Portfolio Review and Sale of EP-145

Mosman Oil and Gas Limited (AIM: MSMN) the helium, hydrogen and hydrocarbon exploration, development and production company, provides an update on its asset portfolio.

As part of its strategic shift to helium exploration, development and commercialisation, Mosman is continuously reviewing the ranking of each project and where the team should focus. Subsequent to the acquisition of Coyote Wash and Sagebrush projects announced in December 2024, a review determined the best allocation of capital and management efforts is to dispose of EP-145 for which the Company has signed an agreement with ASX listed Echelon Resources Limited ("Echelon", ASX:ECH). The net proceeds combined with planned expenditure on EP-145 in 2025 that will no longer be incurred are estimated to be circa A$3 million.

Project review highlights

The Sagebrush Project has the advantages of:

• Leases held by production ("HBP") of circa 40 bopd (gross) providing income
• 10,000 acres of leases with production infrastructure
• Further oil and helium exploration potential identified on seismic
• Activity to be determined by Mosman, with no prescribed expenditure commitments
• Moderate drilling costs US$2.5-3.5 million depending on depth
• Helium infrastructure (pipelines, plants, markets)

The Coyote Wash Project advantages:

• New leases with prospects identified on seismic
• Adjacent to Sagebrush Project
• Activity to be determined by Mosman, with no prescribed expenditure commitments

Compared to EP-145:

• Current commitment to acquire and interpret 2D seismic
• Next 12 month costs estimated to be over A$2.5 million.
• Drilling costs have increased and are estimated to be circa A$20 million based on other wells in the area.
• Following community concern on "fracking", legislative review led to more onerous approvals process and increasing costs

Mosman has agreed a binding heads of terms with Echelon to sell 100% of % EP-145 for A$400,000 in cash and retain a 5% helium and hydrogen royalty (based on sales price, no deduction of costs).

The A$400,000 will be used to progress helium exploration in the USA projects.

The disposal is subject to normal conditions, including entering into a formal sales and purchase agreement and government approvals which are anticipated to take a few months.

Mosman has today completed the acquisition of the outstanding 75% interest from Greenvale Energy Ltd ("Greenvale", ASX:GRV), as announced on 15 October 2024.

The disposal does not include the seismic long lead items being acquired from Greenvale that Mosman expected to be sold separately for circa $A150,000.

The book value in Mosman's accounts of EP-145 (100%) was A$1,503,925 as at 30 June 2024. As an exploration licence, EP-145 has generated no revenue and there are no historic profit or losses.

Ranking of projects in Mosman's portfolio (January 2025)

Andy Carroll, Chief Executive Officer of Mosman, said: "We have taken a commercial decision to focus our capital allocation and future operational activities on our US projects. While EP-145 in the Amadeus Basin has helium potential, the USA has the considerable commercial advantages of a proven helium production basin, lower drilling and operating costs, ready availability of services, production infrastructure and access to markets. We are pleased to retain ongoing interests in helium potential in EP-145 with a royalty interest which does not require any expenditure by Mosman.

"This transaction, once completed, restores Mosman to being fully funded for all exploration commitments in the next 12 months, and with funding available for discretionary exploration activities."