Estrella Resources Confirms 27,371 Tonnes of Manganese at Ira Miri

Estrella Resources Confirms High-Grade Manganese Inventory at Ira Miri, With Exploration Upside Still to Be Unlocked

Estrella Resources (ASX: ESR) has delivered a landmark operational result at its Ira Miri Manganese Project in Timor-Leste, completing a Category B market appraisal extraction programme that has produced 27,371 tonnes of surveyed manganese stockpile inventory — including 4,984 tonnes of high-grade material grading 49.38% Mn. In-situ pit sampling has confirmed ultra high-grade mineralisation up to 60.22% Mn, while the deposit remains open in the pit walls, pit floor, and at depth, preserving substantial exploration upside that the company is now moving to systematically test.

This milestone — achieved in roughly nine months from maiden drilling and during the wet season, using an almost entirely local workforce — positions Estrella as the only company to have taken a manganese discovery from first drill hole to market appraisal extraction in Timor-Leste. This underscores what Managing Director Chris Daws describes as a genuine first-mover advantage in the country.

A Snapshot of What's in the Stockpile

The Stage 1 inventory has been classified into four discrete product categories, providing Estrella with flexibility for customer negotiations, blending options, and pre-shipment quality assurance work. The table below summarises the surveyed inventory:

The total inventory sits within the approved 30,000-tonne Category B extraction limit. Importantly, the 4,984 tonnes of high-grade material at 49.38% Mn represents a commercially compelling product parcel for direct shipping, with sizing and yield studies currently underway to confirm the final pre-shipment product specification for all categories.

The mineralised waste of 6,291 tonnes is reported separately and is excluded from the total ore inventory. It may, however, serve as feed for screening or beneficiation trials, where rejection of clay-rich fines could improve grade and product quality — adding further optionality to the inventory.

Managing Director Chris Daws said:
"Completion of the Ira Miri market appraisal sample and associated tonnage reconciliation is a strong result for Estrella and its shareholders. The programme has delivered 27,371 tonnes of manganese stockpile inventory within the approved Category B limit, including high-grade material, while also confirming product optionality across the stockpile inventory. Ira Miri demonstrates Estrella's first-mover position in Timor-Leste and the Company's ability to rapidly advance a manganese discovery from drilling to market appraisal extraction."

How Was the Inventory Measured? Understanding Bulk Density Reconciliation

For investors unfamiliar with how mining companies quantify stockpile tonnage before a Mineral Resource is formally declared, the methodology used at Ira Miri is worth understanding.

What is the Excavation and Water-Fill Bulk Density Method?

Rather than relying on assumed density figures, Estrella measured the actual physical density of manganese material directly in the pit. The process works as follows:

1. A sample of ore is excavated from a representative location in the pit face.
2. The excavated material is weighed precisely.
3. The void left behind is lined with plastic and filled with a carefully measured volume of water — giving the exact volume of the excavation.
4. Density is then calculated as mass divided by volume.

A total of 39 field in-situ bulk density samples were collected across the full range of manganese material types. A swell factor of 1.073 was then applied to convert in-situ density to loose cubic metre (LCM) bulk density, which was matched against surveyed stockpile volumes to arrive at the final tonnage reconciliation.

Why Does This Matter to Investors?

This method provides a higher degree of confidence in reported tonnage than estimates based purely on drilling or assumed density values. It also confirms compliance with the approved 30,000-tonne Category B extraction limit — a regulatory threshold that governs Estrella's current operating permissions in Timor-Leste.

Furthermore, the range of in-situ assay results from those bulk density samples — from 6.63% Mn in low-grade material to 60.22% Mn in high-grade zones — simultaneously validates both the inventory tonnage and the grade range of the deposit.

Understanding Manganese: A Critical Industrial Metal

What Is Manganese and Why Does It Matter?

Manganese is an essential metallic element used primarily in steelmaking, where it serves as a deoxidiser and desulfuriser. Without manganese, steel production would be impossible. Approximately 90% of all manganese consumed globally is used in iron and steel production, making it one of the most critical industrial metals in existence.

Direct Shipping Ore (DSO) vs Beneficiated Products

High-grade manganese ore like that produced at Ira Miri can often be sold as Direct Shipping Ore (DSO), meaning it requires minimal processing before export. This is commercially attractive because it:

• Reduces processing costs and infrastructure requirements
• Allows a faster path to revenue generation
• Commands premium pricing for high-grade material

Lower-grade material may require beneficiation — a process that concentrates the manganese content by removing impurities. In addition, the presence of multiple grade categories at Estrella Resources Ira Miri high grade manganese inventory in Timor-Leste provides considerable flexibility in product marketing and customer specifications.

Market Context

Global manganese demand is driven primarily by steel production, with China consuming approximately 70% of world production. High-grade manganese ore (above 40% Mn) typically commands significant price premiums over lower-grade material, making the 49.38% Mn high-grade inventory at Ira Miri particularly valuable from a commercial perspective.

