings over 35m, with the best intersections including, 8m at 1,460ppm total rare earth oxide (TREO) from 150m and 4.8m at 311ppm TREO from 232m
In early December Castillo approved further work on known targets within the Luanshya Copper Project located in Zambia.
The company said based on current plans, the work schedule is set to progress during the first half of 2023 focusing on a 6km zone of copper surface anomalism where 14 chargeable zones were delineated.
Then earlier this month, the company reported it had completed an auger sampling program focused on a 6.5km-square REE exploration footprint within the Broken Hill Project’s East Zone.
The objective of the campaign is to determine the full extent of the REE mineralisation within the areas sampled and identify new targets to drill-test.
Samples were taken at depths of 0.1m to 0.4m by hand auger, and the geology team has dispatched all samples to the laboratory for follow-up analyses. These results are expected to be returned early in 2023 and will enable the company to complete a full interpretation of the REE mineralisation potential.
