Marimaca Reports Further High-Grade Copper and Silver Intersections more than 600m from Pampa Medina West Step-Out Drilling

2026-03-11

TSX - Toronto Stock Exchange · Copper · Canada · Drill Results

VANCOUVER, BC / ACCESS Newswire/ March 11, 2026 / Marimaca Copper Corp. ("Marimaca Copper" or the "Company") (TSX:MARI)(ASX:MC2)reports results from the Pampa Medina deposit, located at low altitude approximately 28km east of the Company's Marimaca Oxide Deposit ("MOD") (Figure 1). Drilling intersected high-grade manto-type copper-silver mineralization in significant step-outs west from previous step-out drilling and demonstrates the western continuity of the favourable, mineralized sediment horizons. The Company has not yet completed initial metallurgical programs at Pampa Medina and is therefore not reporting copper equivalent grades at this time. Silver by-products are common in Chilean manto-type deposits, including the nearby Mantos Blancos (Capstone Copper) and Cachorro (Antofagasta Minerals) deposits.

Highlights

Following the success of the 30,000m Phase II program - Marimaca will expand to 10 drill rigs at Pampa Medina with target meterage of 100,000m in 2026, subject to results-based stage-gates

SWRD-02 drilled approximately 600m west of previous drilling (SMRD-24) intersected high-grade mineralization across a sandstone and tuff sequence

74m of 1.21% Cu and 7.9gpt Ag from 520m, including

12m of 2.07% Cu and 17.2gpt Ag from 532m

SMRD-34, drilled in between SWRD-02 and SMRD-24 on a 300m spacing, intersected mineralization in both the near-surface upper volcanics and the lower sediments

36m of 1.08% Cu and 13.8gpt Ag from 158m, including

6m of 3.01% Cu and 37.3gpt Ag from 166m

24m of 1.37% Cu and 12.2gpt Ag from 600m, including

10m of 2.58% Cu and 25.8gpt Ag from 606m

SWRD-01, drilled 300m north of SWRD-02, and 300m west of previously released SMRD-16, also intersected the high-grade lower manto in the interbedded siltstone, sandstone and tuff sequence

38m of 1.43% Cu and 11.8gpt Ag from 694m, including

8m of 2.11% Cu and 15.5gpt Ag from 694m, and

14m of 1.86% Cu and 19.3gpt Ag from 718m

SWRD-04 intersected the upper and lower manto, however mineralization was affected by both pre-and-post mineral dyking

16m at 1.00% Cu and 5.9gpt Ag from 332m, including

4m at 2.51% Cu and 14.5gpt Ag from 338m

8m of 1.17% Cu and 5.0gpt Ag from 368m

Broad lower manto significantly affected by pre-and post-mineral intrusions:

10m of 0.71% Cu and 6.4gpt Ag from 660m

4m of 1.06% Cu and 8.5gpt Ag from 706m

4m of 1.08% Cu and 17.0gpt Ag from 820m

6m of 0.85% Cu and 9.7gpt Ag from 836m

SWRD-03 was affected by splays of the north-south Ancla Fault System zone and intersected lower-grade deep mineralization

18m of 0.55% Cu from 736m

28m of 0.72% Cu and 5.9gpt Ag from 840m

Sergio Rivera, VP Exploration of Marimaca Copper, commented:

"Pampa Medina continues to demonstrate remarkable consistency of grade and thicknesses across the currently defined area of interest. The Phase II program was predominantly 300m-spaced grid-based drilling intended to define the extent of the mineralized system in which we are yet to define the limits. The 2026 program will focus on definition drilling of the identified high-grade corridors between sections N7,441,100 and N7,440,500, as well as Pampa Medina Norte (SMD/SMR-01) in both oxides and sulphides, as well as continued large-scale step-outs to test regional continuity of the favourable host rocks. Our exploration model is strengthening at Pampa and we look forward to updating the market with our evolving interpretations of the manto-system ahead of the Phase III program in 2026.

Hayden Locke, CEO of Marimaca Copper, commented:

"Pampa Medina continues to extend significantly. Our area of interest, defined by drilling, now extends 3km by 2km, but geophysics suggests ongoing potential for extensions. The continuity of mineralization and exceptional grades we are encountering are not unusual for sediment hosted copper deposits, which are known to have a larger footprint compared to the more confined, but vertically extensive, porphyry deposits typical of this region."

