South Oko returns gold up to 7 g/t Au
Altair Minerals Limited
ABN: 72 149 026 308 +61 3 8630 3321 altairminerals.com.au Level 21, 459 Collins Street,Melbourne VIC 3000
ASX MARKET
ANNOUNCEMENT
Wednesday 25 February 2026 ASX : ALR
South Oko Returns High-Grade Gold up to 7g/t; and
Drill Contractor Appointed
SOUTH OKO
▪ A Grab sample collected from base of Trench 2 at South Oko ("SOKO"), exposed sheared quartz and
pyrite, has returned an assay of 7.03g/t Au.
▪ This is the first and only sub-surface grab sample result on the mafic unit, providing the initial groundtruth confirmation of in-situ high-grade gold mineralisation identified at SOKO.
▪ Geological mapping and visual observations from the trenching program have provided strong
encouragement to expand the exploration scope at SOKO. Accordingly, the company will incorporate
a RAB drill rig to undertake preliminary drilling and efficient deeper testing of the saprolite profile.
▪ Shallow RAB drilling across SOKO is expected to commence in parallel with the diamond drill program
at North Peters, accelerating target refinement ahead of larger-scale diamond drilling at SOKO.
▪ RAB drilling will allow a much greater understanding of the exploration data at SOKO versus current
auger drilling:
Allowing 10x more drilling meterage to be completed per day
Allowing for better understanding of mineralisation profile and greater depth penetration
Potential to identify areas of primary mineralisation prior to maiden diamond program
▪ Five trenches spanning a combined ~1.3km length have been completed, logged, sampled and bagged.
▪ SOKO ground geophysics (Magnetics, IP, Pole-Dipole) nearing completion, with results expected
shortly after.
DIAMOND DRILLING
▪ OGD Drilling (Guyana) Inc. ("OGD") appointed as drill contractor for upcoming maiden diamond drill
program.
▪ OGD have previously completed in excess of 200,000m of drilling in Guyana under the guidance of Rich
Munson and Pascal Van Osta, both of whom now hold senior positions at Altair. This appointment
builds on a well-established and trusted working relationship, providing Altair with proven in-country
operational expertise and confidence in the effective execution of its drilling programs.
▪ Initial maiden diamond drill program will be focused on North Peters ("NP"), consisting of 3,000 –
5,000m, expected to commence shortly, no later than mid-April.
▪ In parallel, RAB drilling is expected to commence at SOKO in conjunction with diamond drilling at NP.
▪ Immediately upon completion of diamond drilling at North Peters, Altair intends to commence its
maiden diamond drill program of 10,000 – 15,000m at South Oko.
OLYMPIC DOMAIN
▪ Prior to the 19th February 2026 hearing, Altair Minerals Limited ("ALR") and BHP Olympic Dam
Corporation Pty Ltd ("BHP") had respectively filed competing applications regarding specific
discovery ("Applications"). The Applications are listed for Argument on 16th April 2026. Altair will
continue to defend the fair value of the Olympic Domain Project and ensure its exploration rights are
not diminished.
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Altair Minerals Limited CEO, Faheem Ahmed, commented:
"I'm pleased to provide a broad range of exploration updates across Greater Oko, alongside the initial grab
sample assay results from South Oko (SOKO). As demonstrated, Altair is advancing Greater Oko at a rapid
pace, with multiple exploration programs and logistical operations progressing in parallel.
At SOKO, we are taking a disciplined, scientific and methodical approach to exploration to maximise the
probability of success as we move toward our maiden diamond drilling program. Exploration is a process of
assembling a complex geological puzzle — and with each dataset piece being generated, the picture is
becoming clearer. Encouragingly, we are beginning to see consistent indicators that point toward the
potential for a significant discovery.
The trenching program at SOKO has been instrumental in improving our understanding of the underlying
geology, structural controls and lithological framework. Even prior to receiving assay results, trench
mapping and logging provided critical ground-truth validation, enabling us to refine our geological model.
Importantly, SOKO appears to host the same extensional structural systems as our northern neighbours,
which have led to multiple world-class discoveries and the delineation of two-billion-dollar gold assets
adjacent to Altair's tenure.
The geological sequence being defined at SOKO mirrors the same package of units that hosts multi-million-
ounce gold deposits along strike. We are also observing comparable structural deformation patterns. The
imminent completion of our ground geophysical surveys will provide an additional layer of validation and
further refine our targeting framework.
Notably, the first and only sub-surface grab sample collected from within the mafic unit at SOKO has
returned an exceptional 7.03g/t Au. This result represents a meaningful breakthrough, providing the first
ground confirmation of in-situ high-grade gold mineralisation at the prospect. While previous work at SOKO
had defined strong surface geochemical anomalies, this result materially strengthens our confidence in the
underlying prospectivity of the system and reinforces our strategy as we progress toward drilling.
