Osisko Intersects 256 Metres Averaging 0.85% Cu at Gaspé

Includes 28.5 Metres Averaging 4.74% Cu and 27.4 g/t Ag

MONTREAL, Sept. 10, 2026 (GLOBE NEWSWIRE) -- Osisko Metals Incorporated (the “Company” or “Osisko Metals”) (TSX: OM; OTCQX: OMZNF; FRANKFURT: 0B51) is pleased to announce additional new analytical results from the 2026 drill program at the Gaspé Copper Project, located in the Gaspé Peninsula of Eastern Québec.

New results are presented below (see Table 1), including 28 mineralized intercepts from 12 drill holes. Reported “infill” intercepts are located within the 2026 MRE model (see April 14, 2026 news release), focused on upgrading Inferred Mineral Resources to Measured or Indicated categories, as applicable. “Expansion” intercepts are located outside the 2026 MRE model and comprise either i) in-pit expansion, which offers potential to convert in-pit waste into additional resources within the 2026 MRE Whittle pit; or ii) out-of-pit expansion, consisting of mineralization located outside the 2026 MRE Whittle pit, which may potentially lead to the definition of new resources. Some of the reported intercepts may have contiguous shallower infill as well as deeper expansion (noted as “Both”). Maps showing hole locations are available at www.osiskometals.com.

Osisko Metals Chief Executive Officer Robert Wares commented: “We are very pleased with these excellent new results from the current drilling, particularly the high-grade intercept in hole 30-1228 located 800 metres west of the 2026 MRE model. The mineralized system continues to expand beyond the current pit limits with noticeable grade improvement in the area around Needle Mountain. Additionally, infill holes 30-1233 and 30-1235 produced better-than-average grades at the south end of the 2026 MRE model. New assay results are now being received at a faster pace, and we expect to provide continuous updates throughout the fall.”

Highlights

• 256.5 metres averaging 0.85% Cu (Out-of-pit expansion) in DDH 30-1228, including 28.5 metres averaging 4.74% Cu and 27.4 g/t Ag
• 257.5 metres averaging 0.39% Cu (Infill) in DDH 30-1235
• 177.5 metres averaging 0.40% Cu (Infill) in DDH 30-1233
• 101.0 metres averaging 0.44% Cu (In-pit expansion) in DDH 30-1226
• 67.7 metres averaging 0.63% Cu (Out-of-pit expansion) in DDH 30-1234
• 49.7 metres averaging 0.74% Cu (Out-of-pit expansion) in DDH 30-1225
  
  

Table 1: Infill and Expansion Drilling Results

DDH No.	From (m)	To (m)	Length (m)	Cu %	Ag g/t	Mo %	CuEq* %	Type**
30-1224	123.0	151.0	28.0	0.24	2.35	<0.005	0.24	Expansion 1
and	318.0	366.0	48.0	0.16	1.28	0.041	0.30	Expansion 1
and	390.0	428.0	38.0	0.15	1.44	0.039	0.29	Expansion 1
and	546.8	700.0	153.2	0.20	1.58	0.023	0.28	Expansion 2
30-1225	57.0	75.0	18.0	0.14	1.07	<0.005	0.14	Expansion 2
and	88.3	141.0	52.7	0.36	2.11	<0.005	0.37	Expansion 2
and	178.3	228.0	49.7	0.74	3.86	<0.005	0.75	Expansion 2
and	259.5	265.5	6.0	1.19	6.10	<0.005	1.20	Expansion 2
30-1226	43.0	144.0	101.0	0.44	2.35	<0.005	0.45	Expansion 1
and	196.5	214.5	18.0	0.31	2.07	<0.005	0.32	Expansion 2
and	295.5	324.0	28.5	0.24	2.73	<0.005	0.24	Expansion 2
30-1227	73.0	104.0	31.0	0.20	1.54	<0.005	0.20	Infill
and	144.0	172.5	28.5	0.25	2.24	0.005	0.27	Expansion 1
and	204.0	226.0	22.0	0.18	1.57	0.014	0.23	Expansion 1
and	254.0	277.5	23.5	0.16	1.67	0.008	0.18	Expansion 1
30-1228	33.0	289.5	256.5	0.85	5.13	<0.005	0.86	Expansion 2
(including)	199.5	228.0	28.5	4.74	27.4	0.005	4.78	Expansion 2
30-1229	19.5	157.0	137.5	0.34	1.33	<0.005	0.34	Infill
30-1230	195.6	258.0	62.4	0.17	1.12	<0.005	0.17	Expansion 2
and	292.2	316.5	24.3	0.22	1.24	<0.005	0.22	Expansion 2
30-1231	184.5	240.0	55.5	0.19	1.98	<0.005	0.19	Expansion 2
And	270.6	346.5	75.9	0.28	2.10	<0.005	0.28	Expansion 2
30-1232	30.0	55.0	25.0	0.20	2.42	<0.005	0.20	Expansion 2
30-1233	16.0	193.5	177.5	0.40	2.88	<0.005	0.41	Infill
and	222.0	298.5	76.5	0.42	3.91	<0.005	0.43	Infill
and	327.0	379.5	52.5	0.35	2.93	<0.005	0.35	Infill
30-1234	135.3	203.0	67.7	0.63	3.22	<0.005	0.64	Expansion 2
and	234.0	280.5	46.5	0.29	1.55	<0.005	0.29	Expansion 2
30-1235	47.0	304.5	257.5	0.39	3.60	<0.005	0.40	Infill

