Toronto, Ontario--(Newsfile Corp. - September 14, 2026) - Northmin Corporation (TSXV: NMB) ("Northmin" or the "Company") is pleased to announce positive metallurgical test results on material from the West Pond tailings resource at its 100%-owned Tynagh Project ("Tynagh"), Republic of Ireland.

Highlights:

• Loop Hydrometallurgy Operations Pty Ltd. ("Loop Hydrometallurgy") was engaged for a tailings re-treatment scoping study.

• Testwork was conducted on a representative sample of material from the west tailings pond (a National Instrument 43-101 ("NI 43-101") compliant tailings resource).

• High levels of metals leaching were achieved; silver (93%), zinc (97%), lead (89%) and copper (81%).

• The testwork also demonstrated that leached metals can be recovered from solution to produce saleable products.

• The flowsheet is based on tank leaching at less than 100°C (at atmospheric pressure) using an aqueous solution of simple salts.

• During leaching, sulfide minerals in the tailings material were oxidized to provide acidity for metals leaching; this simplifies the process flow sheet, and can reduce (or eliminate) the requirement for reagent acid.

• The closed-system process has no noxious gaseous emissions or liquid effluents and the solid waste residue is benign.

Julian Vickers, CEO, stated: "The results from this initial study by Loop Hydrometallurgy in Australia are very encouraging and potentially transformative for the surface silver project at Tynagh. The recoveries of silver are excellent at 93% and the high recoveries of other metals will provide significant additional revenue. The operating costs appear favourable and suggest potential for high operating margins from the project (subject to confirmation by further testwork and economic studies). Furthermore, the safe recovery of metals from waste material to valuable metal products provides a close fit to the Government's vision of a circular economy. With these positive results in hand, we are excited to move forward with further techno economic and environmental studies to rapidly advance the project towards production."

Leach Test Work

Northmin prepared a representative bulk sample of material from the West Tailings Pond at Tynagh. Resource drilling samples stored with ALS Laboratories in Ireland were riffle split and composited to form the bulk sample. The bulk sample was then shipped to Loop Hydrometallurgy. Portions of the composite were assayed in duplicate and sent for XRD mineralogy. Results confirmed that contained metal values and mineralogy were representative of the high grade NI 43-101 compliant surface resources at Tynagh.

The test program comprised seven leach test runs. These covered both sequential 'standard' and 'enhanced' leach conditions using variations of Loop Hydrometallurgy's processes. The primary objective was to investigate the conditions required to achieve high levels of metals value dissolution. Secondary objectives were to investigate the possibilities for reduced reagent costs and to demonstrate some alternatives for producing saleable metals products.

About Loop Hydrometallurgy Operations

Loop Hydrometallurgy Operations has developed versatile new technology for the extraction and recovery of base and precious metals from a broad range of mineral resources: concentrates, 'pre-concentrates', ores and tailings. The Halion Loop™ represents a breakthrough opportunity to unlock value from the broad range of low-grade, polymetallic and/or arsenic-contaminated resources.

With no noxious gas emissions and no liquid effluents, the Halion Loop™ technology operates at atmospheric pressure and <100°C, producing high purity metal directly at the mine site. Key deleterious mineral species in the source materials are destroyed, eliminating acid mine drainage risks from those resources. The outcomes of the mild process conditions, together with the minimisation of material transport and elimination or long-term risks, collectively minimises net environmental impact, particularly carbon footprint for metals processing.

Loop Hydrometallurgy's 'standard' Halion Loop™ leaching process typically utilizes three leach stages, however, leach stage 3 may not be required when strong extraction results are achieved in leach stage 2. The enhanced leach uses more oxidizing conditions to attack sulfides in the feed material.

Testwork Results

In the 'standard' leach test runs, the second stage extractions were as follows:

It was therefore concluded that a third stage 'standard' leach was not necessary.

In the 'enhanced' leach tests the extractions were as follows:

Loop Hydrometallurgy reported that the 'enhanced' leach results were strongly encouraging and support both a simplified process flow sheet and the substantial elimination of the need for reagent acid. The results suggest that optimization of the conditions between tests E2 and E3 could facilitate leaching without the need for significant acid or base additions.

With regard to arsenic, the Halion Loop™ process rapidly oxidizes and precipitates any contained arsenic in the form or scorodite. Arsenic levels were tracked during the Tynagh test work and the element was found to be absent in the liquor.

Loop Hydrometallurgy carried out preliminary test work to confirm the scope for selectivity in metal products. Other standard product options also remain available for consideration, and could be produced instead of, or in tandem with, selective metal products.

Additional information regarding the mineral resource and sampling program is contained in the Company's Company's Technical Report entitled Evaluation of the Tynagh Tailings Ponds at Tynagh Mine, County Galway, Ireland (Effective Date: 18 March 2026) which is available on the Company's website and at Sedar. The metallurgical test results reported herein are preliminary in nature and additional work will be required to optimize and confirm process performance and product recoveries.

