Selkirk Copper Mines Inc. (TSX-V: SCMI) (FSE: IO20) (OTCQX: SKRKF) is pleased to announce additional results from the Phase 2 drill program which commenced in May 2026, at the Minto Project in Yukon, Canada.

Highlights

• Step-out drilling at Minto North intersected high-grade mineralization at the southern margin of this priority resource area:
  • 9.27% Cu, 7.43 g/t Au, and 54.9 g/t Ag (15.11% CuEq) over 5.4 m, as well as an additional interval of 0.97% Cu, 2.58 g/t Au, and 8.4 g/t Ag (3.11% CuEq) over 9.0 m, in drill hole 26SCM209
  • This hole ranks amongst the highest-grade intersections that has ever been drilled at Minto Property
• Infill drilling at Area 118 continues to delineate high-grade mineralization within 100 m of historical underground workings:
  • 2.54% Cu, 1.25 g/t Au, and 10.7 g/t Ag (3.45% CuEq) over 3 m, within a broader interval of 1.43% CuEq over 14.8 m, in drill hole 26SCM216
  • 1.61% Cu, 0.59 g/t Au, and 8.3 g/t Ag (2.03% CuEq) over 6.9 m, within a broader interval of 1.02% CuEq over 33.3 m, in drill hole 26SCM207
• Infill drilling at Minto Main intersected additional mineralization within the 114 and 117 Lenses:
  • 1.15% Cu, 0.43 g/t Au, 2.7 g/t Ag (1.42% CuEq) over 9.7 m, as well as a second interval of 0.83% Cu, 0.19 g/t Au, and 2.7 g/t Ag (0.94% CuEq) over 32.1 m, in drill hole 26SCM235
• Infill drilling at Copper Keel continues to delineate additional mineralization within the 101 Lens:
  • 1.30% Cu, 0.34 g/t Au, 3.4 g/t Ag (1.49% CuEq) over 7.0 m, within a broader interval of 0.94% CuEq over 18.0 m, in drill hole 26SCM238

Drilling Milestone Update

• In late August, Selkirk Copper marked a major milestone in drilling activities, recognizing one year of drilling completed since August 23, 2025. As of that date, the team has completed 365 diamond drill holes in 365 days, for a total of 98,467 metres in one year. This represents one of the largest single-year drill programs ever completed in Yukon history and represents approximately 200,000 person-hours and a ~C$45M investment in mineral resource development
• As of September 28, 2026, the Company has completed 52,485 meters of diamond drilling in 224 drill holes within its ongoing Phase 2 drill program

Investor Update and PEA Webinar

• Selkirk Copper will be hosting an Investor Update on Friday October 2, 2026 beginning at 11:00 am EDT/8:00 am PCT (selkirkcopper.com/webinar) to discuss the recently completed Preliminary Economic Assessment, providing insights into the positive results of Phase 1 Drill Program, Mineral Resource Estimate, engineering and development study work, and initial economics of the Minto Project

M. Colin Joudrie, President & CEO, commented: “As the Phase 2 drill program nears completion, the exploration and development team continues to delineate and expand a series of high-grade copper-gold-silver lenses in several zones across the mine site property. With the development of an enhanced structural model and refined targeting methodology, combined with a focused infill drill program designed to convert Indicated & Inferred Resources into Measured & Indicated Resources in support of the planned Feasibility study, we continue to upgrade our understanding of the overall Minto mineral system.

Results from the Phase 2 drill program, particularly high-grade copper-gold-silver intercepts at Minto North and Area 118, are an integral part of Minto Project restart plan providing the information necessary to inform and refine our upcoming Feasibility-level mine planning and development plans. The material being collected in the Phase 2 drill program, along with upgrading our resource modeling work, will be used for a geometallurgical test program that will increase our confidence in expected copper, gold, and silver recoveries.

In addition to expanding and refining our understanding of the mineral resources at the Minto Project, the exploration team is completing a series of geotechnical drill holes that inform and derisk mine development plans. A series of water monitoring wells are also being completed which will inform our amended permit applications as well as enhancing our ability to monitor and model water on site.

This multi-purpose Phase 2 drill program has greatly enhanced our understanding of the Minto Project and the information we are gathering continues to increase our confidence in our restart plan.”

Leif Bailey, Director of Geoscience & Exploration added: “Completion of Selkirk Copper’s first year of drilling is a major milestone for our team. The program represents one of the largest single year diamond drill programs ever completed in Yukon history. This accomplishment is the result of great work and considerable effort by a large and diverse team that came together quickly to work towards a common goal. The results of this drill program demonstrate that considerable potential still exists at Minto for discovery and delineation of high-grade copper, gold, and silver mineralization.”

