Announcement PDF RNS Number : 2503Y Mendell Helium PLC 09 October 2026 Mendell Helium plc (“Mendell Helium” or the “Company”) Buy out of minority investors in Nilson well Mendell Helium (LON: MDH), the helium exploration and production company, is pleased to announce that it has acquired the remaining 25% interest in the Nilson 22‑1 well in Haskell County, Kansas (“Nilson”) for US$186,092 (£138,611) to be satisfied through the issue of 3,094,000 new ordinary shares at a price of 4.48 pence (“Acquisition”). Nilson is located in the Hugoton gas field, one of North America’s most prolific producers of natural gas and helium. Mendell Helium now has a 100% interest in Nilson following the Acquisition. Highlights Nilson is the Company’s most successful well in the Hugoton gas field in south-western Kansas The well was fracked in Q4 2024 following a successful operation that increased flow to over 100 Mcf/day Investors committed US$170,000 to the frack Nilson is connected to the Hugoton gathering system, eliminating the requirement for on-site purification and enabling the Company to generate revenue from helium, methane and natural gas liquids Although revenue generating, Nilson would benefit from a disposal well which would reduce operating costs of trucking water Securing 100% ownership of the well positions Mendell Helium for further development of Nilson Background on the Acquisition On 26 September 2024, Mendell Helium announced plans for a second, much larger frack on the Nilson well. US$170,000 was raised from five third party investors who collectively acquired an approximately 25% economic interest in the well (with Mendell Helium retaining the other 75%). The frack was a success with Nilson’s flow rates increasing to over 100 Mcf/day and ranking it as one of the top producers in the Hugoton region. As with the Company’s production wells in Fort Dodge, water disposal is a key part of the operation and, to date, water at Nilson has been collected on site and disposed of by a water tanker to a suitable location. Trucking water is charged by the barrel and, consequently, the process can become uneconomic at large volumes with prices typically being around US$2.50 – $3.00 per barrel. For this reason, Mendell Helium has explored the possibility of connecting Nilson to a disposal well which would enable it to increase pumping of the well, thereby potentially generating greater gas volumes. Nilson is connected to the extensive infrastructure in the Hugoton gas field with all production being tied to a gathering system from the well head and delivered to the Jayhawk gas processing plant. With no site purification or processing required, Mendell Helium is not constrained from higher production levels contingent on the availability of sufficient water‑disposal capacity. Although there are no immediate development plans, owning 100% of the well gives the Company far greater flexibility on future opportunities and, in the meantime, increases its revenue share from the well to 100%. A sample taken from Nilson returned a helium concentration of 0.61% and a methane concentration of 68.14%. With higher helium prices now being seen as a result of the conflict in the Middle East and robust methane prices, the Board considers that acquiring a 100% interest in Nilson is an attractive proposition. In particular, it is currently in negotiations with its off-taker for the Hugoton region for improved pricing across all constituents of the produced gas stream. Nilson has not been pumping while these adjustments and negotiations have been ongoing so production over the last months has been below the well’s potential but the Company anticipates returning the well to higher production levels in the near term. Terms of the Acquisition The Nilson investors have accepted an offer of, in aggregate, 3,094,000 new ordinary shares in return for their interest in the well. The offer comprises the return of the US$170,000 invested in 2024 to fund the frack together with US$16,092 being their share of profit from the well after satisfying all costs. No premium has been paid to the investors for control of the well. The new ordinary shares have been issued at a price of 4.48 pence being the being the 14 day volume weighted average price up until the date that the offer was made to the minority investors. Admission Application has been made for 3,094,000 new ordinary shares to be admitted to trading on AIM (“Admission”). Admission is expected to occur at 8:00 a.m. on or around 15 October 2026. The new ordinary shares will rank pari passu with the existing Ordinary Shares. Total Voting Rights Following Admission, the Company's enlarged share capital will comprise 357,930,937 Ordinary Shares of 1 pence each. Therefore, the total number of voting rights in the Company will be 357,930,937. This figure may be used by shareholders as the denominator for calculations by which they will determine if they are required to notify their interest in the Company, or a change to their interest in the Company, under the Financial Conduct Authority's Disclosure Guidance and Transparency Rules. Nick Tulloch, Chief Executive Officer of Mendell Helium, said: “Although our focus remains