Osisko Metals Incorporated (the ‘ Company ‘ or ‘ Osisko Metals ‘) ( TSX: OM,OTC:OMZNF ; OTCQX: OMZNF ; FRANKFURT: 0B51 ) is pleased to announce new drill results from the Gaspé Copper Project, located in the Gaspé Peninsula of Eastern Québec.

Osisko Metals CEO Robert Wares commented: ‘The growth potential of the Gaspé Copper deposit continues to be demonstrated with today’s new high-grade results. Holes 30-1106 and 30-1109 reveal the presence of a thick, higher grade tabular zone lying at depth around the E Zone horizon near the eastern margin of our 2024 MRE model. This tabular zone may extend significantly to the east if it correlates to historical drilling results. Our expansion drilling is exceeding expectations, hand-in-hand with the solid infill results on our main resource area.’

New analytical results are presented below (see Table 1), including 26 mineralized intercepts from six new drill holes. Infill intercepts are located inside the 2024 MRE model ( see November 14, 2024 news release ), and are focused on upgrading inferred mineral resources to measured or indicated categories, as applicable. Expansion intercepts are located outside the 2024 MRE model and may potentially lead to additional resources that will be classified appropriately within the next MRE update. Some of the reported intercepts have contiguous shallower infill as well as deeper expansion (noted on Table 1 below as ‘Both’). Maps showing hole locations are available at www.osiskometals.com .

Highlights:

• Drill hole 30-1110
  • 1091.5 metres averaging 0.20% Cu (infill and expansion)
• Drill hole 30-1109
  • 133.7 metres averaging 1.04% Cu (expansion)
• Drill hole 30-1106
  • 159.1 metres averaging 0.45% Cu (expansion)
• Drill hole 30-1103
  • 167.9 metres averaging 0.24% Cu (infill)
• Drill hole 30-1108
  • 134.8 metres averaging 0.22% Cu (infill and expansion)
• Drill hole 30-1111
  • 304.5 metres averaging 0.17% Cu (infill)
  • 206.3 metres averaging 0.33% Cu (expansion)

Table 1: Infill and Expansion Drilling Results

* See explanatory notes below on copper equivalent values and Quality Assurance/Quality Controls.
** ‘Both’ indicates drill holes that have contiguous shallower infill as well as deeper expansion intercepts.

Discussion

Drill holes 30-1103 and 30-1108, both located near the western margin of the 2024 MRE model, cut multiple intersections of mineralized material, 20 to 168 metres thick, distributed in ‘layer cake’ fashion from surface to a vertical depth of 854 and 900 metres, respectively.

Drill hole 30-1106, located near the eastern margin of the 2024 MRE model, cut unmineralized material to a depth of about 600 metres, followed by four mineralized intervals to a vertical depth of 1004 metres. These include a higher-grade interval of 33.8 metres averaging 1.04% Cu and 3.60 g/t Ag located at the level of (and immediately below) the E Zone skarn horizon.

Drill hole 30-1109, also located near the eastern margin of the 2024 MRE model, cut unmineralized material to a depth of about 460 metres, followed by three mineralized intervals to a vertical depth of 860 metres. These also include a higher-grade interval of 133.7 metres averaging 1.04% Cu and 6.48 g/t Ag located in skarn and porcellanites above and below the E Zone skarn horizon.

Both 30-1106 and 30-1109 suggest potential for the presence of a higher-grade tabular deposit around the E Zone horizon that, when combined with historical drilling data, indicates a potential extension eastward towards the previously mined E-32 Zone over a lateral distance of 800 metres.

Drill hole 30-1110, located on top of Copper Mountain near the central part of the 2024 MRE model, intersected 1091.5 metres averaging 0.20% Cu, 1.52 g/t Ag, and 0.017% Mo (0.28% CuEq), including 735.6 metres averaging 0.20% Cu, 1.50 g/t Ag, and 0.015% Mo (infill) and 355.9 metres averaging 0.21% Cu, 1.55 g/t Ag, and 0.021% Mo (expansion), extending mineralization to a vertical depth of 1100 metres and again confirming continuity of mineralization in the core of the deposit.

Drill hole 30-1111, located immediately west of Copper Mountain near the southern lip of the pit, intersected 304.5 metres (from surface) averaging 0.17% Cu and 0.80 g/t Ag followed by three more intersections that included expansion at depth of 206.3 metres averaging 0.33% Cu, 2.39 g/t Ag, and 0.016% Mo, extending mineralization in this area to a vertical depth of 936 metres. The central porphyry intrusion was then intersected and returned 76 metres averaging negligible copper (0.08% Cu) but significant molybdenum (0.023% Mo).

