14 September 2026

Guardian Metal Resources plc

('Guardian Metal' or the 'Company')

 Tungsten Drilling Results Support Potential Resource Growth at Pilot Mountain

Guardian Metal Resources plc (NYSE.A: GMTL, LON: GMET, OTCQB: GMTLF), a strategic exploration and development company focused on tungsten in Nevada, USA, is pleased to announce positive tungsten drilling results from the newly discovered Tremor Zone and the previously untested Good Hope Zone both located on its 100%-owned Pilot Mountain tungsten project (“Pilot Mountain” or the “Project”) in Nevada. The drilling results provide further evidence of the potential to expand the mineralization identified at Pilot Mountain beyond the mineral resources incorporated into the recently completed Pre-Feasibility Study (“PFS”).

The Tremor Zone, a blind tungsten-skarn discovery announced on 4 June 2026, was identified by the Company's in-house technical team while drilling a target adjacent to the tailings storage facility ("TSF") proposed in the recently completed PFS. The drilling results achieved to date have prompted a  relocation of the planned TSF, which requires a revised design but is not expected to materially affect project costs or timeline.¹ Following the receipt of results from the discovery hole PMR26-077, follow-up drilling has been undertaken to test the Tremor Zone's extent along strike and at depth. In parallel, the Company has completed its first-ever drill holes at the Good Hope Zone, one of the Project's at-surface skarn targets that had, until now, remained untested by the Company.

Highlights

• Extensive tungsten mineralization confirmed over 200m strike distance at the Tremor Zone (north), with mineralization remaining open in multiple directions, providing future potential to supplement the Pilot Mountain mineral resources. Drill results for the Tremor Zone (south) are pending.

• Tremor Zone (north) significant downhole drill hole intersections included:
  • PM26-088: 64.15m @ 0.20% WO3 from 139.97m, including:

-          14.27m @ 0.34% WO3 from 147.68m;

• PMR26-078: 15.20m @ 0.28%WO3 from 259.08m;

• PM26-090: 5.11m @ 0.34% WO3 from 101.19m.

• PM26-097 intersected several zones of tungsten mineralization, including

-          16.60m @ 0.19% WO3 from 53.23m downhole including 10.77m @ 0.23% WO3 from 59.06m;

-          44.08m @ 0.18% WO3 from 86.03m downhole including 6.17m @ 0.22% WO3 from 86.03m, and also including 10.84m @ 0.27% WO3 from 111.42m; and,

-          6.68m @ 0.23% WO3 from 144.72m.

• Good Hope Zone drilling returned multiple tungsten drill intersections from near surface, located within 1.1 to 1.3km of the existing Pilot Mountain mineral resource areas. Good Hope downhole drill hole intersections included:
  • GH26-01: 12.95m @ 0.79% WO3 from 12.19m;
  • GH26-02: 13.11m @ 0.42% WO3 from 2.13m. GH26-01 and GH26-02 were twinned holes, with the latter being drilled to recover the upper part of the zone and together they represent a combined apparent thickness of 23 meters which carries an average grade of 0.58% WO3; and,
  • GH26-07: 13.32m @ 0.15% WO3 from 65.84m.

Notes: No Mineral Resource Estimate has been prepared for the Tremor Zone or the Good Hope Zone and further drilling and evaluation will be required to determine their significance to the broader Pilot Mountain Project. Significant mineralized intersections of 5m apparent width at or above the PFS Desert Scheelite and Garnet deposit Mineral Resource Estimate cut-off grade of 0.04% WO3 are summarized in Table 1 and Table 2. Drill collar locations are stated in Table 3 and shown in Figure 1.

