Expanded drilling campaign to commence at Big One

·      The following mineral tenures are held 100% by subsidiaries of Castillo Copper Limited, totalling an area of 736.8 km² in the "Mt Oxide North Project" and as illustrated by Figure B3.

o  EPM 26574 (Valparaisa North) - encompasses the Big One historical mineral resource, Holder Total Minerals Pty Ltd, granted 12-June-2018 for a 5-year period over 100 sub-blocks (323.3Km²), Expires 11-June-2023.

o  EPM 26462 (Big Oxide North) - encompasses the 'Boomerang' historical Prospect and the 'Big One' historical mine, Holder: QLD Commodities Pty Ltd, granted: 29-Aug-2017 for a 5-year period over 67 sub-blocks (216.5Km²), Expires: 28-Aug-2022.

o  EPM 26525 (Hill of Grace) - encompasses the Ayra (previously Myally Gap) significant airborne EM anomaly, Holder: Total Minerals Pty Ltd for a 5-year period over 38 sub-blocks (128.8Km²), Granted: 12-June-2018, Expires: 11-June-2023.

o  EPM 26513 (Torpedo Creek/Alpha Project) - Granted 13-Aug-2018 for a 5-year period over 23 sub-blocks (74.2Km²), Expires 12-Aug-2023; and

o  EPMA 27440 (The Wall) - Granted on the 08-March-2021 over 70 sub-blocks (~215Km²) by Castillo Copper Limited. Expires 7^th March 2026.

FIGURE B3: CASTILLO COPPER PROSPECTS (refer to PDF version linked above)

·      A check on the tenures in 'application status' was completed in 'GeoResGlobe' on the 15th May 2021. 

·      Historical QDEX / mineral exploration reports have been reviewed for historical tenures that cover or partially cover the Project Area in this announcement. Federal and State Government reports supplement the historical mineral exploration reporting (QDEX open file exploration records).

·      Most explorers were searching for Cu-Au-U, and, proving satellite deposit style extensions to the several small sub-economic copper deposits (e.g., Big Oxide and Josephine).

·      With the Mt Oxide North Project in regional proximity to Mt Isa and numerous historical and active mines, the Project area has seen portions of the historical mineral tenure subject to various styles of surface sampling, with selected locations typically targeted by shallow drilling (Total hole depth is characteristically less than 50m).

·      The Mt Oxide North project tenure package has a significant opportunity to be reviewed and explored by modern exploration methods in a coherent package of EPM's, with three of these forming a contiguous tenure package.

·      Various Holders and related parties of the 'Big One' historical mining tenure (ML8451) completed a range of mining activities and exploration activities on what is now the 'Big One' prospect for EPM 26574.  The following unpublished work is acknowledged (and previously shown in ASX releases' reference lists):

o  Katz, E., 1970, Report on the Big One, Mt Devine, and Mt Martin Mining Lease Prospects, Forsayth Mineral Exploration NL, report to the Department of Mines, CR5353, 63pp

o  West Australian Metals NL, 1994. Drill Programme at the "Big One" Copper Deposit, North Queensland for West Australian Metals NL.

o  Wilson, D., 2011. 'Big One' Copper Mine Lease 5481 Memorandum - dated 7 May 2011.

o  Wilson, D., 2015. 'Big One' Mining Lease Memorandum - dated 25 May 2015: and

o  Csar, M, 1996. Big One & Mt Storm Copper Deposits. Unpublished field report.

·      The reader of the current ASX Release is referred to the CCZ's first publication of the 1993 historical reverse circulation drilling results for additional diagrams and drilling information ("Historic drill data verifies grades up to 28.40% Cu from <50m in supergene ore at Mt Oxide Pillar") released on the ASX by CCZ on the 14-January-2020.

·      The SRK Independent Geologists Report released by CCZ on the ASX on 28-July-2020 contains further details on the 'Exploration done by other parties - Acknowledgment and appraisal of exploration by other parties' this report is formally titled "A Competent Persons Report on the Mineral Assets of Castillo Copper Limited" Prepared as part of the Castillo Copper Limited (ASX: CCZ, LSE: CCZ) LSE Prospectus, with the effective date of the 17-July-2020.

·      The Mt Oxide North project is located within the Mt Isa Inlier of western Queensland, a large, exposed section of Proterozoic (2.5 billion- to 540-million-year-old) crustal rocks. The inlier records a long history of tectonic evolution, now thought to be like that of the Broken Hill Block in western New South Wales.

·      The Mt Oxide North project lies within the Mt Oxide Domain, straddling the Lawn Hill Platform and Leichhardt River Fault Trough. The geology of the tenement is principally comprised of rocks of the Surprise Creek and Quilalar Formations which include feldspathic quartzites, conglomerates, arkosic grits, shales, siltstones and minor dolomites and limestones.

·      The Project area is cut by a major fault zone, trending north- northeast - south- southwest across the permits. This fault is associated with major folding, forming several tight synclines- anticline structures along its length.

