D3 Energy Certifies Maiden 14.0 BCF Helium Resource at ER386

D3 Energy Certifies Maiden Helium Resource at ER386, Growing Total Portfolio to 35.6 BCF — A 65% Leap in Scale

D3 Energy Limited (ASX: D3E | OTCQX: DNRGF) has delivered a landmark resource upgrade, announcing the independent certification of a maiden Contingent and Prospective Helium Resource at its ER386 exploration permit in South Africa's Free State Province. The D3 Energy maiden helium resource at ER386 in South Africa has been certified by globally recognised reserves auditor Sproule ERCE, materially expanding D3's total helium resource base and reinforcing its position as the operator of one of the world's most significant helium provinces.

The numbers are striking. ER386's maiden 2C Recoverable Helium Resource of 14.0 BCF, when combined with the previously certified resources at ER315 and PR016, lifts D3's combined 2C Recoverable Helium Resource to 35.6 BCF — a 65% increase on the prior standalone figure.

On the prospective side, the combined portfolio's 2U Prospective Helium Resource reaches 52.5 BCF, nearly doubling the ER315 and PR016 standalone figure with a 94% uplift.

Critically, ER386 covers a total area equivalent to 59% of the combined ER315 and PR016 acreage, and D3 holds a 100% working interest in the permit — meaning every cubic foot of certified resource flows entirely to the company.

"The combined reserve and resource base across ER315, PR016 and ER386 provides D3 with one of the world's most significant helium provinces and one which is becoming increasingly important given its Southern Hemisphere location and the current geopolitical tensions in the Middle East, which we expect will constrain world helium supply for years to come."

— David Casey, Managing Director & CEO, D3 Energy Limited

What Has Been Certified, and Why Does It Matter?

The certification, assessed as of 1 April 2026, was conducted using the SPE Petroleum Resources Management System (PRMS) guidelines, with helium evaluated as a non-hydrocarbon gas under SPE's August 2022 extension framework. Sproule ERCE is a 70-year-old global energy consulting firm with deep geoscience and engineering expertise — its independent stamp of approval carries significant weight with institutional and retail investors alike.

The D3 Energy maiden helium resource at ER386 in South Africa certification breaks down as follows:

Table 1: ER386 Maiden Contingent Resource (BCF)

Table 2: ER386 Maiden Prospective Resource (BCF)

The ER386 Contingent Resource adds directly to what D3 had already certified at ER315 and PR016, creating a combined portfolio of considerable scale.

Table 3: Combined Contingent Resource — ER315, PR016 & ER386 (BCF)

Table 4: Combined Prospective Resource — ER315, PR016 & ER386 (BCF)

D3 already holds Reserves at ER315 and PR016 — the D3 Energy maiden helium resource at ER386 in South Africa certification adds a new layer of Contingent and Prospective Resources that, if advanced, could materially grow the company's Reserve base over time.

The Geology Behind the Numbers: Why ER386 Fits So Neatly Into the Picture

ER386 is not a standalone bet — it is contiguous with D3's flagship ER315 permit and sits within the same Virginia Fault structural corridor that hosts D3's certified reserves and contingent resources at ER315 and PR016. This geological continuity is what gives the ER386 certification its credibility.

Sproule ERCE used reprocessed 2D seismic data to map faults across the project area — the same fault structures that act as conduits for gas migration and generate the damaged zones that serve as reservoir rock.

Flow rates from extended well tests conducted on five wells along the Virginia Fault between July 2024 and March 2025 (RBD01, RBD03, RBD10, RBD12, and Nooitgedacht Major) were used to develop type curves for the 1C, 2C, and 3C Contingent Resource estimates.

Furthermore, while none of these wells sit within ER386, all are located near the permit boundary, providing directly relevant analogues. The geological system across the Free State Province has already delivered independently verified helium concentrations of up to 8% at ER315 — a world-class figure that underpins the quality narrative across the entire acreage position.

Understanding Helium: The Critical Gas Transforming Energy Markets

Helium represents one of the most strategically important gases in the global economy, despite its relatively low profile compared to traditional hydrocarbons. Understanding why helium matters helps explain the significance of D3's resource upgrade.

What Makes Helium Valuable?

Helium is the second lightest element in the universe and possesses unique properties that make it irreplaceable in numerous high-tech applications. Unlike other gases, helium cannot be manufactured — it exists only as a natural byproduct of radioactive decay in certain geological formations.

Key Applications Driving Demand

• Medical Technology: Helium cools the superconducting magnets in MRI machines, making medical imaging possible
• Semiconductor Manufacturing: Computer chip production requires ultra-pure helium for cooling and creating controlled atmospheres
• Space and Defence: Rocket fuel systems and satellite technology depend on helium's inert properties
• Scientific Research: Particle accelerators and quantum computing research require helium's cooling capabilities
• Industrial Welding: High-precision welding applications use helium to prevent contamination

Why Does Supply Present Such a Challenge?

The global helium market faces chronic supply constraints. Traditional sources — primarily natural gas processing facilities in the United States, Qatar, and Algeria — have struggled to meet growing demand. Geopolitical tensions, particularly in the Middle East, have created additional supply uncertainty that shows no sign of abating.