"What is incredibly unusual, is the average true thickness of the mineralized sediments. Drilling shows the high-grade mineralization is generally present over a minimum true thickness of 20m to 30m and, in many cases, is well over 100m in true thickness. When compared to one of the most prolific copper belts on the planet - the Kupferschiefer in Poland and Germany - it is extraordinarily thick. The estimated mining horizon true thickness across Section N7440 800 at Pampa Medina is, on average, more than 10x thicker and, in some cases, more than 50x thicker than the Kupferschiefer deposits currently mined by KGHM. Pampa Medina exhibits similar copper grades and slightly lower average silver grades when compared to those Tier 1 operations, but over significantly larger mineable widths, which indicates efficient, bulk tonnage, mining methods may drive lower unit costs in an eventual operation."

"The silver content provides a valuable addition to the deposit and enhances our view of its potential. We note the highly accretive financings being undertaken around streaming silver and we expect, give the consistency of silver mineralization encountered in this batch of drilling, that it will provide an opportunity for the Company to monetize for the benefit of its shareholders in the future. We are assaying the rest of the drilling completed at Pampa Medina and will release the results to the market when received."

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 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 sulphide-dominant central corridor, infill of the identified oxide extensions, and further step-out drilling to test potential extensions of the broader system identified in geophysical work completed to date.

[](https://app.accessnewswire.com/imagelibrary/5d2a2909-0a68-47d7-bac2-a5f4f0a36f72/1146219/picture2.png)

Figure 1: Regional Map - Marimaca, Pampa Medina and Regional Infrastructure

[](https://app.accessnewswire.com/imagelibrary/a9fcef22-4b4d-4993-9f16-812f27444a7a/1146219/picture3.png)

Figure 2 - Pampa Medina Deposit and Step-out Drilling Locations

[](https://app.accessnewswire.com/imagelibrary/f431e113-51a8-4797-b14c-bf4c0b4ce890/1146219/picture4.png)

Figure 3 - Cross Section Looking North - Pampa Medina 7,440,800 N

[](https://app.accessnewswire.com/imagelibrary/38f4a062-0f13-4d9b-8d7e-d872594d33ff/1146219/picture5.png)

Figure 4 - Cross Section Looking North - Pampa Medina 7,440,500 N

| Hole | Total Depth (m) | | From (m) | To (m) | Intersection (m) | % CuT | gpt Ag | | SWRD-01 | 956 | | 694 | 732 | 38 | 1.43 | 11.8 | | Including | 694 | 702 | 8 | 2.11 | 15.5 | | | | And | 718 | 732 | 14 | 1.86 | 19.3 | | | | | 848 | 868 | 20 | 0.84 | 3.0 | | | | SWRD-02 | 944 | | 520 | 594 | 74 | 1.21 | 7.9 | | Including | 520 | 568 | 48 | 1.62 | 11.5 | | | | Including | 532 | 544 | 12 | 2.07 | 17.2 | | | | | 814 | 842 | 28 | 0.52 | - | | | | SWRD-03 | 956 | | 736 | 754 | 18 | 0.55 | - | | | 822 | 880 | 58 | 0.49 | 3.3 | | | | Including | 840 | 868 | 28 | 0.72 | 5.9 | | | | SWRD-04 | 898 | | 322 | 380 | 58 | 0.49 | - | | Including | 332 | 348 | 16 | 1.00 | 5.9 | | | | Including | 338 | 342 | 4 | 2.51 | 14.5 | | | | And | 368 | 376 | 8 | 1.17 | 5.0 | | | | | 660 | 670 | 10 | 0.71 | 6.4 | | | | | 706 | 710 | 4 | 1.06 | 8.5 | | | | | 820 | 824 | 4 | 1.08 | 17.0 | | | | | 836 | 842 | 6 | 0.85 | 9.7 | | | | SMRD-34 | 950 | | 148 | 194 | 46 | 0.90 | 10.8 | | Including | 158 | 194 | 36 | 1.08 | 13.8 | | | | Including | 166 | 172 | 6 | 3.01 | 37.3 | | | | | 600 | 710 | 110 | 0.57 | 3.9 | | | | Including | 600 | 624 | 24 | 1.37 | 12.2 | | | | Including | 606 | 616 | 10 | 2.58 | 25.8 | | | | And | 684 | 694 | 10 | 0.92 | 5.8 | | |

