REG - Great Southrn.Copper - Geophysics AMT Survey Commences at La Colorada

Great Southern CopperAnnouncement

21/05/2026 07:00

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RNS Number : 2492F  Great Southern Copper PLC  21 May 2026

THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION AS STIPULATED UNDER THE UK
VERSION OF THE MARKET ABUSE REGULATION NO 596/2014 WHICH IS PART OF ENGLISH
LAW BY VIRTUE OF THE EUROPEAN (WITHDRAWAL) ACT 2018, AS AMENDED.  ON
PUBLICATION OF THIS ANNOUNCEMENT VIA A REGULATORY INFORMATION SERVICE, THIS
INFORMATION IS CONSIDERED TO BE IN THE PUBLIC DOMAIN.

 

 

21 May 2026

 

Great Southern Copper plc

("GSC" or the "Company")

 

Geophysics AMT Survey Commences at La Colorada Lithocap, Especularita

 

Survey to target large-scale buried porphyry copper deposits

 

Great Southern Copper plc (LSE: GSCU), the company focused on
copper-gold-silver exploration in Chile, is pleased to announce that it has
commenced an audio-frequency magneto-telluric ("AMT") geophysics survey across
the La Colorada lithocap prospect at its Especularita Project.

 

Highlights:

·    Survey to cover an area of approximately 33 km(2) comprising western
half of the La Colorada lithocap

·    Targeting large-scale porphyry copper deposits at depth below the
high sulphidation lithocap

·    Survey to be completed in two weeks with results expected within 4-6
weeks

·    Results to assist with target vectoring for first-pass scout drilling
of the lithocap

·    GSC holds rights to own 100% of the Especularita Project

·    Project located at low elevation with excellent access to
infrastructure and mining services, and is along trend of major copper
deposits including Los Pelambres, Altar and El Pachon.

 

 

Sam Garrett, Chief Executive Officer of Great Southern Copper, said: "The AMT
geophysics survey is designed to allow us to see through the lithocap blanket
that masks potential porphyry copper deposits at depth. Used in conjunction
with ongoing soil geochemistry and spectral rock studies, the survey will help
refine and prioritise targets for first-pass scout drilling across the
lithocap, which we expect to commence early in the second half of this year.

 

"The AMT technique is ideally suited for mapping deeply buried porphyry copper
deposits because it effectively penetrates thick, conductive cover (such as
volcanic lithocaps) to delineate both the deep, localised resistive intrusions
and the conductive alteration halos characteristic of porphyry systems.

 

"Meanwhile, scout RC drilling is continuing at the Artemisa North target,
while preparation work is advancing at both the Viuda and Cerro Negro
prospects as we progress exploration across multiple targets at Especularita."

 

La Colorada Lithocap Porphyry Copper Targets:

 

The La Colorada lithocap comprises the cornerstone of the Company's flagship
Especularita project located 100 km south of the port of Coquimbo (Figure 1).
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 (Figure 1).

 

Figure 1: GSC's Especularita project is located at low altitude within the
coastal metallogenic belt of northern Chile and within 50km radius of over 50
million tonnes of contained copper metal defined in mines and advanced
projects.

 

Audio-Frequency Magneto-Telluric Survey:

 

The Company has contracted Chile-based Southernrock Geophysics S.A. to
undertake an AMT survey covering an area of approximately 33 km(2) and
comprising the western half of the La Colorada lithocap (Figure 2). The survey
is planned on 500 metres ("m") grid centres and is designed to identify
potential large-scale porphyry copper centres hidden at depth beneath the
high-sulphidation alteration blanket. The survey parameters allow for the
depth of investigation to exceed 1000m below surface, subject to the
resistivity nature of the rock.

 

 

Figure 2: Approximate AMT survey area for the La Colorada lithocap,
Especularita. Field team measuring EM activity on site at La Colorada - note
the highly oxidised and clay-rich lithocap rocks in the background.

 

 

 

Audio-frequency magneto-tellurics (AMT) is a passive electromagnetic
geophysical technique ideally suited for mapping deeply buried porphyry copper
deposits as it effectively penetrates thick, conductive cover (such as
volcanic lithocaps) to delineate the deep, localized resistive intrusions and
conductive alteration halos characteristic of porphyry systems. The method
measures natural electromagnetic (EM) fields on the Earth's surface generated
from lighting (high frequency) and solar winds (low frequency) to map
subsurface electrical resistivity. By analyzing how these waves interact with
different rock types, geophysicists can interpret geological units, fault
zones, and potential mineral deposits down to depths of up to a few
kilometers.

 

Porphyry copper deposits may have distinct three-dimensional electrical
signatures. When integrated through 3D inversion modelling, AMT maps these
contrasts at depths ranging from 100 meters to over 2 kilometers. The
causative porphyry intrusions typically appear as highly resistive bodies
whereas the highly mineralized potassic cores and surrounding phyllic
(pyrite-rich) and argillic alteration zones form conductive anomalies due to
interconnected sulfide minerals and clay alteration.

