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NorthMin Corporation Announces Additional Barite Results Following Reanalysis of Drill Core Samples from Recently Reported High- Grade Copper and Polymetallic Intersections and Provides Update on Drilling Activities

Drill Results Corporate Updates

NorthMin Corporation Announces Additional

Barite Results Following Reanalysis of Drill

Core Samples from Recently Reported High-

Grade Copper and Polymetallic Intersections

and Provides Update on Drilling Activities

Toronto, Ontario--(Newsfile Corp. - August 18, 2026) - Northmin Corporation (TSXV: NMB) ("

Northmin

"

or the "

Company

") is pleased to announce additional barium assay results from the first 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:

New assays from the previously reported copper and polymetallic (Zn-Pb-Ag-Cu) intersections

demonstrate that significant fine-grained barite, an EU-critical raw material, is associated with the

base metal mineralization at Tynagh.

Hole 3615-26-07, which intersected a broad zone of Waulsortian reef-hosted polymetallic

mineralization peripheral to the mine workings, had 27.45m grading 10.08% BaSO

4

(Barite) in

addition to 0.26% Cu, 4.57% Zn+Pb, 0.06% Sb and 20.78 g/t Ag from 90.55m (reported

previously).

Including 10.45m grading 21.4% BaSO

4

from 90.55m.

Hole 3615-26-06 barium assays also confirm the presence of barite associated with base metals

in the Waulsortion reef limestone:

3.6m grading 9.03% BaSO

4

in addition to 0.38% Cu, 2.19% Zn+Pb, 0.04% Sb and 9.62 g/t

Ag from 127.0m.

3.5m grading 9.06% BaSO

4

in addition to 3.5m at 1.03% Cu, 0.17% Zn+Pb, 0.25% Sb and

15.86 g/t Ag from 150.5m.

Barite is also present in the previously unmined sub-reef Lower Muddy Limestone where high-

grade copper was intersected:

6.4m grading 4.41% BaSO

4

in hole 3615-26-07 in addition to 4.92% Cu, 0.98% Sb & 62.04

g/t Ag from 149.0m reported previously.

9.15m grading 3.22% BaSO

4

in hole 3615-26-06 in addition to 0.95% Cu, 2.18% Zn+Pb,

0.14% Sb and 15.58 g/t Ag from 184.25m reported previously.

"The additional barium assays are consistent with historical mine records and the companies own 43-

101 compliant resource estimate on the tailings deposit at Tynagh which shows that the historic mine

extracted significant amounts of barite which was not recovered but deposited in the tailings ponds. The

presence of barite, which is designated a critical raw material by the EU, has potential to add value to

the in-situ polymetallic mineralization at the Tynagh brownfield Ag-Cu-Zn-Pb exploration project" stated

Julian Vickers, CEO.

Exhibit 1. Plan Map of the Tynagh Mine Site Showing Holes Referred to in this Announcement

and New Tailings Sampling Sites.

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10660/310060_468b203a44ac1a0c_001full.jpg

Exhibit 2. Revised Cross-Section Showing Updated Barite Results from 3615-26-07 at Tynagh

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10660/310060_468b203a44ac1a0c_002full.jpg

Exhibit 3. Revised Cross-Section Showing Updated Barite Results from 3615-26-06 at Tynagh.

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10660/310060_468b203a44ac1a0c_003full.jpg

Note on Exhibit 2&3: True thickness of the mineralization in holes 3615-26-06 and 3615-26-07 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. The workings shown are drives and headings including the decline to Zone 3 to the east. Sections prepared by Blackwell

Geoservices, August 2026.

Refer to the company's previous announcement with the base metal results on 13 July 2026 (Link

NorthMin Corporation

).

Exhibit 4. Summary of significant new barite assays (BaSO

4

) and previous base metal and

silver assays from drill hole 3615-26-06 at Tynagh

Hole ID

From

(m)

To

(m)

Int

(m)

BaSO

4

(%)

Cu

(%)

Pb

(%)

Zn

(%)

Zn+Pb

(%)

Sb

(%)

Ag

(g/t)

