Toronto, Ontario--(Newsfile Corp. - September 28, 2026) - Northmin Corporation (TSXV: NMB) ("Northmin" or the "Company") is pleased to announce assay results from the second two drill holes drilled on the Tynagh mine site as part of its hard rock Ag-Cu-Zn-Pb exploration program at the 100%-owned Tynagh Project ("Tynagh"), Republic of Ireland.

Highlights:

• Highest silver and copper assays received by Northmin to date,

  • 2.45m grading 4.03% Cu, 24.87% Zn+Pb, 0.47% Sb and 313.82 g/t Ag from 106.75m in hole 3615-26-08,

  • Including 0.75m grading 933 g/t Ag and 12.75% Cu.

• Two holes, 3615-26-08 and 3615-26-09, intersected numerous mineralized intercepts including broad zones of polymetallic mineralization, some of which contain high-grade intervals of copper, zinc, lead and silver (mentioned above).

• 3615-26-08, targeting polymetallic and copper-silver-antimony mineralization 50m east of the high-grade copper intersection in hole 3615-26-07, intersected a broad zone of Waulsortian reef-hosted polymetallic mineralization with significant copper in the upper reef in addition to a lower reef-hosted high-grade Cu-Zn-Pb-Ag intercept and footwall copper-silver-antimony mineralization.

In the Waulsortian Reef Limestone,

• 33m grading 0.3% Cu, 2.42% Zn+Pb, 0.07% Sb and 21.26 g/t Ag from 56m,

• Including 7m grading 1.01% Cu, 2.88% Zn+Pb, 0.23% Sb and 63.43 g/t Ag,

• And 13m grading 0.11% Cu, 4.04% Zn+Pb and 11.34 g/t Ag from 70m,

• 2.45m grading 4.03% Cu, 24.87% Zn+Pb, 0.47% Sb and 313.82 g/t Ag from 106.75m in a distinctive lower reef unit,

In the previously unmined sub-reef Lower Muddy Limestone,

• 6.9m grading 0.38% Cu and 9.27 g/t Ag from 145.0m,

• Including 3.0m grading 0.67% Cu and 17.81 g/t Ag from 145.0m.

• 3615-26-09, located 43m east of hole 3615-26-06 and 33m west of 3615-26-07, also intersected both Waulsortian reef-hosted and Lower Muddy Limestone- hosted zinc-lead-silver mineralization in addition to a zone of footwall copper-silver-antimony mineralization in the Lower Muddy Limestone close to the Tynagh Fault;

In the Waulsortian Reef Limestone,

• 24.45m grading 0.3% Cu, 1.25% Zn+Pb, 0.06% Sb and 11.05 g/t Ag from 93.8m,

• Including 8.85m grading 0.52% Cu, 1.69% Zn+Pb, 0.1% Sb and 18.25 g/t Ag from 100.0m,

• And 4.45m grading 1.62% Zn+Pb and 3.5 g/t Ag from 113.8m,

In the previously unmined sub-reef Lower Muddy Limestone,

• 19.7m grading 0.11% Cu, 2.4% Zn+Pb and 13.21 g/t Ag from 134.3m,

• Including 6.6m grading 0.26% Cu, 3.69% Zn+Pb and 30.16 g/t Ag from 146.4m

• 5.1m grading 0.78% Cu, 1.1% Zn+Pb, 0.26% Sb and 50.54 g/t Ag from 164m,

• Including 3m grading 1.18% Cu, 1.53% Zn+Pb, 0.43% Sb, and 81.83 g/t Ag.

"Following on from the results of the first two drill holes in July, today's results are further validation of the potential to define broad zones of near-mine reef-hosted polymetallic mineralization and structurally-controlled copper, antimony and silver mineralization along the Tynagh Fault beneath the historically mined Zn-Pb-Ag mineralization. These results also show that the Lower Muddy Limestone beneath the reef limestone is also capable of hosting broad zones of Zn-Pb-Ag mineralization and there is emerging evidence of fault splays within the reef that may explain copper-silver-antimony mineralization away from the main Tynagh Fault. While the first four holes have now tested a strike length of 125m, the observations from another four widely spaced holes that have been completed (assays pending) give us confidence that the project will continue to deliver positive drilling results from across the 1.6km strike of the historically mined deposit.

Exhibit 1. Plan Map of the Tynagh Mine Site Showing New Holes

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Exhibit 2. Plan Map of the Four Holes Drilled to Date with Assay Highlights

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Note on Exhibit 2, 3 & 4: True thickness of the mineralization in holes 3615-26-08 and 3615-26-09 as a percentage of the down-hole interval, is estimated to be in the range 79-88%. The pit outline, underground drives and workings, and historic drill holes are based on digitized maps and mine plans and the reliability of all features cannot be guaranteed. The features should be assumed to be approximate only. Historical records show no evidence of stoping in these sections. None of the four holes drilled by Northmin in Exhibit 2 intersected workings. The workings shown are drives and headings including the decline to Zone 3 to the east. Sections prepared by Blackwell Geoservices, September 2026.

Exhibit 3. Cross-Section Showing Today's Results from 3615-26-08 at Tynagh

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Exhibit 4. Cross-Section Showing Today's Results from 3615-26-09 at Tynagh

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Exhibit 5. Summary of New Assays from 3615-26-08 at Tynagh

Exhibit 6. Summary of New Assays from 3615-26-09 at Tynagh

Exhibit 7. Drill hole information for the holes reported in this announcement.

