Mr. Peeyush Varshney reports

STAGE 2 DRILLING PROGRAM TO EXPAND 'PENCIL PORPHYRY' DISCOVERY AT GOODRICH

Great Plains Metals Corp. has provided the drilling plan and specific target vectors for its coming fully financed Stage 2 diamond drill campaign at the Goodrich copper-gold project in New South Wales, Australia.

Scheduled to mobilize toward the end of this month, this targeted 1,000-metre program is strategically designed to follow up on the Stage 1 discovery hole GGDD004, which intersected a continuous 128-metre intercept of porphyry-style mineralization grading 0.47 per cent copper equivalent (0.34 per cent copper and 0.17 gram per tonne gold) and upon the notable historical intercepts that were announced on Oct. 5, 2026 (Table 1).

Key highlights:

• Building on the pencil porphyry discovery: Campaign targets are to test the immediate lateral and downdip geometry of the newly recognized magmatic monzonite porphyry cupolas, expanding directly on mineralization intercepted in Stage 1 drilling.
• Targeting shallow mineralization: Drilling will simultaneously step out toward near-surface targets highlighted by historical percussion hole YG08, which intersected 33 metres grading 1.76 per cent CuEq (0.65 per cent Cu and 1.43 g/t Au) from one metre deep, including a higher-grade core of 15 metres grading 3.48 per cent CuEq (1.09 per cent Cu and 3.09 g/t Au).
• Tenement EL9243 renewed: The exploration licence EL9243 has recently been renewed until Aug. 5, 2032. The Goodrich project spans an extensive 290 square kilometres across exploration licences EL9243 and EL8538.
• On June 15, 2026, Great Plains Metals completed Stage 1 of the earn-in and joint venture agreement (EJVA), earning 51 per cent. On July 14, 2026, Great Plains Metals announced the commencement of Stage 2 to earn 70 per cent. Under the terms of the EJVA, Great Plains Metals committed to incur a further $1-million (Australian) in exploration expenditure over the next 12 months and complete a minimum of 500 metres of drilling to increase its interest to 70 per cent.

The company anticipates completing Stage 2 ahead of schedule and will, upon receiving positive results, commence planning for further drilling in Q1 2027.

Exploration strategy and vector framework

The Stage 1 discovery program successfully demonstrated that the historical, shallow mine workings at Goodrich represent the upper tip of an intact, multiphase porphyry intrusion system.

By leveraging the preserved historical core and photographic logs archived at the W.B. Clarke Geoscience Centre (Londonderry Drillcore Library), the company's technical team has identified several key unidirectional solidification texture (UST) zones. Because USTs represent the upper contact of a mineralized porphyry intrusion, this coming drill program is designed specifically to test the geometry of these near-surface porphyry cupolas. Mapping the porphyries during Stage 2 will provide the geological constraints required to enable subsequent deeper drilling into the roots of the system.

To trace the boundaries and depth extensions of this pencil porphyry body, the coming campaign utilizes a strict scissored framework to pierce the cupola contact from both flanks:

• The western flank: Collared on the western side of the deposit and drilling toward the east-northeast, these holes project beneath the historic open pit. They are positioned to intercept the downdip extension of the shallow high-grade core of hole YG08 while tracking the western boundary of the core porphyry system.
• The eastern flank: Scissor-collared from the eastern flank and drilling back toward the mine system toward the west-southwest, these trajectories cut back toward the discovery centre. Their primary objective is to delineate structural continuity between discovery hole GGDD004 grading 0.47 per cent CuEq (0.34 per cent Cu and 0.17 g/t Au) over 128 metres and historical drill holes KB1 grading 0.66 per cent CuEq (0.41 per cent Cu and 0.32 g/t Au) over 50.08 metres and DDHG10 grading 0.68 per cent CuEq (0.55 per cent Cu and 0.17 g/t Au) over 37 metres.

To actively mitigate drill-hole stability risks, the company's technical team integrated the proposed paths into a localized underground void spatial map. Collars have been pulled back and dips locked to a minimum of minus 50 degrees to clear old shafts and tunnels, designed to avoid intersection with unbackfilled mine voids (Table 2).

Peeyush Varshney, chief executive officer, commented: "The continuous 128-metre discovery intercept in Stage 1 hole GGDD004 (0.47 per cent CuEq), combined with the historical intercepts recently unlocked across the project, indicates that the historical workings at Goodrich are situated above an intact pencil porphyry system. This upcoming Stage 2 program is designed to systematically test the lateral boundaries and depth continuity of that mineralized body.

"This campaign is fully funded, and, with drill mobilization scheduled imminently, we anticipate being able to deliver a consistent schedule of technical data and assay updates for the market through the fourth quarter."

Qualified person statement

Douglas Kirwin, MSc, FGS, FAusIMM (CP), FSEG, an executive director of Great Plains Metals and a non-independent qualified person as defined by National Instrument 43-101, has reviewed and approved the technical engineering contents, spatial modelling inputs and geological target parameters presented in this news release. Mr. Kirwin cautions that the underlying historical drilling results utilized in Table 1 have not been independently validated to modern standards and directs readers to the comprehensive data verification and campaign-specific limitations detailed in the company's news release dated Oct. 5, 2026. The historical data are, however, considered a reasonable and reliable baseline for the coming Stage 2 exploration targeting.

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 and 90-metre underground shafts 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.

We seek Safe Harbor.