Diamond drilling commences at Cerro Negro

Great Southern Copper plc (LSE: GSCU), the company focused on copper-gold-lithium exploration in Chile, is pleased to announce that diamond drilling has commenced at its Cerro Negro prospect targeting high-grade Cu-Ag-Au mineralisation at the Mostaza mine.

Highlights:

• Phase I diamond drilling has commenced at the Company's high-grade Mostaza Cu-Ag-Au mine prospect with hole CNG25-DD001 in progress
• Diamond drilling aims to confirm historical drilling grades and thickness plus step-out holes are designed to extend the known mineralised zone to depth and along-strike
• Initial drilling plan at Mostaza is for up to 5 to 10 diamond drill holes for up to 500-1,000m
• A historical (1981) non-JORC mineral resource estimate for Mostaza reported 190,600t of measured & indicated sulphide with grades of 1.2% Cu, 80 g/t Ag, and 0.45 g/t Au, plus an additional 63,000t of inferred sulphide resource at depth1
• High-grade (>1.0% Cu) Cu-Ag mineralisation at Mostaza is open in all directions
• Hole CNG25-001 targets reported results of historical resource drilling including2;

§ EDH15: 8m of 2.63% Cu, 153g/t Ag from 37m, within a broader zones of,

• 19m of 1.52% Cu, 92 g/t Ag from 33m, and
• 54m of 0.62% Cu (Ag assays incomplete over full interval) from 10m
• At Viuda prospect, scout RC drilling has been completed and successfully identified porphyry type alteration in all drill holes. Assay results are awaited

Cerro Negro is situated within the Company's Especularita project which is ideally located close to national infrastructure including main highways, powerlines, and towns. The project is located 170km from the port city of Coquimbo, and 130km from Antofagasta Minerals' copper concentrate port at Los Villos. The area lies at an elevation between 800 and 1200m and is accessible year-round for all exploration and mining activity (Figure 1).

Sam Garrett, Chief Executive Officer of Great Southern Copper, said: "We are excited to start the new year with the diamond drilling programme at Mostaza mine. Historical drilling at Mostaza has clearly not tested the extents of mineralisation and was focussed on high grade lenses ignoring broader zones of copper-silver mineralisation.

"Diamond drilling will initially focus on confirming historical grades and drilling out the known high-grade copper-silver-gold mineralisation at the Mostaza mine, before testing along trend to the south where our recent exploration results have confirmed evidence of similar mineralisation at surface.

"The Viuda scout RC drilling programme was completed just before Christmas and successfully identified porphyry style alteration in all the holes. All samples are at the laboratory and we look forward to reporting the results of this work soon."

Drilling Plan at Mostaza:

Phase 1 diamond drilling at Mostaza is planned to confirm historical grades and thickness of mineralisation, infill mineralisation between lenses 1 and 2, and test extensions of the mineralisation both at depth and along trend to the south of Lens 2.

Diamond hole CNG25-DD001 is currently in progress and is designed to confirm historical grades and mineralisation thicknesses intersected in holes EDH 25 plus test down-dip extension of results in holes EDH 23 and EDH 25 (Figure 2,3) which include;

• EDH 15: 54m of 0.62% Cu from 10m (Ag assays not available), including,

o 19m of 1.52% Cu and 92g/t Au from 33m, including

o 8m of 2.63% Cu and 153g/t Ag from 37m

• EDH 23: 16m of 0.47% Cu from 33m (Ag assays not available), including

o 5m of 1.07% Cu and 75g/t Ag from 40m

• EDH 25: 33m of 0.53% Cu from 46m (Ag assays not available), including

o 6m of 1.05% Cu and 81g/t Ag from 49m, and

o 9m of 0.92% Cu and 73g/t Ag from 62m.

Further step-out drillholes will test extensions of the mineralisation to depth below the levels of historical drilling, plus infill mineralisation undefined between Lenses 1 and 2 and test extensions of the mineralisation along trend to the south of Lens 2.

The programme will initially comprise up to 5-10 diamond holes totalling up to 500-1,000m. Scout RC drilling may also be employed to target the strike extent of mineralisation further to the south of the Mostaza pit testing the potential for a broader zone of near-surface oxide copper mineralisation.

Previous work at Mostaza Cu-Ag-Au mine:

Assay results of historical drill holes at Mostaza, including 25 diamond holes (1,025m) plus channel sampling of mine adits were used to report a non-JORC mineral resource estimate of 190,600t of measured and indicated sulphide ore with grades of 1.2% Cu, 80 g/t Ag, and 0.45 g/t Au, plus an additional 63,000t of inferred sulphide resource at depth1.

A review of the historical drilling by GSC demonstrates that high-grade (>1.0% Cu) Cu-Ag mineralisation at Mostaza is open in all directions defining an initial drill target to expand the known orebody along strike and to depth. The data review also showed that 4 of the 25 holes failed to reach the high-grade mineralisation target and 16 holes were terminated in lower grade copper (>0.1% Cu) indicating that a lower cut-off grade has potential to better define the mineralisation trend as well as up-scale the size of the Mostaza deposit2.

Results from recent geological mapping and sampling by GSC confirms that the Mostaza mineralisation extends up to 1.5km along trend to the south of the pit3. To the east of the Mostaza mine mapping indicates potential for a larger mineralised system up to 400m in width comprising an anastomosing network of structurally-controlled Cu-Ag-Ba rich veins hosted within leached and oxidised (lithocap), high sulphidation altered dacitic rocks.

Update on Scout RC Drilling at Viuda:

Scout RC drilling at the Company's Viuda prospect has been completed with 7 holes for 1,020m. Preliminary down-hole geology indicates pervasive pyrite-albite-clay (PAC) alteration of host rocks is dominant and suggestive of a large-scale porphyry type alteration system.

Samples for all the RC drill holes have been despatched to ALS Laboratories in Santiago. Detailed geological logging of the RC holes is continuing in conjunction with field mapping to update the Company's understanding of the porphyry system discovered at Viuda.

Figure 1: Location of Cerro Negro prospect, Especularita Project, Chile, where the Company's Phase 1 diamond drilling programme has commenced.

Figure 2: Cerro Negro Project, Mostaza Mine: Long section of Lens 2 showing the location of the first diamond drillhole, CNG25-DD001, and other planned Phase 1 drillholes. Historical resource blocks, underground mine workings, and drillhole assay results are shown for reference. Hole CNG25-DD001 is located approximately on local grid section S+00. (GSCU has not been able to independently verify the historical channel sample or drill hole assay results).

Figure 3: Cerro Negro Project, Mostaza Mine: Cross section S+00 (local mine grid) of the first diamond drillhole, CNG25-DD001, where it is projected to intersect Lens 2, here shown with a >0.3% Cu grade shell. Historical drillhole assay results are shown for reference. Diamond drillhole CNG25-DD001 is planned to test the high-grade historical intercepts reported in hole EDH25 and test the depth extent of the mineralisation intersected in historical holes EDH25, EDH23 and EDH15 at approximately 60m below the floor of the historical open pit. (GSCU has not been able to independently verify the historical channel sample or drill hole assay results).

Forward Looking and Cautionary Statements