VANCOUVER, BC / ACCESS Newswire / June 8, 2026 / Marimaca Copper Corp. ("Marimaca Copper" or the "Company") (TSX:MARI)(ASX:MC2) is pleased to report additional assay results from its ongoing drilling program at the Pampa Medina deposit, located at low altitude approximately 28km east of the Company's Marimaca Oxide Deposit ("MOD") (Figure 1) in Antofagasta Region, Chile. Drilling completed on 150m centres continues to demonstrate continuity of ultra-high-grade copper-silver mineralization across the central zone of the Pampa Medina deposit, with SPRD-05 intersecting 96m at 1.19% Cu and 11.7g/t Ag, including 16m at 5.70% Cu and 62.6g/t Ag and 4m at 11.32% Cu and 144g.0/t Ag. The sediment-hosted system is demonstrating strong lateral continuity across the initially defined 3km x 1.5km area of interest ("AOI"), reinforcing the significant scale of the deposit.

• High-grade sulphide mantos show strong lateral continuity across the defined AOI, with 150m-spaced delineation drillholes continuing to intersect high grades (>2% Cu) over significant widths in dominantly bornite and chalcocite

• SPRD-05 - drilled east of previously released hole SPRD-06 - intersected the ultra-high grade (UHG) bornite manto at depth in sediments and tuffs

  • 96m of 1.19% Cu and 11.7g/t Ag from 692m (sulphide), including

    • 60m of 1.80% Cu and 18.4g/t Ag from 694m, including

      • 16m of 5.70% Cu and 62.6g/t Ag from 704m, including

      • 4m of 11.32% Cu and 144.0g/t Ag from 706m

    • Details of lithology and grade across the broader intersection are shown in Figure 6

  • Represents one of the strongest bornite-mineralized manto intersections to date at Pampa Medina

  • Near surface oxide mineralization also intersected in volcanics and sediments north of the historic Pampa oxide footprint

    • 22m of 0.40% Cu and 1.9g/t Ag from 60m (oxide)

    • 24m of 0.30% Cu and 1.8g/t Ag from 204m (oxide

  • SPRD-05 was drilled approximately 650m northwest of SMRD-13 which also intersected the UHG bornite zone at depth (see announcement dated July 3 ^rd , 2025)

• SPRD-04 - drilled 150m north of previously released SMRD-13 and ~600m east of SPRD-05 - intersected broad mineralization across sediments and tuffs

  • 22m of 1.97% Cu and 9.2g/t Ag from 610m (sulphide)

  • Shallower intersection of 140m of 0.35% Cu from 366m including higher-grade stacked mantos

    • 32m of 0.71% Cu and 4.1 g/t Ag from 468m (mixed), including

      • 10m of 0.95% Cu and 7.4g/t Ag from 484m (mixed)

• The Company is also completing target-generation geochemical and geophysical programs across the broader Sierra Medina land package, focusing on the Sierra Norte and Pampa Norte areas (see Figure 2)

  • Focus of these programs is identifying continuations of the favourable, mineralized sedimentary units across the broader interpreted sedimentary basin

  • A 400m audio-magnetotelluric (AMT) grid has been completed across the Pampa Norte area, with a higher-resolution 200m grid completed at Sierra Norte

  • Results and interpretations will be released in due course

Sergio Rivera, VP Exploration of Marimaca Copper, commented:

"Results from the 2026 drilling program at Pampa Medina continue to demonstrate the incredible grade and thickness of the mantos at Pampa Medina, which remains open in almost all directions. We are pleased to see that drilling on 150m spacing continues to demonstrate continuity of the high-grade copper and silver mineralization, often across multiple stacked horizons, with SPRD-05 intersecting one of the highest-grade mantos we have seen to date (Figure 5).

We have always said that continuity will be the maker of the Pampa Medina deposit, and our drilling completed to date gives us confidence that we are dealing with a deposit of genuine district significance."

"We are completing a 150m-spaced campaign across the defined initial AOI, after which we will cut off input data for an initial Mineral Resource Estimate (MRE). This maiden MRE will represent a snapshot in time, as following completion of the delineation campaign, we will begin the broader step-out program to the distal northern and western targets in parallel with initial resource work. The consistency of high-grade intersections gives us increasing confidence that the central AOI can support a strong mineral endowment while remaining open for expansion."

Overview of Pampa Medina

Pampa Medina is a manto-style copper deposit dominantly hosted in Jurassic-Triassic sedimentary units (sandstones, conglomerates, tuffs and black shales) overlain by andesitic volcanics and underlain by an Upper Paleozoic complex of metamorphosed sediments, volcanics and intrusions. Key lithological units are intruded by a dyke swarm and affected by post mineral normal faulting. Copper was originally identified in near-surface oxide mineralization dominated by atacamite, chrysocolla and both secondary chalcocite, and has now been identified in high-grade zones of bornite, chalcopyrite, covellite and chalcocite which extend at depth beyond the oxide-primary transition. Elevated silver grades are present in both oxide and sulphide copper-mineralized zones and are generally correlated with copper grade.

