Magnetics Survey Identifies Multiple Targets

Great Southern Copper plc (LSE: GSCU), the company focused on copper-gold and lithium exploration in Chile, is pleased to announce the results of its drone-magnetics survey at its Especularita project.

Highlights:

• High grade Cu-Au prospects, Abundante and Teresita, identified as magnetic anomalies with drilling planned to commence soon
• Multiple targets identified within the NE-trending, Teresita magnetic anomaly corridor
• Bullseye anomalies potentially represent breccia-pipe or pencil-porphyry type Cu deposits
• Significant magnetic lineaments requiring follow-up ground-truthing in the field, particularly against known structurally-controlled vein-breccias systems and vein swarms

Results from the 1,480 line-kilometre drone-magnetics survey1,2 are extremely encouraging and provide additional impetus and clarity to the ongoing exploration programmes at Especularita, targeting the discovery of large-scale and high-grade Cu-Au deposits.

On a project-scale the survey has been very effective at defining the relationships between the dominant geology and alteration domains, most specifically the contact of the Quilitapia batholith and overlying hornfelsed andesitic volcanics and the high-sulphidation lithocap alteration (La Colorada lithocap). The WNW-trending Victoria Fault, which defines the contact of the batholith and hornfelsed volcanics is identified as a dominating regional structure and its intersection with other, large-scale N-S, E-W and NE-trending structures is likely to be a control on the development of high-sulphidation alteration.

In detail, mapping of magnetic lineaments highlights intense structural overprinting and deformation across the survey area which, though anticipated, is not always evident in outcrop. Magnetic lineaments, representative of faults, veins, dykes and jointing, are dominant in a NE and NW orientation, however, N-S and E-W oriented lineaments are also evident.

The magnetic data clearly identifies both the Teresita and Abundante prospects where scout RC drilling is due to commence targeting high grade Cu-Au in rock chip samples with grades up to 3.39% Cu at Abundante3 and 13.7g/t Au and 7.22% Cu at Teresita4.

Sam Garrett, Chief Executive Officer of Great Southern Copper, said: "The results of the magnetics survey have been very effective in assisting with our mapping and understanding of the geology at Especularita. The correlation between magnetic anomalies and known mineralisation at prospects such as Abundante and Teresita is highly encouraging and will greatly benefit our on-going exploration by providing more targets for investigation.

"Subject to final permitting and drill-rig availability, we plan to commence scout RC drilling operations at both Abundante and Teresita as soon as possible and I look forward to updating stakeholders on the results of those programmes."

Magnetic survey and processing:

A 1,480 line-kilometre drone-based magnetics survey was completed by the Company in July this year using Chile-based contractor GFDas UAV & Geosciences1. The drone-mounted magnetometer was flown at an elevation of approximately 30m above ground level on a grid pattern comprising 50m-spaced east-west lines with 500m-spaced north-south tie lines. Details of the survey are summarised in the following table:

Table 1: Especularita drone-magnetics survey parameters.

At the Teresita-Abundante prospect the survey was infilled to 25m-spaced lines, 250m-spaced tie lines and a survey height of 20m above the DEM to provide more detail over the mapped surface footprint of the Abundante tourmaline shingle-breccia3.

The survey flying height was pre-programmed into the drone based on a fixed clearance of 30m above a satellite-determined digital elevation model (ALOS DEM). However, the DEM for the southern portion of the survey was considered unsuitable, requiring the drone to first fly a Lidar survey to create a suitable DEM model before using the magnetometer. The magnetic survey was then flown at a height of 20m above the Lidar DEM.

Processing and interpretation of the drone magnetic data was completed by ExploreGeo based in Perth, Australia. ExploreGeo carefully levelled the drone data and applied a suite of software tools and filters purpose designed to maximise the extraction of detail from the data while suppressing acquisition noise.

Besides interpreting the broader geological domains, ExploreGeo also applied a range of filters to interpret different structural features in the Total Magnetic Intensity ("TMI") data (Figure 1) which allow for mapping of magnetic lineaments representing potential faults, dykes, vein structures, jointing and buried intrusive bodies.

The use of drones for recording the magnetics data has been very effective at reducing the Company's survey costs, CO2 emissions and overall on-ground footprint.

Results:

The final TMI data clearly map out the broad-scale geology domains at Especularita dominated by the weakly magnetic granodiorite in contact with strongly magnetically-altered and hornfelsed andesitic volcanics (Figure 2). Immediately north of the granodiorite and in faulted contact to the east margin of the volcanics, a magnetic "flat zone" is consistent with a region of magnetite destruction associated with the development of the quartz-alunite high-sulphidation alteration of the La Colorada lithocap.

Mapping of magnetic lineaments in the TMI data indicates intense post-intrusive structural activity dominated by a conjugate set of NE and NW-trending structural features (faults, dykes, veins and joints) in the project area (Figure 2). N-S-trending structures are also prevalent in the northern portion of the granodiorite and the lithocap alteration zone.

The Teresita prospect (including the Abundante breccia pipe target) is located within a prominent NE-trending structural corridor clearly defined in the magnetics at the southeastern margin of the granodiorite batholith (Figure 3). NE-trending lineaments in the magnetics coincide closely with outcropping quartz-siderite vein-breccia structures yielding high-grade Cu-Au results in rock chip samples3,4.

Next steps:

The coincidence of outcropping mineralisation with modelled magnetic lineaments is very encouraging and suggests that a programme of ground-truthing interpreted lineaments in the field will be a priority for the Company's district exploration and will greatly assist in defining new targets for prospect-scale exploration programmes.

Reviewing and modelling of the data will continue in order to evaluate potential for buried targets.

References:

• RNS 7231B (06 June 2023): Magnetic surveys commence at Especularita.
• RNS 0817M (12 Sept 2023): Regional stream sediment survey at Especularita defines multiple targets for follow-up.
• RNS 2962G (18 July 2023): High-grade Cu in rock chip samples up to 3.39% Cu from Abundante mine prospect.
• RNS 5675F (11 July 2023): High grade Cu-Au in rock chip samples from Teresita up to 5.97% Cu and 13.7g/t Au.

Figure 1: Examples of final processed images for the Especularita drone magnetics survey including; (top left - bottom right) VRMI Sun045 LIN, VD Sun045, RTP VD Grey. Yellow stars represent location of the Victoria prospect (north) and the Abundante-Teresita prospects (South).

Figure 2: Interpretation of magnetic lineaments - faults, dykes, veins, joints - over image of VD_Grey scale (left), and interpreted broad geology-magnetic domains based on the drone survey data for Especularita. Yellow stars indicate location of Victoria prospect (north) and the Abundante-Teresita prospects (south).

Figure 3: TMI SUN045 image for the Teresita prospect area identifying magnetic lineaments closely associated with high grade copper in rock chip samples.

Forward Looking and Cautionary Statements