High Grade Rock Chips at Especularita

Great Southern Copper plc (LSE: GSCU), the company focused on copper-gold and lithium exploration in Chile, is pleased to announce the results from its exploration programme at the Aurelia prospect, Especularita.

Highlights:

• 76 rock chip assay results received with grades up to 6.76% Cu
• 17 samples (22.4%) report assay grades above 1% Cu
• High grade Cu+Au-Ag mineralisation hosted in skarn altered volcanics and sediments
• Mapping indicates multiple mineralised skarn horizons with strike length up to 2km
• Samples from local artisanal mines grade up to 7.33% Cu
• Prospect within 12km of Pucobre's El Espino deposit (123 Mt @ 0.66% Cu and 0.24 g/t Au)
• Aurelia becomes the fourth prospect, after Victoria, to add to the pipeline of potential drill targets at Especularita, with drilling expected to commence soon at the Abundante and Teresita prospects

Next steps:

• Soil sampling is currently on-going to help map out mineralised target horizons
• Further exploration at Aurelia, including drone magnetics and petro-chemical surveys, is being planned to assist the Company's understanding of the copper mineralisation trends and to help plan for potential scout drilling next year
• In addition, the Company will continue to enhance its concession holding in the prospect area

Sam Garrett, Chief Executive Officer of Great Southern Copper, said: "Our boots-on-ground exploration at Aurelia has delivered yet another high-grade copper target into our prospect pipe-line at Especularita. Being a replacement-type deposit, the Aurelia prospect further highlights the optionality in deposit style that the Especularita project enjoys as a whole. High copper grades and potential for scale combine to make this a very exciting target for the Company and we look forward to advancing our exploration here towards drill-testing."

Sampling and Results:

All rock samples collected are located using hand-held GPS units (WGS84 zone 19S datum, UTM coordinate system) and allocated a unique sample number using a ticket-book system. Samples are transported from the field and delivered by Company employees to ALS Laboratories in Santiago where they are prepared for analysis (weighed, dried, crushed and pulverised). A subsequent 200g split of each sample pulp is then forwarded to the ALS geochemical laboratory in Lima, Peru, where samples are assayed for gold (30g fire assay with ICP-AES finish, ALS code AU-ICP21) and analysed for 48 major, base and trace elements by ICP-MS following a four-acid digest (ALS code ME-MS61).

Of the 76 rock chip samples collected, 36 samples (47%) were anomalous in copper with assay grades ranging from 0.1 - 6.76% Cu. In addition, 35.5% of samples assayed above 0.5% Cu and 22.4% of samples assayed above 1% Cu. This includes assays of character samples of unmineralised rocks collected specifically to assist the Company in understanding the controls on mineralisation at Aurelia and interpreting the detailed geology of the prospect.

Gold and silver are also anomalous in the skarn mineralisation with 17% of samples in this survey returning gold assay grades over 0.1g/t Au (up to 1.19g/t Au) and 23.7% of samples were anomalous in silver (> 1g/t Ag) with assay grades up to 57.9g/t Ag.

Aurelia Cu+Au-Ag prospect, Especularita:

The Aurelia prospect is located in the southeast of the Especularita project area where early reconnaissance work by GSC reported assay grades of up to 7.3% Cu and 2.9g/t Au in samples of skarn mineralisation collected from local artisanal mine dumps1.

Subsequent prospect-scale exploration by GSC has demonstrated that high-grade, replacement style Cu+Au-Ag mineralisation is hosted in skarn altered volcanics and volcano-sedimentary units in contact with a large, Cretaceous-aged, granodioritic batholith (Figure 1 -3). The gently-folded volcanic host rocks typically strike NNW-SSE and are intruded by small dioritic, granitic, and monzonitic plugs and dykes.

The interaction of the intrusions with the volcano-sedimentary rocks has generated widespread contact hornfels in the volcano-sedimentary rocks resulting in brecciation and replacement skarn alteration dominated by prograde (early, high-temperature) calc-silicate epidote and garnet skarn. Later retrograde overprinting of the calc-silicate skarn by magnetite/hematite and chlorite alteration is typical. Locally the skarn altered units are mineralised with chalcopyrite, pyrite, and specular hematite as fractures, disseminations, and replacements which typically weather to copper and iron oxides near the surface. Copper mineralisation occurs associated with all skarn alteration types, though appears to be best developed in garnet skarn with assay grades up to 7.33% Cu. Gold and silver values appear to be more erratic but locally can reach up to 2.9 g/t Au1 and 57.9g/t Ag.

The skarn altered and copper-mineralised horizons vary in width from a few metres up to 20m thickness and have been individually mapped over a strike length of at least 2km (Figure 4). The cumulative strike length of skarn mineralisation mapped at Aurelia to date is approximately 4.5km, although not all is located within the Company's concessions. Additional mineralised skarn horizons, evidenced by isolated artisanal mine workings distal to the main Aurelia trend requires follow-up work and indicates potential for a significantly larger system (Figure 3).

The Aurelia copper mineralised skarn system is located within 12km of the large El Espino Cu-Au skarn deposit (123 Mt @ 0.66% Cu and 0.24 g/t Au)2 which is owned by Chilean company Punta del Cobre and is in the process of development.

References:

• RNS 3666Q (20 Feb 2023): Exploration update at Especularita and San Lorenzo.
• Lopez et al., (2014): Alteration patterns and structural controls of the El Espino IOCG mining district, Chile. Mineralium Deposita, v49 (2), pg 235.

Forward Looking and Cautionary Statements