American Marconi Wireless News - Sterling Metals Discovers Cu-Mo Porphyry Stock 1.5km from MEPS Discovery Zone Confirming Scale of Porphyry Copper System

The blind porphyry stock was drill-intersected approximately 1.5km from the MEPS Discovery ("MEPS Discovery") that is highlighted by a 400 x 400m continuous zone of near-surface copper mineralization centered around discovery hole MEPS-25-02 that contained 265.5m of 1.05% CuEq* including 68.3m of 3.25% CuEq*(see press release dated September 29, 2025). The presence of a Cu-Mo mineralized felsic porphyry stock so far from the MEPS Discovery provides further strong evidence for the presence of a giant porphyry copper system at the Soo Copper Project, located off the Trans-Canada Highway only 70km north of Sault Ste Marie and 20 km from rail and deep-water access.

Highlights

• Drillhole SC-26-01 was designed to test a ZTEM resistivity low geophysical target in proximity to bornite and chalcopyrite exposures in outcrop and as a large step-out to the MEPS Discovery (Figure 1 and 2).

• At approximately 530m vertical depth, a thick zone of altered mafic volcanics transitioned sharply into a coarse-grained felsic porphyry, interpreted as part of a stock-like intrusive body, which was then drilled for over 400m currently continuing at approximately 1000m depth. The porphyry stock contains widespread, overall weak to moderate, but locally strong development of copper sulphides as fine chalcopyrite and bornite disseminations in the groundmass and as coarser grains within veins and is closely associated with potassic feldspar alteration. Molybdenite is also commonly present within quartz veins with or without chalcopyrite (see Figure 3, 4 and 5).

• While assays are not expected for some time, the evidence from this hole suggests this is not the core of the mineralized stock but a peripheral part of a larger copper zone. However, it does confirm that there is a large porphyry stock complex associated with the surface copper showings identified across this 7km x 3km copper corridor of surface showings and drill holes that represent the upper expression of the overall giant footprint of this porphyry copper system.

• The next hole is planned to drill-test the western edge of the same ZTEM anomaly in search of the shoulders of the stock and a possible associated zone of larger, higher grade porphyry copper mineralization.

• A similar ZTEM resistivity anomaly has also been identified beneath the MEPS Discovery area which is also a focus for drill-testing in this winter program (Figure 1).

Neil O'Brien, Chief Geologist of Sterling Metals, comments, "The discovery of a source porphyry stock that hosts widespread potassic alteration and copper mineralization, including bornite, so quickly into the winter program is an incredible early result. It validates both our contention of there being a giant porphyry copper complex underlying a significant area of the Soo Project but also that our exploration targeting approach is right and will lead us to where there is the greatest potential for large concentrations of copper."

Based upon visual core logging, the stock is so far principally composed of a granite porphyry to quartz monzonite porphyry intrusive, compositions that are common to many major porphyry copper systems worldwide. The porphyry contains abundant phenocrysts of feldspar (plagioclase and orthoclase) and quartz with common but lesser mafic phenocrysts (hornblende and biotite). The common presence of both primary igneous hornblende and biotite (Figure 4), both hydrous minerals, in this felsic porphyry is indicative of a 'wet' hydrous source magma that is critical to the late-stage development of abundant, metal-rich, hydrothermal fluids that are ultimately responsible for the mineralization of copper and other metals in porphyry copper systems typically as sulphides within veins crossing the stock and intruded country rocks.

The granite porphyry hosts widespread but patchy potassic feldspar alteration with lesser local zones of epidote alteration and weak to moderate development of porphyry style veining, including early biotite veins and a variety of quartz-sulphide A-veins. Copper is present as very fine disseminations of chalcopyrite throughout much the groundmass of the porphyry, and as larger grains within veins and partly replacing mafic phenocrysts (Figure 3 and 4). Bornite locally replaces chalcopyrite, especially within mafic mineral grains but also within irregularly shaped pegmatitic zones of very coarse grained quartz and potassic feldspar. Molybdenite is present as medium to coarse grains within later, thicker quartz veins with or without chalcopyrite (Figure 4).

There is also strong evidence that other intrusive porphyry phases help comprise the intrusive stock complex, including an early-stage felsic porphyry with a fine grained groundmass reminiscent of the GFP felsic porphyry dykes found at MEPS, that is strongly potassic (biotite) altered and hosts a greater concentration of veins than the granite porphyry (Figure 5). The discovery of this Cu-Mo mineralized, potassic altered and veined granite porphyry stock at 1.5km from the MEPS Discovery supports the Company's contention that the widespread surface copper showings and copper-in-soil anomalies are indicative of the presence of a giant porphyry copper complex that offers tremendous exploration discovery potential.

