REG - Great Southrn.Copper - “Exceptional” Results Confirm Potential of Mostaza

Great Southern CopperAnnouncement

17/03/2025 07:15

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RNS Number : 9022A  Great Southern Copper PLC  17 March 2025

 

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17 March 2025

 

Great Southern Copper plc

("GSC" or the "Company")

 

"Exceptional" High-Grade Cu-Ag Results Confirm Potential of the Mostaza
Deposit, Cerro Negro

 

Assays demonstrate continuity of grade with mineralisation open laterally and
at depth

 

Great Southern Copper plc (LSE: GSCU), the company focused on
copper-gold-silver exploration in Chile, is pleased to report further
exceptional assay results from Phase I drilling at the Mostaza Mine, Cerro
Negro.

 

Highlights:

·    Assay results received for holes CNG25 DD002 - DD005 with significant
intervals including;

Ø DD005:  12.0m of 4.24% Cu and 369.5 g/t Ag from 40m, including

§   7.0m of 5.08% Cu and 449.6 g/t Ag from 45m, within a broader zone of

§ 21.0m of 2.88% Cu and 246.7 g/t Ag from 35m

Ø DD003:  13.0m of 2.48% Cu and 198.1 g/t Ag from 39m, within a broader zone
of

§ 18.6m of 1.85% Cu and 146.6 g/t Ag from 36.6m

Ø DD002:   4.2m of 1.73% Cu and 126.5 g/t Ag from 38.9m

 

·    New results demonstrate continuity of high grades building upon
earlier reported assays for hole CNG25 DD001(1);

Ø DD001:  20.0m of 3.31% Cu and 269.9 g/t Ag from 27m, including

§   7.0m of 5.72% Cu and 489.6 g/t Ag from 31m

 

·    Assay grades consistently significantly higher than reported results
of historical drill program

·    Mineralisation remains open in all directions

·    Assay results for remaining Phase I drill holes, CNG25 DD006 - 009,
are pending

·    Phase II diamond drilling in progress aiming to expand on
historically reported resources and test exploration targets(2)

·    GSC holds option to own 100% of the Mostaza mine and Cerro Negro
project

·    Prospect located at low elevation with excellent access to
infrastructure and mining services

 

Sam Garrett, Chief Executive Officer of Great Southern Copper, said: "These
outstanding results confirm that high grade Cu-Ag mineralisation is continuing
to depth and along strike and demonstrate that the former Mostaza mine has the
potential to be a high-grade high-value Cu-Ag deposit.

 

"Two diamond drill rigs are now on site - one targeting strike and depth
extensions of the Mostaza pit mineralisation and a second rig is exploring the
structural trend to the south following up earlier drilling of holes
DD006-009.

 

"We have entered a very exciting phase of exploration at Cerro Negro and have
a lot of work to do as we progress to demonstrate the potential economic
viability of this exciting deposit."

 

Results of diamond drillholes CNG25 DD002 - DD005

 

Diamond drillholes CNG25 DD002 - DD005 were designed to target shallow
extensions of the historical Mostaza Lens 2 mineralisation at depth and along
strike of the intercept in CNG25 DD001 (Figure 1). Due to access and safety
limitations in the old mine pit the five holes were drilled in a fan pattern
from a centrally located drill pad and were planned to intersect the
mineralised body on an approximate grid pattern.

 

All holes intersected the Lens 2 mineralised body over varying widths and
significant assays are summarised in Table 1. The mineralisation is also
weakly anomalous in Sb-As and exhibits pathfinder anomalism for Bi-Cd-Li-Zn
which is consistent with the high-sulphidation style of mineralisation.