Oliver Friesen, CEO of Guardian Metal, commented: 

"We have always maintained that Pilot Mountain has significant exploration upside, and these results reinforce the potential to expand tungsten mineralization beyond the mineral resources that underpin our recently completed Pre-Feasibility Study. The Tremor Zone did not form part of the PFS mineral resource, yet drilling continues to highlight meaningful size and scale, with mineralization remaining open in multiple directions. This has been sufficient for us to relocate the proposed TSF and preserve the option to incorporate the Tremor Zone into a future mine plan. At the Good Hope Zone, the first holes ever drilled have returned strong tungsten grades from surface, close to the existing resource areas.

"With numerous exploration targets still to be drill tested, we see potential to add further tungsten resources, subject to further drilling and evaluation, while the DFS, engineering and permitting advance in parallel and at pace as we work to make Pilot Mountain the first new tungsten mine on U.S. soil in over a decade."

Further Details

Tremor Zone

The Tremor Zone is a blind tungsten-skarn discovery that is obscured by alluvial cover with no direct surface outcrop. Mineralization was identified during condemnation drilling completed within an area that was under consideration as a location for the TSF. The initial discovery drillhole, PMR26-077 (reported on 4 June 2026), intersected five distinct zones of tungsten-rich skarn mineralisation.1

To date, 8,140 meters across 37 holes of combined core and reverse circulation (“RC”) drilling targeting the Tremor Zone and other condemnation targets has been completed, with the majority of Tremor Zone assays still pending. Mineralization has been confirmed in two separate areas, the northern and southern Tremor Zones, with drilling to date focused on the northern zone. Within the northern zone, mineralization has been confirmed over ~200m of strike extent and ~190m of dip extent and mineralization remains open in multiple directions. Results are still pending for the southern zone which has been intersected in one hole located 180m south of the northern zone and remains open for extension in multiple directions.

The Tremor Zone is located within a part of the Pilot Mountain Project that is royalty free. While the Tremor Zone was not incorporated into the PFS, the Company has retained flexibility within its infrastructure planning to allow for its potential inclusion in future studies, subject to further drilling and technical evaluation.

Good Hope Zone

The Good Hope Zone is one of the Project's at-surface tungsten skarn zones, which had been identified as offering resource growth potential. Mineralization is exposed in a window below younger Tertiary volcanics and is hosted in east-west striking, gently north-dipping beds of Luning Formation limestone adjacent to a large body of quartz monzonite intrusion, which is the causative intrusive phase across Pilot Mountain. The Good Hope Zone is located ~1.3km north of the Desert Scheelite resource area and ~1.1km east of the Garnet resource area. Mineralization at the Good Hope Zone has been defined over a strike length of ~100m starting from surface and down dip for ~65 meters. Mineralization is bound on the west by post-mineral faulting, which opens exploration and expansion potential seeking the offset portion of the zone.

The inaugural drill programme at the Good Hope Zone comprised 1,682m of combined core and RC drilling across 13 holes. Results confirm near surface high-grade mineralization and the potential to add new mineral resources in the future.

Assay Results and Collar Table

Table 1: Tremor Zone Significant Downhole Intersections

Table 2: Good Hope Zone Significant Downhole Intersections

Holes PMR26-081 through PMR26-087, 091, 093 and 094 totaling 2,200 meters were drilled as condemnation holes to target infrastructure areas and confirmed no additional mineralization was present. PMR26-080, PM26-089, 092, 095 and GH26-03 through 05 and RGH-01 through 03 were Tremor or Good Hope Zone exploration step-out holes totaling 1,999m drilled that did not intercept mineralization above a material grade and thickness cut-off of 5m at 0.04% WO3. PM26-096 intercepted significant visual scheelite mineralization and assays are still pending.

Table 3: Drill Hole Collar Table for Holes with Significant Downhole Intersections

Quality Control and Assurance

All samples were submitted to MSA Labs (MSA) of Elko, Nevada which is an ISO9001 and ISO/IEC 17025 accredited laboratory. Samples were analyzed using method ICP-230, with any samples returning >450 ppm W being re-run using lithium borate fusion XRF analyses method. Guardian Metal’s QA/QC program includes regular insertion of standards, duplicates and blanks into the sample stream with stringent review of all results.

