Altair Minerals Strikes 34.56g/t Gold at South Oko, Guyana

Altair Minerals Uncovers 34.56g/t Gold at South Oko as Geophysics Reveal Multiple Large-Scale Drill-Ready Targets

The Altair Minerals South Oko gold discovery in Guyana represents one of the most compelling early-stage exploration updates to emerge from the Guiana Shield in recent months. Altair Minerals Limited (ASX: ALR) has delivered a significant exploration update from its Greater Oko Project, combining high-grade grab sample results with the completed Phase I ground geophysics program at its South Oko ("SOKO") target. The announcement marks a meaningful step-change in the project's maturity — elevating SOKO from a geochemical anomaly into a structurally defined, drill-ready target system, whilst simultaneously advancing diamond drilling at the North Peters ("NP") prospect.

The headline result is a 34.56g/t Au grab sample from Trench 6, the company's first deep trench (~6 metres) at SOKO, which successfully penetrated through the laterite cover into the saprolite horizon where primary gold mineralisation indicators were encountered. A second sample from the same trench returned 27.21g/t Au, reinforcing the interpretation that high-grade primary mineralisation is sitting directly beneath the barren duricrust.

Meanwhile, the completed Pole-Dipole IP survey has identified four coherent, deep-tapping chargeability structures adjacent to the Oko Shear, two of which — Structure M and Structure N — are flagged as priority drill targets. Diamond drilling at North Peters is confirmed to commence this week.

The Headline Numbers at a Glance

From Geochemical Halo to Structural Target: What Does Trench 6 Tell Us?

The significance of the Trench 6 result extends well beyond the headline gold grade. Previous trenching at SOKO, conducted at approximately 3 metres depth, largely remained within anomalous lateritic material — returning elevated geochemical signals but stopping short of the primary mineralised zone. Trench 6 was designed specifically to go deeper, reaching approximately 6 metres to break through the 3–4 metre thick duricrust that blankets the SOKO area.

The return of 34.56g/t Au and 27.21g/t Au from quartz vein exposures at the base of this trench is the first direct evidence that primary gold mineralisation is present at SOKO beneath the leached zone. This is consistent with the company's working exploration model, which posits that the main mineralised system lies below the barren duricrust and is overlain by a highly anomalous geochemical halo in laterites and soils.

Critically, the mineralised material encountered in Trench 6 is associated with deformation zones — a characteristic of orogenic gold systems, where gold-bearing fluids migrate along structural pathways and precipitate in favourable host environments.

CEO Faheem Ahmed commented: "Encouragingly, a grab sample from the Company's first deep trench at SOKO returned the highest grade recorded at the project to date, assaying an outstanding 34.56g/t Au. The duricrust profile across SOKO is generally 3–4m thick, with shallow trenches of approximately 3m depth typically remaining within anomalous lateritic material. In contrast, deeper trenches reaching approximately 6m depth into the saprolite horizon are beginning to demonstrate indications of potential primary mineralisation."

It is important to note that grab samples are selective by nature and are not necessarily representative of broader mineralisation. However, they serve as a meaningful indicator of the presence and grade potential of exposed mineralised zones, particularly when corroborated by structural and geophysical evidence.

Pole-Dipole IP Survey: Seeing Into the Third Dimension

The completion of the Phase I Pole-Dipole IP survey represents the first time Altair has been able to look beneath the surface at SOKO in three dimensions. The survey identified four distinct chargeability structures, with two elevated to priority drill targets.