Next Steps

Northmin has asked Loop Hydrometallurgy to carry out a study to determine the likely economics of the flowsheet. This will take account of expected revenues, operating costs and capital expenditures. The company will also consider different capacity options to inform the optimal ramp up strategy.

Assuming a positive outcome, the company will carry out further test work with Loop Hydrometallurgy to confirm the leach performance and operating costs, refine the product strategy and further define the expected economics. Environmental studies will commence in parallel to support the permitting process.

Qualified Person

Scientific and technical information in this news release has been prepared by and approved by Dr Evan Kirby, a Consulting Metallurgist, Director of Northmin and a qualified person (a "QP") as defined under NI 43-101.

About Northmin Corporation

Northmin Corp. (TSXV: NMB) is an exploration and development company advancing the 100%-owned Tynagh Tailings Recycling Project and the Tynagh Copper-Zinc brownfield exploration project near Loughrea in County Galway, Ireland. The Tailings Ponds have a NI 43-101 compliant resource consisting of 2.69Mt Inferred at 21.6% BaO, 49 g/t Ag, 3.56% Zn, 2.68% Pb and 0.23% Cu in the West Pond, 1.26Mt Indicated at 13.2% BaO, 34 g/t Ag, 3.63% Zn, 2.16% Pb and 0.15% Cu in the East Pond (bottom) and 2.7Mt Indicated at 9.5% BaO, 13 g/t Ag, 1.02% Zn and 0.65% Pb in the East Pond (top). The tailings ponds are accessible and there has been little to no rehabilitation of the site since mine closure in 1982. The Company is also assessing the overburden and low grade ore stockpile on the site and has previously announced high-grade silver results from first pass sampling. The Company also recently announced high-grade copper drill results from below the historic Zn-Pb-Ag mine at Tynagh including 6.4m grading 4.92% Cu, 0.98% Sb & 62.04 g/t Ag from 149.0m in hole 3615-26-07.

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Cautionary Note Regarding Forward-Looking Information

Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. The estimate of Mineral Resources may be materially affected by environmental, permitting, legal, title, taxation, socio-political, marketing or other relevant issues. The quantity and grade of reported Inferred Mineral Resources are uncertain in nature and there has been insufficient exploration to define these Inferred Mineral Resources as Indicated or Measured Mineral Resources. It is uncertain if further exploration will result in upgrading them to the Indicated or Measured category.

Certain information set out in this news release constitutes forward-looking information. Forward looking statements are often, but not always, identified by the use of words such as "seek", "anticipate", "plan", "continue", "estimate", "expect", "may", "will", "intend", "could", "might", "should", "believe" and similar expressions. Forward-looking information in this news release includes, without limitation, statements regarding: the interpretation and significance of the metallurgical test results; the potential for recovery of silver, zinc, lead and copper from the Tynagh tailings resource; the anticipated performance of the proposed flowsheet; the potential production of separate metal products; future metallurgical testing and optimization work; environmental and permitting studies; the potential economics, development strategy and advancement of the Tynagh Tailings Project ; and the Company's future plans, objectives and strategy for the Tynagh Project. Forward-looking statements are based upon the opinions and expectations of management of the Company as at the effective date of such statements and, in certain cases, information provided or disseminated by third parties. Forward-looking information is based on a number of assumptions, including, among others, assumptions regarding the accuracy of geological interpretations, the continuity of mineralization, the availability of financing, the receipt of required permits and approvals, the availability of personnel and equipment, and general business, economic, market and regulatory conditions. Although the Company believes that the expectations reflected in forward-looking statements are based upon reasonable assumptions, and that information obtained from third party sources is reliable, they can give no assurance that those expectations will prove to have been correct. Readers are cautioned not to place undue reliance on forward-looking statements.

These forward-looking statements are subject to a number of risks and uncertainties. Such risks and uncertainties include, without limitation: risks associated with exploration and development activities; uncertainty in the interpretation of metallurgical tests results; risks that future metallurgical testing may not confirm the extraction results reported herein; risks that the proposed process may not produce separate metal products of the anticipated quality, purity or commercial specification; uncertainties regarding process design, optimization and scale-up; risks that anticipated operating parameters, capital costs or operating costs may differ from current expectations; geological, technical and metallurgical risks; the possibility that future exploration results will not confirm expectations; uncertainty regarding the extent and continuity of mineralization; risks relating to the completion and conclusions of economic studies; fluctuations in commodity prices; changes in market conditions; risks relating to permitting and regulatory approvals; environmental and community relations risks; financing risks; and general economic, business and political risks. Actual results may differ materially from results contemplated by the forward-looking statements. Accordingly, the actual events may differ materially from those projected in the forward-looking statements. Such risks include uncertainties relating to exploration activities. When relying on forward-looking statements to make decisions, investors and others should carefully consider the foregoing factors and other uncertainties and should not place undue reliance on such forward-looking statements. The Company does not undertake to update any forward-looking statements, except as may be required by applicable securities laws.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/314116