Pampa Medina Sulphide Drilling Returns 16m at 5.70% Copper in UHG Bornite Zone Extension

Company Overview

Marimaca Copper (TSX: MARI | ASX: MC2) is a copper exploration and development company focused on its Sierra de Medina project in the Antofagasta Region of Chile. The company's asset base includes the Marimaca Oxide Deposit and the Pampa Medina sulphide project, located approximately 28 kilometres to the east. The Sierra de Medina project area covers approximately 14,500 hectares of mining and exploration concessions. Marimaca consolidated the project area and surrounding land packages in 2024.

New Drilling Expands High-Grade Bornite Mineralisation

Marimaca Copper reported results in June 2026 from two drill holes at the Pampa Medina sulphide deposit in northern Chile, with the headline intercept extending the ultra-high-grade (UHG) Bornite Zone and returning one of the highest-grade manto intersections at the project to date, ahead of an initial Mineral Resource Estimate (MRE).

Headline Sulphide Intercept

The lead hole was drilled to a total depth of 836 metres, returning a 96-metre sulphide envelope from 692 metres, grading 1.19% copper and 11.7 grams per tonne (g/t) silver, including 60 metres grading 1.80% copper and 18.4 g/t silver from 694 metres.

Within that envelope, the headline intercept returned 16 metres at 5.70% copper and 62.6 g/t silver from 704 metres, including 4 metres at 11.32% copper and 144.0 g/t silver from 706 metres, one of the highest-grade mantos recorded at Pampa Medina to date. All intersections are reported as downhole lengths; true widths are estimated at 80% of reported intervals.

Vice President of Exploration at Marimaca Copper, Sergio Rivera, pointed to the result as confirmation that high-grade continuity holds across the 150-metre drill spacing:

"We are pleased to see that drilling on 150m spacing continues to demonstrate continuity of the high-grade copper and silver mineralisation, often across multiple stacked horizons, with SPRD-05 intersecting one of the highest-grade mantos we have seen to date."

Northern Extension

A second hole was drilled 150 metres north of a reference position established by earlier drilling and approximately 600 metres east of the lead hole, to a total depth of 732 metres. The hole returned 22 metres at 1.97% copper and 9.2 g/t silver from 610 metres, confirming sulphide grade continuity at this location within the deposit.

At shallower depths, the hole intersected a 140-metre mixed mineralisation zone from 366 metres at 0.35% copper, including 32 metres at 0.71% copper and 4.1 g/t silver from 468 metres and 10 metres at 0.95% copper and 7.4 g/t silver from 484 metres. All intersections are downhole lengths; true widths are estimated at 80% of reported intervals.

Mineralisation Style & UHG Bornite Zone

Pampa Medina is a manto-style copper deposit hosted principally in Jurassic-Triassic sedimentary units comprising sandstones, conglomerates, tuffs, and black shales, overlain by andesitic volcanics and underlain by an Upper Palaeozoic complex. Near-surface oxide mineralisation comprising atacamite, chrysocolla, and secondary chalcocite was the initial form identified at the project; high-grade sulphide zones comprising bornite, chalcopyrite, covellite, and chalcocite have since been confirmed at depth.

High-grade sulphide mantos within the system carry grades above 2% copper across significant widths in multiple stacked horizons, with bornite and chalcocite as the dominant ore minerals. The sediment-hosted system demonstrates continuity across the defined 3-kilometre-by-1.5-kilometre area of interest (AOI).

Rivera framed the deposit's continuity within the broader project context:

"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."

Near-Surface Oxide Extensions

The same hole that returned the headline sulphide intercepts also identified near-surface oxide mineralisation north of the historic footprint at two discrete intervals. From 60 metres, the hole returned 22 metres at 0.40% copper and 1.9 g/t silver; from 204 metres, a second interval returned 24 metres at 0.30% copper and 1.8 g/t silver. Both intervals are downhole lengths; true widths are estimated at 80% of reported intervals.

The oxide intercepts indicate that near-surface copper mineralisation extends beyond the previously defined boundaries of the historic footprint.

Regional Exploration Programmes

Target-generation geochemical and geophysical work is underway across the Sierra de Medina land package, with activity centred on the Pampa Norte and Sierra Norte areas. Audio-Magnetotelluric (AMT) surveys have been completed at Pampa Norte on a 400-metre grid and at Sierra Norte on a higher-resolution 200-metre grid. Results and interpretations from the regional programmes will be released in due course.

The Sierra de Medina land package comprises three tenement groups: 55 concessions held through an ICAL subsidiary, 12 concessions at Pampa Medina under an option agreement with SCM Elenita, and 10 concessions at Madrugador under option agreements with SLM Juanita and SLM Madrugador.

Delineation Programme & MRE Pathway

The company is completing a 150-metre-spaced delineation campaign across the defined area of interest at Pampa Medina, following which input data will be closed for an MRE. The 2026 drilling programme focuses on defining the high-grade central area of interest, delineating oxide extensions, and conducting step-out drilling to test potential extensions beyond the current boundaries. The current drill hole spacing is not yet considered sufficient to establish geological and grade continuities for Mineral Resource Estimation at the Inferred or Indicated category.

Rivera outlined the steps from the current delineation campaign to the initial MRE:

"We are completing a 150m-spaced campaign across the defined initial AOI, after which we will cut off input data for an initial MRE. This maiden MRE will represent a snapshot in time, as following completion of the delineation campaign, we will begin the broader step-out programme to the distal northern and western targets in parallel with initial resource work."

Sampling, QA/QC & QP Statement

Drilling at Pampa Medina employs a reverse circulation (RC) collar and diamond tail configuration, with diamond core recovered in HQ and NQ diameters. RC samples are collected on a 2-metre basis and riffle split to one-eighth volume; diamond core samples are taken on a 2-metre basis and halved using a core splitter. Drill and RC recoveries exceeded 95%. A quality assurance and quality control (QA/QC) programme incorporating blanks, standards, and duplicates was employed throughout.

Sample preparation is conducted at the Andes Analytical Assay preparation laboratory in Copiapó, with assay work completed at the company's Santiago laboratory. Preparation yields a 400 to 600-gram subsample crushed to 95% passing -150 mesh, with a 125-gram split submitted for assaying. All samples are assayed for sequential copper, covering total, soluble, cyanide-soluble, and residual fractions, along with silver and 33 additional elements via optical inductively coupled plasma analysis on a 0.5-gram pulp sample.

Grade-over-width calculations use length-weighted averages with no grade cap or cut-off applied; silver values below the 3 g/t detection limit are assigned a value of zero, and no metal equivalents are reported. The Qualified Person for the purposes of NI 43-101 and Competent Person under the Joint Ore Reserves Committee Code 2012 is Sergio Rivera, Vice President of Exploration at Marimaca Copper, a geologist with more than 40 years of experience and a member of the Colegio de Geólogos de Chile and the Institute of Mining Engineers of Chile.

Next Steps

Marimaca is completing the 150-metre-spaced delineation campaign at Pampa Medina ahead of the data close-off for an initial MRE. Following the delineation phase, step-out drilling to the distal northern and western targets will begin in parallel with initial resource work. Results from the regional AMT programmes at Pampa Norte and Sierra Norte will be released as interpretations are finalised.

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