Announcement • Jul 09
Great Southern Copper Completes Scout RC Drilling Campaign At Especularita Great Southern Copper plc completed its first scout RC drilling programme at the Especularita Project targeting large-scale porphyry copper systems. Seventeen scout RC holes completed for a total of 2,474 metres drilled. The La Colorada advanced argillic lithocap is vast in size and interpreted to represent the upper high-sulphidation levels of an alteration system that is potentially overlying porphyry-related copper mineralisation. Drilling designed to assist with geological interpretation in areas surrounding the advanced argillic lithocap where the Company believes the lithocap has been eroded potentially exposing underlying porphyry-style alteration at surface. Porphyry copper type alteration is evidenced in the drilling at Piedras Blancas, Artemisa North and Victoria. First assay results are expected within the next 2-4 weeks. GSC holds rights to own 100% of the Especularita project. Prospect located at low elevation with excellent access to infrastructure and mining services and along trend of more than 85 million tonnes of contained copper hosted in major deposits including Los Pelambres, Altar and El Pachon. The scout RC drilling programme at Especularita targeted prospects along the western and southern margins of the La Colorada lithocap. The Especularita project is situated at low altitude within the Cretaceous-age coastal metallogenic belt, within a northwest-southeast trending structural lineament that links the project with notable large-scale porphyry Cu-Au mines and projects, including Los Pelambres, Altar and El Pachon. A total of 17 drill holes (comprising 2,474m) have been completed across four target areas on the western and southern flanks of the advanced argillic lithocap alteration including Piedras Blancas, Artemisa North, Victoria and Artemisa South. Drillholes at Piedras Blancas and Artemisa North (RC001 - RC009) intersected a complex of diorites and locally porphyritic microdiorites with widespread strong to intense magnetite-biotite-pyrite alteration overprinted by zones of strong to intense chlorite-sericite alteration with over 10% disseminated pyrite and local quartz and pyrite stockwork veinlets. This alteration is consistent with the outer phyllic alteration zone (or shell) in a porphyry copper type system. Porphyry-copper style potassic alteration, defined by hydrothermal biotite with over 10% disseminated pyrite and minor chalcopyrite and quartz veinlets, intersected in the bottoms of holes RC001 at Piedras Blancas and RC008 at Artemisa North. These two holes lie furthest to the east and were drilled directed towards the lithocap, beneath zones of outcropping quartz-sericite stockwork veining, suggesting the system may be improving in this direction. This potassic alteration was intercepted within a hundred metres of surface suggesting that the system may be telescoped and the porphyry centre could potentially be close to surface. Drilling at Victoria and Artemisa South (RC010 to RC017) was also dominated by variable magnetite-biotite alteration developed in hornfelsed volcanics (Victoria) and diorites to granodiorites (Artemisa South). Phyllic-style pyrite-sericite-chlorite alteration is less intense than the northern areas and seems to be more structurally controlled, which is consistent with the mineralisation observed at surface as vein swarms of carbonate-quartz-sulphide and/or quartz-sericite-chlorite plus sulphides. The intensity of veining and presence of Cu-oxide occurrences increases generally northwards towards the lithocap, further suggesting that the source of the fluids lies to the north and beneath the advanced argillic alteration that defines the La Colorada lithocap. Where preserved, lithocaps overlie and conceal the location and source of potential porphyry Cu mineralisation at depth. They are formed by hot acidic fluids ascending to the surface from the porphyry intrusion below and the subsequent interactions of those fluids with the enclosing wall rocks. Interaction of the rising fluids with porous volcanic rocks, for example, typically results in a laterally extensive, flat-lying 'blanket' of silica-mica-clay-pyrite alteration (defined as advanced argillic alteration) above the porphyry system below. Uplift, weathering and exposure of the pyritic-rich alteration to oxidising surface waters creates highly acidic fluid conditions which then acts to strip (or 'leach') metals and other minerals from the altered rock resulting in a hard, silica-dominant and highly resistive cap-rock overlying the porphyry alteration system. The lithocap may also itself be mineralised - with gold-silver-copper deposits not uncommon within the advanced argillic alteration zones. Due to acid-leaching, the oxidised surface areas of the silica-rich lithocaps are typically barren and chemically inert to depths of up to several hundreds of meters depending upon the weathering and erosion profile which, as a result, can mask the presence of underlying high-sulphidation and porphyry copper mineralisation. Surrounding the vertically-continuous porphyry intrusion(s) the alteration system forms typically as overlapping shell-like carapaces zoning outward from the mineralising porphyry intrusion as; Potassic (magnetite-Kspar) -> phyllic (sericite-chlorite-pyrite) -> propylitic (epidote) alteration shells; Advanced argillic (qtz-al-kaol-pyro-dic) forms near-surface blanket. High pyrite produces acid leaching; High sulphidation Au-Ag+Cu can occur at base of lithocap below the acid-leached weathering zone; Intermediate sulphidation Cu-Pb-Zn-Ag related to late dacitic domes; Porphyry copper grades increase inwards towards the potassic core. GSC's La Colorada advanced argillic lithocap alteration system is vast, measuring over 75km2 in area, and to date the Company has explored less than 25% of the total prospective area. In order to efficiently vector exploration focus towards the hidden porphyry copper zones the Company is undertaking extensive and detailed spectral and low-detection geochemistry surveys to map the temperature-pH mineralogy of the alteration minerals which provides clues to the hot acidic fluid pathways leading down-ward to the porphyry copper mineralisation below the lithocap. This work, combined with the recent AMT surveys and scout RC drilling results will be critical in planning the next phase of exploration drilling of the lithocap to target both high-sulphidation Au-Ag-Cu and porphyry Cu mineralisation. The RC drilling method employed at Especularita collects samples on two-metre intervals. Representative samples for each sample of the cuttings are collected in large, individually numbered plastic bags, which are then weighed and transferred to a riffle splitter where they are separated (or split), and homogenised, three times into two duplicate samples of approximately 5kg each. New Risk • Jun 28
New minor risk - Financial data availability The company's latest financial reports are more than 6 months old. Last reported fiscal period ended September 2025. This is considered a minor risk. If the company has not reported its earnings on time, it may have been delayed due to audit problems or it may be finding it difficult to reconcile its accounts. Currently, the following risks have been identified for the company: Major Risks Share price has been highly volatile over the past 3 months (12% average weekly change). Earnings have declined by 44% per year over the past 5 years. Shareholders have been substantially diluted in the past year (35% increase in shares outstanding). Revenue is less than US$1m. Minor Risks Latest financial reports are more than 6 months old (reported September 2025 fiscal period end). Market cap is less than US$100m (UK£21.6m market cap, or US$28.5m). New Risk • Jun 21
New major risk - Share price stability The company's share price has been highly volatile over the past 3 months. It is more volatile than 90% of British stocks, typically moving 11% a week. This is considered a major risk. Share price volatility increases the risk of potential losses in the short-term as the stock tends to have larger drops in price more frequently than other stocks. It may also indicate the stock is highly sensitive to market conditions or economic conditions rather than being sensitive to its own business performance, which may also be inconsistent. Currently, the following risks have been identified for the company: Major Risks Share price has been highly volatile over the past 3 months (11% average weekly change). Earnings have declined by 44% per year over the past 5 years. Shareholders have been substantially diluted in the past year (37% increase in shares outstanding). Revenue is less than US$1m. Minor Risk Market cap is less than US$100m (UK£20.0m market cap, or US$26.5m). 
