02 June 2026

Quantum Helium Limited

("Quantum" or the "Company")

Operational Update

Sagebrush-1 Extended Production Test

Quantum Helium Limited (AIM: QHE) is pleased to provide a further operational update on the ongoing extended production test at the Sagebrush-1 well in Colorado, USA.

Highlights

• Extended production test continuing at Sagebrush-1

• Initial acid injection programme successfully completed on the upper Leadville zone

• Technical analysis supports progression to the next phase of reservoir stimulation

• Planned fracture stimulation designed to enhance reservoir connectivity

• Preliminary analysis confirms raw gas produced has close similarities to gas analysis conducted in 1994

• Further operational updates expected in due course

Operational Update

Operations continue to advance at Sagebrush-1 as the Company progresses the extended production test designed to evaluate the commercial potential of the helium-bearing Leadville Formation.

Over recent weeks, the Company has undertaken a number of testing, monitoring and acidization activities designed to evaluate reservoir performance and optimise the forward testing programme. As is common during complex testing programmes involving historic wells, certain operational adjustments were required as the programme progressed with testing of the lower Leadville horizon appearing to have been impacted by the performance of downhole testing equipment, requiring additional operational work before testing could continue. These matters have now largely been addressed and the Company has successfully advanced into the next phase of reservoir evaluation.

Following completion of this work, the Company successfully carried out an initial acid injection programme on the upper Leadville dolomite interval at approximately 7,250 feet depth. During the treatment, the formation accepted fluids at increased injection rates and pressures relative to earlier operations, providing encouraging indications regarding communication with the reservoir. The pre-stimulation programme was designed to improve near-wellbore reservoir connectivity and reduce historical formation damage.

Initial engineering analysis indicates the treatment successfully extended beyond the immediate wellbore area and established communication with the targeted reservoir interval, providing valuable insight into reservoir characteristics, response to acidization and the effectiveness of pre-stimulation techniques within the Leadville Formation.

Preliminary gas analysis has confirmed the raw gas has close similarities to the gas analysis conducted in 1994 (which had previously indicated helium content of 2.76%).

Pressure build-up monitoring undertaken following the initial pre-stimulation programme has continued to provide valuable insight into reservoir characteristics and behaviour. The information gathered has helped inform the design of the next phase of operations and further refine the Company's understanding of the Leadville reservoir.

Based on this work, Quantum and its technical team have concluded that the results obtained to date support progression to the next phase of reservoir fracture stimulation. The planned programme is designed to establish communication with undamaged reservoir beyond the immediate wellbore area and provide a more representative assessment of the Leadville Formation's production potential. The Company believes this next phase of testing represents an important step towards evaluating the reservoir's commercial potential.

The Board is encouraged by the technical progress achieved to date. The extended production test has successfully generated valuable reservoir and pressure data which is helping to refine the Company's understanding of the Leadville Formation and guide future development planning. The next phase of fracture stimulation and testing represents an important step towards evaluating the commercial potential of the reservoir.

The Company notes that Sagebrush-1 was originally drilled approximately 30 years ago. Whilst technical and operational challenges can occur when re-entering and testing wells of this age, the successful resolution of these issues has allowed the programme to advance into what the Company considers to be an important phase of reservoir evaluation.

Howard McLaughlin, Chief Executive Officer of Quantum Helium, commented: "The extended production test continues to generate valuable technical information and has significantly improved our understanding of the Leadville reservoir. The data collected to date supports a progression to a larger fracture stimulation programme designed to improve communication with the broader Leadville reservoir and provide a more meaningful assessment of the formation's production potential."

Importantly, the programme has generated exactly the type of reservoir data we set out to obtain. Every stage of testing has improved our understanding of the Leadville Formation and helped define the most effective path forward. The information gathered so far is helping us optimise the programme as we work towards evaluating the commercial potential of the Leadville Formation.

The planned fracture stimulation work is designed to enhance connectivity with the formation and should provide a much more meaningful assessment of reservoir performance. We are encouraged by the results obtained so far and believe the programme is advancing into a particularly important phase.

Preliminary gas analysis has also been encouraging, with the raw gas encountered during the current programme showing close similarities to the gas analysis obtained from Sagebrush-1 in 1994, which previously indicated helium content of 2.76%. Whilst further analysis remains ongoing, this represents another encouraging outcome from the programme to date.

We look forward to updating shareholders as operations continue and additional data becomes available."

Market Abuse Regulation (MAR) Disclosure

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014 ('MAR') which has been incorporated into UK law by the European Union (Withdrawal) Act 2018. Upon publication via Regulatory Information Service ('RIS'), this information is now in the public domain.

Qualified Person Statement

The information contained in this announcement has been reviewed and approved by Howard McLaughlin, Chief Executive Officer for Quantum Helium, who has more than 45 years of experience in the oil and gas industry and is a member of the American Association of Petroleum Geologists.

Enquiries:

Updates on the Company's activities are regularly posted on its website: www.quantum-helium.com

Notes to editors

Quantum (AIM: QHE) is a helium, hydrogen and hydrocarbon exploration, development, and production company with projects in the US and Australia. Quantum's strategic objectives remain consistent: to identify opportunities which will provide operating cash flow and have development upside, in conjunction with progressing exploration. The Company has several projects in the US, in addition to royalty interests in Australia.