World's Largest Pollucite-Hosted Caesium Pegmatite Mineral Resource Defined at Shaakichiuwaanaan

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Rigel and Vega confirmed as a major caesium discovery with potential to be a significant supply source for global markets, including the next wave of terrestrial solar technologies

MONTREAL, July 21, 2025 /PRNewswire/ -- SYDNEY, Australia - July 21, 2025

HIGHLIGHTS

World's largest pollucite-hosted caesium pegmatite deposit confirmed at the Shaakichiuwaanaan Project, with a maiden Mineral Resource Estimate ("Caesium Zone MRE") of: Rigel Caesium Zone Indicated: 163,000 t at 10.25% Cs2O, 1.78% Li2O, and 646 ppm Ta2O5. Vega Caesium Zone Indicated: 530,000 t at 2.61% Cs2O, 2.23% Li2O, and 172 ppm Ta2O5. Inferred: 1,698,000 t at 2.40% Cs2O, 1.81% Li2O, and 245 ppm Ta2O5. Total contained caesium content of 30.5 kt Cs2O Indicated and 40.8 kt Cs2O Inferred, highlighting the scale and global significance of the discovery. Caesium resources in the Rigel and Vega zones are now included within the CV13 Pegmatite open-pit resource that forms part of the Company's consolidated MRE for the Project (including both the CV5 and CV13 pegmatites) ("Consolidated MRE") - that has been updated and restated as follows: Indicated: 108.0 Mt at 1.40% Li2O, 0.11% Cs2O, 166 ppm Ta2O5, and 66 ppm Ga. Inferred: 33.4 Mt at 1.33% Li2O, 0.21% Cs2O, 155 ppm Ta2O5, and 65 ppm Ga. Caesium is a high-value, rare, and critical mineral which is currently supply constrained with only limited sources supplying the global market1. A discovery of this size, grade, and scale has the potential to be a primary source of supply for the global market, including new and potentially growing applications in emerging next generation terrestrial solar panel applications where caesium has been found to play a vital role in significantly improving panel efficiency, stability, and life span. The Company has commenced evaluating options (including a scoping metallurgical program to test pollucite recovery using conventional X-ray ore sorting methods) to advance and incorporate the caesium opportunity at CV13 as a potential additional saleable product into the overall economic development of the Project - to follow completion of the lithium-only Feasibility Study on the CV5 Pegmatite. The Company remains on track to deliver a maiden Ore Reserve and Feasibility Study for lithium at the CV5 Spodumene Pegmatite in CYQ3-2025.

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1 Mineral deposits of pollucite-hosted caesium are extremely rare globally and represent the most fractionated component of LCT pegmatite systems, which are effectively the only primary and economic source of caesium globally. The Company is aware of only three previous pollucite-hosted caesium mines with Bikita in Zimbabwe and Sinclair in Western Australia now reportedly exhausted and Tanco in Manitoba, Canada, approaching the end of its mine-life.

Darren L. Smith, Executive and Vice President of Exploration for the Company, comments: "At Shaakichiuwaanaan, we have now defined the largest reported occurrence of pollucite in the world - by a significant margin. To find a pollucite-hosted caesium deposit of this scale and grade is exceptionally rare, with only three deposits globally known to have produced this extremely high-value critical and strategic mineral."

"The pegmatites of the Shaakichiuwaanaan Project continue to demonstrate their unique, world-class nature for hosting abundant and varied critical minerals. With considerable Mineral Resources for lithium, tantalum, gallium, and now caesium defined - and a Feasibility Study for lithium at CV5 on schedule for completion this quarter - the Company is becoming increasingly well-positioned as an emerging critical minerals powerhouse to global markets."

Ken Brinsden, President, CEO, and Managing Director, comments: "This is another feather in the cap of our technical team, led by Darren, with their hard work resulting in yet another world-class discovery at Shaakichiuwaanaan. What stands out is the sheer scale and grade of this caesium discovery, relative to anything that's been found before globally.

It's also a reflection of the extraordinary geology of this deposit, which hosts lithium, tantalum, and now caesium - all high-value critical minerals - at world-class scale. Given the scale, grade, and proximity to the CV5 Pegmatite, the new caesium discovery at Rigel and Vega has already added further substantial value to the Shaakichiuwaanaan Project."

"What is particularly exciting for investors is that the addressable market for caesium appears to be at a key inflexion point, with its ability to improve the efficiency and stability of next generation terrestrial solar technologies having the potential to drive a massive increase in global demand. Shaakichiuwaanaan stands to play a driving role in the growth of this exciting new market. As we finalize the maiden lithium-only Feasibility Study for the CV5 Pegmatite, we are excited to start work on unlocking the enormous potential of the caesium resource, now outlined to NI 43-101 and JORC standards, for our shareholders," added Mr. Brinsden.

