High-Grade Sediment Hosted Mineralization Extended at Pampa Medina – 300m Western Step-out SMRD-16 Intersects 10m of 4.2% Cu within 70m of 1.0% Cu
High-Grade Sediment Hosted Mineralization Extended at Pampa Medina – 300m
Western Step-out SMRD-16 Intersects 10m of 4.2% Cu within 70m of 1.0% Cu
Vancouver, British Columbia, August 15, 2025 – Marimaca Copper Corp. (“Marimaca Copper” or the “Company”)
(TSX:MARI, ASX:MC2) is pleased to announce further drilling at the Pampa Medina deposit , extending the high -grade
sediment-hosted manto-system 300m to the west from previous drilling. Pampa Medina is located at low altitude
approximately 28km east of the Company’s Marimaca Oxide Deposit (“MOD”) in a flat “pampa” valley within the Atacama
Desert (Figure 1). The Company is executing a 10,000m extensional drilling program with three rigs currently on site.
Highlights
• Hole SMRD-16 extends the high-grade manto-system a further 300m to the west, with varying depths of the oxide
to sulphide transition (Figure 1 and 4)
― Further validation of the Pampa Medina exploration model: a unique stratiform, sediment hosted, copper
system with extensive high-grade sequences
• Interbedded sandstone, shale and conglomerate units continue to deliver the highest-grade zones (>1% Cu) across
broad thicknesses
• The favourable mineralized stratigraphic sequence is now defined by drilling across a 1.2km x 1.2km area at the
Pampa Medina deposit and remains open – extensional drilling will focus on the north and the west
• Highlights from SMRD-16 (true widths estimated to be 95% of reported intersection):
― 70m of 1.0% from 434m including:
10m of 4.2% Cu from 438m downhole within 30m of 2.1% Cu from 434m (Figure 3)
Oxide and secondary sulphide
― 116m of 0.61% Cu from 516m including:
8m of 1.8% Cu from 528m (sulphide)
10m of 1.2% Cu from 568m (sulphide)
20m of 1.1% Cu from 612m (sulphide)
― 50m of 0.53% Cu from 744m including:
10m of 1.1% Cu from 782m (sulphide)
• Hole SMRD-15 demonstrates uplifting of the eastern extension, with a broad zone of near-surface oxide
mineralization intersected at 122m down hole in hosted by remnants of sediments just above the contact with
basement rocks
― SMRD-15 intersected 42m of 0.51% Cu from 158m (oxides)
• SMRD-16 extends the high-grade mineralized manto 300m west along section from previously reported holes (see
Figure 4):
• Hole SMRD-13 (300m west of SMRD-15)
― 6m of 12.0% Cu from 594m downhole within 26m of 4.1% Cu from 580m and a broader 100m of 1.3% Cu from
580m
• Hole SMD-02 (600m east of SMRD-16 on section) (previously reported)
― 40m of 2.1% Cu from 282m downhole within 132m of 1.0% Cu from 278m
• Hole SMRD-12 (300m east of SMRD-16 on section) (previously reported)
― 56m of 1.4% Cu from 566m downhole
• Similar to the MOD, Pampa Medina’s location is expected to drive significant infrastructure and permitting benefits:
― Proximity to other mines and associated infrastructure (Figure 1): 28km from the MOD, 64km from Sierra Gorda
(South32/KGHM), 40km from Mantos Blancos (Capstone Copper), 77km from Spence (BHP), 54km from
Antucoya (Antofagasta Minerals)
― Low altitude, flat “pampa” type surface provides sufficient space for future facilities and infrastructure
― Proximity to existing powerlines, water pipelines, major ports and regional populations
― No private land ownership, limited human impact (no nearby local or indigenous population), extremely arid
location indicates low permitting risks (comparable or superior to the MOD) associated with potential
development
Sergio Rivera, VP Exploration of Marimaca Copper, commented:
“SMRD-16 is a further 300m step out to the west of the previously announced SMRD-12 and has intersected a similar broad
zone of high-grade copper mineralization, including 70m at 1.0% and a number of discrete very high-grade zones.
“The area of interest currently confirmed by drill intersections extends over 1.2km east-west by 1.2km north-south, with an
average true thickness of between 50m to 100m. We currently have no observable reasons to indicate that mineralization
would not be continuous while the sedimentary unit exists and, as a result, we see enormous potential to both the north
and west of the current drilling.
“To the east, the block was uplifted significantly, which caused a thinning of the mineralization. Despite this, we intersected
a broad zone of oxide copper mineralization at above economic cut -off grades for Pampa Medina and we, therefore,
continue to see strong potential for oxide resource growth in all directions.
