Ottawa, Ontario--(Newsfile Corp. - September 15, 2026) - Arc Mineral Royalties Ltd. (TSXV: ARO) ("Arc" or the "Company") is pleased to note Sinclair Gold Ltd.'s (ASX: SGC) ("Sinclair Gold") announcement dated September 14, 2026, of an updated interim JORC 2012 Mineral Resource for the Mt Henry Gold Project ("Mt Henry" or the "Project") in Western Australia.¹

The updated interim Mineral Resource comprises 33.9 million tonnes grading 1.2 g/t gold for 1.3 million ounces in the Measured and Indicated categories, and 14.0 million tonnes grading 1.2 g/t gold for 0.5 million ounces in the Inferred category. Total contained gold has approximately doubled from the 0.9 million total ounces reported when Sinclair Gold acquired the Project in February 2026.

Arc holds a 1% net smelter return ("NSR") royalty over the entire Project, with an option to acquire an additional 1% NSR royalty for A$10 million, exercisable for 30 days following Sinclair Gold's announcement of a 2.0Moz JORC Mineral Resource.

Highlights

• Only 20,426 meters (41%) of Sinclair Gold's ongoing 50,000 meter drill program are included, reflecting a July 31, 2026 data cut-off.

• 1.3Moz, or more than 70% of the Resource, is in the higher-confidence JORC Measured and Indicated categories. All resource growth comes from drilling on the Mt Henry and Selene deposits.

• 1.6Moz (~90%) of the combined Mt Henry and Selene Resource ounces are within 200 meters of surface, highlighting the shallow nature of the Resource and its open-pit potential.

• Mt Henry and Selene resources constrained within optimized pit shells using a conservative A$3,900/oz gold price (US$2,816/oz²), approximately 40% below spot at the time of Sinclair's announcement.

• Five rigs are currently drilling, with assays pending from 25 holes outside the current resource footprint. Both deposits remain open along strike and at depth.

• Sinclair Gold expects drilling to continue through calendar 2026, with another resource update expected before the end of FY2027. Sinclair Gold is well funded, with A$38.2 million cash as of June 30, 2026.

Adam Davidson, Chief Executive Officer of Arc, commented:

"Sinclair Gold's continued exploration success at Mt Henry demonstrates the value of holding a royalty over a growing asset. As the resource expands, Arc gains exposure to a potentially larger future production base, without contributing to the cost of the drilling that delivers that growth. This is a key attraction of the royalty model and central to our investment in Mt Henry.

"With only 41% of the planned drilling incorporated in this interim estimate, five rigs operating, and assays pending from outside the resource footprint, we look forward to further results as Sinclair Gold continues to explore and advance the Project."

Mt Henry Gold Project - JORC 2012 Mineral Resource³

Mt Henry is an advanced brownfields gold project approximately 20km south of Norseman and 220km south of Kalgoorlie. Its resources lie on granted mining tenure with access to regional infrastructure. Further technical details and assumptions are set out in Sinclair Gold's September 14, 2026 announcement, "Mt Henry Resource Doubles to 1.8Moz at 1.2g/t Gold".

The updated Mt Henry and Selene resources are reported at a 0.5 g/t gold cut-off within optimized pit shells using a gold price of A$3,900/oz. The estimate incorporates new drilling, updated geological interpretations, and revised reporting parameters. Resources at North Scotia and stockpiles are unchanged; North Scotia retains a 0.4 g/t cut-off and A$2,160/oz pit-shell assumption. Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability.

About Arc Mineral Royalties Ltd.

Arc Mineral Royalties Ltd. is a mining royalty and streaming company focused on establishing a portfolio of high-conviction royalty assets. Through a strategic partnership with Karri Capital Partners, Arc combines an experienced royalty management team with project development expertise to pursue both traditional royalty transactions and differentiated royalty creation opportunities. Arc's foundational asset is a 1% NSR royalty over the Mt Henry Gold Project in Western Australia, with an option to acquire an additional 1% NSR royalty.

Qualified Person

The scientific and technical information in this news release has been reviewed and approved by Brian Wolfe, B.Sc., MAIG, Principal Consultant Geologist, an independent Qualified Person as defined under National Instrument 43-101 - Standards of Disclosure for Mineral Projects ("NI 43-101").

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. No securities regulatory authority has either approved or disapproved of the contents of this news release.

Cautionary note regarding forward-looking information
This news release contains certain information which constitutes forward-looking information within the meaning of applicable Canadian securities legislation. Any statements that are contained in this news release that are not statements of historical fact may be deemed to be forward-looking information. Forward-looking information is often identified by terms such as "may", "should", "anticipate", "expect", "potential", "believe", "intend" or the negative of these terms and similar expressions. Forward-looking information in this news release includes, but is not limited to, statements regarding the use of financing proceeds, future acquisitions, portfolio growth, the exercise of the additional royalty option, exploration and resource updates at Mt Henry, and Arc's strategy and objectives. Forward-looking information is based on management's current expectations and assumptions and is subject to risks, uncertainties and other factors that may cause actual results to differ materially, including commodity prices, market conditions, regulatory approvals, transaction completion risk, operator performance and the risks disclosed in the Company's public filings on SEDAR+. Should one or more of the risks or uncertainties underlying these forward-looking statements materialize, or should assumptions underlying the forward-looking information prove incorrect, actual results, performance or achievements, could vary materially from those expressed or implied by the forward-looking information. Readers should not place undue reliance on forward-looking information. Except as required by law, Arc undertakes no obligation to update or revise such information.

¹ Sinclair Gold announcement dated 14 September 2026
² Reserve Bank of Australia FX rate of A$1=US$0.722, as at 10 September 2026
³ Source: Sinclair Gold, September 14, 2026, Table 2. Effective July 31, 2026 for Mt Henry and Selene; June 30, 2025 for North Scotia and stockpiles. Figures are rounded and may not sum. Mt = million tonnes; koz = thousand ounces.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/314292

Source: Arc Mineral Royalties Ltd.