3615-26-06

127

130.6

3.6

9.03

0.38

1.19

1.00

2.19

0.04

9.62

including

127

128

1

5.78

1.09

1.73

0.35

2.08

0.10

9.75

& including

128.8

130.6

1.8

12.35

0.10

1.41

1.81

3.21

0.01

11.74

3615-26-06

133.5

135.55

2.05

4.06

0.00

0.06

0.82

0.87

-

1.92

3615-26-06

142.65

145.3

2.65

4.96

0.02

2.06

1.05

3.11

-

8.86

3615-26-06

150.5

154

3.5

9.06

1.03

0.01

0.16

0.17

0.25

15.86

including

152.25

152.9

0.65

21.1

4.61

0.05

0.71

0.76

1.09

71.3

3615-26-06

154

157.7

3.7

4.0

0.13

1.31

0.04

1.35

0.02

3.55

3615-26-06

168.9

175

6.1

1.25

0.99

2.39

0.46

2.85

0.18

22.25

including

168.9

171.7

2.8

0.42

0.91

5.20

0.91

6.11

0.17

32.11

& including

173.7

174.1

0.4

1.36

4.95

0.02

0.5

0.52

1.28

93.2

3615-26-06

180.8

181.6

0.8

0.51

1.25

0.47

0.19

0.66

0.39

46.5

3615-26-06

184.25

193.4

9.15

3.22

0.95

1.52

0.65

2.18

0.14

15.58

including

184.25

185.8

1.55

5.25

0.23

3.70

3.44

7.15

-

5.49

3615-26-06

185.8

192

6.2

1.43

1.22

1.32

0.10

1.42

0.19

19.40

Exhibit 5. Summary of significant new barite assays (BaSO

4

) and previous base metal and

silver assays from drill hole 3615-26-07 at Tynagh

Hole ID

From

(m)

To

(m)

Int

(m)

BaSO

4

(%)

Cu

(%)

Pb

(%)

Zn

(%)

Zn+Pb

(%)

Sb

(%)

Ag

(g/t)

3615-26-07

90.55

118

27.45

10.18

0.26

3.00

1.57

4.44

0.06

20.78

Including

90.55

101

10.45

21.40

0.50

1.41

0.99

2.39

0.12

18.10

which includes

97

99.75

2.75

45.82

0.83

0.87

0.12

0.99

0.18

29.03

& including

102.95

106.2

3.25

3.75

0.29

0.53

0.77

1.30

0.07

10.59

& including

109.2

118

8.8

4.22

0.10

7.33

3.32

10.65

0.03

38.36

which

includes*

110.2

114

3.8

1.86

0.03

3.57

7.00

10.57

0.01

24.87

&*

114

117

3

9.16

0.23

16.42

0.36

15.58

0.07

79.10

3615-26-07

135

136

1

2.04

1.31

3.87

0.36

4.23

0.30

94.3

3615-26-07

141

156.3

15.3

1.92

2.16

0.49

0.28

0.77

0.42

32.01

including

149

155.4

6.4

4.41

4.92

0.17

0.50

0.67

0.98

62.04

which includes

153.45

155.4

1.95

8.86

10.08

0.02

1.18

1.20

2.36

136.46

Note on tables above: True thickness of Deeper Cu-Ag mineralization in hole 3615-26-07 as a percentage of the down-hole interval, is estimated to

be 88%; "-" means less than 0.01%. *Note 'from' and 'to' depths as some 'included' intervals are presented to show variation in Zn and Pb grades

within the same broader intersection e.g. 6.8m grading 13.31% Zn+Pb and 48.79 g/t Ag from 110.2m reported in the highlights is included in the table

as separate Zn-rich (3.8m) and Pb-rich (3m) intersections. Refer to the company's previous announcement with the base metal results and table of

drill hole information on 13 July 2026 (Link

NorthMin Corporation

).

Tynagh Barium Analyses - Further Information

Northmin previously announced base metal results including high-grade copper intersections and

intersections of broad polymetallic mineralization from its first two angled drill holes, 3615-26-06 and

3615-26-07, in Zone 2 (Open Pit Area) on 13 July 2026. The holes targeted 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. Following the recognition of fine-grained barite in the core,

additional assays were required by an X-Ray Fluorescence (XRF) method to determine reliable barium

values. Following the receipt of the base metal assays, pulps of 89 mineralized samples within and

surrounding the previously reported significant intersections were re-analyzed by XRF methods to give a

reliable barium value and determine the most appropriate method to analyze barite in future drill

samples.

Barium values in the polymetallic reef-hosted mineralization were found to be significant. When

converted to BaSO

4

, the broad 27.45m intersection in hole 3615-26-07 has 10.08% BaSO

4

including

10.45m grading 21.4% BaSO

4

from 90.55m in the Waulsortian Reef Limestone. In addition to the newly

reported barium assay, this intersection was previously reported as 27.45m grading 0.26% Cu, 4.57%

Zn+Pb, 0.06% Sb and 20.8 g/t Ag from 90.55m.

The copper mineralization in the lower muddy limestone is also associated with barite but generally at

lower levels compared to the polymetallic reef-hosted mineralisation. The high-grade copper intersection

of 6.4m grading 4.92% Cu from 149.0m in hole 3615-26-07 has 4.41% BaSO

4

in addition to 0.98% Sb

& 62.04 g/t Ag as reported previously.

The summary results for all significant intersections are shown in the tables above in Exhibit 4 & 5.