The swift execution of programs is a result of the diligent efforts by our on-ground Guyana exploration team
– led by Pascal Van Osta. We expect numerous high impact catalysts and exploration results over the coming
months as we head into our diamond drill program."
Figure 1: Plan view of the Greater Oko Project and four key target areas defined to date – South Oko (SOKO), North Peters
(NP), Old Granny (OG) and Kmung (KM) with Altair's project size in comparison to its two predecessors G2 Goldfields
($2.2 Billion Market Cap) and GMining Ventures ($1 Billion takeover of Oko West from Reunion Gold). For clarity, both G2
and GMIN resources are located outside of Altair's Greater Oko Project.1,2,3,4,9,10,11,12,13,14,19,20
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South Oko Exploration Update
The exploration team continues to make rapid progress at South Oko, with auger, trench and systematic soil
sampling advancing in parallel. Ground geophysical surveys, including magnetics and induced polarisation
(IP) utilising a pole–dipole configuration, are also nearing completion, with results expected shortly.
The geochemical programs have been strategically designed to generate complementary datasets that
integrate well with geophysics. Together, these programs are aimed at rapidly refining and prioritising
multiple high-confidence targets at SOKO ahead of the planned large-scale diamond drilling campaign.
Trenching Geology
A total of five trenches has been completed to date, including systematic sampling and bagging, covering
approximately ~1.3km of strike. The sixth and seventh trenches are scheduled for completion shortly and
will then be followed by sampling, dispatchment and assays.
Detailed trench mapping and geological logging at South Oko ("SOKO") have proven to be highly effective in
refining the Company's understanding of the underlying geology, structural framework and mineralisation
controls. The data generated to date has been instrumental in vectoring exploration towards:
a) Right Geology: Delineation of mafic units and vectoring the granitoid-greenstone contact.
b) Right Structure: Identifying of shear zones, foliation and favourable structural corridors.
c) Right Lithology: Improved understanding of the weathering profile, volcanic-sedimentary host units,
metamorphism, leached duricrust development and regolith architecture.
Trench 1: Confirmed the presence of the Oko Pluton Granitoid, which intersected through weathered felsic
granite unit.
Trench 2: Represented a major breakthrough in confirming the extension of the shear structure present at
neighbouring deposits and the key structural element in emplacing multi-million-ounce deposits along
strike. Trench 2 predominantly intersected mafic meta-volcanics which showed a gradual change in
brecciated texture to fine grained, locally sheared with minor folds and quartz veins. A grab sample of the
quartz vein within Trench 2 assayed an exceptional 7.03g/t Au, being the first confirmation of high-grade
in-situ mineralisation present within SOKO.
Trench 4: Successfully confirmed presence of the foliated volcaniclastics and sedimentary host unit
(VCSHU), which is an important local lithological unit that hosts the bulk of mineralisation at the Oko West
deposit – due to the VCSHU being conducive to shearing, fracturing and porosity for gold enrichment.
Trench 5: Demonstrated the northern continuity of the volcaniclastic and sedimentary unit encountered in
Trench 4. Trench 5 initiated within a unit of sheared mafic volcanics on the eastern border and the remainder
of the trench continued through the package of volcaniclastic and sedimentary units towards to west.
Trench 6: Predominantly consisted of a mafic intrusive and transitioning to mafic volcanics with significant
sheared zones observed at the contact between the intrusive and volcanic units. Trench 6 ended on the
western border within the unit of sheared mafic volcanics. Quartz veining was observed periodically through
this trench at 7m, 183m and 196m.
The trenches to date have confirmed SOKO hosts all key geological elements and signatures analogous to
the world-class discoveries adjoining the project area – outlining a significant discovery potential at SOKO.
The trenching to date in summary has confirmed:1,3
• Presence of sheared structures and confirmation of the Oko Shear extension – which is the key
structural host to over 9Moz Au in recent discoveries along strike.
• Presence of sheared mafic volcanics and the key mineralisation hosting unit of volcaniclastic-
meta sediments, seen at neighbouring deposits.
• Confirmation that the Oko Shear Contact sits between Trench 1 (Oko Pluton Granite) and
Trench 2 (Mafic Volcanics), with a package of volcaniclastic sediments sitting in between the two
trenches – analogous to the overall geological sequence of neighbouring discoveries.
With highlights from the limited grab sampling program reported, having confirmed:
• High-grade gold and in-situ mineralisation hosted within sheared quartz.
• The first and only grab sample taken sub-surface within a trench positioned on the mafic
geological unit has returned 7.03g/t Au.
• Saprolite grab samples continue to show anomalous levels of gold up to 778ppb Au, indicating
the anomalous footprint still retains potential to grow.
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Soils
From the 2026 program, 450 points across the western extension of W1 target area has now been
completed, with another 44 samples expected to be completed by this week prior to dispatching for assays.
