REG - Great Southrn.Copper - Drilling Extends Copper Mineralisation at Mostaza

Great Southern CopperAnnouncement

04/02/2025 07:15

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RNS Number : 7484V  Great Southern Copper PLC  04 February 2025

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.

 

 

04 February 2025

 

Great Southern Copper plc

("GSC" or the "Company")

 

Drilling Extends Copper Mineralisation to Depth and Along Trend of Mostaza
Mine

 

Confirms visible Cu-Ag-Au mineralisation over 270m in step-out drilling to
South of Mine

 

 

Great Southern Copper plc (LSE: GSCU), the company focused on
copper-gold-lithium exploration in Chile, is pleased to provide an update on
its Phase 1 diamond drilling programme at the Cerro Negro project in northern
Chile, where drilling at the historical Mostaza mine commenced on 5 January
2025(1).

 

Highlights:

 

·    Eight diamond holes completed (867m) to date in Phase 1 drilling at
Mostaza, Cerro Negro

·    All holes intersected visual evidence of high-grade copper
mineralisation comprising abundant disseminations, veins, crackle-vein
networks and breccia-hosted chalcocite-bornite-chalcopyrite in zones up to
32.3m downhole width* (Figures 1 and 2)

·    The mineralised intercept for CNG25 DD001 closely correlates with the
width of the mineralised intercept in historical drill hole EDH-25 (33m of
0.53% Cu, including 6m of 1.05% Cu and 81g/t Ag, and 9m of 0.92% Cu and 73g/t
Ag(2)), confirming that Lens 2 occurs as a west-dipping tabular body that is
open at depth

·    Step-out drill holes CNG25 DD002-005 confirm that Lens 2
mineralisation extends further to depth and along strike of historical drill
intercepts at the Mostaza mine

·    Lens 2 mineralisation potentially thickening with depth

·    Continuity of mineralisation along trend up to 270m south of the mine
is confirmed with significant copper intersections identified in exploration
holes CNG25 DD006, 007, and 008 targeting outcropping lenses 3 and 4

·    Hole CNG DD007 intersected 32m* of high-grade copper mineralisation
from 87m

·    Samples for holes DD001 - 005 have been dispatched to ALS
laboratories for assaying

·    Drilling is now underway on hole CNG25 DD009.

 

 

Sam Garrett, Chief Executive Officer of Great Southern Copper, said: "Our
Phase I diamond drilling programme at Mostaza has been very successful to date
with three of the four objectives achieved, namely, the width of
mineralisation reported in historical drill holes is confirmed, mineralisation
extending at depth and along strike of historical holes below the Mostaza mine
is confirmed, and copper mineralisation extending along trend to the south of
the mine is also confirmed.

 

All that remains is to receive the assay results from the laboratory which we
are hopeful will confirm historical high-grade copper-silver grades and
establish the gold grade of the system. Mineralisation in core includes
evidence of intense chalcocite-bornite-chalcopyrite mineralisation of
high-sulphidation type suggestive of what could be the upper levels of a
porphyry system.

 

The progress to date is highly encouraging and is delivering exciting results
which will positively impact our on-going exploration focus and plans at
Mostaza and Cerro Negro."

 

Diamond drill campaign at Cerro Negro

 

As previously reported, CNG25 DD001, was drilled to 103.5m depth and
intersected 20m* of intensely altered and mineralised rock between 27m and 47m
depth down-the-hole (Figure 1) confirming both the continuity and thickness of
Cu-Ag mineralisation in Lens 2 below the historical open pit and reported in
historical hole EDH-25(3).