Figure 1: Map of Drill Holes Showing Planned PFS Pits, Mine Infrastructure, Waste Rock Storage Facility and Revised Tailings Storage Facility Locations

Figure Notes: Garnet Pit and Desert Scheelite Pit outlines represent the extents of the planned open pits modelled in the recent Pre-Feasibility Study. WRSF = Waste Rock Storage Facility. TSF = Tailings Storage Facility.

References

1 Company announcement, Discovery of Tremor Zone at Pilot Mountain Tungsten Project, dated 4 June 2026
( https://polaris.brighterir.com/public/guardian_metal_resources/news/rns/story/xlnlypw )

2 Company announcement, U.S. Department of Defense Awards US$6.2M to Golden Metal Resources for the Pilot Mountain Project, dated 23 July 2025
( https://polaris.brighterir.com/public/guardian_metal_resources/news/rns/story/wvm0n3w )

COMPETENT PERSON STATEMENT

The technical information contained in this disclosure has been read and approved by Mr Nicholas O'Reilly (MSc, DIC, MIMMM QMR, MAusIMM, FGS), who is a qualified geologist and acts as the Competent Person under the AIM Rules - Note for Mining and Oil & Gas Companies. Mr O'Reilly is a Principal consultant working for Mining Analyst Consulting Ltd which has been retained by Guardian Metal Resources plc to provide technical support.

This announcement contains inside information for the purposes of Article 7 of EU Regulation 596/2014 (which forms part of domestic UK law pursuant to the European Union (Withdrawal) Act 2018). The Directors of the Company are responsible for this announcement.

Forward Looking Statements

This announcement contains forward-looking statements relating to expected or anticipated future events and anticipated results that are forward-looking in nature and, as a result, are subject to certain risks and uncertainties, including general economic, market and business conditions, competition for qualified staff, the regulatory process and actions, technical issues, new legislation, potential delays or changes in plans, uncertainties resulting from operating in a new political jurisdiction, uncertainties regarding the results of exploration, the timing and granting of prospecting rights, the timing and granting of regulatory and other third party consents and approvals, Guardian Metal’s or any third party’s ability to execute and implement future plans, and the occurrence of unexpected events.

Forward-looking statements are subject to risks and uncertainties, including those described in the Company’s filings with the U.S. Securities and Exchange Commission. Guardian Metal undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required by law.

This announcement does not purport to be full or complete. No reliance may or should be placed by any person for any purpose on the information contained in this announcement or its accuracy, fairness or completeness. The information in this announcement is subject to change.

For further information visit www.Guardianmetalresources.com or contact the following:

About Guardian Metal Resources 

Guardian Metal Resources PLC (NYSE.A: GMTL, LON:GMET, OTCQB:GMTLF) is a strategic mineral exploration company driving the revival of U.S. mined tungsten production and strengthening America's defense metal independence. The Company is advancing two co-flagship tungsten projects, Pilot Mountain, one of the largest undeveloped tungsten deposits in the U.S. and Tempiute, formerly America's largest producing tungsten operation, both located in Nevada, one of the top-rated mining jurisdictions in the United States.

In July 2025, the U.S. Department of War (DoW) under Title III of the Defense Production Act of 1950, as amended, invested US$6.2M in Golden Metal Resources (USA) LLC, a wholly-owned subsidiary of Guardian Metal Resources PLC, to support the Pilot Mountain PFS.2 The Company completed a U.S. listing on the NYSE American on March 20, 2026. 

Tungsten is a strategic metal critical to the defense, energy transition, technology and industrial sectors. In the context of shifting geopolitical dynamics and tightening Chinese export restrictions, Guardian Metal is well positioned to play a leading role in re-establishing a secure, domestically mined U.S. supply chain for this vital defense metal.