Structure M — The Standout Feature

Structure M is the most prominent chargeability anomaly identified in the survey. It is interpreted as representing a large-scale, coherent sulphide body that:

• Extends over a ~2.5km defined strike length
• Reaches up to 250m in width
• Remains open at depth and along strike to the south
• Cuts through geochemical anomalies associated with both the W1 and W3 targets
• Is the most well-defined and deepest tapping structure in the survey

"Structure 'M' continues to stand out as a priority target, representing a deep-seated chargeability anomaly interpreted to be confined between two competent rock units. Importantly, the structure demonstrates exceptional continuity across survey sections." — Faheem Ahmed, CEO

Structure N — High-Priority and Geochemically Supported

Structure N is a second well-defined chargeability feature that is particularly compelling due to its direct coincidence with a soil geochemical anomaly high. Furthermore, it demonstrates several characteristics that elevate it to high-priority status:

• Located adjacent to the Oko Shear
• ~600m strike length, widths of 100–250m
• Supported by both chargeability and resistivity responses
• Coincides with the W1 geochemical target
• Described as "deep-tapping" in nature

Supporting Structures

Critically, these four structures represent just a ~2.5km segment of Altair's broader 15km exposure along the Oko Shear contact — underscoring the substantial exploration upside that remains across the broader project.

Understanding Induced Polarisation (IP) Surveys: A Key Tool for Investors to Know

What Is an IP Survey?

An Induced Polarisation (IP) survey is a geophysical technique that measures the electrical chargeability of subsurface rocks. When a current is passed through the ground and then switched off, certain minerals — particularly sulphides — continue to discharge electricity for a short period, creating a measurable "chargeability" response.

Why Does It Matter Here?

In orogenic gold systems like SOKO, gold mineralisation is frequently associated with sulphide minerals such as pyrite. The presence of sulphides generates chargeability responses that can be detected by IP surveys even beneath thick cover like the laterite duricrust at SOKO. The Pole-Dipole variant of the IP survey provides enhanced depth penetration, making it particularly well-suited to "see through" the weathered surface material and image the deeper structural roots of the system.

What Does It Mean for Investors?

The identification of coherent, large-scale chargeability structures at depth provides a framework for targeted, de-risked drilling. Rather than drilling based solely on surface geochemistry, Altair can now orient drill holes to test specific subsurface targets with known dimensions and geometry.

Magnetic Inversion Adds Structural Clarity Across SOKO

Complementing the IP survey, the ground magnetics program — processed to produce Reduce to Pole, Analytic Signal, Tilt Derivative, and 3D Inversion models — has provided additional insight into the structural architecture controlling potential gold emplacement at SOKO.

Key findings include:

• Regional NE-SW fabric defines the primary lithological framework across the area
• NNE-SSW to N10–20° structures crosscut this fabric and are interpreted as the key fluid pathways for gold mineralisation — notably, these structures align with the orientation of nearby known deposits
• The Oko Shear contact is clearly delineated by an abrupt change in magnetic susceptibility at the transition from felsic granites to greenstones
• The Analytic Signal has identified two major structural ridges — the eastern one coinciding with the W1 soil anomaly and the western one coinciding with the W3 soil anomaly
• At depth, a low susceptibility corridor defines a deep-tapping structural control interpreted as a shear zone

This polyphase deformation history is considered highly favourable for gold emplacement, as repeated structural reactivation creates the pathways and traps necessary for orogenic gold systems to develop.

North Peters: Diamond Drilling Commences This Week

Whilst SOKO continues to build its structural and geochemical case, the company's North Peters prospect is entering a new phase. A total of 28 regional step-out RAB holes have been completed at NP, averaging approximately 31 metres in depth. Following analysis of these results, infill and step-out diamond drilling at North Peters is scheduled to commence this week.

Diamond drilling is a higher-resolution technique that recovers intact core samples, enabling detailed geological logging, structural measurements, and accurate grade estimation — representing a significant technical escalation from the RAB drilling programme.

A Substantial Pending Assay Pipeline

Importantly, SOKO's exploration story is far from complete in terms of results flow. The following samples remain pending assay:

• 400+ soil samples
• 200 auger holes
• 1.5km of trench samples

This pipeline provides a strong basis for continued newsflow over the coming months as results are received and reported.