2026 Phase 2 Drill Program

The Phase 2 drill program was planned with a target of 50,000 metres focused on expansion, exploration, and infill drilling of key target areas, as well as geotechnical data collection to support the upcoming Feasibility Study.

Compared to the Phase 1 program, the Phase 2 program has had higher drilling productivity, increased efficiency of logistics to support drilling, and lower average cost per metre drilled. Because of these improvements, the Exploration team has identified opportunities to complete additional metres while remaining on-schedule and on-budget.

As of September 28^th, 52,485 metres of drilling has been completed in 224 drill holes, representing 105% of the planned meterage. The drill program is anticipated to continue until mid-October. During late August the scale of the program was reduced from four drill rigs to two drill rigs. The last portion of the drill program will be focused on geotechnical data collection, water monitoring well installations, and exploration of recently identified geophysical targets.

Reported here are results from holes drilled in June 2026. Turnaround time for assay results is currently approximately eight weeks. Assay results are expected to continue being released throughout the fall and winter of 2026.

Table 1: Summary of Phase 2 Drilling Completed by Location

Figure 1: Plan view of the Minto Mine Property showing surface projections of mineralized zones as well as Phase 1 and Phase 2 drill collars. Drill hole results presented in this release are highlighted

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Minto North Drill Results

At Minto North, the Phase 2 drill program is targeting infill and expansion of priority areas within the early planned life of mine, including the high-grade 202 Lens. Reported here are seven drill holes targeting the 202 Lens, including five infill holes and two holes targeting resource expansion. Six out of seven drill holes intersected significant mineralization.

Notable amongst these results is drill hole 26SCM209, which is a 35-metre step-out from previous drilling in the southern portion of the 202 Lens. This hole intersected two intervals of mineralization, including one of the highest-grade intercepts that has ever been drilled on the Minto Property: 9.27% Cu, 7.43 g/t Au, and 54.9 g/t Ag (15.11% CuEq) over 5.4 m. The grade of this intercept ranks within the 99^th percentile of all historical drilling at Minto, within a historical database of more than 4,300 significant intercepts. Peak values from individual one metre samples within this intercept include 17.5% Cu, 15.9 g/t Au, and 81.9 g/t Ag. The interval is comprised of semi-massive bornite, chalcopyrite, and magnetite within a migmatite host rock. Additional drilling has been completed southwards of hole 26SCM209, with assay results pending.

Also notable within these results is drill hole 26SCM224, which is a 35-metre step-out from previous drilling in the northwestern part of the 202 Lens. This hole returned an intersection of 1.25% CuEq over 17.6 m and demonstrates that the 202 Lens remains open for expansion towards the northwest. Additional drilling is proposed for this area to continue investigating the size potential of this priority mining area.

Results from holes 26SCM209 and 26SCM224 also indicate an apparent structural control on high-grade mineralization within the deposit area. Within the 202 Lens, higher-grade and thicker mineralization is observed to be focused along a north-northwest trend. Similar north-northwest trends of increased grade and thickness are observed elsewhere within the deposit area, including at Minto Main, Area 118, and Copper Keel. At a smaller scale, tight to isoclinal folds are commonly observed to have similar north-northwest trending fold axes. In some folds, accumulations of chalcopyrite and bornite occur within the north-northwest trending fold hinge. Figure 3 below depicts an example of one such isoclinal fold in the Minto Main area with chalcopyrite accumulation along the fold hinge. The exploration team is evaluating the hypothesis that high-grade mineralization such as seen in drill hole 26SCM209 may represent a larger-scale example of a structural control related to folding and deformation that localizes high-grade mineralization within the 202 Lens.

Figure 2: Cross section and plan view of drill holes intersecting the 202 Lens at Minto North

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Figure 3: Drill core photographs of massive sulphide mineralization at Minto North; and mineralization hosted within an isoclinal fold hinge at Minto Main

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Area 118 Drill Results

In Area 118, Phase 2 drilling is targeting expansion and delineation of several mineralized lenses located nearby existing underground development. Reported here are five drill holes targeting infill of modelled lenses, all of which intersected mineralization. The results confirm the modeled geometry and increase the confidence in grade estimation within these lenses.

Notable results reported here from Area 118 include hole 26SCM198, 26SCM207, and 26SCM216. These three holes targeted the 114 Lens in an area located within 100 metres of the existing underground decline. Previous mining activity occurred to the west of this area, as shown in Figure 4. Hole 26SCM198 indicates the potential for mineralization in this area to host significant grades, with an intercept of 1.53% Cu, 0.58 g/t Au, and 7.6 g/t Ag (1.94% CuEq) over 9.1 metres. Mineralization in this area remains open to the south and southeast and is an opportunity for further resource expansion.