Mineralization at Gaspé Copper is of porphyry copper/skarn type and occurs as disseminations and stockworks of chalcopyrite with pyrite or pyrrhotite and minor bornite and molybdenite. At least five retrograde vein/stockwork mineralizing events have been recognized at Copper Mountain, which overprint earlier prograde skarn and porcellanite-hosted mineralization throughout the Gaspé Copper system. Porcellanite is a historical mining term used to describe bleached, pale green to white potassic-altered hornfels. Subvertical stockwork mineralization dominates at Copper Mountain whereas prograde bedding-replacement mineralization, that is mostly stratigraphically controlled, dominates in the area of Needle Mountain, Needle East, and Copper Brook. High molybdenum grades (up to 0.5% Mo) were locally obtained in both the C Zone and E Zone skarns away from Copper Mountain.

The 2022 to 2024 Osisko Metals drill programs were focused on defining open-pit resources within the Copper Mountain stockwork mineralization ( see May 6, 2024 MRE press release ). Extending the resource model south of Copper Mountain into the poorly-drilled prograde skarn/porcellanite portion of the system subsequently led to a significantly increased resource, mostly in the Inferred category ( see November 14, 2024 MRE press release ).

The current drill program is designed to convert the November 2024 MRE to Measured and Indicated categories, as well as test the expansion of the system deeper into the stratigraphy and laterally to the south and southwest towards Needle East and Needle Mountain respectively. The November 2024 MRE was limited at depth to the base of the L1 skarn horizon (C Zone), and all mineralized intersections below this horizon represent potential depth extensions to the deposit, to be included in the next scheduled MRE update in Q1 2026.

All holes are being drilled sub-vertically into the altered calcareous stratigraphy, which dips 20 to 25 degrees to the north. The L1 (C Zone) the L2 (E Zone) skarn/marble horizons were intersected in most holes, as well as intervening porcellanites that host the bulk of the disseminated copper mineralization.

Table 2: Drill hole locations

Explanatory note regarding copper-equivalent grades

Copper Equivalent grades are expressed for purposes of simplicity and are calculated taking into account: 1) metal grades; 2) estimated long-term prices of metals: US$4.25/lb copper, US$20.00/lb molybdenum, and US$24.00/oz silver; 3) estimated recoveries of 92%, 70%, and 70% for Cu, Mo, and Ag respectively; and 4) net smelter return value of metals as percentage of the price, estimated at 86.5%, 90.7%, and 75.0% for Cu, Mo, and Ag respectively.

Qualified Person

The scientific and technical content of this news release has been reviewed and approved by Mr. Bernard-Olivier Martel, P. Geo. (OGQ 492), an independent ‘qualified person’ as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (‘NI 43-101’).

Quality Assurance / Quality Control

Mineralized intervals reported herein are calculated using an average 0.12% CuEq lower cut-off over contiguous 20-metre intersections (shorter intervals as the case may be at the upper and lower limits of reported intervals). Intervals of 20 metres or less are not reported unless indicating significantly higher grades . True widths are estimated at 90- 92% of the reported core length intervals.

Osisko Metals adheres to a strict QA/QC program for core handling, sampling, sample transportation and analyses, including insertion of blanks and standards in the sample stream. Drill core is drilled in HQ or NQ diameter and securely transported to its core processing facility on site, where it is logged, cut and sampled. Samples selected for assay are sealed and shipped to ALS Canada Ltd.’s preparation facility in Sudbury. Sample preparation details (code PREP-31DH) are available on the ALS Canada website. Pulps are analyzed at the ALS Canada Ltd. facility in North Vancouver, BC. All samples are analyzed by four acid digestion followed by both ICP-AES and ICP-MS for Cu, Mo and Ag.

About Osisko Metals

Osisko Metals Incorporated is a Canadian exploration and development company creating value in the critical metals sector, with a focus on copper and zinc. The Company acquired a 100% interest in the past-producing Gaspé Copper mine from Glencore Canada Corporation in July 2023. The Gaspé Copper mine is located near Murdochville in Québec ‘ s Gaspé Peninsula. The Company is currently focused on resource expansion of the Gaspé Copper system, with current Indicated Mineral Resources of 824 Mt averaging 0.34% CuEq and Inferred Mineral Resources of 670 Mt averaging 0.38% CuEq (in compliance with NI 43-101). For more information, see Osisko Metals’ November 14, 2024 news release entitled ‘Osisko Metals Announces Significant Increase in Mineral Resource at Gaspé Copper’. Gaspé Copper hosts the largest undeveloped copper resource in eastern North America, strategically located near existing infrastructure in the mining-friendly province of Québec.