firmly on Fort Dodge, it is important to remember that we also have five production wells in the world-famous Hugoton gas field. Their flow rates and helium composition may not be as high as Fort Dodge to the east but they benefit from access to production infrastructure meaning we have no obligation to purify the gas stream and earn revenue from all the valuable component, not just the helium. Nilson has long been our flagship well in the Hugoton exhibiting flow rates that can rival the very best wells in that region. Taking 100% control of the well, through this cost-effective mechanism, gives us more flexibility in the future as we examine possible opportunities for improved pricing, economic water disposal and higher production.” ENDS Engage with the Mendell Helium management team directly by asking questions, watching video summaries and seeing what other shareholders have to say. Navigate to our Interactive Investor website here: https://mendellhelium.com/link/PKa6Ve Enquiries: Investor questions on this announcement We encourage all investors to share questions on this announcement via our investor website https://mendellhelium.com/s/a6a55a Mendell Helium plc Nick Tulloch, CEO Via our website investors@mendellhelium.com Cairn Financial Advisers LLP (Nominated Adviser) Ludovico Lazzaretti / Liam Murray Tel: +44 (0) 20 7213 0880 SI Capital Limited (Broker) Nick Emerson Tel: +44 (0) 1483 413500 Fortified Securities Guy Wheatley Tel: +44 (0) 203 4117773 CREST Corporate Broking Jerry Keen Tel: +44 (0) 20 3973 3678 AlbR Capital Limited Gavin Burnell / Colin Rowbury / Jon Belliss Tel: +44 (0) 207 4690930 St Bride’s Partners / Spire (Public & Investor Relations) Alan Green Tel: +44 (0) 20 7236 1177 Overview of Mendell Helium Mendell Helium is a helium producer in Kansas, USA where it operates through its wholly owned subsidiary M3 Helium. M3 Helium’s flagship well, Rost 1-26, is in Fort Dodge, just to the east of Dodge City, Kansas. It has been tested as containing 5.1% helium composition and a drill stem test yielded a maximum flow rate of approximately 2,900 Mcf per day. Water removed from Rost 1-26 is delivered to Brobee, a nearby disposal well that has been permitted at 10,000 barrels of water per day at 1,200 psi. Production at Rost 1-26 commenced in early November 2025 and the most recently recorded flow rate in December 2025 was 250 Mcf per day equating to approximately $1.4 million of helium per year (at $300/Mcf helium). M3 Helium has subsequently drilled a second well, Rost 2-26, which is currently being de-watered and early results have been encouraging. In particular Rost 2-26 has reported a helium composition of 11.5%. It also owns additional leases in the Fort Dodge area capable of supporting up to eight new production wells. M3 Helium has also agreed a joint venture with Ritchie Exploration, Inc. to recomplete the Schneweis Ventures 13A, a well with a drill stem test of over 10,000 Mcf per day and a historic flow rate of 300 Mcf per day. Since coming back on line, the well has recorded peak flow rates of up to 700 Mcf per day, although rates have been variable during de-watering. At the Rost wells in Fort Dodge, M3 Helium treats the raw gas on site to concentrate the helium and has leased two tube trailers which it uses for deliveries to its offtaker. M3 Helium also has interests in five producing wells (Peyton, Smith, Nilson, Bearman and Dimmitt) within the Hugoton gas field in South-Western Kansas, one of the largest natural gas fields in North America. Significantly these wells are in the proximity of a gathering network and the Jayhawk gas processing plant meaning that producing wells are all tied into the infrastructure. Forward Looking Statements These forward-looking statements are not historical facts but rather are based on the Company's current expectations, estimates, and projections about its industry; its beliefs; and assumptions. Words such as 'anticipates,' 'expects,' 'intends,' 'plans,' 'believes,' 'seeks,' 'estimates,' and similar expressions are intended to identify forward-looking statements. These statements are not a guarantee of future performance and are subject to known and unknown risks, uncertainties, and other factors, some of which are beyond the Company's control, are difficult to predict, and could cause actual results to differ materially from those expressed or forecasted in the forward-looking statements. The Company cautions security holders and prospective security holders not to place undue reliance on these forward-looking statements, which reflect the view of the Company only as of the date of this announcement. The forward-looking statements made in this announcement relate only to events as of the date on which the statements are made. The Company will not undertake any obligation to release publicly any revisions or updates to these forward-looking statements to reflect events, circumstances, or unanticipated events occurring after the date of this announcement except as required by law or by any appropriate regulatory authority. This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact rns@lseg.com or visit www.rns.com. 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