Figure 4: Plan view of drill holes intersecting the 114 Lens in Area 118. Mineralization in this area remains open to the south and southeast of previous mining areas

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Minto Main Drill Results

In the Minto Main area, Phase 2 drilling is targeting expansion and delineation of mineralized lenses located between and beneath previous open pit and underground mining areas. Reported here are four drill holes targeting infill of the 114 and 117 Lenses. All four holes intersected mineralization, however the grade in two of these holes is lower than expected. The results confirm the modeled geometry and provide information to better constrain potentially economic mining areas within the mineralized lenses.

Drill hole 26SCM235 was designed to infill a 90-metre gap within the previous drilling in the central portion of the 117 and 114 Lens. This hole returned two significant intercepts, including an interval of 1.42% CuEq over 9.7 metres in the 114 Lens and an interval of 0.94% CuEq over 32.1 metres in the 117 Lens. Mineralization in both lenses is characterized by disseminated to folioform chalcopyrite and bornite within a foliated granodiorite host rock. Compared to other locations within the mine area, this location is characterized by a relatively weaker, diffuse foliation and disseminated mineralization. Additional drill results are pending in the Minto Main area.

Figure 5: Cross section view of hole 26SCM235 in the Minto Main area

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Copper Keel Drill Results

At Copper Keel, Phase 2 drilling is targeting infill and expansion of several shallowly dipping mineralized lenses. Reported here are nine drill holes targeting the eastern portion of the 101 Lens within the Copper Keel resource area. Five of these holes intersected mineralization and confirmed modelled lens geometry.

Notable results reported here include hole 26SCM234, which returned an intercept of 2.29% CuEq over 5 metres; and hole 26SCM238, which returned an intercept of 0.94% CuEq over 18 metres. These results indicate that significant mineralization can occur within some portions of the Copper Keel area, however other areas contain lower grades that may not warrant inclusion into a mine plan. Additional geological modelling is planned to better constrain potentially economic domains within the Copper Keel area

Figure 6: Cross section view of Copper Keel, looking to the northeast

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Regional Exploration Update

A modest-sized program of helicopter-supported regional exploration was completed during July to September. This represents Selkirk Copper’s first effort to evaluate a regional land package of 26,850 hectares of mineral claims located within a highly prospective district. This district contains numerous “Minto style” mineral occurrences comprising copper-gold mineralization hosted within the same host rocks as the Minto deposit. Many of the mineral occurrences within Selkirk Copper’s mineral claims have not had any substantial exploration activity in more than ten years.

The objective of the 2026 exploration program was to begin an assessment of these mineral claims, utilizing knowledge and learnings from the deposit that can be applied across the district. The program included geological and structural mapping, geochemical soil sampling, and airborne geophysical surveys. A program of geochemical and geophysical orientation surveys was completed within the deposit area to help corroborate interpretation of regional results.

The airborne geophysical surveys included a QMAGT full-tensor magnetic gradiometric survey and also a QAMT passive airborne electromagnetic survey. Both surveys utilized Superconducting Quantum Interference Device sensors that are capable of very high detail and sensitivity. These survey instruments are new technologies that operationalize 20 years of research and testing. The QAMT survey completed at Minto represents one of the first-ever applications of this technology to a Canadian mineral exploration project.

Results of this regional exploration program are pending and interpretations will be ongoing this winter to develop targets for further assessment in 2027.

Table 2: Collar Locations and Header Information

Table 3: Significant Interval Table

Investor Update and PEA Webinar

Selkirk Copper will be hosting an Investor Update on Friday October 2, 2026 beginning at 11:00 am EDT/8:00 am PCT (selkirkcopper.com/webinar) to discuss the recently completed Preliminary Economic Assessment, providing insights into the positive results of Phase 1 Drill Program, Mineral Resource Estimate, engineering and development study work, and initial economics of the Minto Project. Colin Joudrie (President & CEO) and other members of Selkirk Copper’s management team will discuss the significant strides the Company has made over the past 14-months and key areas of focus in the planned Feasibility Study. Participants will be able to submit questions they would like to have addressed during the event.