*  See explanatory notes below on copper equivalent values and Quality Assurance/Quality Controls.
**  Infill refers to intercepts within the current MRE model; Expansion 1 refers to in-pit intercepts outside of the current MRE model; Expansion 2 refers to out-of-pit intercepts outside of the current MRE model. “Both” indicates drill holes that have contiguous shallower infill as well as deeper expansion intercepts.

Discussion

Drill hole 30-1224, located near the core processing facility, approximately 200 metres west of western limit of the 2026 MRE model, is a northeasterly dipping hole that cut four mineralized intervals, the first three being in-pit expansions and the fourth (deepest) interval being the longest and an out-of-pit expansion, consisting of 153.2 metres averaging 0.20% Cu, 0.023% Mo and 1.58 g/t Ag, extending mineralization in this area to a vertical depth of 660 metres.

Drill hole 30-1225, located on the western margin of the Needle Mountain pit, is an easterly dipping hole that was drilled under the pit wall, threading through a pillar of the B Zone underground workings and stopping in a stope of the C Zone underground workings. It cut three mineralized intervals (all out-of-pit expansions), including 52.7 metres averaging 0.36% Cu and 2.11 g/t Ag, followed by a deeper interval of 49.7 metres averaging 0.74% Cu and 3.86 g/t Ag (B Zone level). This hole also intersected a short interval of 6.0 metres averaging 1.19% Cu before intersecting the C Zone stopes.

Drill hole 30-1226 is located near the eastern margin of the Needle Mountain pit, approximately 260 metres southwest of the limit of the 2026 MRE model, and tested an area where little mineralization was expected from historical drilling. It is a northeasterly dipping hole that cut three mineralized intervals. The first, an in-pit expansion, averaged 0.44% Cu and 2.35 g/t Ag over 101.0 metres (mostly oxidized mineralization). The next two intervals (out-of-pit expansions below the pit floor) averaged 0.31% Cu and 2.07 g/t Ag over 18.0 metres and 0.24% Cu and 2.73 g/t Ag over 28.5 metres, extending mineralization in this area to a vertical depth of 305 metres.

Drill hole 30-1227, located near the western margin of the 2026 MRE model, is a westerly dipping hole designed to better define the boundary of the 2026 MRE model. It cut four narrow mineralized intervals, the first being an infill interval and the other three being in-pit expansions. The intervals vary from 22.0 to 31.0 metres wide with grades averaging 0.16% to 0.25% Cu. Mineralization along this boundary was extended to a vertical depth of 260 metres.

Drill hole 30-1228, located on the western margin of the Needle Mountain pit, is a southeasterly dipping hole that was drilled under the pit wall, threading through pillars of both the B Zone and C Zone underground workings. It cut one long mineralized interval (out-of-pit expansion) comprising 256.5 metres averaging 0.85% Cu and 5.13 g/t Ag, including a high grade sub-interval of 28.5 metres averaging 4.74% Cu and 27.4 g/t Ag (C Zone level). Mineralization in this drill hole extended 50 metres below the C Zone to a vertical depth of 275 metres. This drill hole demonstrates the potential for higher grade mineralization surrounding old underground workings, within residual pillars, between the B and C Zones and deeper below the C Zone.

Drill hole 30-1229, located at the southern end of the 2026 MRE model on the northern flank of Needle East Mountain, is an infill vertical hole that was drilled to test around and under historical underground workings to a level below the C Zone. This hole intersected 137.5 metres averaging 0.34% Cu and 1.33 g/t Ag, but failed to drill through the B Zone pillar and consequently did not penetrate either the B nor C Zones.

Drill hole 30-1230, located on the north flank of Needle Mountain on the western margin of the modelled mineralized system, is a northeasterly dipping hole that cut two mineralized intervals (both out-of-pit expansions), including 62.4 metres averaging 0.17% Cu and 1.12 g/t Ag (above C Zone horizon), followed by a deeper interval of 24.3 metres averaging 0.22% Cu and 1.24 g/t Ag (below C Zone horizon), extending mineralization in this area to a vertical depth of 305 metres. The C Zone horizon in this hole consisted of unmineralized marble.

Drill hole 30-1231, located near the southeastern margin of the Needle Mountain pit, approximately 820 metres southwest of the limit of the 2026 MRE model, is an easterly dipping hole that cut two mineralized intervals (out-of-pit expansions), the first averaging 0.19% Cu and 1.98 g/t Ag over 55.5 metres (above C Zone horizon), and the second averaging 0.28% Cu and 2.10 g/t Ag over 75.9 metres (below C Zone horizon), extending mineralization in this area to a vertical depth of 340 metres. The C Zone horizon in this hole consisted of unmineralized marble.