“Our strategy remains to step out significantly to try to define the limits of what is a very large system, but we will now also
turn our attention to planning an infill campaign in the broader Pampa Medina project area with the objective of
delineating updated resources for the project.”
Hayden Locke, President and CEO of Marimaca Copper, commented:
“The depth of these new intersections continue to indicate that it will be an underground opportunity, once the Pampa
Medina oxide open pit has been considered. Our early analysis indicates an economic cut-off grade requirement of between
0.5% and 0.8%, depending on copper price. With that in mind, we are targeting mineralized intersections with true widths
exceeding 20m at an average copper grade of 1.0% or more. The last four drill holes have delivered widths and grades that
materially surpass this requir ement and, as a result, we see enormous potential for a large scale, highly economic,
underground copper mining opportunity.
“Sergio Rivera and our exploration team continue to deliver outstanding value with the extension of the thick, high grade
manto mineralization to the west. The continued exploration success at Pampa Medina reinforces our goal at Marimaca:
to become a significant copper producer with the unique, low-cost, advanced-stage asset in the MOD, and transformational
district scale upside anchored by Pampa Medina and Madrugador.
“With the upcoming release of the MOD DFS, our strategy remains multi-pronged: 1) deliver a near-term, low-cost 50ktpa
copper cathode mine in a Tier -1 jurisdiction; 2) advance the Pampa Medina and Madrugador Oxide projects to grow our
cathode production and extend mine life; and 3) continue to define the district-scale exploration potential of our large land
package.”
Overview of Pampa Medina
Pampa Medina is a stratiform or 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 meta morphosed sediments, volcanics and intrusions . It´s intruded by a dyke swarm and affected by post
mineral normal faulting (Figure 4). Copper was originally identified in near-surface oxide mineralization dominated by
atacamite, chrysocolla and both secondary and primary chalcocite , and has now been identified in high -grade zones of
chalcopyrite and bornite which extend laterally down-dip beyond the oxide-primary transition.
Following Marimaca’s consolidation of the project area and surrounding land packages in 2024, the Company
reinterpreted all available geological information (for the first time as one) and developed an updated geological model
for Pampa Medina, which identified the lower sedimentary units of interbedded sandstones, shales and conglomerates as
the productive horizons for future drill targeting. Oxide copper mineralization was logged in historical drilling in near-
surface, uplifted blocks , with the model of continuity in the intact lithological sequence in deeper blocks for primary
mineralization to be tested by Marimaca’s 2025 drilling campaign.
SMRD-16 materially extends the high -grade manto to the west, increasing the defined mineralized stratigraphy across a
1.2km by 1.2km area (Figures 2 and 4). Weakly mineralized sandstones were intercepted from 116m, with the main high-
grade mixed-sulphide, sediment hosted mineralization starting at 438m downhole. Hole SMRD-15 was planned to confirm
the uplifted basement in the eastern direction of the Pampa Medina main target. Oxide mineralization was intercepted at
122m, extending to 204m depth (Figure 3). Exploration focus will remain on the western and northern regions of the
Pampa Medina main target, which both remain open.
Figure 1: Regional Map – Marimaca, Pampa Medina and Regional Infrastructure
25km
Figure 2 – Pampa Medina Deposit and Step-out Drilling Locations
Figure 3 – Pampa Medina Lithology – SMRD-16 Downhole Sequence
Figure 4 – Cross Section Looking North – Pampa Medina SMRD-15 to SMRD-16
Table 1: Table of Intersections
Hole Easting Northing Elevation Azimuth Inclination Depth
SMRD-15 7440799.14 407698.23 1267.17 270 -60 580
SMRD-16 7440819.3 406488.16 1282.01 270 -60 850
Table 2: Drill Collars
Sampling and Assay Protocols
True widths are estimated as 95% 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
Hole Total
Depth (m)
From (m) To (m) Intersection
(m) % CuT
SMRD-
15
580
122 200 78 0.31
Including 158 200 42 0.51
Including 188 198 10 0.83
SMRD-
16 850
236 266 30 0.43
And 434 794 360 0.49
Including 434 504 70 1.03
Including 434 464 30 2.10
Including 438 448 10 4.24
Including 516 632 116 0.61
Including 516 536 20 0.91
Including 528 536 8 1.80
Including 568 590 22 0.90
Including 568 578 10 1.24
Including 612 632 20 1.14
Including 744 794 50 0.53
Including 782 792 10 1.10