Guardian Metallic Sources PLC Pronounces Pilot Mountain Pre-Feasibility Progress Replace

Maiden S-Okay 1300 Technical Abstract Report Delivers 16% Improve in Open Pit Constrained Indicated Mineral Sources vs 2018 Scoping Examine; Drilling Ongoing

LONDON, UK / ACCESS Newswire / December 19, 2025 / Guardian Metallic Sources plc (‘Guardian Metallic’ or the ‘Firm’) (LON:GMET)(OTCQB:GMTLF), a strategic exploration firm centered on tungsten in Nevada, USA, is happy to announce the submission to the SEC of a S-Okay 1300 Technical Abstract Report (“TRS”) and up to date Mineral Useful resource Estimate (“Useful resource” or “MRE”) on the 100%-owned Pilot Mountain tungsten Venture (“Pilot Mountain” or the “Venture”) situated in Nevada, USA. Importantly, in accordance with Regulation S-Okay 1300 17 CFR Half 229 Subpart 229.1300 (“S-Okay 1300”), the up to date MRE is pit-constrained and subsequently doubtlessly appropriate for open-pit mining, providing a possible pathway to improvement and positioning the Firm, topic to allowing, financing and additional technical work, to help the event of a domestically mined supply of tungsten in america for the primary time in additional than a decade. The TRS may also underpin the technical disclosures required for the Firm’s deliberate itemizing on a U.S. securities change.

Tungsten is a key defence and industrial metallic and has been designated as a strategic precedence by the U.S. authorities. Guardian Metallic’s mission is to convey into manufacturing two of its tungsten initiatives, Pilot Mountain and Tempiute, because the cornerstone of U.S. tungsten provide, straight supporting nationwide efforts to reshore mined manufacturing. Considerably, this could mark a serious step within the U.S. effort to scale back reliance on international provide chains and reinforce financial and defence safety, laying the groundwork for sturdy, long-term worth creation.

The TRS, dated 15 December 2025, was ready by the Certified Particular person RESPEC Firm LLC (“RESPEC “) of Speedy Metropolis, South Dakota, USA in accordance with america Securities and Change Fee (“SEC”) necessities below S-Okay 1300 and will probably be publicly obtainable by way of the SEC Digital Knowledge Gathering, Evaluation and Retrieval (EDGAR) system sooner or later.

Oliver Friesen, CEO of Guardian Metallic, commented:

“Supported by the U.S. Division of Struggle’s US$6.2 million Protection Manufacturing Act (DPA) Title III funding in Guardian Metallic’s wholly-owned subsidiary, Golden Metallic Sources (USA) LLC, we’re making sturdy progress towards finishing the Pre-Feasibility Examine (“PFS”) and advancing in direction of our aim of delivering the primary new mined supply of tungsten on U.S. soil in additional than a decade.

“The inaugural pit-constrained Mineral Useful resource for Desert Scheelite, ready in accordance with S-Okay 1300, represents the end result of over 12 months of diligent drilling accomplished by our in-country Nevada-based operations workforce. This Useful resource, which features a 16% improve in pit constrained Indicated tonnage, establishes a stable basis for future useful resource progress, and, extra importantly, represents an necessary step in supporting a possible U.S. itemizing.¹

“Concurrently, drilling is ongoing at Desert Scheelite, focusing on a number of areas that stay open for growth. A second drill rig has been secured and is scheduled to mobilise early within the New 12 months, enabling an expanded drill programme at Desert Scheelite in addition to a number of different underexplored tungsten zones throughout the Venture together with the Garnet Zone. Outcomes from this work are anticipated to be included right into a future MRE replace, which can underpin the progressing PFS.

“Now greater than ever, the Firm believes that america requires a safe domestically mined supply of tungsten, and Guardian Metallic is firmly centered on delivering that consequence.”

Marc Leduc, P.Eng., Operations Supervisor of Guardian Metallic, commented:

“Preparation of the Pre-Feasibility Examine continues to advance effectively. All key technical and engineering research required to help the PFS are at the moment underway, together with mine planning, metallurgy, infrastructure research, hydrogeological drilling, and environmental baseline research to help mine allowing.