Guyana: An Exploration Address That Has Attracted Tier-1 Capital

The Greater Oko Project sits within a jurisdiction that has seen remarkable validation over recent years. Guyana is positioned on the Guiana Shield, which hosts a geological extension of the same Birimian Greenstone Belt that underpins world-class gold discoveries across West Africa. The region is considered significantly underexplored relative to its West African geological equivalent.

The scale of recent M&A activity in the region provides context for the value that major capital has assigned to Guiana Shield discoveries:

Altair's 590km² contiguous landholding at Greater Oko sits approximately 1.5km from a 5.9Moz discovery expected to enter production within the next 18 months. The company holds the right to earn up to 70% of the Greater Oko Project, subject to conditions precedent.

It is worth noting that these regional comparisons are provided for context only. The presence of nearby discoveries or geological similarities does not guarantee that Altair will successfully delineate a JORC-compliant mineral resource at Greater Oko.

What's Next: Upcoming Catalysts and Exploration Pipeline

The company has outlined an active near-term programme across both its key targets:

Immediate (Weeks)

• Diamond drilling commences at North Peters this week
• Assay results from 400+ soil samples, 200 auger holes, and 1.5km of trenching at SOKO expected progressively

Near-Term (Months)

• Further trenching at SOKO to follow up on primary mineralisation evidence from Trench 6
• Geochemical follow-up programmes guided by IP and magnetic inversion results
• Scale-up of programmes at both NP and SOKO being finalised by the exploration team
• Potential drill target definition at SOKO following structural confirmation

Ongoing

• Continued fieldwork aiming to generate steady exploration results refining current targets and developing new targets across the broader 590km² landholding along 15km of Oko Shear exposure

Why This Announcement Matters for the Investment Case

Several threads come together in this update that collectively represent a meaningful de-risking of the SOKO target and acceleration of the broader Greater Oko exploration programme. Consequently, the Altair Minerals South Oko gold discovery in Guyana warrants close attention from investors tracking early-stage exploration on the Guiana Shield.

1. Primary mineralisation confirmed at SOKO. The 34.56g/t Au and 27.21g/t Au grab samples from Trench 6 provide the first direct evidence of high-grade primary gold below the duricrust, upgrading SOKO's exploration status significantly.

2. Structural targets now have three-dimensional definition. The Pole-Dipole IP survey and magnetic inversion together provide a coherent subsurface model. Structure M and Structure N are now well-defined, large-scale drill targets with known geometry and coincident geochemical support.

3. Drill activity is active and accelerating. Diamond drilling at North Peters commences this week, adding an immediate newsflow catalyst.

4. Large pending assay pipeline supports continued newsflow. Over 400 soil samples, 200 auger holes, and 1.5km of trenching await assay at SOKO, providing a basis for ongoing result releases.

5. Only a 2.5km segment of a 15km shear exposure has been surveyed. The four chargeability structures identified represent a fraction of Altair's exposure along the Oko Shear, leaving substantial room for further target generation.

Key Takeaway:
Altair Minerals has meaningfully advanced SOKO from a surface geochemical anomaly to a structurally defined, three-dimensionally imaged system with primary gold mineralisation confirmed at depth. With Structure M extending over 2.5km and Structure N sitting directly beneath a soil geochemical high, two compelling drill targets are now clearly defined. Combined with diamond drilling commencing at North Peters this week and a large pending assay pipeline, ALR enters a high-activity period that warrants close attention from investors tracking early-stage gold exploration on the Guiana Shield.

Want to Know More About Altair Minerals and the Greater Oko Project?

With high-grade gold confirmed at depth, large-scale drill-ready targets now structurally defined, and diamond drilling already underway at North Peters, Altair Minerals (ASX: ALR) is entering a pivotal period of exploration activity across its 590km² Greater Oko landholding in Guyana. Investors seeking to learn more about the company, its projects, and the investment case behind one of the Guiana Shield's most active early-stage explorers can visit the official Altair Minerals website at altairminerals.com.au.