Following Marimaca's consolidation of the project area and surrounding land packages in 2024, the Company reinterpreted all available geological information and developed an updated geological model for Pampa Medina, which identified the lower sedimentary units of interbedded sandstones, shales, tuffs and conglomerates as the priority target horizons for future drilling. Marimaca's 2026 drilling campaign will focus on three priority goals: definition of the high-grade central AOI, delineating the identified oxide extensions, and further step-out drilling to test potential extensions of the broader system identified in geophysical work completed to date.

Table 1: Table of Intersections

Table 2: Drill Collars

Sampling and Assay Protocols

True widths are estimated as 80% of reported intervals, based on down-hole bedding and structural measurements. DDH holes were sampled on a 2m continuous basis, halved by a conventional core splitter on site with one half sent to the Andes Analytical Assay preparation laboratory in Copiapó and the pulps then sent to the same company laboratory in Santiago for assaying. Samples were prepared using the following standard protocol: drying; crushing all sample to -1/4" and passing through a secondary crusher to better than 80% passing -10#; homogenizing; splitting; pulverizing a 400-600g subsample to 95% passing -150#; and a 125g split of this sent for assaying. All samples were assayed for sequential copper %CuT (total copper); %CuS (acid soluble copper), %CuCN (cyanide soluble copper) and CuRes (residual copper), In addition to copper analyses, multi-element analysis including silver (Ag) was undertaken using ICP (multi-element Optical Inductively Coupled Plasma). A full QA/QC program, involving insertion of appropriate blanks, standards and duplicates was employed with acceptable results. Pulps and sample rejects are stored by Marimaca Copper for future reference.

Qualified Person / Competent Person

The technical information in this news release, including the information that relates to geology, drilling and mineralization was prepared under the supervision of, or has been reviewed by Sergio Rivera, Vice President of Exploration, Marimaca Copper Corp, a geologist with more than 40 years of experience and a member of the Colegio de Geólogos de Chile and of the Institute of Mining Engineers of Chile, and who is the Qualified Person for the purposes of NI 43-101 responsible for the design and execution of the drilling program.

The information in this announcement which relates to exploration results for the Pampa Medina Project is based on, and fairly reflects, information and supporting documentation prepared by Sergio Rivera, VP Exploration of Marimaca, a Competent Person who is a member of the Comision Minera (Chilean Mining Commission), Colegio de Geólogos de Chile and of the Institute of Mining Engineers of Chile. Mr. Rivera has sufficient experience that is relevant to the style of mineralisation and types of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the Joint Ore Reserves Committee Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves. Mr. Rivera consents to the inclusion in this announcement of the matters based on his information in the form and context in which it appears.

Contact Information
For further information please visit www.marimaca.com or contact:

Tavistock
+44 (0) 207 920 3150

Emily Moss
[email protected]

Forward Looking Statements

This news release includes certain "forward-looking statements" under (without limitation) applicable Canadian securities legislation, including, without limitation, statements regarding the development of activities at Pampa Medina, the potential growth of Pampa Medina, and the discovery's potential to complement the MOD. There can be no assurance that such statements will prove to be accurate, and actual results and future events could differ materially from those anticipated in such statements. Forward-looking statements reflect the beliefs, opinions and projections on the date the statements are made and are based upon a number of assumptions and estimates that, while considered reasonable by Marimaca Copper, are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies. Many factors, both known and unknown, could cause actual results, performance or achievements to be materially different from the results, performance or achievements that are or may be expressed or implied by such forward-looking statements and the parties have made assumptions and estimates based on or related to many of these factors. Such factors include, without limitation: risks that the development activities at Pampa Medina will not progress as anticipated, or at all, risks related to share price and market conditions, the inherent risks involved in the mining, exploration and development of mineral properties, the uncertainties involved in interpreting drilling results and other geological data, fluctuating metal prices, the possibility of project delays or cost overruns or unanticipated excessive operating costs and expenses, uncertainties related to the necessity of financing, uncertainties relating to regulatory procedure and timing for permitting submissions and reviews, the availability of and costs of financing needed in the future as well as those factors disclosed in the annual information form of the Company dated March 27, 2025 and other filings made by the Company with the Canadian securities regulatory authorities (which may be viewed at www.sedar.com). Readers should not place undue reliance on forward-looking statements. Marimaca Copper undertakes no obligation to update publicly or otherwise revise any forward-looking statements contained herein whether as a result of new information or future events or otherwise, except as may be required by law.

None of the TSX, ASX or the Canadian Investment Regulatory Organization accepts responsibility for the adequacy or accuracy of this release.

This announcement was authorised for release to the ASX by the Board of Directors of the Company.

Appendix 1 - JORC Code 2012 Table 1 (ASX Listing Rule 5.7.1)

Section 1 Sampling Techniques and Data

Section 2: Reporting of Exploration Results

SOURCE: Marimaca Copper Corp.