In addition to the Gaspé Copper project, the Company is working with Appian Capital Advisory LLP through the Pine Point Mining Limited joint venture to advance one of Canada ‘ s largest past-producing zinc mining camps, the Pine Point project, located in the Northwest Territories. The current mineral resource estimate for the Pine Point project consists of Indicated Mineral Resources of 49.5 Mt averaging 5.52% ZnEq and Inferred Mineral Resources of 8.3 Mt averaging 5.64% ZnEq (in compliance with NI 43-101). For more information, see Osisko Metals ‘ June 25, 2024 news release entitled ‘Osisko Metals releases Pine Point mineral resource estimate: 49.5 million tonnes of indicated resources at 5.52% ZnEq’. The Pine Point project is located on the south shore of Great Slave Lake, NWT, close to infrastructure, with paved road access, an electrical substation and 100 kilometres of viable haul roads.

For further information on this news release, visit www.osiskometals.com or contact:

Don Njegovan, President
Email: info@osiskometals.com
Phone: (416) 500-4129

Cautionary Statement on Forward-Looking Information

This news release contains ‘forward-looking information’ within the meaning of applicable Canadian securities legislation based on expectations, estimates and projections as at the date of this news release. Any statement that involves predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often, but not always, using phrases such as ‘expects’, or ‘does not expect’, ‘is expected’, ‘interpreted’, ‘management’s view’, ‘anticipates’ or ‘does not anticipate’, ‘plans’, ‘budget’, ‘scheduled’, ‘forecasts’, ‘estimates’, ‘potential’, ‘feasibility’, ‘believes’ or ‘intends’ or variations of such words and phrases or stating that certain actions, events or results ‘may’ or ‘could’, ‘would’, ‘might’ or ‘will’ be taken, occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward-looking information. This news release contains forward-looking information pertaining to, among other things: the tax treatment of the FT Units; the timing of incurring the Qualifying Expenditures and the renunciation of the Qualifying Expenditures; the ability to advance Gaspé Copper to a construction decision (if at all); the ability to increase the Company’s trading liquidity and enhance its capital markets presence; the potential re-rating of the Company; the ability for the Company to unlock the full potential of its assets and achieve success; the ability for the Company to create value for its shareholders; the advancement of the Pine Point project; the anticipated resource expansion of the Gaspé Copper system and Gaspé Copper hosting the largest undeveloped copper resource in eastern North America.

Forward-looking information is not a guarantee of future performance and is based upon a number of estimates and assumptions of management, in light of management’s experience and perception of trends, current conditions and expected developments, as well as other factors that management believes to be relevant and reasonable in the circumstances, including, without limitation, assumptions about: the ability of exploration results, including drilling, to accurately predict mineralization; errors in geological modelling; insufficient data; equity and debt capital markets; future spot prices of copper and zinc; the timing and results of exploration and drilling programs; the accuracy of mineral resource estimates; production costs; political and regulatory stability; the receipt of governmental and third party approvals; licenses and permits being received on favourable terms; sustained labour stability; stability in financial and capital markets; availability of mining equipment and positive relations with local communities and groups. Forward-looking information involves risks, uncertainties and other factors that could cause actual events, results, performance, prospects and opportunities to differ materially from those expressed or implied by such forward-looking information. Factors that could cause actual results to differ materially from such forward-looking information are set out in the Company’s public disclosure record on SEDAR+ (www.sedarplus.ca) under Osisko Metals’ issuer profile. Although the Company believes that the assumptions and factors used in preparing the forward-looking information in this news release are reasonable, undue reliance should not be placed on such information, which only applies as of the date of this news release, and no assurance can be given that such events will occur in the disclosed time frames or at all. 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 Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Exchange) accept responsibility for the adequacy or accuracy of this news release. No stock exchange, securities commission, or other regulatory authority has approved or disapproved the information contained herein.

Photos accompanying this announcement are available at

https://www.globenewswire.com/NewsRoom/AttachmentNg/1435bbf7-6580-47e7-9906-c67a832e9456

https://www.globenewswire.com/NewsRoom/AttachmentNg/ffb2d0f5-e4f4-4672-8e6e-e41e07fc2f68

(TheNewswire)

Vancouver, British Columbia TheNewswire – September 15th, 2025 Prismo Metals Inc. (the ‘ Company ‘ ) (CSE: PRIZ,OTC:PMOMF) (OTCQB: PMOMF) is pleased to report that its exploration team has identified porphyry style mineralization at its Silver King project located outside the town of Superior in Arizona. Given the proximity of the nearby Resolution Copper deposit (a joint venture between Rio Tinto and BHP), the team is excited about the potential of this same style of mineralization identified at surface within the eastern portion of our claim.

