Great Southern Copper

Especularita

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GREAT SOUTHERN COPPER

The Company has now completed three phases of diamond drilling at Mostaza within Cerro Negro. Ground-based geophysics at Mostaza has defined a 2.5km southward extension of the mineralised trend. Phase III diamond drilling was completed in January 2026 and was designed to test deeper and lateral targets generated by PDIP and AMT results, identifying multiple stacked high-grade Cu-Ag lenses and significantly advancing the understanding of the mineralised system.

At Viuda Negra, the Company has completed ground magnetic surveying, with results now being incorporated into drill planning to further test the geological model for Maricunga-style gold-silver mineralisation.

These campaigns are intended to build sufficient confidence to support a future resource drilling programme across the best prospects.

The geology of Especularita is dominated by an extensive lithocap alteration zone formed at the intersection of several sets of crustal-scale structures and the contact margin of the Quilitapia Granodiorite and overlying andesitic volcanics.

Remote sensing studies by GSC suggest that the lithocap alteration, which comprises an inner advanced argillic core enveloped by a more extensive halo of silica-argillic alteration (silica cap) is larger and more intense than that associated with the large Andacollo copper and gold mine located in the same coastal metallogenic belt some 90km to the north. Such lithocap systems are common above and/or lateral to porphyry Cu-Au mineralising systems and may themselves be mineralised or barren.

Evidence of small-scale and artisanal copper and gold mining is extensive in the district and particularly concentrated both at the contact of the granodiorite with the overlying volcanics as well as preferentially located around the base of the lithocap alteration zone providing strong evidence for the potential of discovering porphyry copper style mineralisation beneath the lithcap.

Besides significant porphyry mineralisation potential, exploration by the Company across its Especularita concessions, including regional drilling, magnetics, stream sediment and mapping surveys, plus detailed prospect-scale work, has also identified evidence of large-scale IOCG (Iron-oxide Copper-Gold) and IRGS (Intrusive-related Gold System) type mineralisation styles.

The Company’s exploration team is working to establish a pipe-line of advanced exploration targets which it aims to drill test over the coming years.

Following the signing of new option agreements over the Cerro Negro and Artemisa concessions in 2024, which include the Mostaza Mine and Viuda Negra Prospect respectively, GSC strengthened its pipeline of additional targets to support its growth ambitions. The Company’s primary focus is on drilling at the Mostaza Mine in order to progress it towards future resource definition, as well as exploration drilling at the Viuda Negra Prospect.

Phase I and II diamond drilling campaigns have now been completed at the Cerro Negro prospect, targeting high-grade Cu-Ag mineralisation beneath the historical Mostaza mine pit. Phase II confirmed mineralisation up to 500 metres south of the pit, with best intercepts including 10.4% Cu and 672g/t Ag. Subsequent ground-based geophysical surveys, including gradient array IP, PDIP and AMT, defined a 2.5-kilometre-long anomaly south of Mostaza consistent with sulphide mineralisation,now guiding a Phase III drill programme scheduled to commence in August 2025. Phase III drilling identified multiple stacked high-grade Cu-Ag lenses, representing the largest and most advanced drilling campaign at Cerro Negro to date, and further reinforced the scale potential of the mineralised system.

Elsewhere at Especularita, scout drilling at Viuda Negra confirmed porphyry-style alteration, with hydrothermal breccias and quartz-magnetite vein swarms intersected in multiple holes, and assays pending. At the Viuda Negra prospect, seven RC holes intersected structurally controlled Au-Ag mineralisation, including 12m @ 1.5g/t Au and 0.47% Cu, with vectoring analysis suggesting the system may strengthen further to the south and east.

Earlier drilling at Teresita and Abundante confirmed IRGS-style and breccia-hosted mineralisation, with encouraging sample grades including up to 13.7g/t Au and 7.22% Cu, though current efforts are now focused on the Cerro Negro–Mostaza–Viuda corridor, where technical progress has been most compelling.

The Especularita project, located approximately 250km north of the capital, Santiago and within the coastal metallogenic belt, comprises 16,816 ha of exploitation and exploration concessions both granted and in the process of being granted. GSC has the option to own 100% of the mining rights of the project via three Purchase Option Agreements, subject to the payment of annual option fees and concession rent fees.

EXPLORATION SNAPSHOT

GALLERY