 

Drillhole CNG25 DD002 was drilled to intersect the lens approximately 25m
north of hole DD001 and returned 4.2m @ 1.73 % Cu, 126.5 g/t Ag, and 0.0824 %
Sb from 38.9m. CNG25 DD003, which was designed to test the lens below hole
DD002, intersected 18.6m @ 1.85% Cu, 146.58 g/t Ag from 36.6m, including 13m @
2.48 % Cu, 198.09 g/t Ag from 39m, with maximum grades of 1m @ 4.64 % Cu,
406.00 g/t Ag, and 0.22% Sb from 50m. These results appear to demonstrate that
both Cu-Ag grade and thickness the lode is increasing with depth.

 

Hole CNG25 DD005 was drilled below hole DD001 and intersected broad intervals
of high-grade Cu-Ag similar to mineralisation seen in hole DD001(1) including
7m @ 5.08 % Cu, 449.57 g/t Ag from 45m, and 2m @ 6.05 % Cu within a broader
lens-wide zone of 21m @ 2.89 % Cu, 246.71 g/t Ag from 35m.. Maximum grades of
6.2 % Cu, 567 g/t Ag, and 0.23 % Sb are reported over 1m.

 

Hole CNG DD004 was drilled to the north of DD002 and intersected only weakly
altered and mineralised "proto-lens" in a zone of faults and dykes where the
lens was otherwise expected, suggesting the lode has been structurally
displaced or "pinched out" in this location.

 

A summary of all Phase I assay results to date are shown in Table 1 below.

 

 Hole_ID            From (m)  To (m)   Interval (m)  Cu     (%)      Ag    (g/t)     Sb (ppm)

 CNG25  DD001       27        47       20.0          3.31            269.9           934
               inc  31        38       7.0           5.72            489.6           1085
               inc  35        38       3.0           6.62            562.7           407

 CNG25  DD002       38.9      43.1     4.2           1.73            126.5           824

 CNG25  DD003       36.6      55.2     18.6          1.85            146.6           798
               inc  39        52       13.0          2.48            198.1           1049
               inc  48        51       3.0           3.31            254.7           1608
               inc  50        51       1.0           4.64            406.0           2150

 CNG25  DD004       no significant intercepts

 CNG25  DD005       35        56       21.0          2.89            246.7           978
               inc  37        52       15.0          3.79            328.4           1252
               inc  40        52       12.0          4.24            369.5           1279
               inc  45        52       7.0           5.08            449.6           1309
               inc  45        47       2.0           6.05            547.5           645

Table 1: Summary of significant intercepts for Phase I GSC drill holes.

 

The Mostaza Cu-Ag deposit, Cerro Negro

The high-grade Cu-Ag mineralisation at Mostaza is confined to a north-south
trending, structurally-controlled lode, or "lens" (specifically Lens 2), of
variable width (<4-20m) that dips moderately steeply to the west (Figure
2). Copper mineralisation comprises abundant disseminations, veinlets, crackle
networks, and breccia matrix fillings of hypogene black to dark metallic grey
chalcocite with lesser bluish bornite and traces of chalcopyrite and pyrite
(Figure 3). Petrographic confirmation is pending, however, the copper
mineralogy may include other silver-rich copper minerals such as stromeyerite
(AgCuS) for example.

 

Lens 2 host rocks are intensely altered and appear to comprise multiple
generations of breccia, tuffisite, and felsic intrusive altered to texturally
destructive illite ± montmorillonite overprinted by probable alunite ±
dickite ± pyrophyllite (to be confirmed by petrographic studies). The
high-grade Cu-Ag mineralised lens exhibits sharp contacts and is bounded to
the east and west by faults that are typically invaded by narrow (<1-2m)
andesite to rhyolite dykes. Outside of the bounding dykes and faults, the
enclosing wall rocks consist of an east-dipping bedded sequence of fresh,
black volcanic lava flows and red, hematite-rich phreatic and/or
phreatomagmatic breccias that might be part of a large dome-diatreme complex
outcropping to the east.