Tynagh Drilling Results - Further Information

The two angled drill holes, 3615-26-08 and 3615-26-09, are the third and fourth holes drilled by the Company in Zone 2 (Open Pit Area) to target both the polymetallic in-situ reef-hosted mineralization and the copper mineralization hosted in the reef and in the Lower Muddy Limestone adjacent to the Tynagh Fault. Both holes have intersected encouraging mineralization including broad intersections of polymetallic mineralization and high-grade Cu-Pb-Zn-Ag mineralization in the Waulsortian Reef. Both holes also intersected further copper-silver-antimony mineralization adjacent to the main Tynagh Fault in the Lower Muddy Limestone. Significantly, hole 3615-26-09 also intersected zinc and lead mineralization in the Lower Muddy Limestone with 19.7m grading 0.11% Cu, 2.4% Zn+Pb and 13.21 g/t Ag from 134.3m, demonstrating that all lithologies near the fault can host polymetallic mineralization. No mine workings were intersected in the two holes reported here and there is no evidence of previous stoping in the drilling area as shown in Exhibit 2.

The first four holes, drilled as part of the current 10-hole drill program, cover a strike length of 125m and demonstrate reasonable continuity of the polymetallic mineralization within the reef. To date, high-grade copper-silver-antimony mineralization has been intersected along the Tynagh Fault in the Lower Muddy Limestone but also in the lower micrite reef in hole 3615-26-08 where the highest silver assay to date was returned; 0.75m grading 12.85% Cu and 933g/t Ag within an intersection of 2.45m grading 4.03% Cu, 24.87% Zn+Pb, 0.47% Sb and 313.82 g/t Ag from 106.75m. The distribution of Cu-Ag-Sb mineralization, typical of feeder zones within Irish-type zinc-lead systems, along with drill core observations suggest that this mineralization may be associated with splays oblique to the main Tynagh fault. Further drilling in combination with digitization and modelling of historic drillhole and mine data will shed more light on the structural model.

Barite mineralization was observed in core, mainly in the Waulsortian Reef Limestone. Pulps of mineralized samples within and surrounding the reported significant intersections will be re-analysed for barium by method Ba-XRF05SQ, a semi-quantitative cost-effective method.

The new results reported here are highly encouraging and consistent with the Company's view that significant zones of shallow bulk polymetallic mineralization remain in-situ in the micrite reef banks peripheral to the high-grade historic workings while there is strong potential for the discovery of further Cu-Ag-Sb zones in reef and sub-reef lithologies along the Tynagh fault. The Company looks forward to providing further updates as more assays are received.

Qualified Person

Technical information in this news release has been prepared by and approved by Aiden Lavelle EurGeol, P.Geo, General Manager Ireland for Northmin and a qualified person (a "QP") as defined under National Instrument 43-101. Standards of Disclosure for Mineral Projects ("NI 43-101").

Sampling and Analytical Procedures

All core drilled at Tynagh and reported in this announcement was NQ (47.6mm) and was cut in half using a rock saw. Sample intervals vary between 0.5m to 2.92m with an average (over 160 samples) of 1.18m. The half-core samples are bagged, labelled and sealed at the Company's core shed facility on the Tynagh Mine Site, 15km from Loughrea in County Galway, Ireland. The core sampling was carried out by the QP. Transport of samples in sealed nylon sacks was by the QP to ALS Laboratories in nearby Loughrea town. ALS Minerals is a large, independent and ISO certified analytical service company, originally based in Loughrea to serve the Tynagh mine. Sample preparation at the ALS facility was by method Prep-31, comprising fine crushing 70% < 2mm, riffle splitter, pulverise up to 250g 85% < 75um. Analytical procedures are 48 element four acid ICP-MS (codes ME-MS61). Over-limit analyses for Ag, Cu, Zn, Pb, Sb and As was by method ME-OG62. One sample exceeding 20% lead (Pb) and 30% zinc (Zn) were analysed by XRF by method ME-XRF15c. Barium values are not reported above as barite requires an alternative analysis method. The Company will conduct further barite analyses on pulps from samples in the mineralized intervals.

Quality Assurance/Quality Control (QA/QC) Information

Northmin inserts certified reference materials ("CRMs" or "Standards") as well as blank material and quarter core duplicates, to its sample stream as part of its industry-standard QA/QC program. The QC results have been reviewed by the QP, who is satisfied that all the results are within acceptable parameters. The QP has validated the sampling and chain of custody protocols used by Northmin.

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 1985. 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 drill results; the continuity, extent, grade and nature of mineralization; the interpretation of geological and structural controls on mineralization; the existence and potential of copper, silver, antimony, zinc and lead mineralization at the Tynagh Project; exploration targets and exploration potential; the significance of fault splays and other structural controls on mineralization; the planned completion of the remaining drill holes in the current exploration program; future drilling, exploration, metallurgical, technical and evaluation programs; the potential for the delineation of mineral resources; 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, geological and structural models, 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 drilling, sampling and assay results; geological, technical, structural and metallurgical risks; the possibility that future exploration results will not confirm expectations; uncertainty regarding the extent, continuity and grade of mineralization; risks associated with the use and verification of historical data; 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.

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