PATRIOT BATTERY METALS INC. (THE "COMPANY" OR "PATRIOT") (TSX: PMET) (ASX: PMT) (OTCQX: PMETF) (FSE: R9GA) is pleased to announce a maiden Mineral Resource Estimate for caesium (the "Caesium Zone MRE") at the Rigel and Vega zones at its 100%-owned Shaakichiuwaanaan Property (the "Property" or "Project") located in the Eeyou Istchee James Bay region of Quebec. The Rigel and Vega zones are hosted within the CV13 Pegmatite, which is located ~3 km west-southwest along geological trend of the CV5 Pegmatite that is accessible year-round by all-season road, and is situated ~13 km south of the all-weather Trans-Taiga Road and powerline corridor.

The Company has now confirmed that the Shaakichiuwaanaan Project hosts the world's largest pollucite-hosted caesium pegmatite deposit (Figure 1, Figure 2, Figure 3, Table 2) after declaring a maiden Caesium Zone MRE of:

Rigel Caesium Zone Indicated: 163,000 t at 10.25% Cs2O, 1.78% Li2O, and 646 ppm Ta2O5. Vega Caesium Zone Indicated: 530,000 t at 2.61% Cs2O, 2.23% Li2O, and 172 ppm Ta2O5. Inferred: 1,698,000 t at 2.40% Cs2O, 1.81% Li2O, and 245 ppm Ta2O5. The Caesium Zone MRE for Rigel and Vega, hosted within the open-pit resource component of the CV13 Pegmatite - which forms part of the Company's Consolidated MRE for the Project (including both the CV5 and CV13 pegmatites) - has a total contained caesium metal content of 30.5 kt Cs2O Indicated and 40.8 kt Cs2O Inferred. The Rigel and Vega zones were interpreted using a 0.50% Cs2O grade constraint based on mineral processing analogues and mineralogical analysis supporting pollucite as the predominant Cs-bearing mineral present. Coincident with the pollucite-hosted caesium at Rigel and Vega is high-grade lithium and tantalum, present in the host minerals spodumene and tantalite, respectively, which may be co-recovered as separate concentrates.

The footprint of caesium mineralization at Rigel has been traced over a general area of at least 200 m x 100 m and consists of a single, shallow dipping lens at a depth of ~50 m with a true thickness of

The Consolidated MRE2, which includes the Rigel and Vega caesium zones, was most recently announced on May 12, 2025; however, that has now been updated and restated herein this announcement with the inclusion of caesium reporting as part of the overall consolidated resources for the CV5 and CV13 pegmatites.

The restatement of the Consolidated MRE also includes a minor adjustment to the tonnage and tantalum grade at the CV13 Pegmatite. The Consolidated MRE is as follows (Table 1).

Indicated: 108.0 Mt at 1.40% Li2O, 0.11% Cs2O, 166 ppm Ta2O5, and 66 ppm Ga. Inferred: 33.4 Mt at 1.33% Li2O, 0.21% Cs2O, 155 ppm Ta2O5, and 65 ppm Ga.

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2 The Consolidated MRE cut-off grade is variable depending on the mining method and pegmatite (0.40% Li2O open-pit, 0.60% Li2O underground CV5, and 0.70% Li2O underground CV13). A grade constraint of 0.50% Cs2O was used to model the Rigel and Vega caesium zones, which are entirely within the CV13 Pegmatite's open-pit mining shape. The Effective Date of the MREs is June 20, 2025 (through drill hole CV24-787). Mineral Resources are not Mineral or Ore Reserves as they do not have demonstrated economic viability.

ABOUT CAESIUM

Mineral deposits of pollucite-hosted caesium are extremely rare globally and represent the most fractionated component of LCT pegmatite systems, which are effectively the only primary economic source of caesium globally. Economic deposits of caesium pegmatite are typically on a smaller scale of

Globally, it is estimated only three (3) primary caesium mines have historically operated and all were pollucite hosted - Tanco (Canada), Bikita (Zimbabwe), and Sinclair (Australia). At Bikita and Sinclair, the pollucite resources are reportedly to have been exhausted in 2018 and 2019, respectively. Tanco is understood to be approaching the end of its mine-life with extraction from existing tailings piles and/or mine remnants being explored. At Sinclair3, the mine produced 18,629 tonnes of pollucite pegmatite ore grading 8.3% Cs2O for a contained metal content of 1,551 tonnes Cs2O. In comparison to the size of the interpreted caesium zones at Vega (~800 m x 250 m) and Rigel (~200 m x 100 m), the primary ore body at Sinclair was relatively small and measured ~60 m long, up to 20 m wide, and up to 10 m thick, and was situated at a depth~40 m from surface.