 

Insufficient drilling is available to date to allow detailed interpretation of
the architecture of the deposit. The lack of high-grade mineralisation
intersected in hole DD004 indicates late-stage structural dislocation occurs
resulting in variable localised thinning or boudenaging of the lenses. Broad
zones of weakly anomalous silver (>0.1ppm Ag) in hole DD004 might also
suggests the potential for this hole to be adjacent to significant lode
mineralisation. The narrower lode width intersected in hole DD002 suggests
also that mineralisation may be "stoped out" in places by post-mineral dykes
of the same type that intrude the bounding fault structures.

 

The high-grade Cu-Ag mineralogy type and associated advanced argillic style
alteration suggests the lodes at Mostaza are part of a high-sulphidation
epithermal system, potentially related to a yet-to-be-discovered porphyry
style deposit occurring at depth.

 

The Lens 2 mineralisation is interpreted to form one of a number of Cu-Ag rich
bodies mapped at surface which have historically been interpreted as discrete
"lenses" but which collectively have the potential to make up an anastomosing
network of structurally controlled zones of mineralisation continuous over a
strike length of greater than 1-2km.

 

The results of CNG25 DD001- DD005 targeting mineralisation beneath the
existing Mostaza open pit demonstrate that the deposit continues at depth and
along strike from the historical drilling and is open in all directions
(Figure 4).

 

 

 

Figure 1: Cerro Negro Project, Mostaza Mine: Simplified schematic long section
of Lens 2 with circles showing the approximate location of where Phase 1
drillholes intersect the hanging wall of the mineralised lens. The apparent
thickness of copper mineralisation is indicated below each intersection point.
Note that mineralisation remains open at depth and along strike. Historical
resource blocks are for reference.

 

Figure 2: Cerro Negro Project, Mostaza Mine: Schematic cross section through
drillholes CNG25 DD001 and DD005 showing Cu-Ag intercepts and the preliminary
geological interpretation and relationship to historical drillholes. Note the
extrapolations from diamond holes DD001 and DD005 to the historical drillholes
EDH25, 23 and 15 are based on assay results only because historical drill core
and logs are unavailable.

 

Figure 3: Cerro Negro Project, Mostaza Mine. Photograph of core from hole
CNG25 DD002 and DD003, on the left, and DD005 on the right, with grades of Cu
% and Ag g/t. The black disseminations, veinlets and crackle fill are Cu-Ag
bearing sulphides and sulfosalt minerals in association with minor silica and
baryte gangue cutting clay-rich alteration.

 

 

Core preparation, sampling and assaying

 

The Mostaza diamond drill core is collected from site by GSC staff and
transported to the Company's nearby sampling facilities where it is then
processed for geological, geotechnical, petrophysical and geochemical data.
Sampling intervals are selected principally on geologic boundaries and may
vary in length up to 2m. The core is cut into two halves using an electric
diamond brick saw with half-core samples each allocated a unique identifier
code and bagged-tagged separately. Samples for each complete hole are
transported by GSC personnel to ALS laboratories in Santiago, Chile for sample
preparation (drying, weighing, crushing and grinding). A final 200g aliquot of
each sample is forwarded by ALS to their laboratories in Lima, Peru where it
is assayed for Au (by 30g fire assay with ICP-AES finish method) plus a suite
of 48 base metals and trace elements including Cu and Mo (by four acid digest
ICP-MS method).

 

Sampling and assaying QAQC protocols employed by the company for this drilling
project include routine insertion of standard reference materials including
standards and blanks. Results for each SRM is assessed to monitor the accuracy
and precision of the assay data from ALS for the core samples.

 

Next steps

Phase II diamond drilling at Mostaza has commenced and is designed to include
resource and exploration drilling. Metallurgical studies of drill core,
stockpiles and tailings are also being planned. Extensions of mineralisation
at depth and along trend under cover may also be targeted with geophysical
surveys.

