Core Silver Commences Diamond Drilling at the Touleary Project

VANCOUVER, BC / ACCESS Newswire / September 9, 2026 / Arcus Development Group Inc. ("Arcus") (TSXV:ADG) and Core Silver Corp. ("Core" or "Core Silver") (CSE:CC)(FSE:8ZR)(OTCQB:CCOOF) (together, the "Companies") are pleased to announce that the 2026 diamond drilling program (the "Program") has commenced at the Touleary Project (the "Project") located approximately 115 km South of Dawson, Yukon Territory. The program will consist of approximately 3,000 metres. Initial testing will be focused on the 2011 Discovery Zone.

Highlights:

• Historic drilling was limited to a small section of the Discovery Zone.

  • Tested approximately 335 metres of strike length to a vertical depth of approximately 250 metres.

• Interpreted potential of the Discovery Zone indicates approximately 3.5 kilometres of untested strike-length.

• Additional target areas with no historic drilling, including Target-4 and Target-8, are also potential drill targets to be tested in the 2026 program (Figure 2).

  • Both areas have significant hand-pit and soil sample assays with coincident geophysical anomalies and/or prospective underlying geology.

*Reported intervals represent drill-core lengths. True widths of the mineralized intervals have not yet been determined. For more information, please refer to Arcus' technical report on the Touleary Project dated effective November 3, 2025, and available under its profile at www.sedarplus.ca.

"The drill is turning at the Touleary Project," said Nick Rodway, President and CEO of Core Silver. "This is the first drill program at the Project since 2011 and represents an important step toward evaluating the broader scale of the mineralized system. The program is designed to follow up the significant copper-gold-zinc-silver intersections encountered by historical drilling while also providing flexibility to test compelling undrilled targets elsewhere on the Project."

Figure 1: Touleary Project location and infrastructure; NOTE: The Northern Access Route is still under construction.

TARGETS FOR EXPLORATION

The 2026 drilling program will begin at the "Discovery Zone" / Target-1 (Figures 2 & 3) which was identified through work completed from 2009 to 2011 by Arcus including soil sampling, airborne geophysics, trenching, and diamond drilling.

• The 2011 diamond drilling returned significant assay results including:

  • TL-11-005

    • 2.25m @ 7.18% Cu, 3.55g/t Au, 4.30% Zn, 116g/t Ag (115.62 - 117.87m)

    • 14.15m @ 1.45% Cu, 0.73g/t Au, 0.28% Zn, 16.5g/t Ag (124.5 - 138.65m)

  • TL-11-002

    • 3.17m @ 2.38% Cu, 2.01g/t Au, 1.38% Zn, 32.9g/t Ag (124 - 127.17m)

  • TL-11-001

    • 6.09m @ 1.37% Cu, 0.80g/t Au, 0.41% Zn, 14.5g/t Ag (85.61 - 91.7m)

  • TL-11-003

    • 0.59m @ 1.42% Cu, 1.15g/t Au, 2.81% Zn, 36.4g/t Ag (64.21 - 64.80m)

    • 0.61m @ 4.01 % Cu, 2.18g/t Au, 0.93% Zn, 73.9g/t Ag (90.36 - 90.97m)

The total interpreted strike-length of the Discovery Zone geophysical signature is approximately 3.5 kilometres with only 335 metres having been tested by limited historic drilling.

Target-4 (Figure 4) was identified by a three (3) kilometre linear geophysical signature with correlating anomalous copper and zinc soil samples. No recent follow-up or historic drilling in this area. Target-8 (Figure 5) was identified by an underlying interpreted vent-complex (mapped) with multiple clusters of coincident anomalous copper, gold, silver, and zinc soil and hand-pit samples. No recent follow-up or historic drilling in this area.

Figure 2: 2026 proposed exploration areas; Soil samples (Cu ppm) shown as circles; Background is airborne geophysics (First Vertical Derivative).

Figure 3: Discovery Zone (Target 1) was identified by work completed from 2009 to 2011 including soil sampling, airborne geophysics, trenching, and diamond drilling; Background is airborne geophysics (First Vertical Derivative).

Figure 4:Target-4 was identified by a three (3) kilometre linear geophysical signature with correlating anomalous copper and zinc soil samples.

Figure 5: Target-8 was identified by an underlying interpreted vent-complex (mapped) with multiple clusters of coincident anomalous copper, gold, silver, and zinc soil and hand-pit samples.

TOULEARY VMS POTENTIAL

The Touleary Project benefits from several key characteristics commonly associated with major VMS systems, including:

• A large prospective land package within a well-established copper-rich geological belt with the potential for multiple types of mineralized systems.

• Strong exploration upside in an area that has seen limited modern systematic exploration.

• Exposure to both base and precious metals, providing leverage to multiple long-term commodity demand themes.

• Proximity to improving regional infrastructure, including the proposed Northern Access Route.

The proposed Northern Access Route and related infrastructure initiatives are viewed by management as potentially transformational for the broader region. Improved access into the Yukon's White Gold District could materially reduce exploration and development costs, improve logistics, lengthen operating seasons and unlock access to vast areas of highly prospective ground across the Tintina Belt that historically remained difficult and expensive to explore.