 

Subsequent drill-holes CNG25 DD002 to 005 were designed as step-out holes from
hole DD001 to test the continuity of Lens 2 mineralisation along strike and to
depth of the historical drilling (the "Mine Zone"). All holes successfully
intersected Lens 2 (Figure 3) with down-hole widths* of visible mineralisation
reported as follows;

 

CNG25 DD001: 20m* of visible copper mineralisation from 27.00 to 47.00m

CNG25 DD002: 4.3m* of visible copper mineralisation from 38.90 to 43.20m
(off-set by dyke)

CNG25 DD003: 18.8m* of visible copper mineralisation from 36.60 to 55.40m
(thickening with depth)

CNG25 DD004: 3m* of visible copper mineralisation from 28.70 to 31.70m
(off-set by dykes/faults)

CNG25 DD005: 23.5m* of visible copper mineralisation from 32.90 to 56.40m
(thickening with depth)

 

Drill holes CNG25 DD006 to 008 targeted mineralisation below Lenses 3 and 4
(the "South Zone", Figure 4) located 270m along trend to the south of the
Mostaza mine. These lenses were not effectively drill tested previously, with
historical holes terminated short of the target. All three exploration holes
intersected visible copper mineralisation (Figure 2) confirming the continuity
of these lenses at depth. Importantly, DD007 intersected a 32m* down-hole
interval of variably intense chalcocite-bornite-chalcopyrite mineralisation
(Figure 5). A summary of the visual mineralised intervals includes;

 

CNG25 DD006: 8.6m* of visible copper mineralisation from 124.40 to 133.06m

CNG25 DD007: 32.3m* of visible copper mineralisation from 87.00 to 119.30m

CNG25 DD008: 21m* of visible copper mineralisation from 4.5 to 25.5m

 

In all cases mineralisation is of high-sulphidation style and mineralogy and
occurs as abundant disseminations, veinlets, crackle networks and breccia
matrix fillings of hypogene chalcocite, bornite, chalcopyrite and lesser
pyrite, associated with minor quartz-baryte gangue and intense
quartz-alunite-dickite/pyrophyllite alteration that overprints earlier
pervasive illite-montmorillonite alteration (see Figures 1 and 2).

 

Zonation in the copper mineralogy is evident with mineralisation in the
northern holes (DD001-005, Figure 1) being dominated by chalcocite-bornite and
the southern holes (DD006-008, Figure 2) being higher in chalcopyrite and
bornite. This mineralisation is the same as seen in the bottom of the open-pit
and historical stockpiles where rock sampling by GSC returned assay grades up
to 4.64% Cu and 177ppm Ag(4).

 

The mineralisation and its associated alteration occur in structurally
controlled "lenses" or "lodes" of felsic porphyry, "tuffisite" and polymictic
rock-flour matrix breccia. In places the lenses may be bounded by faults and
or cut by narrow inter-mineral to late-mineral andesitic dykes with intensely
clay-altered margins.

 

These are preliminary observations, and detailed core logging and geological
interpretation is ongoing.

 

Figure 1: Cerro Negro Project, Mostaza Mine: Photographs of drill core from
CNG25 DD001. Left: Crackle and veinlet hosted chalcocite-bornite (cc-bo; black
mineral) cutting illite and locally quartz-alunite-dickite/pyrophyllite
altered polymictic breccia (30.4m depth). Right: 5cm thick vein of
steely-black chalcocite (cc) mineralisation (33.2m depth). Bottom: Intense
crackle and disseminations of black chalcocite (cc) in polymictic breccia
(36.7 to 37.2m depth). All drill core is HQ diameter 6.35cm thick. Note: core
photos illustrate examples of the style and textures of copper mineralisation
observed within the mineralised intervals and are not necessarily
representative the entire mineralised zone.

 Figure 2: Cerro Negro Project, Mostaza Mine: Photographs of drill core from
CNG25 DD007, over 200m south of mineralisation shown in Figure 4. Upper Left:
chalcopyrite (cpy) dominated breccia matrix within intensely silicified rock
(113m depth). Upper Right: intense disseminated, crackle and breccia matrix
mineralisation of purple bornite (bo) and yellow chalcopyrite (116.4 to 118.4m
depth). Lower Left and right: Intense dissemination and breccia infill by
bornite-chalcocite, bo-cc, (90.4m depth) and chalcopyrite, cpy, (103m depth).
All drill core is HQ diameter 6.35cm. Note: core photos illustrate examples of
the style and textures of copper mineralisation observed within the
mineralised intervals and are not necessarily representative the entire
mineralised zone.