 

 

 

 

 

 HOLE_ID      SAMPLE  FROM   TO     LONG  LITHOLOGY             Cu %   Ag g/t  Sb ppm

              ID      (m)    (m)    (m)
 CN25-DDH001  994564  0      2      2     Saprock               0.017  0.43    13.45
 CN25-DDH001  994565  2      4      2     Black Breccia         0.057  3.96    30.60
 CN25-DDH001  994566  4      6      2                           0.007  0.62    2.91
 CN25-DDH001  994567  6      8      2                           0.008  0.41    4.66
 CN25-DDH001  994568  8      10     2     Red Breccia           0.001  0.05    1.84
 CN25-DDH001  994569  10     12     2                           0.002  0.07    2.01
 CN25-DDH001  994571  12     14     2                           0.001  0.06    2.10
 CN25-DDH001  994572  14     16     2                           0.003  0.19    3.62
 CN25-DDH001  994573  16     18     2                           0.002  0.10    3.68
 CN25-DDH001  994574  18     20     2                           0.004  0.22    5.38
 CN25-DDH001  994575  20     22.9   2.9                         0.002  0.10    3.60
 CN25-DDH001  994576  22.9   24.6   1.7                         0.032  1.01    6.89
 CN25-DDH001  994578  24.6   26     1.4   Dyke                  0.010  0.12    3.21
 CN25-DDH001  994579  26     27     1                           0.012  0.70    93.20
 CN25-DDH001  994580  27     28     1     Lens 2                2.670  193.00  666.00
 CN25-DDH001  994581  28     29     1                           1.850  169.00  464.00
 CN25-DDH001  994582  29     30     1                           1.530  138.00  328.00
 CN25-DDH001  994583  30     31     1                           1.650  129.00  491.00
 CN25-DDH001  994585  31     32     1                           4.910  455.00  377.00
 CN25-DDH001  994586  32     33     1                           5.600  451.00  1215.00
 CN25-DDH001  994587  33     34     1                           6.050  528.00  3460.00
 CN25-DDH001  994588  34     35     1                           3.650  305.00  1320.00
 CN25-DDH001  994589  35     36     1                           6.600  530.00  868.00
 CN25-DDH001  994590  36     37     1                           6.790  575.00  206.00
 CN25-DDH001  994591  37     38     1                           6.460  583.00  146.00
 CN25-DDH001  994592  38     39     1                           2.380  182.00  352.00
 CN25-DDH001  994594  39     40     1                           0.515  23.90   109.50
 CN25-DDH001  994595  40     41     1                           1.550  74.90   1130.00
 CN25-DDH001  994596  41     42     1                           1.145  78.10   2080.00
 CN25-DDH001  994598  42     43     1                           2.460  158.00  2480.00
 CN25-DDH001  994599  43     44     1                           1.905  139.00  758.00
 CN25-DDH001  994600  44     45     1                           1.995  152.00  490.00
 CN25-DDH001  994601  45     46     1                           4.750  395.00  1055.00
 CN25-DDH001  994602  46     47     1                           1.750  139.00  687.00
 CN25-DDH001  994603  47     48     1                           0.393  24.70   85.80
 CN25-DDH001  994605  48     49     1     Dyke                  0.013  0.93    39.30
 CN25-DDH001  994606  49     50     1                           0.005  0.44    26.40
 CN25-DDH001  994607  50     51     1     Red Breccia           0.006  0.41    27.80
 CN25-DDH001  994608  61     62     1                           0.002  0.15    6.26
 CN25-DDH001  994609  71     72     1                           0.001  0.08    10.35
 CN25-DDH001  994610  81     82     1                           0.003  0.09    17.45
 CN25-DDH001  994612  91     92     1                           0.002  0.12    13.65
 CN25-DDH001  994613  101    102    1                           0.001  0.06    8.60
 CN25-DDH002  994614  0      2      2     Saprock               0.010  0.18    10.20
 CN25-DDH002  994615  2      4      2                           0.005  0.20    2.56
 CN25-DDH002  994616  4      6      2     Black Breccia         0.007  0.40    3.17
 CN25-DDH002  994617  6      8.29   2.29                        0.024  0.43    8.11
 CN25-DDH002  994618  8.29   10     1.71  Red Breccia           0.001  0.02    1.54
 CN25-DDH002  994619  10     12     2                           0.001  0.03    1.72
 CN25-DDH002  994620  12     14     2                           0.002  0.04    2.12
 CN25-DDH002  994621  14     16     2                           0.001  0.03    2.28