The Northern Access Route in the Yukon refers to a planned multi-million-dollar resource and development route designed to connect Dawson City with major mining developments in the west-central region, particularly the Coffee Mine. The road will traverse and service the heart of the prolific White Gold District. It is designed to service major proposed mining operations, including the Coffee Mine and the Casino Mine, while improving exploration access for junior mining companies. Development of the route requires ongoing government-to-government collaboration and agreements with local First Nations to ensure local socioeconomic benefits.

TOULEARY PROJECT GEOLOGY

The geology of the Touleary Project is shown in Figure 6. The Project is underlain by the metasiliciclastic rocks of the Snowcap Assemblage and volcanic rocks of the Finlayson Assemblage (Ryan and Gordey, 2001). Lesser amounts of younger Paleozoic and Mesozoic rocks belonging to the Simpson Range, Sulphur Creek Suite, and Stikine Suite are inferred along narrow regions of the Project area in comparison. The current Project scale geology map has been derived from the mapping by Ryan and Gordey in 2001 which collected much of the limited data from ridgetop traverses, road cuts and lesser creek exposures.

The characteristics of the two main lithostratigraphic units are summarized as follows:

• Snowcap Assemblage (Neoproterozoic)

  • Comprises the basement of the YTT and consists dominantly of metasiliciclastic rocks including quartzite, psammite, pelitic and calc-silicate schists. These rocks are typically poly-deformed and metamorphosed to amphibolite facies.

• Finlayson Assemblage (Devonian)

  • Comprises Upper Devonian to Lower Mississippian metavolcanic and metasedimentary/volcaniclastic stratigraphy. Volcanic assemblages are distinctly bimodal and, where observed in drill core at the Touleary Project, are dominated by mafic endmembers relative to their felsic counterparts. The Finlayson Assemblage hosts VMS mineralization on the Touleary Project and sulphide horizons at the Discovery Zone are mostly developed in felsic volcaniclastic zones within the mafic dominant section. Hydrothermal alteration of these facies is present as talc chlorite where mafic volcanics are present and varying degrees of silicification and sericite alteration where the felsic facies are present.

Government geological mapping originally inferred much of the Touleary Project as being underlain by basal stratigraphy of the Finlayson Group successions below the region of active VMS deposition. Detailed analysis of the processed airborne magnetic data coupled with the drill discovery geological information, VTEM data and the Project-wide soil geochemistry, allowed for a significant reinterpretation of the geological and structural architecture of the project area. This reinterpretation identified a much more extensive distribution of fertile volcanic host stratigraphy in addition to potential vent complexes, regions of complex folding and directional structural offsets.

Figure 6: Touleary Project geology; Vent complexes interpreted from geophysics and soil sample geochemistry.

TOULEARY PROJECT MINERALIZATION

Mineralization at the Touleary Project is typical of Volcanogenic Massive Sulphide (VMS) systems developed in Devonian-Mississippian age submarine volcanic host rocks of the Finlayson Assemblage.

The closest analogues of these systems located in the Finlayson District are ~450 km southeast along the displaced Tintina Fault Zone in southeastern Yukon. Restoration of the Finlayson District to its original position places it adjacent to the Touleary area.

Volcanogenic massive sulphide (VMS) deposits have also been referred to as volcanic-associated, volcanic-hosted, and volcano-sedimentary-hosted massive sulphide deposits. They typically occur as lenses of polymetallic massive sulphide that form at or near the seafloor in submarine extensional volcanic environments. VMS deposits are grouped according to precious and base metal content and host-rock lithology. The presence of Au and Ag can contribute significantly to the economics of VMS deposits.

NATIONAL INSTRUMENT 43-101 DISCLOSURE

Nicholas Rodway, P.Geo, (Licence No. 46541) (Permit to Practice No. 1000359) is President, CEO and Director of Core Silver, and qualified person as defined by National Instrument 43-101- Standards of Disclosure for Mineral Projects. Mr. Rodway has supervised the preparation, verified and approved the technical content in this release on behalf of both Arcus and Core. Verification included reviewing historical assessment reports and laboratory certificates. No limitations were noted during the verification process.