·      The Desktop studies commissioned by CCZ on the granted mineral tenures described four main styles of mineralisation account for most mineral resources within the rocks of the Mt Isa Province (after Withnall & Cranfield, 2013).

o  Sediment hosted silver-lead-zinc - occurs mainly within fine-grained sedimentary rocks of the Isa Super basin within the Western Fold Belt. Deposits include Black Star (Mount Isa Pb-Zn), Century, George Fisher North, George Fisher South (Hilton) and Lady Loretta deposits.

o  Brecciated sediment hosted copper - occurs dominantly within the Leichhardt, Calvert, and Isa Super basin of the Western Fold Belt, hosted in brecciated dolomitic, carbonaceous, and pyritic sediments or brecciated rocks proximal to major fault/shear zones. Includes the Mount Isa copper orebodies and the Esperanza/Mammoth mineralisation.

o  Iron-oxide-copper-gold ("IOCG") - predominantly chalcopyrite-pyrite magnetite/hematite mineralisation within high grade metamorphic rocks of the Eastern Fold Belt. Deposits of this style include Ernest Henry, Osborne, and Selwyn; and

o  Broken Hill type silver-lead-zinc - occur within the high-grade metamorphic rocks of the Eastern Fold Belt. Cannington is the major example, but several smaller currently sub-economic deposits are known.

·      Gold is primarily found associated with copper within the IOCG deposits of the Eastern Fold Belt. However, a significant exception is noted at Tick Hill where high grade gold mineralisation was produced, between 1991 and 1995 by Carpentaria Gold Pty Ltd, some 700 000 tonnes of ore was mined at an average grade of 22.5 g/t Au, producing 15 900 kg Au. The Tick Hill deposit style is poorly understood (Withnall & Cranfield, 2013).

·      ROM Resources had noted in a series of recent reports for CCZ on the granted tenures, that cover the known mineralisation styles including:

o  Stratabound copper mineralisation within ferruginous sandstones and siltstones of the Surprise Creek Formation.

o  Disseminated copper associated with trachyte dykes.

o  Copper-rich iron stones (possible IOCG) in E-W fault zones; and

o  possible Mississippi Valley Type ("MVT") stockwork sulphide mineralisation carrying anomalous copper-lead-zinc and silver.

·      The Mt Oxide and Mt Gordon occurrences are thought to be breccia and replacement zones with interconnecting faults. The Mt Gordon/Mammoth deposit is hosted by brittle quartzites, and Esperanza by carbonaceous shales. Mineralisation has been related to the Isan Orogeny (1,590 - 1,500 Ma).

·      Mineralisation at all deposits is primarily chalcopyrite-pyrite-chalcocite, typically as massive sulphide within breccias.

·      At the Big One prospect, West Australian Metals NL described the mineralisation as (as sourced from the document "West Australian Metals NL, 1994. Drill Programme at the "Big One" Copper Deposit, North Queensland for West Australian Metals NL."):

o  The targeted lode / mineralised dyke is observable on the surface. The mineralisation targeted in the 1993 drilling programmed is a supergene copper mineralisation that includes malachite, azurite, cuprite, and tenorite, all associated with a NE trending fault (062^o to 242^o) that is intruded by a porphyry dyke.

o  The mineralised porphyry dyke is vertical to near vertical (85^o), with the 'true width' dimensions reaching up to 7m at surface.

o  At least 600m in strike length, with strong Malachite staining observed along the entire strike length, with historical open pits having targeted approximately 200m of this strike. Exact depth of mining below the original ground surface is not clear in the historical documents, given the pits are not battered it is anticipated that excavations have reached 5m to 10m beneath the original ground surface.

o  Associated with the porphyry dyke are zones of fractured and/or sheared rock, the siltstones are described as brecciated, and sandstones around the shear as carbonaceous.

o  The known mineralisation from the exploration activities to date had identified shallow supergene mineralisation, with a few drillholes targeting deeper mineralisation in and around the 200m of strike historical open cut pits.

o  A strongly altered hanging wall that contained malachite and cuprite nodules. Chalcocite mineralization has been identified but it is unclear on the prevalence of the Chalcocite; and

o  The mineralisation was amenable to high grade open pit mining methods of the oxide mineralization (as indicated by numerous historical open pit shallow workings into the shear zone).

·      Desktop studies commissioned by CCZ and completed by ROM Resources and SRK Exploration have determined that the Big One prospect is prospective for Cu, Co, and Ag.

·      Desktop studies commissioned by CCZ have determined the Boomerang prospect contains:

o  Secondary copper staining over ~800m of strike length.

o  Associated with a major east-west trending fault that juxtaposes the upper Surprise Creek Formation sediments against both the underlying Bigie Formation and the upper Quilalar Formation units.

·      At the 'Flapjack' prospect there is the additional potential for:

o  Skarn mineralisation for Cu-Au and/or Zn-Pb-Cu from replacement carbonate mineralisation, particularly the Quilalar Formation.

o  Thermal Gold Auroele mineralisation is a potential model due to the high silica alteration in thermal aureole with contact of A-Type Weberra Granite - related to the Au mineralisation; and/or

o  IOCG mineralisation related to chloride rich fluids.

