Vecta Helium Project Update

6 May 2025

Mosman Oil and Gas Limited

("Mosman" or the "Company")

Vecta Helium Project Update

Mosman Oil and Gas Limited (AIM:MSMN) the helium, hydrogen and hydrocarbon exploration, development and production company, announces the drilling rig has been mobilised on the Vecta project, Colorado, USA, at which Mosman has a 20% working interest ('WI').

Further to the announcement that Vecta Oil and Gas Limited ("Vecta"), as the Operator, had signed a drilling rig contract with Desert Eagle Drilling LLC ("DED") and several matters needed to be resolved before drilling would start, Vecta has advised the drilling rig is now on location at the Billy Goat lease for the first of the five wells to be drilled in this campaign. At Billy Goat the Company is targeting the Lyons formation with an anticipated target depth of 1200 feet.

The rig crew has a scheduled break and drilling is expected to commence once they return on 13 May.

Photo: Mosman team inspecting DED rig on 11 April 2025 drilling on nearby Red Rocks Project

Andy Carroll, Chief Executive Officer of Mosman, said: "We are pleased to have progressed to the point of drilling rig on location and drilling commencing soon at these five wells at Vecta. Each of the prospects has been identified by Vecta based on years of experience and a thorough review of existing data, and we are pleased to be in a joint venture with Vecta.

"Each prospect has its own individual characteristics. Mosman considers the key factors to be the helium concentration and the reservoir pressure that indicates the well production potential. One of the prospects is near the Model Dome field that was produced in the 1920s and had helium concentrations of 7-11%.

"I am encouraged to see positive results at the Blue Star Helium/Helium One projects in the same area as the Vecta Project."

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 the publication of this announcement via Regulatory Information Service ('RIS'), this information is now considered to be in the public domain.

Enquiries:

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

Notes to editors

Mosman (AIM: MSMN) is a helium, hydrogen and hydrocarbon exploration, development, and production company with projects in the US and Australia. Mosman'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 exploration projects in the Amadeus Basin in Central Australia.