QAQC Procedures and Data Validation

The Company is drilling NQ-diameter core and completing geological logging and oriented core structural data collection. Following data collection, core is cut along the long axis, with half of the core going to the lab for chemical analysis and the remaining half kept in sequence as record. The half core samples are packaged with the corresponding sample tag id and sealed. All sampling is conducted by Selkirk Copper and is subject to Company standard internal quality control and quality assurance programs. QAQC procedures include the insertion of certified reference material, coarse blank materials, and field duplicate analysis, as well as standard laboratory procedures to monitor contamination during preparation, analytical accuracy, and precision. QAQC insertion rates by Selkirk Copper approximate 15% of all samples at set intervals.

For the Phase 2 drill program, all samples were sent to ALS’s prep facility in Whitehorse, then shipped to ALS’s analytical laboratory in Vancouver. All samples are prepared by crushing rock to 70% passing 2mm screen, then splitting a 250g sub-sample using a riffle splitter before being pulverized 85% passing 75 microns. Gold is analyzed by 30 g Fire Assay (Au-AA23) with atomic absorption analysis followed by gravimetric finish for overlimit results. Copper is analyzed by four-acid digest (ME-ICP61) with inductively coupled plasma – atomic emission spectroscopy (ICP-AES) finish. If copper overlimit results are triggered a second four-acid digest for high grade copper (Cu-OG62) is conducted. Samples containing greater than 1000 ppm copper are also analyzed for soluble copper using a sulphuric acid leach (Cu-AA05) analysis with AAS finish. ALS Vancouver holds an ISO/IEC 17025 standard accreditation.

QAQC results are reviewed by Selkirk Copper upon receipt of assay results. Overall, QAQC results show strong analytical performance across Cu, Au, and Ag datasets. All control standards are within acceptable tolerance, with no significant outliers or systematic bias observed.

Primary intervals are reported as drill core length, with true widths estimated to be approximately 80 – 90% of core lengths, based on the sub-horizontal to shallow-dipping nature of the modelled mineralized zones.

Mineral Resource Estimate Details

The following table summarizes the current Minto Mineral Resource Estimate:

Table 4: Global Mineral Resource Estimate for the Minto Project (Effective Date: June 10, 2026)

References

¹ See 2026-09-14 Technical Report “NI 43-101 2026 Mineral Resource Estimate Update for the Minto Property, Yukon, Canada” effective date 2026-06-10 filed by Selkirk Copper Mines Inc., available on SEDAR+ (sedarplus.ca).

Technical aspects of this news release have been reviewed, verified and approved by Leif Bailey, P.Geo., Director of Geoscience & Exploration of Selkirk Copper Mines Inc., who is a qualified person as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects.

About Selkirk First Nation

Selkirk First Nation is centered in Pelly Crossing, a community in central Yukon, 280 km north of Whitehorse. They are a self-governing First Nation, having signed its Final and Self-Government Agreements in 1997. Selkirk First Nation owns 4,740 square kilometers of Settlement Land, including 2,408 square kilometers where they own both the surface and subsurface. Selkirk First Nation is one of three self-governing Northern Tutchone First Nations in the Yukon. The Selkirk First Nation, indirectly, holds a controlling equity stake in Selkirk Copper.

About Selkirk Copper

Selkirk Copper is a well-financed, newly formed company with a controlling interest held by the Selkirk First Nation through its wholly owned subsidiary, that, in partnership with the Selkirk First Nation, is completing a thorough exploration drilling campaign and a restart and redevelopment plan for the former Minto copper-gold-silver mine based on best-in-class environmentally sustainable mining, development and reclamation practice. Selkirk Copper controls 26,850 hectares of prospective mineral claims located in the Minto-Carmacks copper belt as well as significant open-pit and underground infrastructure, a 4,100 tonne per day processing plant, 400-person full-rotation camp, water treatment facilities, numerous ancillary buildings, and mobile equipment centered on the former Minto copper-gold-silver mine. Selkirk Copper’s mineral tenure, operation infrastructure, access roads, and powerline is located on or adjacent to Lands of the Selkirk First Nation much of which is surrounded by prospective Selkirk First Nation Category A Lands.

Selkirk Copper Mines Inc. is listed on the TSX Venture Exchange under the symbol (TSX-V: SCMI), has a secondary listing on the Frankfurt Exchange under the symbol (FSE: IO20), and its common shares trade under the symbol (OTCQX: SKRKF) on the OTCQX® Best Market, a U.S. marketplace operated by OTC Markets Group Inc.

On behalf of the Board of Directors of Selkirk Copper Mines Inc.

Colin Joudrie
President and Chief Executive Officer

For more information, please contact:

Colin Joudrie, President & CEO
colin.joudrie@selkirkcopper.com
(604) 760-3157

Justin Stevens, Vice-President Corporate Development
justin.stevens@selkirkcopper.com
(604) 240-2959

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.