Oreterra Wraps up Phase 1 Drilling at Trek South with Visible Copper Minerals and Broad Intercepts of Porphyry-Style Alteration Above Postulated Intrusion; Planning for 2027[...]

Toronto, Ontario - September 16, 2026 - Oreterra Metals Corp. ("Oreterra" or the "Company") (TSXV: OTMC) (OTCID: OTMCF) (FSE: D4RO) (WKN: A421RQ) is pleased to report that the Phase 1, first-ever drill program at its Trek South porphyry copper-gold prospect, strategically located in B.C.'s Golden Triangle adjacent to the southeast of Teck-Newmont's Galore Creek joint venture, has now concluded. 13 holes were drilled during the program, 11 on Trek South 'A' Zone and 2 on Trek South 'Toe' Zone (Figure 1), for a total of 4,500 metres. Assay results are anticipated later in the fall and will be used to guide a Phase 2 program in planning for 2027. An orderly camp demob is underway ahead of deteriorating weather conditions with key camp infrastructure including tent pads, materials and drill pads left in place to facilitate both an earlier start and lower costs for the 2027 field season.

Program Highlights (Refer to Figures 1 and 2, and Photos 1 to 3):

• Multi-hundred metre porphyry-style alteration intercepts in central holes: Central holes TS26-06, TS26-09 and TS26-10 (Trek South 'A' Zone (Figure 1)) all delivered multi-hundred metre intercepts of strong to intense porphyry-style alteration;
• Copper minerals accompany the alteration: Alteration in the above three holes is accompanied by visually encouraging observations of copper minerals including one or several of bornite ± chalcopyrite ± chalcocite ± malachite ± chrysocolla (see Photo 1) ranging from trace amounts over down-hole widths spanning several hundred metres to locally appreciable amounts over ten of metres;
• Underlying source intrusion is zeroed-in and primed for drilling: The above three holes are believed to lie above an underlying source intrusion which will be a key target of the Phase 2 program in planning for 2027. The presence of bornite and intergrown chalcocite in the system is highly suggestive of a high-temperature magmatic (i.e. porphyry) source at depth;
• Abundant copper minerals at the new Trek South Zone 'C': Field work on the east side of Trek South glacier has identified a large new area of intensely altered boulders bearing some of the most abundant visible copper mineralization seen on the property to date, now designated 'Trek South C Zone' (Photo 2). Planning to drill this is in 2027 is underway;
• Trek South target area increases in size: Along with the Trek South 'B' Zone identified on the southwest side of the glacier in August 2025, strong porphyry-style alteration often accompanied by visible copper mineralization is now known to be present around almost the entire 1 km² perimeter of the Trek South glacial basin (Figure 2);
• Trek South 'Toe' Zone first-ever drill intersections: Drilling of two short holes on the Trek South 'Toe' Zone, believed to represent an Eskay Creek / VMS style of mineralization, has returned visually highly promising results including multi-metre intersections of strong chalcopyrite mineralization (Figures 1, 2 and Photo 3). Assays of Toe Zone surface exposures have in the past returned high-grade Cu, Au, Ag, Zn & Sb (antimony) values.

"Trek South continues to be exceptionally encouraging as a new, large-scale porphyry prospect," said Kevin Keough, CEO. "The Phase 1 drill program has given us everything we expected to see, shy of the actual location of a source intrusion, though we now have a very good sense as to where it may be. The visually exciting alteration and mineralization observed in drilling at Trek South 'A' Zone (Photo 1) and 'Toe' Zone (Photo 3), coupled with the new prospecting results at the 'B' and 'C' Zones (Photo 2), have provided the basis for advancing to Phase 2, and we're very much looking forward to a return to the property next year, with camp infrastructure and drill pads remaining in place to facilitate this."

QA/QC

The drill holes discussed in this news release are being sampled from top to bottom by sawing the core length-wise in half with a rock saw and submitting ½ of the sawn core for gold analyses by fire assay and multi-element analyses by an initial four-acid digestion followed by ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) analysis. The maximum sample length is 1.5 metres. The samples are being sent to the ALS prep facility in Terrace and laboratory in Vancouver, BC for analysis. A rigorous quality assurance and quality control program is in place in the form of alternating blanks, Certified Reference Material standards, and pulp or coarse reject duplicates inserted at every 10^th position in the sample series.

‍Qualified Person

The technical information in this news release has been reviewed and approved by John Biczok, P.Geo., Vice President, Exploration for Oreterra Metals Corp. and a Qualified Person as defined by National Instrument 43-101.

‍About Oreterra Metals Corp.

Oreterra Metals Corp. is a TSXV-listed mineral exploration company focused primarily on copper and gold. The Company holds several wholly-owned porphyry copper-gold prospects in British Columbia's Golden Triangle, the most significant of which is the large-scale Trek South prospect, only recently revealed by glacial ice melt, located adjacent to the southeast of Teck-Newmont's Galore Creek project. Additional wholly-owned Oreterra interests include two former producers in Nevada: the Kinkaid claims in the Walker Lane trend covering numerous shallow Au-Cu-Ag workings over what is believed to be one or more porphyry centres, and the Scossa mine property in the Sleeper trend which is a former high-grade gold producer. The Company also holds a 100% interest in the large-scale Lundmark-Akow Lake Au-Cu property adjacent to the northwest of the Musselwhite Mine, where drilling by the Company has produced highly encouraging, broad VMS-style Au-Cu intersections. Oreterra also retains an ongoing interest in several properties including a 2% NSR on McEwen Mining's Hislop gold property in Ontario and a 2% NSR on Enduro Metals' Newmont Lake Au-Cu-Ag property in BC. Technical presentations on each of the Kinkaid, Scossa and Lundmark-Akow Lake properties, authored by J. Biczok, P.Geo, are available at https://www.oreterra.com/investors.

For further information please visit www.oreterra.com or contact:

Kevin M. Keough Stephen Burega

Chief Executive Officer and Director President and Director

Tel: 613 622-1916 Tel: 647 515-3734

Email: [email protected] Email: [email protected]

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

Cautionary Statement Regarding Forward-Looking Information

This news release includes certain "forward-looking statements" which are not comprised of historical facts. Forward-looking statements include estimates and statements that describe the Company's future plans, objectives or goals, including words to the effect that the Company or management expects a stated condition or result to occur. Forward-looking statements may be identified by such terms as "believes", "anticipates", "expects", "estimates", "may", "could", "would", "will", or "plan". Since forward-looking statements are based on assumptions and address future events and conditions, by their very nature they involve inherent risks and uncertainties. Although these statements are based on information currently available to the Company, the Company provides no assurance that actual results will meet management's expectations. Risks, uncertainties and other factors involved with forward-looking information 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 include, but are not limited to failure to identify mineral resources, delays in obtaining or failures to obtain required governmental, environmental or other project approvals, political risks, inability to fulfill the duty to accommodate First Nations, uncertainties relating to the availability and costs of financing needed in the future, changes in equity markets, inflation, changes in exchange rates, fluctuations in commodity prices, delays in the development of projects, capital and operating costs varying significantly from estimates and the other risks involved in the mineral exploration and development industry, and those risks set out in the Company's public documents filed on SEDAR. 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.