Helium accumulates in underground reservoirs when uranium and thorium decay over millions of years. These natural accumulations represent finite resources that cannot be replenished. The Free State Province's geological characteristics — including the fault structures that trap gases and provide migration pathways — create ideal conditions for helium concentration.

Understanding Contingent vs. Prospective Resources: A Quick Primer for Investors

For investors newer to resources investing, distinguishing between resource classification categories is essential for interpreting this announcement accurately.

What Are Contingent Resources?

Contingent Resources refer to quantities of gas estimated to be potentially recoverable from known accumulations, but not yet classified as Reserves due to one or more contingencies. In ER386's case, key contingencies include:

• Confirmation of source gas composition through compositional analysis within the ER386 permit area
• Demonstration of commercial flow rates from within the permit
• Conversion of the exploration right to a production right

What Are Prospective Resources?

Prospective Resources relate to undiscovered accumulations that require both discovery and development to be realised. They carry both a chance of discovery and a chance of development and, as Sproule ERCE notes, there is no certainty that any portion will be discovered.

The distinction tells investors where value sits on the risk-reward spectrum:

Key Glossary of Terms

• BCF: Billion cubic feet — the standard volumetric unit used for gas resources
• 2C / 2U: Best estimate cases for Contingent and Prospective Resources respectively, per the SPE PRMS framework
• PRMS: Petroleum Resources Management System — the internationally recognised framework for classifying oil and gas resources
• Working Interest: D3 holds 100% of ER386, meaning full economic exposure to any development upside
• Virginia Fault: The primary structural corridor hosting D3's certified resources across the Free State portfolio
• Sproule ERCE: Independent reserves auditor with a 70-year global track record

The Geopolitical Dimension: Southern Hemisphere Supply in a Disrupted World

D3 management has been explicit about the strategic significance of ER386's location. The Middle East — historically a significant source of helium, particularly from Qatar — is experiencing ongoing geopolitical tensions that the company expects will constrain global helium supply for years to come.

South Africa's Free State Province sits entirely in the Southern Hemisphere, insulated from the supply disruption risks currently affecting Northern Hemisphere-facing sources. For industrial consumers of helium — from semiconductor manufacturers to medical imaging providers to defence contractors — supply chain diversification is no longer a theoretical concern; it is an operational imperative.

D3's portfolio, moreover, now spans 479,409 acres across the Free State Province through ER315, PR016, ER386, ER391, ER392, ER393, and Technical Cooperation Permit TCP273. This positions the company as a potentially significant alternative supplier at a time when geographic and geopolitical differentiation carries real commercial value.

What Comes Next: The Road From Resource to Production

D3's current focus is advancing ER315 and PR016 toward production, with a Production Right Application (PR016) currently under assessment by South Africa's Petroleum Agency SA (PASA). That initial Production Right Application area covers just 15% of ER315 and approximately 9% of D3's total exploration right acreage — meaning ER386 and the remaining acreage represent the company's broader, longer-dated appraisal and development pipeline.

For ER386 specifically, the pathway forward includes:

1. Drilling and testing of exploration wells within the ER386 permit area to confirm gas composition, reservoir quality, and well deliverability
2. Acquisition and analysis of new 2D seismic to map additional fault structures — this work is planned to commence in 2027
3. Conversion of the Exploration Right to a Production Right, which is one of the key contingencies currently preventing the Contingent Resources from being reclassified as Reserves
4. Compositional analysis confirming source gas characteristics within ER386 itself

The structured, sequential nature of these steps reflects a disciplined approach to de-risking the resource before committing to full development capital.

The Investment Case: Scale, Quality, and Strategic Positioning

The D3 Energy maiden helium resource at ER386 in South Africa certification strengthens the company's investment thesis across three mutually reinforcing pillars.

1. Scale

A combined 2C Recoverable Helium Resource of 35.6 BCF across three permits, with a 2U Prospective Resource of 52.5 BCF sitting behind it, places D3 among a very small group of helium-focused explorers with resources of genuine global significance. The addition of ER386 — at a 65% uplift to the combined 2C figure — demonstrates that the Free State Province continues to deliver beyond initial expectations.

2. Geological Quality

The Free State system has consistently delivered helium concentrations of up to 8% — a benchmark concentration that speaks to the purity and economic attractiveness of the resource. The geological continuity confirmed through ER386's certification, via the Virginia and Ventersburg Faults, validates that the system extends meaningfully beyond the initial ER315 footprint.

3. Strategic Differentiation

D3's Southern Hemisphere location, 100% working interest in ER386, and early-mover position across nearly half a million acres in a proven helium province combine to create a differentiated asset profile. In addition, the company has expanded into Australia through helium and hydrogen permits in the Arckaringa Basin, broadening its critical gases exposure whilst keeping the primary development focus on South Africa.

Key Takeaway: D3 Energy has materially grown its resource base with the independent certification of a maiden Contingent and Prospective Resource at ER386, lifting its combined 2C Recoverable Helium Resource to 35.6 BCF — a 65% increase. With a 100% working interest in ER386, geological continuity confirmed across the Virginia Fault system, and a Production Right Application already under assessment at its flagship ER315 and PR016 permits, D3 is building one of the most significant helium portfolios in the world at a time when global supply pressures are intensifying. Investors focused on critical gas exposure with genuine scale should be paying close attention to upcoming exploration well results and the progress of D3's Production Right Application.

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