The market for caesium compounds and metals is largely opaque because it is not publicly traded like copper or gold, but rather through bi-lateral and term contracts. Further, prices vary depending on its contained caesium form, purity and end-product use. Caesium carbonate (Cs2CO3≥99%) currently trades at approximately US$120/kg, however in its refined form caesium metal (Cs >99.5%), is a high value commodity comparable to gold and currently trades around US$2,540/oz (or ~US$81 per gram4) (excluding VAT, Price Sourcing - Shanghai Metal Markets).

Caesium is currently supply constrained, with only limited sources supplying the global market. A discovery of this size, grade, and scale has the potential to be a primary source of supply for global markets. This includes existing applications for caesium in oil/gas drilling, medical imaging and now new and potentially growing applications in the terrestrial solar panel industry which has the potential to drive a significant increase in global demand. Caesium has been found to play a vital role in significantly improving next generation solar panel efficiency, stability, and life span through the application of perovskite crystal structures.

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3 Management cautions that past results or discoveries on other mineral properties or mines owned by third parties (i.e., Tanco, Bikita, Sinclair) may not necessarily be indicative to the presence of mineralization on the Company's properties or the economic viability of any such mineralization. There can be no assurance that future exploration efforts will result in the identification of additional mineral resources or reserves, or that the estimate of mineral resources reported within will be economically extracted in the future.

4 Assumes conversion from troy ounce.

NEXT STEPS

With the maiden MRE for the Rigel and Vega caesium zones now completed, the Company is actively evaluating options to advance and incorporate the caesium opportunity at CV13 as a potential additional saleable product into the overall economic development of the Project - to follow completion of the lithium-only Feasibility Study on the CV5 Pegmatite.

This includes completing various environmental baseline studies and additional drilling to further convert Inferred Resources to the Indicated category and in support of future development (e.g. geomechanical drill holes). Additionally, the Company has commenced industry engagement with end users of caesium as well as initiated a scoping metallurgical program targeting pollucite mineral recovery using conventional X-ray ore sorting methods, which will inform a more expansive test program that will also include subsequent recovery of spodumene (lithium) and tantalite (tantalum). The scoping metallurgical program is using mineralized drill core collected from the Vega Caesium Zone with subsequent testwork to expand to the Rigel Caesium Zone.

In addition, the Company is also focused on completion of the remaining deliverables for its lithium-focused Feasibility Study on the CV5 Pegmatite. The Feasibility Study is well advanced and remains on schedule for completion in CYQ3-2025, with the Company recently announcing an update on its progress on March 18, 2025.

Figure 1: Plan view footprints of the Vega and Rigel caesium zone geological models based on a 0.5% Cs2O grade constraint within the wider CV13 Pegmatite body. (CNW Group/Patriot Battery Metals Inc.)

Figure 2: Tonnage vs grade chart highlighting Rigel and Vega caesium zones as the largest pollucite-hosted caesium pegmatite Mineral Resource in the world. Mineral Resource data sourced through July 11, 2025, from corporate disclosure. Deposit/Project data presented includes the total caesium zone resource tonnage. Mineral Resources are presented on a 100% basis. Data is presented for all documented in-situ pollucite-hosted caesium pegmatite deposits/projects to the knowledge of the Company. See Appendix 2 for further details and supporting information. (CNW Group/Patriot Battery Metals Inc.)

Figure 3: Pollucite mineralization in high-grade caesium drill intersection at ~64.5 m depth in drill hole CV23-271 at the Rigel Zone, CV13 Pegmatite. Interval grades(5) 22.69% Cs2O over 1.0 m (64.0 m to 65.0 m) with XRD-Rietveld reporting a pollucite content over the interval of 58%. [ (5) Refer to news release dated April 9, 2025. ] (CNW Group/Patriot Battery Metals Inc.)

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5 Refer to news release dated April 9, 2025.

MINERAL RESOURCE STATEMENT (NI 43-101)

Table 1: Consolidated Mineral Resource Statement for the Shaakichiuwaanaan Project.