Drill hole 30-1232, located between Needle East and the Needle Mountain pit, is a westerly dipping hole that was drilled to test an area where no mineralization was expected from historical drilling. This hole intersected one zone of mineralization consisting of 25.0 metres averaging 0.20% Cu and 2.42 g/t Ag (out-of-pit expansion), within the Indian Cove Formation, as well as several scattered, thin intersections (5 to 10 metres thick) to a vertical depth of 280 metres.

Drill hole 30-1233 is a vertical infill hole located near the southern margin of the 2026 MRE model. It was drilled through a pillar of the B Zone underground workings and cut three mineralized intervals from surface that returned 177.5 metres averaging 0.40% Cu and 2.88 g/t Ag (B Zone level and above), followed by 76.5 metres averaging 0.42% Cu and 3.91 g/t Ag (C Zone level extending to 45 metres below this level), and then a third interval of 52.5 metres averaging 0.35% Cu and 2.93 g/t Ag (below C Zone level). This hole extends mineralization in this area to a vertical depth of 380 metres.

Drill hole 30-1234, located on the northwestern margin of the Needle Mountain pit, on the western margin of the modelled mineralized system, is a vertical hole that extended a 2024 Osisko hole (30-1038) to deeper levels. This hole cut two mineralized intervals (both out-of-pit expansions), including 67.7 metres averaging 0.63% Cu and 3.22 g/t Ag (B Zone horizon and below), followed by a deeper interval of 46.5 metres averaging 0.29% Cu and 1.55 g/t Ag (below C Zone horizon), extending mineralization in this area to a vertical depth of 280 metres. The second interval reports the merged meterage of both holes. The C Zone horizon in this hole consisted of unmineralized marble.

Drill hole 30-1235 is a vertical infill hole located near the southern margin of the 2026 MRE model, approximately 170 metres southwest of 30-1233. It was drilled through a pillar of the B Zone underground workings and cut one continuous mineralized interval, from near surface, that returned 257.5 metres averaging 0.39% Cu and 3.60 g/t Ag (from B Zone level to below C Zone level). This hole extends mineralization in this area to a vertical depth of 305 metres.

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. One prograde and at least five retrograde vein/stockwork mineralizing events have been recognized at Copper Mountain, which overprint earlier, stratiform, carbonate replacement 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-parallel mineralization, which is mostly stratigraphically controlled, dominates in the area of lower Copper Mountain, 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), and additional drilling in 2025 led to an additional significant increase in resources, mostly in the Measured and Indicated categories (see April 14, 2026 MRE press release).

The current drill program is designed to convert the bulk of the remaining 2026 MRE Inferred resources to Measured and Indicated categories, as well as test the expansion of the overall resource laterally to the west, and to the south/southwest towards Needle East and Needle Mountain respectively.

Table 2: Drill hole locations

DDH No.	Azimuth (°)	Dip (°)	Length (m)	UTM E	UTM N	Elevation
30-1224	70	-70	741	315787	5425813	569
30-1225	98	-47	266	315352	5425252	734
30-1226	70	-70	435	315961	5425168	701
30-1227	248	-70	339	316101	5425612	571
30-1228	130	-74	345	315357	5425341	725
30-1229	0	-90	162	316420	5425456	612
30-1230	75	-80	354	315463	5425655	634
30-1231	85	-78	384	315408	5425045	772
30-1232	250	-70	354	315978	5425040	727
30-1233	0	-90	489	316360	5425511	585
30-1234	0	-90	321	315394	5425418	722
30-1235	0	-90	447	316282	5425365	629

Explanatory note regarding copper-equivalent grades

Copper Equivalent (CuEq) grades are presented for illustrative purposes only to express the combined value of copper, molybdenum, and silver as a single copper grade. CuEq grades are calculated using long-term metal prices of US$4.50/lb copper, US$20.00/lb molybdenum, and US$45.00/oz silver, and incorporate assumptions for metallurgical recoveries, payable metal factors, smelting and refining charges, transportation costs, and royalties. Hence the CuEq calculation is essentially based on net smelter return (NSR) values. NSR for each metal is estimated by applying metallurgical recoveries, payable factors, metal prices, and applicable smelting, refining, transportation, and penalty charges to the in-situ metal grades. CuEq grades are derived using a linear regression relationship established between copper grade and copper NSR, and then calculated by substituting total NSR (Cu + Mo + Ag) for copper NSR in the regression equation. The simplified formula is expressed as CuEq (%) = Cu (%) + 3.40327 × Mo (%) + 0.00008 × Ag (g/t)

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 10 metres or less are generally not reported unless considered material.   True widths are estimated at 80 – 90 % 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 site is located near Murdochville in Québec's Gaspé Peninsula. The Company is currently focused on resource expansion of the Gaspé Copper deposits, with current pit-constrained Measured and Indicated Mineral Resources of 1.83 Bt averaging 0.32% CuEq and Inferred Mineral Resources of 239 Mt averaging 0.46% CuEq (in compliance with NI 43-101). For more information, see Osisko Metals' April 14, 2026 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.

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