 CN25-DDH002  994622  16     18     2                           0.001  0.01    3.21
 CN25-DDH002  994623  18     20     2                           0.002  0.03    4.20
 CN25-DDH002  994624  20     22     2                           0.003  0.12    6.26
 CN25-DDH002  994625  22     24     2                           0.011  0.15    5.55
 CN25-DDH002  994626  24     26     2                           0.005  0.09    6.60
 CN25-DDH002  994627  26     26.77  0.77                        0.045  0.87    5.29
 CN25-DDH002  994628  26.77  28     1.23                        0.089  2.11    80.70
 CN25-DDH002  994630  28     28.75  0.75  Hydrothermal Breccia  0.359  5.00    357.00
 CN25-DDH002  994631  28.75  30     1.25  Dyke                  0.026  0.89    86.10
 CN25-DDH002  994632  30     32     2                           0.011  0.80    82.50
 CN25-DDH002  994633  32     34     2                           0.012  0.25    6.77
 CN25-DDH002  994634  34     36     2                           0.009  0.14    2.54
 CN25-DDH002  994635  36     38     2                           0.007  0.26    35.90
 CN25-DDH002  994636  38     38.9   0.9                         0.003  0.19    3.74
 CN25-DDH002  994638  38.9   40     1.1   Lens 2                1.870  107.00  500.00
 CN25-DDH002  994639  40     41     1                           1.725  126.00  333.00
 CN25-DDH002  994640  41     42     1                           2.130  160.00  1465.00
 CN25-DDH002  994641  42     43.1   1.1                         1.220  116.00  1010.00
 CN25-DDH002  994643  43.1   45     1.9   Red Breccia           0.004  0.29    25.50
 CN25-DDH002  994644  55     57     2                           0.002  0.17    20.70
 CN25-DDH003  994645  0      1      1                           0.016  0.33    6.22
 CN25-DDH003  994646  1      2      1                           0.015  0.09    5.56
 CN25-DDH003  994647  2      3      1     Black Breccia         0.014  0.84    7.63
 CN25-DDH003  994648  3      4      1                           0.005  0.48    2.17
 CN25-DDH003  994649  4      5      1                           0.007  0.72    1.71
 CN25-DDH003  994650  5      6      1                           0.006  0.48    1.63
 CN25-DDH003  994651  6      7.5    1.5                         0.011  0.61    3.48
 CN25-DDH003  994652  7.5    9      1.5   Red Breccia           0.001  0.03    1.51
 CN25-DDH003  994653  9      11     2                           0.001  0.01    1.51
 CN25-DDH003  994654  11     13     2                           0.001  0.03    1.96
 CN25-DDH003  994655  13     15     2                           0.001  0.01    2.26
 CN25-DDH003  994656  15     17     2                           0.003  0.12    3.07
 CN25-DDH003  994657  17     19     2                           0.002  0.03    3.78
 CN25-DDH003  994658  19     21     2                           0.003  0.02    6.01
 CN25-DDH003  994659  21     23     2                           0.003  0.04    5.43
 CN25-DDH003  994660  23     25     2                           0.002  0.01    4.79
 CN25-DDH003  994661  25     27     2                           0.002  0.02    5.59
 CN25-DDH003  994662  27     29     2                           0.008  0.15    7.27
 CN25-DDH003  994663  29     31     2                           0.031  0.71    8.74
 CN25-DDH003  994666  31     32.27  1.27                        0.064  8.04    56.90
 CN25-DDH003  994667  32.27  33.27  1                           0.044  1.82    32.00
 CN25-DDH003  994668  33.27  35     1.73  Dyke                  0.011  0.16    13.25
 CN25-DDH003  994669  35     36.6   1.6                         0.013  0.30    86.40
 CN25-DDH003  994670  36.6   37.1   0.5   Lens 2                0.182  13.20   20.60
 CN25-DDH003  994671  37.1   38     0.9                         1.055  79.90   178.50
 CN25-DDH003  994672  38     39     1                           0.153  12.70   25.90
 CN25-DDH003  994673  39     40     1                           1.020  101.00  161.50
 CN25-DDH003  994676  40     41     1                           2.510  230.00  299.00
 CN25-DDH003  994677  41     42     1                           2.350  218.00  320.00
 CN25-DDH003  994678  42     43     1                           2.590  254.00  325.00
 CN25-DDH003  994679  43     44     1                           2.430  169.00  830.00
 CN25-DDH003  994680  44     45     1                           3.220  213.00  1510.00
 CN25-DDH003  994681  45     46     1                           2.440  170.00  1730.00
 CN25-DDH003  994682  46     47     1                           2.360  184.00  1635.00