Table 1: Table of Intersections

| Hole ID | Type | Easting | Northing | Elevation | Azimuth | Dip | Depth | | SWRD-01 | RCD | 406194.26 | 7440803.69 | 1288.92 | 270 | -55 | 955.6 | | SWRD-02 | RCD | 406198.93 | 7440504.24 | 1287 | 270 | -55 | 944 | | SWRD-03 | RCD | 405899.9 | 7440801.41 | 1296.05 | 270 | -55 | 956 | | SWRD-04 | RCD | 405900.19 | 7440502.19 | 1293.18 | 270 | -55 | 898 | | SMRD-34 | RCD | 406399.17 | 7440496.46 | 1282.63 | 270 | -55 | 950 |

Table 2: Drill Collars

Sampling and Assay Protocols

True widths are estimated as 80-90% 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.comor contact:

Tavistock +44 (0) 207 920 3150 Emily Moss marimaca@tavistock.co.uk

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

Nature and quality of sampling (eg cut channels, random chips, or specific specialised industry standard measurement tools appropriate to the minerals under investigation, such as down hole gamma sondes, or handheld XRF instruments, etc). These examples should not be taken as limiting the broad meaning of sampling.

Include reference to measures taken to ensure sample representivity and the appropriate calibration of any measurement tools or systems used.

Aspects of the determination of mineralisation that are Material to the Public Report.

In cases where ‘industry standard' work has been done this would be relatively simple (eg ‘reverse circulation drilling was used to obtain 1 m samples from which 3 kg was pulverised to produce a 30 g charge for fire assay'). In other cases more explanation may be required, such as where there is coarse gold that has inherent sampling problems. Unusual commodities or mineralisation types (eg submarine nodules) may warrant disclosure of detailed information. | All current drilling conducted at Sierra Medina, which includes the Pampa Medina deposit, was completed under the supervision of a registered professional geologist as a Competent Person/Qualified Person (QP) who is responsible and accountable for the planning, execution, and supervision of all exploration activity as well as the implementation of quality assurance programs and reporting.

Drilling reported is Reverse Circulation "RC" collared and Diamond ("DDH") tailed drilling

Assay samples were prepared at a laboratory site in Copiapó and assayed by Andes Analytical Assay Ltd. (AAA) in Santiago.

Sierra Medina´s DDH holes are drilled and sampled on a continuous 2-meter 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.

Sierra Medina RC holes are drilled and sampled on a continuous 2-meter basis and riffle split on site up to one-eighth (12.5%) of its volume, after which samples are sent for preparation and assaying.

Marimaca staff supervised all the drilling and sampling.

DD recoveries were controlled by accurate core recovery measurement control was extended toward the division process realized in the drill location.

DD recoveries were measured by core length measurement and compared with the effective core run. Marimaca technical staff checked all data.

Measured recoveries are over 95% for DDH drilling, without significant variations and unrelated to copper grades.

RC recoveries were controlled by weighing samples and accurate control was extended toward the division process realized in the drill location.

RC recoveries were measured in weight percent as compared with a theoretical sample weight. Marimaca technical staff checked all data.

Measured recoveries are over 95% for RC drilling, without significant variations and unrelated to copper grades. | | Drilling techniques | -

Drill type (eg core, reverse circulation, open-hole hammer, rotary air blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple or standard tube, depth of diamond tails, face-sampling bit or other type, whether core is oriented and if so, by what method, etc). | -

Drilling reported RC collared and DDH-tailed drilling, DDH drilling commenced when the contact between the upper volcanics and upper sediments is encountered, which is variable in depth

DDH drilling is drilled in HQ and NQ standard core diameters | | Drill sample recovery | -

Method of recording and assessing core and chip sample recoveries and results assessed.

Measures taken to maximise sample recovery and ensure representative nature of the samples.

Whether a relationship exists between sample recovery and grade and whether sample bias may have occurred due to preferential loss/gain of fine/coarse material. | -

Marimaca staff supervised all the drilling and sampling.

DD recoveries were controlled by accurate core recovery measurement control was extended toward the division process realized in the drill location.

DD recoveries were measured by core length measurement and compared with the effective core run. Marimaca technical staff checked all data.

RC recoveries were controlled by weighing samples and accurate control was extended toward the division process realized in the drill location.

RC recoveries were measured in weight percent as compared with a theoretical sample weight. Marimaca technical staff checked all data.

Earlier from Marimaca Copper Corp.

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