Drilling Program at Pampa Medina Continues to Demonstrate Continuity and Scale of Sediment-Hosted Copper System

Drilling Program at Pampa Medina Continues to Demonstrate Continuity and Scale of

Sediment-Hosted Copper System

Vancouver, British Columbia, May 19th, 2026 – Marimaca Copper Corp. (“Marimaca Copper” or the “Company”)

(TSX:MARI, ASX:MC2) is pleased to report new assay results from its ongoing 2026 step-out exploration drilling programs

at the Pampa Medina deposit, located at low altitude approximately 28km east of the Company's Marimaca Oxide Deposit

("MOD") (Figure 1). The program includes drilling on 150m intervals to test the continuity between previous 300m scouting

holes and continues to demonstrate the exceptional grade and continuity of the high-grade m anto-type copper-silver

mineralization, across the initial 3km x 1.5km area of interest. Results from the current exploration drilling further validates

the consistency of both oxide and sulphide mineralisation across the high-grade central zone. Step-out drilling continues

to expand the mineralized sedimentary horizon , with high-grade intercepts reported over 300m from previous drilling in

the south-western area of interest (Figure 2).

▪ SPRD-06 contains 5 high-grade vertically stacked mantos (each of strong grade-thickness) across a total mineralized

package of sediments and tuffs exceeding 400m in thickness

▪ Stacking of multiple high-grade mineralized sedimentary units is a key difference between other known

sedimentary hosted copper deposits globally (e.g. Kupferschiefer, Kamoa-Kakula)

▪ Additional drilling at 150m spacing continues to demonstrate the continuity of the high-grade copper mantos with

multiple holes returning high grades over significant thickness (Figure 3)

▪ SPRD-06 – drilled between previously released holes SMRD-16 and SMRD-20 on 150m spacing and intersected high-

grade mineralization sections hosted in the upper and lower sediments

▪ Broader intercept of 424m of 0.58% Cu and 2.2g/t Ag from 424m, containing five high-grade, stacked mantos

― 32m of 1.02% Cu and 3.1 g/t Ag from 432m (oxide)

― 8m of 2.54% Cu and 21.0 g/t Ag from 494m within 22m of 1.23% Cu and 11.8 g/t Ag from 492m (mixed)

― 12m of 2.23% Cu and 19.7 g/t Ag from 568m within 22m of 1.53% Cu and 13.6 g/t Ag from 564m

(sulphide)

― 10m of 1.38% Cu and 4.4 g/t Ag from 698m (sulphide)

― 8m of 1.29% Cu and 10.8 g/t Ag from 752m (sulphide)

▪ SPRD-02 – step-out drilling between previously released holes SMD-02 and SMRD-22 on 150m spacing intersected

mineralization in the near-surface upper volcanics and lower sediments

▪ 166m of 0.50% Cu and 3.9 g/t Ag from 222m (oxide), including

― 24m of 1.17% Cu and 11.8g/t Ag from 222m, including

▪ 10m of 2.47% Cu and 27.4g/t Ag from 228m (oxide)

― 14m of 1.07% Cu and 6.6 g/t Ag from 300m (oxide)

▪ 6m of 0.94% Cu from 520m (sulphide) within 12m of 0.64% Cu from 520m

▪ SWRD-05 drilled 300m south of previously released SWRD-02 intersected high-grade mineralization in the lower

sediments

▪ 30m of 1.00% Cu and 7.3 g/t Ag (sulphide) from 536m, including

― 4m of 2.29% Cu and 29.0 g/t Ag from 596m (sulphide)

▪ Both within 68m of 0.73% Cu and 5.1 g/t Ag from 532m (sulphide)

▪ SPRD-01 – step-out drilling 150m north of previously released SMD-02 also intersected high-grade near-surface

volcanics and upper sediments

▪ 146m of 0.41% Cu and 1.9g/t Ag from 286m, including

― 50m of 0.56% Cu and 2.4g/t Ag (oxide) from 290m, including

▪ 10m of 1.90% Cu and 10.6g/t Ag from 306m

― 24m of 0.61% Cu and 1.7g/t Ag from 372m (mixed), including

▪ 14m of 0.79% Cu and 2.9g/t Ag from 382m

▪ SPRD-03 – step-out drilling 150m south of previously released hole SMRD-13 intersected mineralization in the near-

surface volcanics and but was affected by pre and post mineral dyking

▪ 14m of 0.31% Cu from 52m (oxide), including

▪ 8m of 0.42% Cu from 56 m

▪ Further assays from the step-out program focused on the south-western extent of the sediment horizon partially

affected by subparallel WNW late faulting and dyking. However, mineralization now extends to the upper volcanics

adding continuity to the rock units covering the sediments.