 CN25-DDH003  994683  47     48     1                           1.400  95.20   793.00
 CN25-DDH003  994684  48     49     1                           2.390  122.00  1595.00
 CN25-DDH003  994685  49     50     1                           2.890  236.00  1080.00
 CN25-DDH003  994686  50     51     1                           4.640  406.00  2150.00
 CN25-DDH003  994687  51     52     1                           1.975  177.00  1205.00
 CN25-DDH003  994688  52     53     1                           0.666  34.90   133.50
 CN25-DDH003  994689  53     54     1                           0.152  13.80   295.00
 CN25-DDH003  994690  54     55.2   1.2                         0.115  9.40    491.00
 CN25-DDH003  994692  55.2   57     1.8   Dyke                  0.008  0.39    6.04
 CN25-DDH003  994693  57     59     2                           0.007  0.37    19.75
 CN25-DDH003  994694  59     60     1     Red Breccia           0.017  0.88    38.40
 CN25-DDH003  994695  60     61     1                           0.002  0.12    24.80
 CN25-DDH003  994696  71     73     2                           0.001  0.12    6.06
 CN25-DDH003  994697  81     83     2                           0.002  0.07    10.20
 CN25-DDH003  994698  91     93     2                           0.002  0.09    7.36
 CN25-DDH004  994699  0      1      1     Saprock               0.005  0.24    3.60
 CN25-DDH004  994700  1      2      1                           0.008  0.05    1.50
 CN25-DDH004  994701  2      3      1     Red Breccia           0.007  0.41    3.31
 CN25-DDH004  994702  3      4      1                           0.005  0.69    1.68
 CN25-DDH004  994703  4      5      1                           0.006  0.23    1.53
 CN25-DDH004  994704  5      6      1                           0.064  0.15    5.67
 CN25-DDH004  994705  6      7      1                           0.020  0.25    5.16
 CN25-DDH004  994706  7      9      2                           0.010  0.06    2.14
 CN25-DDH004  994707  9      11     2                           0.001  0.02    1.48
 CN25-DDH004  994708  11     13     2                           0.001  0.01    1.53
 CN25-DDH004  994709  13     15     2                           0.001  0.02    1.79
 CN25-DDH004  994710  15     17     2                           0.002  0.03    2.67
 CN25-DDH004  994711  17     19     2                           0.003  0.02    2.11
 CN25-DDH004  994712  19     21     2                           0.003  0.01    3.23
 CN25-DDH004  994713  21     23     2                           0.002  0.02    4.16
 CN25-DDH004  994714  23     25     2                           0.001  0.01    3.75
 CN25-DDH004  994715  25     26.7   1.7                         0.004  0.03    4.95
 CN25-DDH004  994718  26.7   27.7   1                           0.043  0.25    4.53
 CN25-DDH004  994719  27.7   28.7   1                           0.077  0.62    3.15
 CN25-DDH004  994720  28.7   29.8   1.1                         0.031  3.21    8.66
 CN25-DDH004  994721  29.8   30.8   1                           0.010  0.12    3.40
 CN25-DDH004  994722  30.8   31.7   0.9                         0.026  0.79    3.65
 CN25-DDH004  994723  31.7   33     1.3                         0.008  0.22    4.55
 CN25-DDH004  994724  33     34     1                           0.001  0.01    4.29
 CN25-DDH004  994725  34     36     2                           0.002  0.05    6.23
 CN25-DDH004  994726  36     37.4   1.4                         0.062  1.38    8.11
 CN25-DDH004  994727  37.4   38.4   1                           0.041  2.04    26.00
 CN25-DDH004  994728  38.4   39.4   1                           0.010  0.16    4.69
 CN25-DDH004  994729  39.4   40.4   1     Proto-Lens 2          0.008  0.33    7.51
 CN25-DDH004  994732  40.4   41.5   1.1                         0.042  1.22    31.80
 CN25-DDH004  994733  41.5   42.2   0.7   Red Breccia           0.034  1.42    11.15
 CN25-DDH004  994734  42.2   44     1.8   Fine Dyke             0.009  0.27    8.54
 CN25-DDH004  994735  48     49     1     Red Breccia           0.021  0.88    23.50
 CN25-DDH004  994736  59     61     2                           0.008  0.46    5.02
 CN25-DDH004  994737  69     71     2                           0.006  0.13    7.30
 CN25-DDH004  994738  79     81     2                           0.002  0.02    4.23
 CN25-DDH004  994739  83     84     1                           0.001  0.07    1.41
 CN25-DDH004  994741  89     91     2                           0.002  0.02    4.94