Figure 1: Plan map illustrating 8km copper corridor, as defined by copper in surface showings and drill holes, associated with underlying resistivity lows along 800m depth slice

Figure 2: Cross Section illustrating ZTEM resistivity target and main rock units intercepted in drill hole; transition from basalt to porphyry stock at approximately 530m vertical depth

Figure 3: Example in SC-26-01 of porphyry stock 740m downhole with close up illustrating early biotite (dark) veining and quartz-sulphide (light) A-veining

Figure 4: Examples within SC-26-01 of different types of Cu-Mo veining and disseminated chalcopyrite within porphyry stock

Figure 5: Example in SC-26-01 of clasts of potassic-altered, fine-grained felsic porphyry (dark), reminiscent of bornite-related GFP porphyry dykes at MEPS Discovery, hosted by coarser grained granite porphyry and crosscut by significant density of porphyry style A-veins

Sterling will be attending PDAC 2026 at the Metro Toronto Convention Centre (MTCC) from Sunday, March 1 to Monday, March 2, 2026, participating in Core Shack - Session A, Booth 3113A. Shareholders and investors are invited to meet with members of Sterling's management and technical team at the Company's exhibit in the MTCC South Building.

Interval Width and Copper Equivalent Calculations

Intervals may not represent true widths which are not yet known and capping has not been applied to grades. Copper Equivalent (CuEq) for drill intersections is calculated based on a three-year trailing average for each commodity (2023, 2024 and 2025) which equates to US$ 4.18/lb Cu, US$ 2,600/oz Au, US$ 30.54/oz Ag and US$ 21.46/lb Mo, with 80% metallurgical recoveries assumed for all metals. The formula is: CuEq % = Cu % + (0.907 x Au g/t) + (0.0107 x Ag g/t) + (0.00051 x Mo ppm).

Sampling Procedures - Quality Assurance/Quality Control

Analytical services were provided by Actlabs, which is an independent, CALA- and SCC-accredited analytical services firm registered to ISO 17025 and ISO 9001 standard. Drill core samples were logged and split in half with a diamond core saw. Half-core samples were securely stored at the core logging facility until being delivered to Actlabs Thunder Bay lab by commercial transport. Samples were crushed (

Laboratory QA/QC for the ICP analysis was 14% for each batch, including 5 method reagent blanks, 10 in-house controls, 10 samples duplicates, and 8 certified reference materials. An additional 13% QA/QC was performed as part of the instrumental analysis to ensure quality in the areas of instrumental drift. Laboratory quality control for the gold fire assay included two blanks per 42 samples, three sample duplicates and 2 certified reference materials, one high and one low (QC 7 out of 42 samples). In-house QA/QC included the systematic insertion of blanks, duplicates, and certified reference materials (CRM).

Qualified Person

Jeremy Niemi, P.Geo., Senior Vice President, Exploration and Evaluation for Sterling Metals has reviewed and approved the technical information presented herein.

About the Soo Copper Project

The Soo Copper Project sits just 20 minutes off the Trans-Canada Highway, one hour north of Sault Ste. Marie, and 20km from rail and deep-water access. With near-surface copper-one of the most critical of all critical metals-alongside gold, and with the project now demonstrating both scale and grade, Sterling sees the potential for Soo Copper to become a nationally significant asset as Canada accelerates its efforts to secure strategic copper resources. Prime Minister Carney's recent designation of copper as one of Canada's first five strategic assets underscores the importance of this discovery and its potential to emerge as a key project of national interest.

About Sterling Metals

Sterling Metals is a mineral exploration company focused on large scale and high-grade Canadian exploration opportunities. The Company is advancing the 25,000-hectare Soo Copper Project in Ontario which has past production, and multiple breccia and porphyry targets strategically located near robust infrastructure and the 29,000-hectare Adeline Project in Labrador which covers an entire sediment-hosted copper belt with significant silver credits. Both opportunities have demonstrated potential for important new copper discoveries, underscoring Sterling's commitment to pioneering exploration in mineral rich Canada.

Sterling Metals acknowledges that its exploration activities within the Soo Copper project are conducted on the traditional lands of the Batchewana, Garden River, and Michipicoten First Nations of the North Shore of Lake Superior. We recognize and respect the longstanding and diverse relationships Indigenous Peoples have with the land and are committed to engaging in a manner that is respectful, transparent, and inclusive.

For more information, please contact:

Sterling Metals Corp.
Mathew Wilson, CEO and Director

Tel: (416) 643-3887
Email: [email protected]
Website: www.sterlingmetals.ca

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SOURCE: Sterling Metals Corp.

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S.F.Warren--AMWN