Grande Portage Resources Advances 2026 Drill Program and Field Activities, Confirms 100% Warrant Exercise

Vancouver, British Columbia–(Newsfile Corp. – August 13, 2026) – Grande Portage Resources Ltd. (TSXV: GPG) (OTCQX: GPTRF) (FSE: GPB) (“Grande Portage” or the “Company”) is pleased to announce that it has reached the midpoint of the 2026 drilling program at the New Amalga Gold Project located in southeast Alaska.

As of August 9, crews have drilled 1,605 metres out of 3,255 planned metres (49%) and completed 5 out of 12 planned drillholes. Meanwhile large amounts of critical data have been collected on hydrogeological and geotechnical conditions in key areas of the deposit along with additional resource definition. This rock mass data is of great importance for the upcoming environmental review and permitting process as well as to inform mine development plans.

Ian Klassen, the Company’s President & CEO said, “This year’s drill program marks a pivot from pure exploration to a focus on data collection for mine development planning. This adds complexity including a larger amount of personnel, equipment, and helicopter logistics. Grande Portage would like to thank all of our contractors and personnel for their effective coordination and successful efforts in reaching the midpoint of the 2026 drilling program.”

In addition to drilling, construction activities have advanced for the development of environmental monitoring infrastructure at the site, including the installation of a river-monitoring gauge station (Fig. G) as well as completion of concrete works for the foundation of the first of two planned meteorological towers (Fig. H & Fig. I). Completion of the second tower’s foundation is scheduled for August with tower erection planned in September.

Environmental baseline data collection has also made excellent progress with the completion of wetlands mapping for the project area as well as ongoing wildlife, botanical and geochemical studies.

Photos from 2026 field program:

Fig. A: Drill pad construction

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Fig. B: Drilling operations

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Fig. C: Core logging tent at the drill rig

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Fig. D: Logging core while still in the split-tube core barrel to preserve maximum geotechnical information

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Fig. E: First core of 2026

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Fig. F: Ongoing drilling in all weather conditions

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Fig. G: New river monitoring gauge installed in Herbert River at project site

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Fig. H: Aerial view of construction work at meteorological tower site

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Fig. I: Construction equipment transported by helicopter to meteorological tower site

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Kyle Mehalek, P.E., is the QP within the meaning of NI 43-101 and has reviewed and approved the technical disclosure in this release. Mr. Mehalek is independent of Grande Portage within the meaning of NI 43-101.

Full Share Purchase Warrant Exercise

The Company is pleased to announce that shareholders have exercised 100% of the 6,005,431 outstanding common share purchase warrants at an exercise price of $0.25 per warrant, ahead of their August 12, 2026 expiry date. The warrant exercises have generated $1.50 million in additional proceeds, further strengthening the Company’s treasury and financial position.

The proceeds will be used to advance the Company’s ongoing field programs in S.E Alaska, expand its technical team, and support general corporate activities as Grande Portage continues to advance its exploration and development initiatives.

Ian Klassen further commented, “We remain deeply appreciative of our long-standing and supportive shareholders. The exercise of these warrants further strengthens Grande Portage’s financial position and enhances our financial flexibility as we continue to advance exploration and field activities at the New Amalga Gold Project. This continued shareholder support provides a strong foundation as we build momentum toward the next stage of the project’s development.”

Incentive Stock Options

The Company wishes to announce that, subject to TSX Venture Exchange approval, it has granted incentive stock options to various advisors & consultants to purchase up to 275,000 common shares exercisable on or before August 12, 2031 at a price of $0.35 per share.

About Grande Portage

Grande Portage Resources Ltd. is a publicly traded mineral exploration company focused on advancing the New Amalga Mine project, the outgrowth of the Herbert Gold discovery situated approximately 25 km north of Juneau, Alaska. The Company holds a 100% interest in the New Amalga property. The New Amalga gold system is open to length and depth and is host to at least six main composite vein-fault structures that contain ribbon structure quartz-sulfide veins. The project lies prominently within the 160km long Juneau Gold Belt, which has produced over eight million ounces of gold.

The Company’s updated NI#43-101 Mineral Resource Estimate (MRE) reported at a base case mineral resources cut-off grade of 2.5 grams per tonne gold (g/t Au) and consists of: an Indicated Resource of 1,438,500 ounces of gold at an average grade of 9.47 g/t Au (4,726,000 tonnes); and an Inferred Resource of 515,700 ounces of gold at an average grade of 8.85 g/t Au (1,813,000 tonnes), as well as an Indicated Resource of 891,600 ounces of silver at an average grade of 5.86 g/t Ag (4,726,000 tonnes); and an Inferred Resource of 390,600 ounces of silver at an average grade of 7.33 g/t silver (1,813,000 tonnes). The MRE was prepared by Dr. David R. Webb, Ph.D., P.Geol., P.Eng. (DRW Geological Consultants Ltd.) with an effective date of July 17, 2024. Additional information on the New Amalga Mine project is available in the technical report titled “Preliminary Economic Assessment for the New Amalga Gold Project Juneau District, Southeast Alaska” dated February 11, 2026, which is available under Grande Portage’s SEDAR+ profile at www.sedarplus.ca.

Cautionary Statement Regarding Forward-Looking Information

This news release includes certain “forward-looking statements” under applicable Canadian securities legislation. Forward-looking statements include estimates and statements that describe the Company’s future plans, objectives or goals, including words to the effect that the Company or management expects a stated condition or result to occur. Forward-looking statements may be identified by such terms as “believes”, “anticipates”, “expects”, “estimates”, “may”, “could”, “would”, “will”, or “plan”. Forward-looking statements or information contained in this release include, but are not limited to, statements or information with respect to: the commercial offtake, equity investment and construction loan and overrun facility from Ocean Partners, including terms, timing, benefits and synergies and use of proceeds thereof; Ocean Partners’ future share holdings; and advancement of the Project, including the proposed path to production timeline, economics and timing of the Environmental Impact Statement. Since forward-looking statements are based on assumptions and address future events and conditions, by their very nature they involve inherent risks and uncertainties, These assumptions, risks, uncertainties and other factors include, among others: ability to finalize definitive agreements relating to the commercial offtake, equity investment and construction loan and overrun facility, complete the transactions contemplated herein, and to obtain all necessary approvals; risks associated with the exploration and development of the New Amalga Mine and our mineral resources; including obtaining all necessary approvals and the timing thereof; the current or future price of gold, silver and other commodities; anticipated costs, expenses and working capital requirements; ability to meet the proposed production timeline for the Project; general business and economic conditions and political climate; and other assumptions, risks, uncertainties and other factors as described in the Company’s filings with Canadian securities regulators. There can be no assurance that such statements will prove to be accurate, as actual results and future events could differ materially from those anticipated in such statements. Accordingly, readers should not place undue reliance on forward-looking statements. The Company disclaims any intention or obligation to update or revise any forward-looking information, whether as a result of new information, future events or otherwise, other than as required by law.

NEITHER THE TSX VENTURE EXCHANGE NOR ITS REGULATION SERVICE PROVIDER (AS THAT TERM IS DEFINED UNDER THE POLICIES OF THE EXCHANGE) ACCEPTS RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF THIS NEWS RELEASE

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