 CN25-DDH004  994742  99     101    2                           0.001  0.02    4.22
 CN25-DDH005  994743  0      1      1     Saprock               0.004  0.12    3.09
 CN25-DDH005  994744  1      2      1                           0.031  0.23    1.35
 CN25-DDH005  994745  2      3      1     Black Breccia         0.011  0.09    5.50
 CN25-DDH005  994746  3      4      1                           0.006  0.41    3.43
 CN25-DDH005  994747  4      5      1                           0.005  0.46    1.53
 CN25-DDH005  994748  5      6      1                           0.004  0.40    1.92
 CN25-DDH005  994749  6      7.2    1.2                         0.020  0.44    12.00
 CN25-DDH005  994750  7.2    9      1.8                         0.037  0.30    4.21
 CN25-DDH005  994751  9      11     2     Red Breccia           0.001  0.02    1.64
 CN25-DDH005  994752  11     13     2                           0.001  0.02    1.66
 CN25-DDH005  994753  13     15     2                           0.001  0.02    2.01
 CN25-DDH005  994754  15     17     2                           0.002  0.03    2.73
 CN25-DDH005  994755  17     19     2                           0.002  0.03    3.90
 CN25-DDH005  994756  19     21     2                           0.002  0.03    5.25
 CN25-DDH005  994757  21     23     2                           0.003  0.04    5.13
 CN25-DDH005  994758  23     25     2                           0.002  0.02    4.98
 CN25-DDH005  992609  25     26.6   1.6                         0.003  0.06    5.17
 CN25-DDH005  992612  26.6   27.6   1                           0.002  0.02    5.08
 CN25-DDH005  992613  27.6   28.6   1                           0.021  0.61    6.92
 CN25-DDH005  992614  28.6   29.7   1.1   Proto-Lens 2          0.066  4.56    30.70
 CN25-DDH005  992615  29.7   32     2.3   Dyke                  0.009  0.21    16.45
 CN25-DDH005  992616  32     32.9   0.9                         0.012  0.24    61.40
 CN25-DDH005  992617  32.9   34     1.1   Hydrothermal Breccia  0.209  7.01    21.70
 CN25-DDH005  992618  34     35     1                           0.004  0.29    12.60
 CN25-DDH005  992619  35     36     1     Lens 2                0.399  26.90   218.00
 CN25-DDH005  992620  36     37     1                           0.707  63.30   325.00
 CN25-DDH005  992621  37     38     1                           2.170  180.00  1505.00
 CN25-DDH005  992622  38     39     1                           2.330  195.00  1225.00
 CN25-DDH005  992623  39     40     1                           1.455  117.00  709.00
 CN25-DDH005  992624  40     41     1                           3.280  293.00  2310.00
 CN25-DDH005  992625  41     42     1                           1.550  137.00  863.00
 CN25-DDH005  992626  42     43     1                           2.590  252.00  930.00
 CN25-DDH005  992627  43     44     1                           3.700  275.00  1080.00
 CN25-DDH005  992630  44     45     1                           4.200  330.00  999.00
 CN25-DDH005  992631  45     46     1                           5.910  567.00  538.00
 CN25-DDH005  992632  46     47     1                           6.180  528.00  752.00
 CN25-DDH005  992633  47     48     1                           5.480  473.00  1580.00
 CN25-DDH005  992634  48     49     1                           3.570  309.00  1095.00
 CN25-DDH005  992635  49     50     1                           5.130  455.00  1155.00
 CN25-DDH005  992636  50     51     1                           4.150  383.00  1805.00
 CN25-DDH005  992637  51     52     1                           5.140  432.00  2240.00
 CN25-DDH005  992638  52     53     1                           0.636  37.60   354.00
 CN25-DDH005  992639  53     54     1                           0.485  26.40   322.00
 CN25-DDH005  992640  54     55     1                           0.155  7.88    46.80
 CN25-DDH005  992641  55     56     1                           1.360  92.90   488.00
 CN25-DDH005  992642  56     56.5   0.5   Red Breccia           0.017  1.28    27.10
 CN25-DDH005  992643  56.5   57.5   1                           0.014  0.52    24.70
 CN25-DDH005  992644  57.5   58.5   1                           0.008  0.22    20.90
 CN25-DDH005  992646  68     70     2     Dyke                  0.013  0.47    4.17
 CN25-DDH005  992647  78     80     2     Red Breccia           0.002  0.07    22.10
 CN25-DDH005  992648  88     90     2                           0.002  0.25    20.40
 CN25-DDH005  992649  98     100    2     Dyke                  0.002  0.03    9.12

