Mr. Peeyush Varshney reports

GREAT PLAINS METALS CONFIRMS "PENCIL PORPHYRY" DISCOVERY WITH A 128-METER INTERCEPT AT GOODRICH PROJECT, NSW

Great Plains Metals Corp.'s assay results have confirmed the discovery of a pencil porphyry at the Goodrich copper-gold project in New South Wales, Australia.

Laboratory assays from drill hole GGDD004 have successfully verified a continuous, 128-metre intercept of porphyry-style mineralization. This broad intersection validates the company's porphyry exploration thesis: the historical, shallow Goodrich mine workings represent the upper tip of a multiphase, intact porphyry system.

Key drill highlights:

• Discovery hole intercept: Drill hole GGDD004 intersected 128 metres of mineralization with 0.34 per cent copper and 0.17 gram per tonne gold from 81.45 m downhole.
• Mineralized magmatic cupola: A prominent high-grade zone right at the porphyry contact returned 3.55 metres at 2.80 per cent Cu and 0.18 g/t Au from 81.45 m.
• Continuous disseminated chalcopyrite: Multiple subintervals dissected by postmineral dikes confirm continuous mineralization, including 26 metres at 0.52 per cent Cu and 0.24 g/t Au from 102 m and five metres at 0.66 per cent Cu and 0.49 g/t Au from 158 m.
• Near-surface depth: Importantly, the 128-metre mineralized intercept begins near surface at just 81.45 metres depth.

Technical evaluation and drill hole comparative data

The initial phase 1 diamond drilling program was designed to test porphyry-style mineralization below the former Goodrich mine. Drill hole GGDD004 intersected significant disseminated copper and gold mineralization hosted in a monzonite porphyry stock. Drill hole GGDD003 intersected altered monzonite porphyry representing the inner propylitic halo of the Goodrich porphyry.

Technical analysis of drill hole GGDD004

The mineralized unidirectional solidification texture (UST) zone intersected at 81.4 metres represents the cupola contact of a mineralized monzonite porphyry stock (that is, the top of the system) and comprises magmatic bands of milky quartz, coarse chalcopyrite and pyrite aggregates, and minor magnetite. Below the UST zone, hydrothermal alteration consists of pervasive white mica-chlorite and pale albite, which appear to overprint an earlier K-spar-biotite assemblage to varying degrees. The entire 128 metres of monzonite porphyry has disseminated chalcopyrite and pyrite with traces of molybdenite in rare quartz veins. After 209 metres, the hole transitions into an inner propylitic zone with increasing epidote, chlorite and pyrite. Several relatively narrow intercepts of postmineral trachyte dikes are present throughout the hole.

Technical analysis of drill hole GGDD003

Drill hole GGDD003 intersected altered chlorite-white mica-epidote monzonite porphyry considered to represent the inner propylitic halo of the Goodrich porphyry. Two intervals displaying UST textures were observed at 31.8 metres and 76.8 metres depth, both of which were associated with copper mineralization (similar to those in GGDD004 but less well developed). A significant fault was intersected at 82 m, after which only weak mineralization and alteration were encountered.

The other two diamond drill holes: GGDD005 and MRDD001 did not encounter significant mineralization. Hole GGDD005 was designed to test a magnetic-high target 100 metres southeast of the Goodrich mine. It was terminated at 161.2 metres and drilled weakly magnetic unmineralized monzonite/granodiorite. Hole MRDD001 was collared next to the small historical workings at Mount Rose and was terminated at 140.1 metres after encountering weak pervasive chlorite-epidote altered monzonite with minor disseminated pyrite.

Historical drill core review at Londonderry

Per the company's news release dated July 14, 2026, a review was being conducted of historical core archived at the New South Wales Mines Department facility in Londonderry. Detailed logging identified that extensive, highly altered intervals from historical drill holes DDHG4 (Baker Ltd., 1980) and GRDD01 (Malachite Resources, 1999) were never submitted for assay.

A total of 324 samples was compiled and delivered to Intertek Laboratories in nearby Orange. Assays are expected within the next few weeks and will be integrated into the regional porphyry cluster model. The company will provide further updates in due course.

Phase 2 drilling

The company announced previously the completion of Stage 1 of the earn-in and joint venture agreement, achieving a 51-per-cent interest and the commencement of Stage 2, which, upon completion, will result in Great Plains Metals owning a 70-per-cent interest. The company will now form a subsidiary company (GPS Goodrich) in New South Wales, Australia, which will then hold the tenements that comprise the Goodrich project. GPS Goodrich will then undertake the process for the transfer of land access agreements and the approval of work programs. Upon completion, which is anticipated in Q4 2026, the phase 2 drill program will commence.

Peeyush Varshney, chief executive officer, commented: "The results from drill hole GGDD004 confirming the discovery of a pencil porphyry at Goodrich is a very exciting milestone for GPS. Intersecting 128 metres of copper-gold mineralization starting from just 81 metres from the surface is significant and represents a new exploration opportunity consistent with other porphyry deposits in the Lachlan fold belt, a mineral province that has historically produced over 80 million ounces of gold and 13 million tonnes of copper.

"The presence of multiple textbook UST cupola textures indicates potential for significant porphyry mineralization that the old-timers missed. Combined with our ongoing review of previous drilling and unassayed historical core, these definitive data points give our technical team the co-ordinates needed to expand this porphyry footprint when phase 2 diamond drilling commences."

About Great Plains Metals Corp

Great Plains Metals is an emerging, Australia-focused exploration company targeting copper-gold porphyry and district-scale critical mineral discoveries. The company's fast-track discovery strategy centres on technically validating high-grade, drill-ready targets situated within premier geological jurisdictions:

• The flagship Goodrich project (New South Wales): Located in the heart of New South Wales's premier copper-gold jurisdiction -- near the Yeoval township and roughly 70 kilometres northwest of Orange -- the project spans an extensive 290 square kilometres across exploration licences EL9243 and EL8538. The Goodrich project is situated within the world-class Lachlan fold belt.
• Proven mineral footprint: Historically the largest mine in the Yeoval district, Goodrich operated intermittently between 1868 and 1912. Production from its historic 46-metre open-pit shaft and 90-metre underground shaft yielded an estimated 300 tonnes of copper, 159 kilograms of gold and 62 kilograms of silver, notably supporting a local smelter facility during its peak operational phases. Modern geological modelling suggests this historical mining merely exposed the upper tip of a significantly larger, robust porphyry core system below the old mine.
• Strategic district-scale upside: Great Plains Metals holds a 37.1-per-cent equity stake in Eversley Resources, giving the company low-cost exposure to the Eversley North Gawler Craton project in South Australia. Spanning an extensive 2,584 square kilometres within the prolific Olympic Dam IOCG (iron oxide copper-gold) province, the project targets shallow, high-intensity IOCG systems alongside a near-surface ionic clay rare earth element (REE) prospect. With a native title mining agreement for exploration secured and target depths uniquely shallow at under 150 metres, the project represents immediate, high-value asset diversification.

Qualified person (QP)

The scientific and technical data contained in this news release has been reviewed and approved by Douglas Kirwin, who serves as the qualified person under the definition of National Instrument 43-101.

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