“The outcomes of those workstreams will probably be built-in right into a complete improvement plan, which can kind the premise of the Venture’s Mine Plan of Operations and underpin the allowing pathway and subsequent mine improvement actions.”

MAIDEN S-Okay 1300 MINERAL RESOURCE AND PFS PROGRESS

• The Firm has efficiently accomplished its first MRE ready in accordance with S-Okay 1300 at Desert Scheelite, representing solely one of many Venture’s 4 identified at-surface tungsten-rich skarn zones. The PFS is advancing effectively with a extremely certified multi-disciplined specialist workforce.

• The institution of the Venture’s first ever Useful resource, ready in accordance with S-Okay 1300, represents a key milestone because the Firm builds in direction of a possible itemizing on a U.S. securities change.¹

• The Useful resource was accomplished by RESPEC Firm LLC – an skilled specialist mining engineering agency primarily based in Speedy Metropolis, South Dakota and Reno, Nevada (Desk 1).

• Importantly, the Useful resource incorporates knowledge from 68 drillholes at Desert Scheelite accomplished by the Firm. For the reason that MRE knowledge cutoff of October 20, 2025, an additional eight drillholes have been accomplished, with extra drilling deliberate to additional check extensions of Desert Scheelite the place the Useful resource stays open alongside strike (east and west) and down dip. These just lately accomplished and future deliberate drillholes will probably be included into an additional up to date MRE anticipated previous to completion of the PFS.

• The MRE replace will embody a latest intercept in drillhole PM25-065 which returned a 26.8m intersection (from 172.17m – 198.97m) with one of many strongest visible (below ultra-violet mild) intersections of scheelite (CaWO₄) mineralisation famous by the Firm on the Venture up to now.

• To help the deliberate 2026 MRE, the Firm has secured a second exploration drill rig, scheduled to reach on web site early in 2026. This extra rig will allow the testing of a number of identified at-surface tungsten zones throughout the Venture that haven’t but been adequately drill tested-including at Desert Scheelite and the Garnet Zone-and may also present extra capability for additional engineering-related drilling.

• The PFS, supported by a US $6.2m DoW DPA III funding in Guardian Metallic’s wholly-owned subsidiary, Golden Metallic Sources (USA) LLC², is progressing effectively and is being led by the Firm’s Operations Supervisor, Marc Leduc, P.Eng., a extremely skilled mine builder. Mr. Leduc and the Firm’s technical workforce are joined by a bunch of extremely skilled companions who’re engaged to progress the varied ongoing PFS workstreams together with:

  • Samuel Engineering, Inc. (Denver, Colorado)*: General PFS lead, metallurgy, course of engineering and plant design, monetary modelling and remaining report preparation.

  • RESPEC Firm LLC (Speedy Metropolis, South Dakota and Reno, Nevada): Useful resource modelling, geotechnical engineering and mine design.

  • KTW Environnemental (Boise, Idaho): Venture allowing.

  • Life Cycle Geo LLC (Longmont, Colorado): Geochemical characterisation and baseline knowledge assortment.

  • Clear Creek Associates (Scottsdale, Arizona): Hydrogeology.

  • Qualus, LLC (Lake Mary, Florida): Energy engineering.

  • Westland Engineering & Environmental Companies, a Trinity Consultants Group (Reno, Nevada): Baseline knowledge assortment and allowing.

  • NewFields Mining Design & Technical Companies, LLC (Denver, Colorado): Tailings and waste design.

  • Reliant Nicely Drilling and Pump Corp. (Tucson, Arizona): Hydrogeological drilling companies.

• In whole, greater than 25 specialists from 8 impartial corporations with many years of U.S.-focused mine design, engineering, procurement and building administration expertise are at the moment engaged by the Firm’s Pilot Mountain PFS workforce. Guardian Metallic’s homeowners workforce features a group of geologists, geotechnicians and engineers with over 100 years’ of mixed exploration, mine constructing and operations expertise.

• The PFS examine is anticipated to be accomplished by the tip of H1 2026, and mine allow functions will probably be submitted promptly thereafter. Additional PFS progress updates will probably be supplied and any preliminary outcomes from any of the above ongoing workstreams will probably be launched when allowable, together with pending drilling outcomes from each the Desert Scheelite and Garnet Zones. The Firm’s goal is to realize preliminary business manufacturing earlier than the tip of 2028.

