Pampa Medina Continues to Deliver Extraordinary Cu-Ag Grade-Widths – Drilling Intersects 216m of 1.0% Cu and 7.2g/t Ag including 62m of 2.2% Cu and 21.5g/t Ag from SPRD-15

Pampa Medina Continues to Deliver Extraordinary Cu-Ag Grade-Widths – Drilling

Intersects 216m of 1.0% Cu and 7.2g/t Ag including 62m of 2.2% Cu and 21.5g/t Ag from

SPRD-15

Vancouver, British Columbia, September 8, 2026 – Marimaca Copper Corp. (“Marimaca Copper” or the “Company”)

(TSX: MARI, ASX: MC2) is pleased to report further assay results from its ongoing drilling program at the Pampa Medina

deposit, located approximately 28km east of the Company’s Marimaca Oxide Deposit (“MOD”) in Chile’s Antofagasta

Region (Figure 1). Drilling within the central high-grade sulphide zone continues to deliver consistent, high-grade results

within the defined 3km x 1.5km area of interest (“AOI”). The mineralization across the target lithological horizons continues

to show continuity both horizontally and vertically. Drilling on 150m centers return ed 216m of 0.96% Cu and 7.2g/t Ag

from 466m, including 62m of 2.20% Cu and 21.5g/t Ag from 602m downhole from SPRD-15. Step-out drill holes outside of

the central corridor extended the mine ralized sediment horizon 300m to the south and west , with strong results from

SPRD-12, SPD-13 and SPRD-17. Additional scouting RC holes were completed to the north and northwest of the defined

AOI to determine the depth of the start of the target sediments (see Figure 3).

 Drilling on 150m spacing continues to validate the continuity of the thick, ultra high-grade, stacked-mantos across

the core of Pampa Medina

 SPRD-15 intersected thick, continuous, high-grade mineralization at the target manto horizon:

 216m of 0.96% Cu and 7.2g/t Ag from 466m (sulphide), including

― 82m of 1.72% Cu and 16.3g/t Ag from 600m, including

 62m of 2.20% Cu and 21.5g/t Ag from 602m, including

 14m of 3.05% Cu and 26.7g/t Ag from 606m, and

 12m of 3.25% Cu and 36.7g/t Ag from 632m

― 6m of 2.00% Cu and 12.0g/t Ag from 506m

 The manto demonstrates remarkable continuity of high-grade mineralization vertically across the horizon (see

Figure 4) – a defining feature of the Pampa Medina deposit

 SPD-13 – drilled near the current south-east limit of the historical oxide and new sulphide zones – provided

meaningful extensions to both zones (see Figure 3 and 8)

 Intersected multiple stacked high-grade mantos at depth across a broad interval of 222m of 0.50% Cu from

194m, including

― 18m of 1.01% Cu from 246m (oxide)

― 28m of 1.07% Cu from 322m (mixed), including

 12m of 1.90% Cu from 338m

― 48m of 1.05% Cu from 368m (sulphide), including

 12m of 1.99% Cu from 404m

 SPRD-12 significantly extended the stacked, high grade, sulphide manto (Figure 3 and 7)

 Intersection 300m to the west of previous drilling, with broad zones of high-grade mineralization, including:

― 56m of 0.95% Cu and 4.2g/t Ag from 748m (sulphide), including

 22m of 1.80% Cu and 9.7g/t Ag from 750m, including

 8m of 2.42% Cu and 9.0g/t Ag from 750m

 8m of 1.20% Cu and 2.8g/t Ag from 796m

 SPRD-17 – drilled 150m east of previously released SMRD-16 (Figure 6) – intersected multiple stacked mantos

across 104m of 0.65% Cu from 522m, including

 30m of 0.96% Cu from 522m (sulphide), including

― 20m of 1.28% Cu and 2.3g/t Ag from 524m

 40m of 0.89% Cu from 586m (sulphide), including

― 14m of 1.36% Cu and 4.0g/t Ag from 586m

 SPRD-10 drilled on the southern fence, west of SPD-13, intersected

 28m of 0.88% Cu and 5.4g/t Ag from 594m (sulphide), including

― 16m of 1.37% Cu and 8.5g/t Ag (sulphide) from 594m

 14m of 0.96% Cu and 7.3g/t Ag from 704m (sulphide)

 SPRD-11 – drilled 200m west of SPRD-10 – intersected 10m of 1.02% Cu and 5.0g/t Ag from 552m and was impacted by

late dykes

 SPRD-14 and SPRD-16A were drilled within the high-grade central zone on 150m centers and intersected post-mineral

faulting at depth

 SPRD-14 intersected near-surface oxide mineralization: 30m of 0.61% Cu and 4.2g/t Ag from 238m

 SPRD-16A also intersected near surface-oxide mineralization: 36m of 0.77% Cu from 184m, including 12m of

1.58% Cu and 3.2g/t Ag from 204m

 SMRD-35 intersected near-surface oxide and mixed mineralization southwest of the historical oxide footprint

 26m of 0.45% Cu and 2.9g/t Ag from 88m (oxide)

 32m of 0.74% Cu and 4.6g/t Ag from 302m (oxide)

 Deeper drilling impacted by a zone of post-mineralization WNW faults and dykes

 SMRD-04 and SMRD-05, the diamond-tailed extensions of the historical SMR-04 and SMR-05 RC holes, intersected

moderate mineralization at depth into the basement units

 Scout RC holes were collared to the north and northwest of the currently defined AOI to test the depth and extent

of the sedimentary horizons

 SWR-10, SWR-11, SWR-13 and SMR-36 did not intersect the target sedimentary horizon at downhole depths

ranging from 540m to 700m and will be extended through diamond drilling

 SWR-13 ended in mineralization at the limits of RC capability – intersected 8m at 1.47% Cu and 7.5 g/t Ag

from 580m in volcanics, interpreted to be above the contact of the upper sedimentary sequence which was

not intersected

 SWR-12A intersected the sedimentary horizon at greater depth, including 8m grading 1.17% Cu and 11.8 g/t

Ag from 578m, before drilling was halted due to the technical limitations of RC drilling at depth

 Diamond drilling to extend these holes is now underway

Sergio Rivera, VP Exploration of Marimaca Copper, commented:

“The results from SPRD -15 are an excellent example of one of the defining features of Pampa Medina: extremely thick,

continuously mineralized, high-grade manto horizons within the sedimentary sequence. The consistency of the high-grade

mineralization across the target horizon is remarkable and drilling continues to demonstrate the strong lateral and vertical

continuity of the stacked-manto system within the central zone.

Equally encouraging are the results from SPRD -12, SPD -13 and SPRD -17, which extend the mineralized sedimentary

horizons beyond the central corridor and confirm the presence of stacked mantos across a broader footprint. Our drilling

to the north and northwest is also providing important information on the geometry of the sedimentary basin, where the

target sedimentary horizons appear to deepen beyond the practical limits of RC drilling. Diamond tails are now underway

to test these areas. Pampa Medina remains open in several directions and is materially under-tested, and these results

continue to strengthen our view that we are defining a large, high-grade copper-silver system."

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) overl ain 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 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 is focused 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.

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

25km

Figure 2: Pampa Medina within Broader 100%-owned Sierra de Medina Property Block

Figure 3: Current Drilling Results and Drilling to Date within Pampa Medina Area of Interest (AOI)

Figure 4: Downhole Lithology and Mineralized Intersection – SPRD-15 from 602m Downhole

Figure 5: Cross Section Looking North – Pampa Medina 7,440,950 N

Figure 6: Cross Section Looking North – Pampa Medina 7,440,800 N