·      At the 'Crescent' prospect there is the additional potential for:

o  Skarn mineralisation for Cu-Au and/or Zn-Pb-Cu from replacement carbonate mineralisation, particularly the Quilalar Formation; and/or

o  Thermal Gold Auroele mineralisation is a potential model due to the high silica alteration in thermal aureole with contact of A-Type Weberra Granite - related to the Au mineralisation; and

o  IOCG mineralisation related to potassic rich fluids.

·      At the 'Arya' prospect there is the additional potential for:

o  Supergene mineralisation forming at the surface along the fault, fault breccia, and the Surprise Creek Formation 'PLrd' rock unit ('Prd' historical).

o  Epigenetic replacement mineralisation for Cu (with minor components of other base metals and gold) from replacement carbonate mineralisation, particularly the Surprise Creek Formation.

o  Skarn mineralisation for Cu-Au and/or Zn-Pb-Cu from replacement carbonate mineralisation, particularly the Surprised Creek Formation.

o  Sulphide mineralisation within breccia zones, along stress dilation fractures, emplaced within pore spaces, voids, or in other rock fractures; and/or

o  IOCG mineralisation related to chloride rich fluids.

·      A selection of publicly available QDEX documents / historical exploration reports have been reviewed, refer to Section 2, sub-section "Further Work" for both actions in progress and proposed future actions.

·      The SRK Independent Geologists Report released by CCZ on the ASX on 28-July-2020 contains further details on the 'Geology - Deposit type, geological setting and style of mineralisation': this report is formally titled "A Competent Persons Report on the Mineral Assets of Castillo Copper Limited" Prepared as part of the Castillo Copper Limited (ASX: CCZ, LSE: CCZ) LSE Prospectus, with the effective date of the 17-July-2020.

·      This ASX release concerns itself with geophysical survey whereas previous ASX releases have discussed the 2020 drilling program in detail.

·      The new work was a ground geophysical dipole-dipole IP survey so there was no sample to aggregate.

·      The strike of the dyke is at 73 degrees (east) and variably 70-85 degrees dip to the south. The mineralised zones for copper (>500ppm) interested in drillholes range from 1m to 44m wide apparent, averaging 9m apparent (6.8m true width).  The IP survey was designed to intersect the strike of the mineralisation at a perpendicular angle.

·      All mineralised intervals (i.e., >500ppm) have been reported in this and previous ASX releases as the "as-intersected" apparent thickness (in metres) and given that most drillholes dip at -60 degrees from the horizontal, true intersection widths will be less, but will be calculated during the block modelling process.

·      Appropriate diagrams are presented in the body and the Appendices of the current ASX Release. Where scales are absent from the diagram, grids have been included and clearly labelled to act as a scale for distance.

·      Maps and Plans presented in the current ASX Release are in MGA94 Zone 54, Eastings (mN), and Northing (mN), unless clearly labelled otherwise.

·      A series of cross-sections were generated at Big One displaying copper analyses in ppm to aid interpretation and exploration planning as can be seen in Figure B4, below, which shows the geological section through which IP Line 3 traverses.

FIGURE B4: NORTH-SOUTH CROSS-SECTION AT BO_306RC (refer to PDF version linked above)

·      All survey lines except Line 6 which was scrapped in favour of extending Line 3 are discussed in detail in Appendix 3, following the JORC Table 1.

·      Several airborne EM and magnetic surveys have been conducted nearby by historical explorers and Castillo Copper has conducted its own surface sampling program prior to drilling commencing as noted above.

·      As a result of further examination CCZ's geology team made the following recent key interpretations:

o  The full assay results, which included the entire twenty-one (21) drill-holes completed are awaiting some clarifications and re-assay of composites before a complete assessment of the data can be made and reported.  Surface geochem sampling plots for copper ppm (Figure B5, below) highlight drilled and some undrilled anomalies.

o  The presence of at least two mineralised lenses and a low-grade halo (100-1,500ppm) around the main ore body appears to hold along strike.

o  For drill-holes 213RC, 301RC, 303RC, 307RC, and 313RC the mineralisation is spread out which is significant given the trachyte to diorite dyke is generally 4-6m wide.

o  There is more than one dyke, however they may be offshoots of the main body.  Compositions vary as rock types logged from the chips in both 1993 and the current campaign include trachyte, diorite, and granite (more probably a porphyritic syenite).

o  Some of the drillholes will need to be deepened (or used as a seed hole for downhole EM) as they appear not to have been drilled deep enough to intersect the projected dyke at depth.  The affected holes are 201RC, 202RC, 203RC, and 304RC.

o  Planning for the IP Survey highlighted more target areas near Big One to the south and south-west where there are more trachyte dyke swarms that could be affected by structural control.

·      Future potential work is described within the body of the ASX Release, and will include:

o  Of the current planned drilling program, eleven (11) of the reverse circulation drillholes are designed to target chargeability anomalies identified from interpretation of the resistivity 3D block model.

o  Geological mapping and rock chip sampling over the anomalous chargeability zones along each survey line

o  Ground gravity and/or magnetic surveys.

o  Reverse Circulation Drilling

o  Diamond Coring.

o  Block modelling and wireframing.

o  Resource Estimation.