MINERAL RESOURCE DETAILS

The up to date Mineral Useful resource Estimate applies a 0.06% tungsten trioxide (WO₃) cut-off grade, reflecting elevated tungsten costs because the 2018 MRE and the deliberate open-pit mining method. The MRE additionally incorporates the beneficial tungsten recoveries demonstrated in historic metallurgical check work. An preliminary preliminary pit design has been developed and helps each the Indicated and Inferred Mineral Sources.

Importantly, the Desert Scheelite Deposit now includes a excessive proportion of pit-constrained Indicated Mineral Sources, offering a robust basis for the continued PFS. The now established MRE, ready in accordance with S-Okay 1300, is anticipated to develop additional as outcomes from ongoing exploration drilling are included right into a future replace.

Drilling accomplished by the Firm throughout 2024 and 2025 efficiently achieved its key targets, together with re-estimating the Mineral Useful resource below S-Okay 1300 primarily based on extra drilling and up to date technical work, upgrading total useful resource confidence, producing materials for detailed metallurgical check work (at the moment underway), and offering the information required to help mine planning and allowing actions, that are additionally now in progress.

When in comparison with the Mineral Useful resource estimate underpinning the 2018 Scoping Examine, the up to date useful resource sensitivity evaluation exhibits that the tonnage of Indicated Sources inside a projected open-pit design has elevated by roughly 16%.

Desk Error! No textual content of specified model in doc. Desert Scheelite Mineral Sources

Notes:

1 The efficient date of Desert Scheelite Mineral Useful resource assertion is December 1, 2025.

2 Mineral Useful resource acknowledged in metric tonnes.

3 Common grades of the tabulations are comprised of the weighted common of block-diluted grades inside an optimised pit.

4 The Desert Scheelite Mineral Useful resource reduce‑off grade of 0.06% WO₃ was chosen by the authors. Working assumptions had been utilized to determine a theoretical pit restrict, together with a WO₃ worth of $65,500/t, a mean restoration of 80% WO₃, a processing charge of 4,000 tonnes/day, $2.75/t mining price for open pit, $15.64/t processing price, $3.00/t processed for G&A, and an 83% payability. Blocks exterior the pit restrict are usually not thought-about to be financial presently.

5 The accent metals Ag, Cu, and Zn proven on this desk are the portions contained inside the mineral sources utilizing the cut-off grade established for the first commodity (WO₃). No impartial cut-off grade has been utilized to those accent metals. Reported portions of accent metals are subsequently thought-about by-products of the first metallic useful resource and their worth is contingent upon the flexibility to economically extract the by-products together with the first commodity.

6 The estimate of mineral sources could also be materially affected by geology, environmental, allowing, authorized, title, taxation, sociopolitical, advertising and marketing, or different related points.

7 Rounding as required by reporting tips could lead to obvious discrepancies between tonnes, grade, and contained metallic content material.

8 Mineral Sources are usually not Mineral Reserves and shouldn’t have demonstrated financial viability. An Inferred Mineral Useful resource has a decrease degree of confidence than an Indicated Mineral Useful resource and should not be transformed to a Mineral Reserve. RESPEC moderately expects that continued exploration and delineation will improve nearly all of Inferred Mineral Sources to Indicated Mineral Sources.

FURTHER PFS UPDATES

Ongoing work contains open-pit mine design and optimisation, detailed metallurgical check work, hydrogeological drilling to help future mine allowing, geochemical characterisation of waste rock, tailings design, and geotechnical investigations to help the deliberate open pit and related mine infrastructure. Research assessing choices for all required mine and mill infrastructure are additionally underway.

The PFS is being coordinated by Guardian Metallic’s in-house workforce in collaboration with Samuel Engineering, Inc. and the varied engineering contractors outlined above. Useful resource drilling at Desert Scheelite is ongoing and can ramp up into Q1 2026 upon the supply of a further drilling rig, with drillholes additionally deliberate at a few of the different Venture goal areas. An up to date MRE is anticipated previous to the completion of the PFS which is focused for completion by finish of H1 2026.