▪ SWRD-07, drilled 300m west of SWRD-06B, intersected mineralization in the upper sediments and basement

metasediments but was impacted by pre and post mineral dykes

▪ 20m of 0.52% Cu and 5.1g/t Ag from 436m (sulphide)

▪ SWRD-06B, drilled 300m west of SWRD-05, intersected the lower manto in the interbedded siltstone, sandstone

and tuff sequence

▪ 4m of 1.15% Cu and 27.0g/t Ag from 644m (sulphide)

▪ SWRD-08A, drilled 300m west of previously released SWRD-04, intersected mineralization in the upper volcanics

and upper sediment horizon

▪ 28m of 0.52% Cu and 1.5g/t Ag from 202m (oxide)

▪ 12m of 0.67% Cu and 3.2g/t Ag from 418m (mixed)

▪ 6m of 1.01% Cu and 11.0g/t Ag from 454m (mixed)

▪ SWRD-09, drilled 300m west of previously released SMRD-33 intersected mineralization near-surface volcanics and

the lower manto

▪ 10m of 0.62% Cu and 7.8g/t Ag from 168m within 16m of 0.45% Cu and 5.3g/t Ag from 166m (oxide)

▪ 6m of 0.82% Cu and 3.7g/t Ag from 594m (mixed)

▪ SMRD-14 drilled 300m north of hole SWRD-08A, intersected mineralization hosted by sandstones from the upper

sedimentary unit

▪ 8m of 0.52% Cu from 408 m within 12m of 0.40% Cu from 406 m (oxide)

▪ 8m of 0.67% Cu from 432m within 14m of 0.54% Cu from 428 m (oxide)

▪ 14m of 0.51% Cu and 1.12 g/t Ag from 478 m (mixed)

Sergio Rivera, VP Exploration of Marimaca Copper, commented:

“Our 2026 step-out drilling program continues to deliver exceptional results at Pampa Medina. We are not only seeing

consistent, high-grade copper intersections, with multiple broad intervals returning above 2% copper across the western

step-out holes, but also compelling continuity in the central high-grade zone (Figures 2, 3 and 4) . Multiple holes in this

release intersected >3 high-grade stacked mantos each reporting thick intersections of strong grades.

The copper and silver mineralisation we see across both the oxide and sulphide zones is consistent with our geological

model and confirms the scale and grade potential of the Pampa Medina system. We are increasingly confident that we are

dealing with a deposit of genuine district significance.”

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 central zone, 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 Historic Oxide Deposit and Current Drilling Locations (Previous Drilling in Grey Traces)

Figure 3 – Cross Section Looking North – Pampa Medina 7,440,950 N

Figure 4 – Cross Section Looking North – Pampa Medina 7,440,200 N

Hole Total

Depth (m) From (m) To (m) Intersection

(m) % CuT g/t Ag

SPRD-01 792

286 432 146 0.41 1.9

Including 290 340 50 0.56 2.4

Including 306 316 10 1.90 10.6

And 372 396 24 0.61 1.7

Including 382 396 14 0.79 2.9

SPRD-02 750

222 388 166 0.50 3.9

Including 222 246 24 1.17 11.8

Including 228 238 10 2.47 27.4

Including 234 238 4 4.60 50.5

And 300 314 14 1.07 6.6

520 532 12 0.64 -

Including 520 526 6 0.94 -

SPRD-03 700

52 66 14 0.31 -

Including 56 64 8 0.42 -

SPRD-06 904

424 848 424 0.38 2.2

Including 432 464 32 1.02 3.1

And 492 514 22 1.23 11.8

Including 494 502 8 2.54 21.0

Including 500 502 2 4.14 29.0

And 562 584 22 1.53 13.6

Including 568 576 8 2.70 24.5

And 698 708 10 1.38 4.4

Including 752 760 8 1.29 10.8

SWRD-05 886

26 36 10 0.64 -

532 600 68 0.73 5.1

Including 534 570 36 0.94 6.3

Including 536 566 30 1.00 7.3

Including 536 546 10 1.30 12.4

And 564 566 2 2.36 26.0

And 596 600 4 2.29 29.0

SWRD-06B 860 644 648 4 1.15 27.0

SWRD-07 750

428 458 30 0.42 3.4

Including 436 456 20 0.52 5.1

454 460 6 1.01 11.0

538 544 6 0.35 -

SWRD-08A 500

202 230 28 0.52 1.5

418 430 12 0.67 3.2

454 460 6 1.01 11.0

SWRD-09 950

166 182 16 0.45 5.3

Including 168 178 10 0.62 7.8

592 608 16 0.68 3.4

Including 594 600 6 0.82 3.7

SMRD-14 838

406 418 12 0.40 -

Including 408 416 8 0.52 -