‘ This region is world-class for porphyry systems and base and precious metals, and we believe there is significant untapped potential. Our recent field work at the Silver King mine was successful in identifying several exploration targets apart from the historic silver mine deposit including polymetallic veins, manto replacements and a strongly altered intrusion with stockwork quartz-pyrite veining. Identifying this porphyry style mineralization on the claim block is a very positive development ,’ said Dr. Craig Gibson , Chief Exploration Officer.

Figure 1 . Map showing Silver King project and nearby mineral deposits.

The Silver King deposit is located three kilometers from the Resolution Copper deposit and the high-grade Magma mine, a former copper and silver producer, located 0.6 to 1.5 kilometers to the southwest Mineralization at Silver King is hosted by the same rock sequence that hosts those two deposits but is exposed at surface and is not covered by the thick sequence of unmineralized volcanic rocks that covers Resolution Copper. From 1911 to 1996 the Magma mine was developed on veins and replacement deposits in the Paleozoic and Precambrian strata and intrusive rocks, producing approximately 27.6 million short tons of ore averaging about 4.9% copper with important quantities of zinc, gold (689K oz) and silver (34.3M oz) (Briggs, 2015), eventually leading to the discovery of the nearby Resolution copper deposit (Fig. 1).

M ineralization similar to that at the Magma mine is exposed in several historic mine workings with abundant oxide copper minerals, mainly malachite, which were developed along a northeast dipping limestone horizon near the contact with a quartz diorite intrusion and quartzite along the same structural and stratigraphic trend of the Magma mine. The largest occurrence, at the Black Diamond mine in the eastern portion of the claim block, was developed on a large outcrop of abundant specular hematite and malachite replacing a limestone bed (Fig. 2) .

Additionally, an erosional window in a regional quartz diorite has exposed a felsic intrusion to the east of the Silver King workings that was identified in historical records and now confirmed by Prismo geologists.  This felsic intrusion, previously described as a breccia pipe, is characterized by very strong stockwork quartz-pyrite veining in a quartz-sericite altered host rock. This target contains anomalous metal values in soil samples analyzed with the XRF. According to historical reports it has high salinity fluid inclusions typical of a porphyry system, providing evidence for porphyry mineralization on the Silver King claim package.

Figure 2 . Geologic and land map of the Silver King project showing newly described veins in magenta (Ag-Pb-Zn) and green (Cu-Ag) and replacement mineralization in red. The strongly altered intrusion with stock work quartz-pyrite veining is indicated by the crosshatch.

‘Much of the focus of the exploration program to date consisted of a property wide survey of historic mines and prospects surrounding the Silver King workings, ‘ said Gordon Aldcorn, President of Prismo .

‘ The exploration work has resulted in the identification of several mineralized occurrences on the property, including veins in the vicinity of the Silver King mine, and replacement and skarn mineralization in limestone units of the sedimentary sequence near the contact.’

Part of the initial exploration program consisted of a reconnaissance survey of the geology and mineral occurrences as well as a geochemical and alteration mineral survey around the surface expression of the Silver King deposit and a second separate target to the east.

The geochemical survey used a handheld XRF instrument to measure soil samples, and showed discrete anomalies for Cu, Ag, and Sb around the historic glory hole, with the copper geochemistry also associated with the ENE striking Cu bearing vein mentioned previously (Fig. 3). Twenty-nine samples have been submitted to the lab, with an additional fifteen samples from the Ripsey mine.

This initial phase of Prismo exploration on the Silver King project is already generating a better understanding of potential with new structures not fully uncovered in historical mining approaches. This work also helps qualify our upcoming drill program which is currently in the permitting stage and is anticipated to be advanced shortly.

Figure 3 . Soil geochemistry maps for Cu, Ag, and Sb from the Silver King mine.  Contours are from values measured in soils by a handheld XRF in the field, with ranges for Cu at 5,619 ppm to 12.5 ppm, Ag at 186 ppm to 1.3 ppm, and Sb at 300 ppm to 3.9 ppm.

Click Image To View Full Size

As previously reported in Primo’s news release of August 28, 2025, the Company geologists identified two previously undescribed veins in the area surrounding the historic glory hole developed on the original exposure of high-grade silver at the Silver King deposit.  Visual inspection and analysis with a handheld XRF show two distinct veins, one with abundant silver lead and zinc and the other with copper and silver values.