References

1 Firm announcement, Intention to checklist within the US, dated 8 September 2025
(https://polaris.brighterir.com/public/guardian_metal_resources/information/rns/story/rdo0dpx)

2 Firm announcement, U.S. Division of Protection Awards $6.2M to Golden Metallic Sources for the Pilot Mountain Venture, dated 23 July 2025
(https://polaris.brighterir.com/public/guardian_metal_resources/information/rns/story/wvm0n3w)

QUALIFIED PERSON

RESPEC is the creator of the TRS and the Certified Particular person below merchandise 1302 of Regulation S-Okay, has reviewed and accepted the inclusions of its abstract of the TRS on this announcement.

This announcement features a abstract of the principle components of the PFS which is included in a Technical Report Abstract which has been ready in accordance with S-Okay 1300, as adopted by the SEC. The efficient date of the MRE within the TRS is 1 December 2025.

COMPETENT PERSON STATEMENT

The technical info contained on this disclosure has been learn and accepted by Mr Nick O’Reilly (MSc, DIC, MIMMM QMR, MAusIMM, FGS), who’s a professional geologist and acts because the Competent Particular person below the AIM Guidelines – Notice for Mining and Oil & Fuel Corporations. Mr O’Reilly is a Principal guide working for Mining Analyst Consulting Ltd which has been retained by Guardian Metallic Sources plc to offer technical help.

This announcement comprises inside info for the needs of Article 7 of EU Regulation 596/2014 (which kinds a part of home UK legislation pursuant to the European Union (Withdrawal) Act 2018).

Ahead Trying Statements

This announcement comprises forward-looking statements referring to anticipated or anticipated future occasions and anticipated outcomes which can be forward-looking in nature and, because of this, are topic to sure dangers and uncertainties, akin to common financial, market and enterprise circumstances, competitors for certified employees, the regulatory course of and actions, technical points, new laws, uncertainties ensuing from potential delays or modifications in plans, uncertainties ensuing from working in a brand new political jurisdiction, uncertainties concerning the outcomes of exploration, uncertainties concerning the timing and granting of prospecting rights, uncertainties concerning the timing and granting of regulatory and different third occasion consents and approvals, uncertainties concerning the Firm’s or any third occasion’s capacity to execute and implement future plans, and the prevalence of surprising occasions.

Precise outcomes achieved could range from the knowledge supplied herein because of quite a few identified and unknown dangers and uncertainties and different components.

Nothing on this announcement is meant to represent a proposal of securities on the market or a solicitation of any provide to amass securities in any jurisdiction.

For additional info go to www.Guardianmetalresources.comor contact the next:

About Guardian Metallic Sources

Guardian Metallic Sources PLC (LON: GMET, OTCQX: GMTLF) is a strategic mineral exploration firm driving the revival of U.S. mined tungsten manufacturing and strengthening America’s protection metallic independence. The Firm is advancing two co-flagship tungsten initiatives, Pilot Mountain, one of many largest undeveloped tungsten deposits within the U.S. and Tempiute, previously America’s largest producing tungsten operation, each situated in Nevada, one of many top-rated mining jurisdictions within the U.S.

In July 2025, the U.S. Division of Struggle (DoW) below Title III of the Protection Manufacturing Act of 1950, as amended, invested US$6.2M in Golden Metallic Sources (USA) LLC, a wholly-owned subsidiary of Guardian Metallic Sources PLC, to help the Pilot Mountain PFS. The Firm has introduced plans to pursue a U.S. itemizing within the first half of 2026.

Tungsten is a strategic metallic crucial to the protection, vitality transition, expertise, and industrial sectors. Within the context of shifting geopolitical dynamics and tightening Chinese language export restrictions, Guardian is effectively positioned to play a number one position in re-establishing a safe, domestically mined U.S. provide chain for this very important protection metallic.

This info is supplied by RNS, the information service of the London Inventory Change. RNS is accepted by the Monetary Conduct Authority to behave as a Major Info Supplier in the UK. Phrases and circumstances referring to the use and distribution of this info could apply. For additional info, please contact rns@lseg.com or go to www.rns.com.

SOURCE: Guardian Metallic Sources PLC

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