Glossary of Key Terms

What the Pit Has Revealed About the Deposit

One of the most significant outcomes of the extraction programme is the geological insight it has delivered. Before mining commenced, the Ira Miri deposit was understood primarily through drilling. The open pit has now given Estrella's geological team three-dimensional physical exposure of the manganese system, and the picture that has emerged is more encouraging than drilling alone suggested.

Key geological findings include:

• Mineralisation type confirmed: Ira Miri hosts a stratiform, sediment-hosted manganese system, with primary mineralisation stratabound within the Noni Formation — comprising metallic grey manganese oxides interbedded with red-brown mudstone and thin beds of white sandstone and chert.
• More pods than drilling implied: Direct pit exposure has identified a greater number and cumulative volume of dense, boudinaged manganese pods than was apparent from the drill programme alone — a positive revision to the deposit model.
• Open in all directions: Mineralisation remains open in the pit walls, below the pit floor, and along strike, with the pit floor itself remaining in ore.
• Geophysical targets at depth remain untested: Previous IP survey work has already identified deeper chargeability anomalies beneath the current pit floor and along strike — and these priority targets have not yet been drilled.

The structural complexity of the deposit — folded, faulted, and boudinaged manganese pods within the Noni Formation host sequence — means that the true scale of the system is not yet defined. This is precisely why the planned geophysical programme represents a significant near-term catalyst.

What Comes Next: A Fully Loaded Pipeline

Estrella has outlined a clear, multi-track work programme across commercial, technical, and exploration workstreams. The near-term pipeline is summarised below:

The IP/resistivity survey scheduled for late May to early June is the most immediate technical catalyst. The results will directly inform the scale of the Ira Miri system and guide the targeting of follow-up drilling — with the ultimate aim of building a resource base sufficient to support a Category A Mining Licence application, which would represent a significant step-up in Estrella's operating permissions in Timor-Leste.

The Investment Case: First Mover in an Underdeveloped Jurisdiction

The Ira Miri result needs to be understood in its broader context. Timor-Leste has had virtually no systematic modern mineral exploration prior to Estrella's entry. The first documented modern exploration dates to 1937, and prior to Estrella, no minerals drilling, no close-spaced geophysics, and no systematic exploration had taken place in the country.

Estrella holds multiple Exploration and Evaluation Concessions across the country in a joint venture structure with local partner Murak Rai Timor (Estrella 70%), with all concessions and permits reported as current and in good standing.

The key pillars of the investment case as it stands today:

1. Proven operational execution: Moving from maiden drilling to a completed market appraisal extraction in approximately nine months — through the wet season, with a predominantly local workforce — demonstrates meaningful operational capability in a frontier jurisdiction.
2. High-grade product confirmed: The 4,984 tonnes at 49.38% Mn high-grade parcel, combined with in-situ grades up to 60.22% Mn, positions the company to pursue direct shipping ore sales in the near term.
3. Product optionality: The classification of the inventory into four distinct grade categories gives Estrella flexibility in customer negotiations and the ability to offer blended or single-grade product parcels.
4. Exploration upside is real and near-term testable: The deposit is open in multiple directions, known geophysical anomalies at depth remain undrilled, and the IP/resistivity programme in late May/June will directly test the scale of the system.
5. Diversified project pipeline: Beyond Ira Miri, the company is advancing additional manganese targets, accelerating exploration targeting manganese, gold, and copper, and expects a maiden JORC Mineral Resource Estimate at the Werumata Limestone Project in the near term.
6. First-mover tenure position: The breadth of the Estrella Resources Ira Miri high grade manganese inventory in Timor-Leste concession portfolio, combined with established local operating experience and relationships, is a competitive position that would be difficult and time-consuming for a later entrant to replicate.

Why Investors Should Keep Estrella on Their Radar

Estrella Resources has moved decisively from explorer to near-term shipper. The completion of the Category B market appraisal extraction is not a theoretical milestone — it has produced a defined, graded, surveyed inventory that is now being prepared for export.

At the same time, the geological picture revealed by the open pit has materially improved confidence in the system's scale, while confirming that the most prospective targets at depth remain undrilled. With the IP/resistivity geophysics campaign imminent, export and trans-shipment approvals advancing, and the Werumata Mineral Resource Estimate pending, the Estrella Resources Ira Miri high grade manganese inventory in Timor-Leste is heading into a period where multiple value-creating events are expected in close succession.

Key Takeaway:
"Estrella Resources has established itself as the leading minerals explorer in Timor-Leste, with a confirmed high-grade manganese inventory, an imminent geophysics programme to test significant depth extensions, and a clear pathway to first shipment. With multiple catalysts expected across the remainder of 2025 and into 2026, investors have good reason to follow this story closely as it moves from market appraisal to potential Category A development."

Want to Be First to Know About the Next Major Mineral Discovery?

Discovery Alert's proprietary Discovery IQ model scans ASX announcements in real time, instantly identifying high-potential mineral discoveries across 30+ commodities — just as Estrella Resources' Ira Miri result demonstrates how quickly exploration stories can evolve from first drill hole to market-ready inventory. Visit the Discovery Alert discoveries page to explore historic examples of exceptional returns, and begin your 14-day free trial today to position yourself ahead of the broader market.