As previously reported, in Figure 9 below, the W1 target currently represents the most compelling
geochemical anomaly at SOKO, particularly when taking into the consideration its position with the Oko
Shear Contact, lithology and confirmation of favourable geological package from trenching.
The W1 target is a ~2km strike length, >100ppb Au gold in soil anomaly, which is larger than the soil
anomalism that led to the Oko West discovery (measuring ~1.7km strike, >100ppb Au contour)1.
Furthermore, the W1 target remains open both to the west and southwest, making the extensional sampling
imperative to gain a further understanding of the anomaly distribution and vector towards the potential
nearby source deposit that has led to this distinct and prominent surface anomalism.
Figure 10 below demonstrates that as soil sampling moves towards the west, into higher elevations, the
laterite duricrust develops a leached cap that masks anomalies. This phenomenon can be visible in the soil
sampling lines directly west of the Oko West pit outline, which presumably has masked gold anomaly
responses on the duricrust.
As seen in Figure 10 above and Figure 11 below, the Oko West soil sampling program had also displayed a
prominent cluster of >50ppb Au anomalies sitting directly on top of the 5.9Moz Au deposit, in stark contrast
to the remainder of the intermittent and sporadic anomalies along the grid. Similarly, the W1 target
represents an emergence of a second distinct contiguous cluster of gold in soil anomalies which stands out
from the remainder of the grid and is highly prospective of a secondary source deposit.
Figure 10 displays the key structural control (Oko Shear Contact) which has hosted a chain of major
discoveries, distinguished in the image by the abrupt contrast between the Oko Pluton and greenstone belt.
The W1 target area demonstrates the robust geochemical anomalism which is probable to be a result of a
proximal source sitting adjacent to the controlling structure.
Furthermore, anomalies identified in the erosional surfaces adjacent to the duricrust is a highly compelling
indicator for a prospective blind target. In Figure 11 below, this phenomenon is visible by the soil anomalies
on the W3 Target (just south of W1 Target), with anomalies situated on the erosional surface of the duricrust
(highlighted by dark purple circles) – representing a secondary compelling target area. Given the potential
drill target to the south of W1 area is situated under a duricrust, it is likely to mask any soil sampling response
and more than likely will require auger/RAB drilling to penetrate below transported duricrust material into
the saprolite to determine the continuity and validate if a gold anomaly is truly present.
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Grab Samples
A total of 11 grab samples were collected during this campaign. Of these, two samples were taken from
mafic greenstones located west of the Oko Shear Contact. Only one sub-surface sample was collected from
a weathered quartz outcrop at the base of Trench 2, which returned a high-grade result of 7.03g/t Au.
The remaining grab samples were collected in and around the SOKO camp area, including from historic
artisanal workings and tailings overlaying the Oko Pluton Granitoid. Notably, in one area, during excavation
activities for camp logistics had exposed weathered quartz within saprolite, which was grab sampled and
returned a highly anomalous assay of 778ppb Au. This sample was located approximately 500m east of the
Oko Shear Contact within the felsic unit and highlights the significant gold anomalism surrounding the main
shear corridor. The result reinforces the scale of the system and the potential for additional mineralised
zones to be defined through systematic exploration.
In addition, two grab samples collected from historic sandy alluvial tailings, which returned highly
anomalous values of 217ppb Au and 122ppb Au respectively. These samples are situated between the W1
and E1 targets and may indicate continuity between the two anomalous corridors, supporting the potential
for these zones to amalgamate into a broader mineralised system.
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Drill Contractor Appointed
Altair has contracted OGD Drilling (Guyana) Inc. ("OGD") to undertake its maiden diamond drilling program
in Guyana, commencing at North Peters Prospect no later than mid-April. Drilling will begin immediately
upon completion of the North Peters drill camp.
OGD have previously completed in excess of 200,000m of drilling in Guyana under the guidance of Rich
Munson and Pascal Van Osta, both of whom now hold senior positions at Altair. This appointment builds on
a well-established and trusted working relationship, providing Altair with proven in-country operational
expertise and confidence in the effective executing of its drilling programs.
The North Peters maiden diamond drill program is expected to comprise approximately 3,000 – 5,000m.
Upon completion, drill rigs will be mobilised to the South Oko prospect to undertake a further ~15,000m of
diamond drilling. The commencement of drilling at North Peters marks the beginning of an extensive 12+
month drilling campaign across multiple high-priority targets and prospects, with the objective of delivering
at least one potential major discovery prior to completion.
Following encouraging geological observations from the initial trenching program at South Oko, the
Company believes an expanded exploration scope is warranted. Accordingly, in parallel with the diamond
drilling program at North Peters, a short-hole and wide-spaced RAB drilling program will commence at South
Oko.
The RAB program is designed to systematically test saprolite at depth, refine the understanding of
mineralisation zones and geochemical anomalies, and assess the potential for intersecting primary gold
mineralisation. Furthermore, RAB drilling