Major copper discovery at Big One Deposit extended

·      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":

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 mine 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) - An application lodged on the 12-Dec-2019 over 70 sub-blocks (~215Km²) by Castillo Copper Limited.

·      A check on the tenures in 'application status' was completed in 'GeoResGlobe' on the 23^rd December-2020. 

·      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 the reference list):

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.

·      For the historical drilling (1970 and 1993) all drillhole information was coded to the same formatted spreadsheets used currently by CCZ, being hand-encoded from hard copy reports, plans, and cross-sections.

·      For CCZ's current drilling program:

o  This information has been recorded in formatted spreadsheets during the drilling and will be checked and verified at the conclusion of the current program. The current reported holes (307-314RC) are listed in Appendix 2, with previous drilling collars listed in the 11^th January ASX release (307-314RC).

·      Queries on some assays are currently pending on CCZ's current drilling program.

·      For historical surface sampling, Independent Laboratory Assay results for soil and rock chip samples from the Big One Deposit were averaged if more than one reading or determination was given.

·      Copper grades were reported in this ASX release as per the received laboratory report, i.e., there was no cutting of high-grade copper results as they are directly relatable to high grade mineralisation styles readily visible in the relevant samples and modelling has yet not commenced.

·      There were no cut-off grades factored into any assay results reported, however once modelling commences a high cut-off grade of 10,000ppm or 10% copper will be used.

·      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.

·      This part will be done once CCZ's current drilling program is completed and all samples have been assayed and verified.

·      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 A2-1 in the ASX release:

·      Comprehensive reporting is planned once CCZ's current drilling program has all sample queries returned and have been verified.

o  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.

·      Previous surface sampling is as follows:

o  Rock chip samples were taken at areas of interest from observed mineralisation along the line of lode of the mineralised dyke, secondary structures, and surrounding spoil heaps.

o  Rock chip samples were taken at areas of interest from observed mineralisation along the line of lode of the mineralised dyke, secondary structures, and surrounding spoil heaps.

o  8 rock chip samples collected from rock faces and/or outcrops. A statistical summary of the 8-rock chip sample assay results is presented below:

o  16 rock chip samples collected from stockpiles, shaft waste piles, and/or boulders of rock onsite. A statistical summary of the 16-rock chip sample assay results is presented below:

·      A complete comparison of visual mineralisation to laboratory assays is given in Table A3-1 at the end of the section.  All intersected intervals are apparent thicknesses in metres.

·      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.

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

o  Surface IP and downhole EM surveys.

o  Diamond Coring.

o  Block modelling and wireframing.

o  Resource Estimation.