Figure 4 . Location of the Company’s projects within the Arizona Copper Belt

Qualified Person

Dr. Craig Gibson, PhD., CPG., a Qualified Person as defined by NI-43-01 regulations and Chief Exploration Officer and a director of the Company, has reviewed and approved the technical disclosures in this news release. The historic data presented in this press release was obtained from public sources, should be considered incomplete and is not qualified under NI 43-101, but is believed to be accurate. The Company has not verified the historical data presented and it cannot be relied upon, and it is being used solely to aid in exploration plans. References to mineralization at the Magma Mine and Resolution Copper deposit is not necessarily indicative of mineralization on the Silver King property.

1. (2) Briggs, D., 2015, Superior, Arizona: An old mining camp with many lives, Ariz. Geol Survey Contributed Report CR-15-D, 13p.

About the Silver King and Ripsey Mines

Discovered in 1875, the Silver King mine was one of Arizona’s most important historic producers, yielding nearly 6 million ounces of silver at grades of up to 61 oz/t.  The Silver King mine sits only 3 km from the main shaft of the Resolution Copper project — a joint venture between Rio Tinto and BHP and one of the world’s largest unmined copper deposits with an estimated copper resource of 1.787 billion metric tonnes at an average grade of 1.5% copper (1) . The unique land position is fully surrounded by Resolution Copper’s claim block, offering strategic upside. Selected samples from small-scale production in the late 1990s returned grades as high as 644 oz/t silver (18,250 g/t) and 0.53 oz/t gold (15 g/t), indicating that high-grade mineralization remains.

The Ripsey mine is a historic gold-silver-copper producer located about 20 km west of the Hot Breccia project. Historic mine workings consisting of tunnels and shafts on several levels were developed along a vein over about 400 meters of strike length and 160 meters vertically. A small tonnage of mineral was produced by the Optionor in the late 1990’s. Limited sampling by Dr. Craig Gibson from the mine workings has yielded 15.9 g/t gold and 275 g/t silver over 0.75 meters and 8.7 g/t gold, 181 g/t silver, 3% copper and 9% zinc over 1 meter.  No modern exploration has been carried out at the project, providing significant exploration upside and multiple drill targets.

About Prismo Metals Inc.

Prismo (CSE: PRIZ,OTC:PMOMF) is a mining exploration company focused on advancing its Silver King, Ripsey and Hot Breccia projects in Arizona and its Palos Verdes silver project in Mexico.

Please follow @PrismoMetals on , , , Instagram , and

Prismo Metals Inc.

1100 – 1111 Melville St., Vancouver, British Columbia V6E 3V6

Phone: (416) 361-0737

Contact:

Alain Lambert, Chief Executive Officer alain.lambert@prismometals.com

Gordon Aldcorn , President gordon.aldcorn@prismometals.com

Cautionary Note Regarding Forward-Looking Information

This release includes certain statements and information that may constitute forward-looking information within the meaning of applicable Canadian securities laws. Forward-looking statements relate to future events or future performance and reflect the expectations or beliefs of management of the Company regarding future events. Generally, forward-looking statements and information can be identified by the use of forward-looking terminology such as ‘ intends’ or ‘ anticipates ‘, or variations of such words and phrases or statements that certain actions, events or results ‘ may’, ‘ could’, ‘ should’, ‘ would’ or ‘ occur’. This information and these statements, referred to herein as ‘forward‐looking statements’, are not historical facts, are made as of the date of this news release and include without limitation, statements regarding discussions of future plans, estimates and forecasts and statements as to management’s expectations and intentions with respect to, among other things: the timing, costs and results of drilling at Hot Breccia.

These forward‐looking statements involve numerous risks and uncertainties, and actual results might differ materially from results suggested in any forward-looking statements. These risks and uncertainties include, among other things: delays in obtaining or failure to obtain appropriate funding to finance the exploration program at Silver King.

In making the forward-looking statements in this news release, the Company has applied several material assumptions, including without limitation, that: the ability to raise capital to fund the drilling campaign at Silver King and the timing of such drilling campaign.

Although management of the Company has attempted to identify important factors that could cause actual results to differ materially from those contained in forward-looking statements or forward-looking information, there may be other factors that cause results not to be as anticipated, estimated or intended. 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 and forward-looking information. Readers are cautioned that reliance on such information may not be appropriate for other purposes. The Company does not undertake to update any forward-looking statement, forward-looking information or financial outlook that are incorporated by reference herein, except in accordance with applicable securities laws. We seek safe harbor.

Copyright (c) 2025 TheNewswire – All rights reserved.