 

Next Steps:

 

Scout RC drilling is currently in progress at the Artemisa North target with 3
holes completed for 414m. The fourth hole ART26-RC008 is currently in progress
at a depth of 220m. Samples for holes ART26-RC005 and RC006 have been
delivered to ALS Laboratories in Santiago by GSC personnel. Once completed at
Artemisa North, the scout RC drilling programme will progress to test the
Artemisa South and Victoria targets.

 

Exploration work, including mapping and sampling, is in progress at both the
Cerro Negro and Viuda prospects in preparation for drilling. Metallurgical
studies are also underway for Mostaza core samples from Phases I and II of the
drilling at Cerro Negro.

 

 

Engage with the GSC management team directly by asking questions, watching
video summaries and seeing what other shareholders have to say. Navigate to
our Interactive Investor hub here: https://gscplc.com/ (https://gscplc.com/)

 

 

Enquiries:

 

 Great Southern Copper plc             https://gscplc.com/link/eXgR4y (https://gscplc.com/link/eXgR4y)
 Sam Garrett, Chief Executive Officer  +44 (0) 20 7138 3204

 SI Capital Limited
 Nick Emerson                          +44 (0) 1483 413500

 BlytheRay
 Megan Ray / James Mulligan            +44 (0) 20 7138 3204

                                       GSC@blytheray.com

 

Subscribe to our news alert service: https://gscplc.com/auth/signup
(https://gscplc.com/auth/signup)

 

 

Notes for Editors:

 

About Great Southern Copper

 

Great Southern Copper PLC is a UK-listed mineral exploration company focused
on the discovery of copper-gold-silver deposits in Chile. The Company has the
option to acquire mining rights to 100% of Especularita project in the
under-explored coastal belt of Chile that is prospective for large scale
copper-gold-silver deposits. Chile is a globally significant mining
jurisdiction being the world's largest producer and exporter of copper.

 

The Especularita Project is located in the coastal metallogenic belt of Chile
which hosts significant copper mines and deposits, including Teck's Carmen de
Andacollo copper mine, and boasts excellent access to infrastructure such as
roads, power and ports. Significant historical small-scale and artisanal
workings for both copper and gold are readily evident in the exploration
project area. The coastal belt offers deposit type optionality for copper
including porphyry and IOCG style deposits as well as newly recognised
intrusive-related copper and gold deposits.

 

Great Southern Copper is strategically positioned to support the global market
for copper - a critical battery metal in the clean energy transition around
the world. The Company is actively engaged in exploration and evaluation work
programmes targeting both large tonnage, low to medium grade Cu-Au as well as
high-grade Cu-Ag-Au deposits.

 

Further information on the Company is available on the Company's website:
https://gscplc.com (https://gscplc.com)

 

Competent Person Statement

 

The information in this announcement that relates to exploration results is
based on and fairly represents information reviewed or compiled by Mr Sam
Garrett, a Competent Person who is a Member of the Australian Institute of
Geoscientists and a Fellow of the Society of Economic Geologists. Mr Garrett
is the CEO and a shareholder of Great Southern Copper PLC. Mr Garrett has
sufficient experience that is relevant to the styles of mineralisation and
types of deposit under consideration and to the activity being undertaken to
qualify as a Competent Person as defined in the 2012 Edition of the
"Australasian Code for Reporting of Exploration Results, Mineral Resources and
Ore Reserves". Mr Garrett has provided his prior written consent to the
inclusion in this announcement of the matters based on information in the form
and context in which it appears.

 

This announcement includes information that relates to Exploration Results
prepared and first disclosed under the JORC Code (2012) and extracted from the
Company's previous LSE announcements as noted, and the Company's Prospectus
dated 20 December 2021. Copies of these announcements are available from the
LSE Announcements page of the Company's website: www.gscplc.com
(http://www.gscplc.com) .

 

The Company confirms that it is not aware of any new information or data that
materially affects the information included within the Prospectus dated 20
December 2021.

 

Forward Looking and Cautionary Statements

Some statements in this announcement regarding estimates or future events are
forward-looking statements. They include indications of, and guidance on,
future earnings, cash flow, costs and financial performance. Forward-looking
statements include, but are not limited to, statements preceded by words such
as "planned", "expected", "projected", "estimated", "may", "scheduled",
"intends", "anticipates", "believes", "potential", "predict", "foresee",
"proposed", "aim", "target", "opportunity", "could", "nominal", "conceptual"
and similar expressions. Forward-looking statements, opinions and estimates
included in this report are based on assumptions and contingencies which are
subject to change without notice, as are statements about market and industry
trends, which are based on interpretations of current market conditions.
Forward-looking statements are provided as a general guide only and should not
be relied on as a guarantee of future performance. Forward-looking statements
may be affected by a range of variables that could cause actual results to
differ from estimated or anticipated results and may cause the Company's
actual performance and financial results in future periods to materially
differ from any projections of future performance or results expressed or
implied by such forward-looking statements. So, there can be no assurance that
actual outcomes will not materially differ from these forward-looking
statements.

 

 

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