Phase II Drilling Commences at the Mostaza Deposit

Great Southern Copper plc (LSE: GSCU), the company focused on copper-gold and silver exploration in Chile, is pleased to announce that Phase II drilling has commenced at its Mostaza Cu-Ag prospect, Cerro Negro.

Highlights:

• Phase II drilling commenced at Mostaza utilising two diamond drill rigs
• Drilling to target depth and strike extensions to high-grade Cu-Ag mineralisation following results of CNG25-DD0011

o 20m @ 3.31% Cu and 270g/t Ag from 27m, including

o 7m @ 5.72% Cu and 490g/t Ag from 31m

• Exploration drilling along trend south of the Mostaza pit also planned
• Initial plans are to drill approximately 1,000-1,500m with additional drilling subject to results
• Results for Phase II drilling to assist commencement of metallurgy and geotechnical studies
• Core samples for Phase I drill holes CNG25002 - 009 are at ALS Laboratories with assay results pending

Sam Garrett, Chief Executive Officer of Great Southern Copper, said: "Following the exciting results delivered by the first hole of our Phase I drill programme, our team in Chile is champing at the bit to get started with the Phase II drilling at Mostaza.

"This programme represents a significant escalation of activity at Cerro Negro and aims to take maximum advantage of the Phase I drilling permit process which allowed for drilling to April of this year. Preparations to extend the drilling time-frame are also in progress.

"Besides continuing to deliver important information regarding the geology of the Mostaza deposit, the results for this drilling will also contribute to the commencement of metallurgical and geotechnical studies."

GSC Commences Phase II Drilling at Mostaza Cu-Ag mine, Cerro Negro

Two diamond drill rigs, from Chilean company R. Muñoz based in nearby La Serena, arrived on site on Monday 10 March and have commenced drilling operations including environmental and safety inspections and inductions.

One rig is positioned within the Mostaza mine pit area to test for depth and strike extensions to the known mineralisation intersected by Phase I drillholes CNG25DD001 - DD005, including CNG25DD001 which intersected 20m @ 3.31% Cu and 269.89 g/t Ag from 27m depth1.

The purpose of this drilling is to expand the historical resource area on a semi-regular grid pattern that will, if results warrant, allow progression to a new JORC resource estimate.

The second rig is positioned approximately 500m along strike to the south where it will test new exploration targets below and around Lens 4, where limited historical drilling reportedly failed to reach the intended target mineralisation.

Results for the Phase II drilling will also be used to commence metallurgical and geotechnical studies.

References:

• RNS 5182Y_LSE_Cerro Negro assays return 20m @3.3% Cu & 270g/t Ag

Forward Looking and Cautionary Statements