REFERENCES

Ryan, J.J. and Gordey, S.P., 2001 Geology, southern Stewart River area, Yukon Territory (Parts of 115J14, 115O2,3,4,5,6,7); Geological Survey of Canada, Open File 4338, scale 1:100,000.
Bennett, V., 2012 Touleary Project, Dawson Range Mineral Belt, Yukon, Canada - SEM Study. Report prepared for Arcus Development Group Inc.
Leitch, C., 2011 Petrographic report on ten samples from the Touleary project, Yukon. Report prepared for Arcus Development Group Inc. by Vancouver Petrographics Ltd.
Smith, H, 2009 Assessment Report describing geochemical sampling and prospecting at the Touleary Project, western Yukon. Report prepared by Archer, Cathro & Associates (1981) Limited.
Hannington, M.D., Galley, A.G., Herzig, P.M., and Petersen, S. 1998 Comparison of the TAG mound and stockwork complex with Cyprus-type massive sulphide deposits, in Proceedings of the Ocean Drilling Program, Scientific Results Volume 158: p. 389-415.
Galley, A.G., Hannington, M.D., and Jonasson, I.R., 2007 Volcanogenic massive sulphide deposits, in Goodfellow, W.D., ed., Mineral Deposits of Canada: A Synthesis of Major Deposit-Types, District Metallogeny, the Evolution of Geological Provinces, and Exploration Methods: Geological Association of Canada, Mineral Deposits Division, Special Publication No. 5, p. 141-161
Franklin, J.M., and Hannington, M.D., 2002 Volcanogenic massive sulphides through time: Geological Society of America, 2002 Annual Meeting, Abstracts with Programs, v. 34, p. 283.
Singer, D.A., 1995 World-class base and precious metal deposits - a quantitative analysis: Economic Geology, v. 90, p. 88-104.
Wengzynowski, W.A, B.A,.Sc, P. Eng, Technical Report describing Geology, Mineralization, Geochemistry, Geophysics, Trenching and Diamond Drilling at the Touleary Project, November 3, 2025

ABOUT THE COMPANIES

About Core Silver Corp.

Core Silver Corp. is a Canadian mineral exploration company focused on the acquisition and development of mineral projects in British Columbia, Canada. The Company currently holds 100% ownership in the Blue Project Mineral Tenure, which covers a land area of114,074 hectares (~1,140 km²). The project lies within the Atlin Mining District, a well-known gold mining camp located in the unceded territory of the Taku River Tlingit First Nation and the Carcross/Tagish First Nation. The Blue Project hosts a major structural feature known as The Llewellyn Fault Zone ("LFZ"). This structure is approximately 140km in length and runs from the Tally-Ho Shear Zone in the Yukon, south through the Blue Project to the Alaskan Panhandle Juneau Ice Sheet in the United States. Core Silver believes that the south Atlin Lake area and the LFZ has been neglected since the last major exploration campaigns in the 1980s. The LFZ plays an important role in mineralization of near surface metal occurrences across the Blue Project Mineral Tenure. The past 50 years have seen substantial advancements in the understanding of porphyry, skarn, and carbonate replacement type deposits both globally and in British Columbia's Golden Triangle. The Company has leveraged this information at the Blue Project Mineral Tenure to tailor an already proven exploration model and believes this could facilitate a major discovery. Core Silver is excited to become one of Atlin Mining District's premier explorers where its team believes there are substantial opportunities for new discoveries and development in the area.

About Arcus Development Group Inc.

Arcus was established in June 2006 by a group of mineral industry veterans and investors with records of entrepreneurial success. Arcus is focused on creating shareholder value through the acquisition and advancement of high-quality, early-stage mineral exploration projects. Its principal asset is the Touleary Project in Yukon, which hosts a historical drill-confirmed polymetallic VMS discovery and multiple additional exploration targets.

On Behalf of the Boards of Directors

ARCUS DEVELOPMENT GROUP INC.

"Darryl Jones"
Interim CEO
Tel: 604.788.9533
CORE SILVER CORP.

"Nicholas Rodway"
President & CEO
Tel: 604.681.1568

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

FORWARD LOOKING INFORMATION

This news release includes certain statements that constitute "forward-looking statements", and "forward-looking information" within the meaning of applicable securities laws (collectively "forward-looking statements"). These include, without limitation: (a) statements regarding Arcus' and Core Silver's commencement and plans to undertake a diamond drilling program on the Touleary Project and other exploration activities thereon; statement regarding the potential of the Touleary Project and the ongoing infrastructure developments; and statements regarding Core Silver's Blue Project Mineral Tenure and Core Silver's beliefs and expectations with respect to discovery potential on its mineral Project and becoming a premier explorer in the Atlin Mining District. When used in this news release, words such as "anticipated", "expected", "future", "opportunity", "ongoing", "potential", "proposed", "vision" and similar expressions are intended to identify these forward-looking statements as well as phrases or statements that certain actions, events or results "could", "may", "should", "will", "would" or the negative connotation of such terms. Forward-looking statements are based on information available at the time those statements are made and/or management's good faith belief as of that time with respect to future events and are subject to risks and uncertainties that could cause actual performance or results to differ materially from those expressed in or suggested by the forward- looking statements. Forward-looking statements speak only as of the date those statements are made. Except as required by applicable law, the Companies assume no obligation to update or to publicly announce the results of any change to any forward-looking statement contained or incorporated by reference herein to reflect actual results, future events or developments, changes in assumptions or changes in other factors affecting the forward-looking statements. If either of the Companies updates any one or more forward-looking statements, no inference should be drawn that the Companies will make additional updates with respect to those or other forward-looking statements. All forward-looking statements contained in this news release are expressly qualified in their entirety by this cautionary statement.

SOURCE: Core Silver Corp.

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