 

Table 2: Cerro Negro Project, Mostaza Mine; Mostaza drill core assay results
for Cu, Ag and Sb.

 

 

Cautionary note:

The Company cautions that all references to "resources", "mineral resources",
or "mineral resource estimates" in this RNS are historical and were prepared
and reported prior to the implementation of the JORC code and therefore are
non-JORC compliant. The Company advises that the resource categories used in
the historical estimates, for example "measured, indicated, demonstrated and
inferred", may not have the same meaning or degree of confidence as current
JORC categories. Historical records indicate that the quoted non-JORC
resources were calculated using the polygonal method based on underground
sampling, 1024m of drilling in 25 holes, and geological cross-sections and
level plans. GSC is presenting this information for historical context only
and is not treating it as a current mineral resource estimate. The Company has
not been able to independently verify the results of historical drilling or
mine channel samples. References to mineralised grade intervals in drill holes
are considered apparent thicknesses as there is not sufficient geological
information to calculate true thickness of mineralised intercepts at this
time.

 

References:

1.       RNS 5182Y (26 February 2025): Cerro Negro assays return 20m of3.3%
Cu & 270g_t Ag

2.       RNS 2017A (11 March 2025): Phase II Resource Drilling Commences at
the Mostaza Cu-Ag Deposit

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-silver 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. 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 Especularita and San Lorenzo
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.

 

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 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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