Conceptual

Mining

Constraint

Pegmatite

Classification

Tonnes

(t)

Li2O

(%)

Cs2O

(%)

Ta2O5

(ppm)

Ga

(ppm)

Contained

LCE

(Mt)

Open-Pit

CV5

Indicated

97,757,000

1.39

0.09

163

66

3.35

Underground

4,071,000

1.08

0.06

186

66

0.11

Total

101,828,000

1.38

0.09

164

66

3.46

Open-Pit

CV5

Inferred

5,745,000

1.16

0.09

163

61

0.17

Underground

8,153,000

1.24

0.07

136

60

0.25

Total

13,898,000

1.21

0.08

147

60

0.41

Open-Pit

CV13

Indicated

5,996,000

1.89

0.60

201

76

0.28

Underground

167,000

0.85

0.06

132

60

0.00

Total

6,163,000

1.86

0.59

199

76

0.28

Open-Pit

CV13

Inferred

18,020,000

1.44

0.32

168

70

0.64

Underground

1,462,000

1.05

0.08

75

55

0.04

Total

19,482,000

1.41

0.30

161

69

0.68

CV5 +

CV13

Indicated

107,991,000

1.40

0.11

166

66

3.75

Inferred

33,380,000

1.33

0.21

155

65

1.09

Table 2: Mineral Resources at the Rigel and Vega Caesium Zones within the CV13 Pegmatite.

Caesium

Zone

Classification

Tonnes

(t)

Cs2O

(%)

Li2O

(%)

Ta2O5

(ppm)

Contained

Cs 2 O

(t)

Rigel

Indicated

163,000

10.25

1.78

646

16,708

Inferred

-

-

-

-

-

Vega

Indicated

530,000

2.61

2.23

172

13,833

Inferred

1,698,000

2.40

1.81

245

40,752

Rigel + Vega

Indicated

693,000

4.40

2.12

283

30,541

Inferred

1,698,000

2.40

1.81

245

40,752

Mineral Resources were prepared in accordance with National Instrument 43-101 - Standards for Disclosure of Mineral Projects ("NI 43-101") and the CIM Definition Standards (2014). Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. This estimate of Mineral Resources may be materially affected by environmental, permitting, legal, title, taxation, sociopolitical, marketing, economic, or other relevant issues. The independent Competent Person (CP), as defined under JORC, and Qualified Person (QP), as defined by NI 43-101 for this resource estimate is Todd McCracken, P.Geo., Director - Mining & Geology - Central Canada, BBA Engineering Ltd. The Effective Date of the estimate is June 20, 2025 (through drill hole CV24-787). Estimation was completed using a combination of inverse distance squared (ID2) and ordinary kriging (OK) for CV5 and inverse distance squared (ID2) for CV13 in Leapfrog Edge software with dynamic anisotropy search ellipse on specific domains. Drill hole composites at 1 m in length. Block size is 10 m x 5 m x 5 m with sub-blocking. Both underground and open-pit conceptual mining shapes were applied as constraints to the Consolidated MRE Statement to demonstrate reasonable prospects for eventual economic extraction. Cut-off grades for open-pit constrained resources are 0.40% Li2O for both CV5 and CV13, and for underground constrained resources are 0.60% Li2O for CV5 and 0.70% Li2O for CV13. Open-pit and underground Mineral Resource constraints are based on a long-term average spodumene concentrate price of US$1,500/tonne (6% basis FOB Bécancour) and an exchange rate of 0.70 USD/CAD. Mineral Resources for the Rigel and Vega zones are hosted within the CV13 Pegmatite's open-pit conceptual mining shape and, therefore, are included within the Consolidated Mineral Resource Statement for CV5 and CV13 pegmatites. The Rigel and Vega zones were interpreted using a 0.50% Cs2O grade constraint based on mineral processing analogues and mineralogical analysis supporting pollucite as the predominant Cs-bearing mineral present. Rounding may result in apparent summation differences between tonnes, grade, and contained metal content. Tonnage and grade measurements are in metric units. Conversion factors used: Li2O = Li x 2.153; LCE (i.e., Li2CO3) = Li2O x 2.473, Ta2O5 = Ta x 1.221, Cs2O = Cs x 1.0602 Densities for pegmatite blocks (both CV5 & CV13) were estimated using a linear regression function (SG = 0.0674x (Li2O% + 0.81 x B2O3%) + 2.6202) derived from the specific gravity ("SG") field measurements and Li2O grade. Non-pegmatite blocks were assigned a fixed SG based on the field measurement median value of their respective lithology. SENSITIVITY ANALYSIS

The following Table 3 and Figure 4 outline the corresponding tonnage and caesium grade at various cut-off grades for the Caesium Zone MREs, hosted within the CV13 Pegmatite and the Consolidated MRE. In addition to evaluating sensitivities to cut-off grades, this table can help relate the tonnage and grades at Shaakichiuwaanaan more directly to those calculated for peer deposits, which may have applied different cut-off grades to their resources.