 

The wall rocks on either side of the lens are dominated by red polymictic
rock-flour matrix breccias with textural characteristics suggestive of a
phreatic or phreatomagmatic origin, including fluidisation and injection
textures, lack of sorting, and possible juvenile fragments. On the west side
the red polymictic breccia is in faulted contact with regionally extensive
black monomictic volcanic breccias. To the east the red breccia forms part of
a large dome-diatreme complex typical of the upper parts of
porphyry-epithermal systems.

 

Drilling at Cerro Negro continues with drillhole CNG25 DD009 planned to test
the "Middle Zone" between holes DD001-005 (Mine Zone) and DD006-008 (South
Zone). See Figure 4.

 

The core is being processed and evaluated for sampling. The Company looks
forward to providing further updates as results arise.

 

Figure 3: Cerro Negro Project, Mostaza Mine: Long section of Lens 2 with
circles showing the location of where phase 1 drillholes are projected to
intersect the hanging wall of the mineralised lens. The exact intersection
points are subject to confirmation. Completed drill holes are shown with their
final end-of-hole (EOH) depths. The apparent thickness of visible copper
mineralisation is shown in bold below each intersection point. Note that
mineralisation remains open at depth and along strike. Historical resource
blocks, underground mine workings, and channel sample and drillhole assay
results (coloured) are shown for reference. (GSCU has not been able to
independently verify the historical channel sample or drill hole assay
results).

 

Figure 4: Cerro Negro Project, Mostaza Mine: Plan map showing the approximate
locations of mineralised lenses at surface, historical drill holes, and
current GSC drilling. Note the scale.

 

Figure 5. Cerro Negro Project, Mostaza Mine: Preliminary cross section across
Lenses 3, 4 and 5. Note that mineralisation remains open at depth and along
strike. Historical drillhole assay results (coloured) are shown for reference.

 

 

Cautionary note:

*Apparent thickness: There is not sufficient geological information to
calculate true thickness of mineralised intercepts at this time.

Photographs of core and mineralisation are for visual purposes only to assist
in explanation and description of mineralisation styles and textures observed
in the core and do not convey any information as to the copper grade of the
mineralisation photographed or the mineralised zones as a whole. The company
will report assay grades when they are received from the laboratory and have
been assessed.

 

 

References:

1.            RNS 2189S (06 January 2025): Diamond drilling
commences at Cerro Negro

2.            RNS 6179C (03 September 2024): GSC expands target at
Mostaza mine, Cerro Negro

3.            RNS 5778T (16 January 2025): First drill hole at
Cerro Negro

4.            RNS 3120K (31 October 2024): Cerro Negro Results Up
To 4.64% Cu and 177ppm Ag

 

 

Enquiries:

 

 Great Southern Copper plc
 Sam Garrett, Chief Executive Officer      +44 (0) 20 4582 3500

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

 Gracechurch Group
 Harry Chathli, Alexis Gore, Henry Gamble  +44 (0) 20 4582 3500

 

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 and lithium deposits in Chile. The Company has
the option to acquire rights to 100% of two projects in the under-explored
coastal belt of Chile that are prospective for large scale copper-gold
deposits. In addition, the Company has the option to acquire rights to 100% of
a lithium project located in the Salar de Atacama district of Chile. Chile is
a globally significant mining jurisdiction being the world's largest copper
producer and the second-largest producer of lithium.

 

The two, early-stage Cu-Au projects comprise the San Lorenzo and Especularita
Projects, both 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 both exploration project areas.

 

The Company's Monti Lithium project is strategically located in the pre-Andean
region of Salar de Atacama which is Chile's premier lithium-producing region
with well-established lithium mining operations and infrastructure.

 

Great Southern Copper is strategically positioned to support the global market
for copper and lithium - both critical battery metals 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 and Li deposits as well as high-grade Cu-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.

 

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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