Barium values by XRF were reported by ALS Minerals as % Ba and converted to BaSO

4

by multiplying

by a factor of 1.7 based on the standard conversion of Ba to BaSO

4

based on the atomic weights of the

elements.

Hard Rock Drilling Update

Northmin is continuing its exploration program to test in-situ polymetallic mineralization peripheral to the

historic workings and deeper copper mineralization in the lower muddy limestone along the Tynagh

Fault, beneath the historic workings. A further two diamond drill holes have been completed with a third

underway on the mine site. Cutting of core samples is underway and assay results will be reported in due

course.

A total of 10 holes were permitted in the initial program including the two holes with assays

reported above and all holes are scheduled to be completed by late September. The Company intends

to submit drilling permits for an enlarged drill program in the coming weeks. The company is digitizing

detailed underground assay maps that it has located for Zone 2 mineralisation (beneath the open pit)

and these will be used to guide future drilling to target polymetallic mineralization peripheral to the

historic underground workings which exploited high-grade Zn-Pb mineralization. There is good initial

evidence from a substantial amount of channel sampling along the underground drives that a lower-

grade halo surrounds the higher-grade mineralization and further drilling is aimed at validating the

remaining mineralization potential. The Qualified Person ("the "QP"), as defined under National

Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101"), has not done sufficient

work to classify the historical estimates as current mineral resources or mineral reserves and considers

the reported mineralization historical in nature. These results have not been fully verified by the QP as the

original core, assay certificates, and quality control data are partially unavailable to the Company. While

the Company believes these historic results are highly relevant to future exploration targeting in the area,

it is not treating the historical estimate as current mineral resources or mineral reserves and believes

that they should not be relied upon as a current representation of mineralization. Additional modern

drilling and data verification would be required to confirm these historical results. The reader should refer

to Notes and Disclosure on Historical Production at Tynagh in the Northmin announcement dated July

13, 2026.

Tailings Drilling Update

Northmin previously announced that it has received permission to conduct a 39-hole infill drilling program

across the tailings ponds at Tynagh with a permit determination that is valid until 08 June 2028.

The company has now completed drilling at 7 sites on the West Tailings Pond and 3 sites on the East

Tailings Pond with a Soilmec geotechnical rig to obtain fresh samples to use for future metallurgical

testing. The holes drilled on the West Pond were infill holes and sample material from those will also be

sent to ALS Minerals in Loughrea for geochemical analysis. The West Pond has a current (2026) NI 43-

101 resource in the inferred category totaling 2.69Mt at 3.56% Zn, 2.68% Pb, 0.23% Cu, 49ppm Ag and

21.6% BaO (28.8% BaSO

4

). It is expected that the new samples will contribute to upgrading a portion of

the inferred resource estimate to indicated category. The mineral resource in the East Tailings Pond is

already in the indicated category and is also NI 43-101 compliant. The company now has sufficient

material to advance the next phase of testwork on its Silver Tailings Recycling Project. We look forward

to providing further updates as results become available.

Exhibit 6. Soilmec Geotechnical Rig Recovering Tailings Samples from the West Pond at

Tynagh.

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/10660/310060_468b203a44ac1a0c_004full.jpg

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 and the previous announcement (13 July 2026) was HQ

(63.5mm) and was cut using a rock saw. Sample intervals vary between 0.4m to 2.05m with an average

(over 168 samples) of 1.03m. 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 for based

metals at the ALS facility was by method Prep-31, comprising fine crushing 70% < 2mm, riffle splitter,

pulverize up to 250g 85% < 75um. Analytical procedures are 48 element four acid ICP-MS (codes ME-

MS61). Over-limit analyses for Ag, Cu, Zn and Pb was by method ME-OG62. One sample exceeding

20% lead (Pb), 4 samples exceeding 1% Antimony (Sb) and three samples exceeding 1% arsenic (As)

content were analyzed by XRF by method ME-XRF15c.

Barium values were subsequently analyzed by XRF methods on pulps of 89 selected samples including

sufficient QAQC samples within the reported intersections. Hole 3615-26-06 was analyzed by method

Ba-XRF05SQ, a semi-quantitative cost-effective method, while samples from hole 3625-26-07 were

analyzed by method ME-XRF15b, a fusion XRF method. The Company intends to use method Ba-

XRF05SQ going forward for routine barium assays on samples with significant base metal

mineralization.

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. (TSX.V: 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 waste stockpile on the site and has previously

announced high-grade silver results from first pass sampling. The Company is also assessing the waste

stockpile on the site and 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.

ON BEHALF OF THE BOARD OF DIRECTORS

Julian Vickers

Chief Executive Officer

E:

[email protected]

|

T: 647.202.3904

E:

[email protected]

|

T: +353-86-392-1523

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