Table 3: Sensitivity Analysis for Caesium at the Rigel and Vega Zones.

Table 3: Sensitivity Analysis for Caesium at the Rigel and Vega Zones. [ 1. This table should not be interpreted as a Mineral Resource. The data is presented to demonstrate the tonnage and grade sensitivity to various cut-off grades. The selected grade constraint for modelling the Rigel and Vega caesium zones was 0.50% Cs2O. / 2. Errors may occur in totals due to rounding. ] (CNW Group/Patriot Battery Metals Inc.)

1.

This table should not be interpreted as a Mineral Resource. The data is presented to demonstrate the tonnage and grade sensitivity to various cut-off grades. The selected grade constraint for modelling the Rigel and Vega caesium zones was 0.50% Cs2O.

2.

Errors may occur in totals due to rounding.

Figure 4: Grade-tonnage curves for the Rigel and Vega Caesium Zone MREs at the CV13 Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

GEOLOGICAL AND BLOCK MODELS

The Rigel and Vega caesium zones have been geologically modelled using a 0.50% Cs2O grade constraint within the wider CV13 Pegmatite body (Figure 1). The grade constraint is supported by mineralogical analysis that confirms pollucite as the predominant caesium-bearing mineral above this threshold and which may be recoverable using well-understood mineral processing methods. These geological models acted as hard boundaries within the wider CV13 Pegmatite body for subsequent block modelling and resource estimation.

Using the 0.5% Cs2O grade constraint, the footprint of caesium mineralization at Rigel has been traced over a general area of at least 200 m x 100 m and consists of a single, shallow dipping lens at a depth of ~50 m with a true thickness of

The geological and block models, classification, and sections for the Rigel and Vega zones are presented in Figure 5 through Figure 10. Respective figures for the CV13 and CV5 pegmatites are presented in the Company's news release dated May 12, 2025, as well as Figure 11 to Figure 14 for ease of reference herein.

Rigel and Vega Caesium Zones

Figure 5: Plan view of the Rigel and Vega caesium zones at the CV13 Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

Figure 6: Plan view of the Indicated (green) and Inferred (blue) block model classifications for the Rigel and Vega caesium zones at the CV13 Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

Figure 7: Oblique view of the Rigel and Vega caesium zone block models within the conceptual open-pit mining constraint shape for the CV13 Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

Figure 8: Oblique view of the Rigel and Vega caesium zone block models within the conceptual open-pit mining constraint shape for the CV13 Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

Figure 9: Simplified cross-section of the Rigel Caesium Zone geological model at the CV13 Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

Figure 10: Simplified cross-section of the Vega Caesium Zone geological model at the CV13 Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

CV13 Pegmatite

Figure 11: Oblique view of the CV13 Spodumene Pegmatite block model (classified & constrained) with respect to applied open-pit and underground conceptual mining constraint shapes. (CNW Group/Patriot Battery Metals Inc.)

Figure 12: Plan view of the global Indicated (green) and Inferred (blue) block model classifications for the CV13 Spodumene Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

CV5 Pegmatite

Figure 13: Oblique view of the CV5 Spodumene Pegmatite block model with respect to applied open-pit and underground conceptual mining constraint shapes. (CNW Group/Patriot Battery Metals Inc.)

Figure 14: Oblique view of the global Indicated (green) and Inferred (blue) block model classifications for the CV5 Spodumene Pegmatite. (CNW Group/Patriot Battery Metals Inc.)

ASX LISTING RULE 5.8

As the Company is listed on both the Toronto Stock Exchange (the "TSX") as well as the Australian Securities Exchange (the "ASX"), there are two applicable regulatory bodies resulting in additional disclosure requirements. This MRE has been completed in accordance with the Canadian National Instrument 43-101 - Standards of Disclosure for Mineral Projects. Additionally, in accordance with ASX Listing Rule 5.8 and the JORC 2012 reporting guidelines, a summary of the material information used to estimate the Mineral Resource for the Rigel and Vega caesium zones at the Shaakichiuwaanaan Project is detailed below. For additional information, please refer to JORC Table 1, Section 1, 2, and 3, as presented in Appendix 1 of this announcement.

As the change in lithium, tantalum, and gallium Mineral Resources for the Consolidated MRE, which includes both the CV5 and CV13 pegmatites, is considered not a material change (as presented herein Table 1), the detailed summary, figures/diagrams, and technical parameters applied