Mr. Jason Barnard reports

RIO GRANDE RESOURCES PROVIDES 2025 FALL EXPLORATION UPDATE FOR ITS WINSTON GOLD AND SILVER PROPERTIES AND ENGAGES DAHROUGE GEOLOGICAL CONSULTING

Rio Grande Resources Ltd. has engaged Dahrouge Geological Consulting Ltd. to advance exploration at its flagship Winston gold and silver project, located in the Black Range of Sierra county, New Mexico. The program will be highlighted by a comprehensive site visit scheduled for early December, 2025. Dahrouge, a leading North American geological consulting firm with U.S. operations based in Denver, Colo., brings extensive expertise in project generation, resource evaluation and technical program design. The engagement is formalized under a master service agreement, with an initial scope of work, which commenced in October.

"We are excited to formally engage Dahrouge Geological Consulting to lead the next phase of systematic exploration at Winston," said Jason Barnard, president and chief executive officer of Rio Grande Resources. "Their methodical approach, which begins with validating historical data and culminates in a targeted drill program, aligns perfectly with our strategy to unlock the significant potential of this past-producing gold and silver property. The upcoming site visit and sampling program are critical first steps in refining our geological model and defining drill targets. We look forward to providing further updates as this work progresses."

Mr. Barnard added: "We are also pleased to have recently appointed Harpreet Bajaj to the role of corporate secretary. With her extensive background in TSX Venture compliance and corporate governance, she will be an invaluable asset as we advance our corporate and exploration objectives."

The Winston project is a drill-ready, approximately 3,000-acre property located in located in the prolific Chloride mining district of Sierra county, New Mexico. It is home to three historic mines: the two patented Ivanhoe and Emporia claims, and the four Little Granite claims, which make up part of the 147 unpatented Bureau of Land Management (BLM) mining claims. Each mine produced high-grade gold and silver during full-time operations over a century ago. The property hosts high-grade, low-sulphidation epithermal gold-silver veins, situated within a prolific structural trend that also possesses the key geological ingredients for carbonate replacement deposit (CRD) formation. This dual-model potential significantly elevates the project's prospectivity, offering not only near-term, high-grade vein targets but also the potential for a larger, district-scale CRD system.

The Dahrouge technical team will conduct a detailed comprehensive program starting next month, including a site visit, a field assessment, geological mapping and channel sampling of exposed mineralized veins. The data collected, combined with a compilation and review of all existing project data, will be used to build a 3-D geologic model. The primary objective of this work is to delineate high-priority targets for a planned drill program designed to test the interpreted high-grade vein structures.

Rio Grande is committed to systematically advancing the Winston project and will update shareholders as new data are received, compiled and interpreted from the upcoming field activities.

Corporate secretary appointment

Rio Grande is also pleased to announce the appointment of Ms. Bajaj as its corporate secretary. Ms. Bajaj is a finance and compliance professional with over 17 years of experience in investment banking, regulatory compliance and corporate governance. Her career includes key roles at numerous publicly listed companies and as a member of a multinational bank's due diligence division. Her expertise includes regulatory frameworks, risk management and corporate secretarial services for both public and private companies. Known for her strategic insight and attention to detail, Ms. Bajaj brings valuable knowledge and a commitment to operational excellence.

Equity grant

The company has granted 30,000 stock options, exercisable at 42 cents for a period of three years, and 25,000 RSUs (restricted share units), subject to vesting provisions, to certain employees and consultants. All stock options and RSUs issued are subject to a statutory hold period of four months and one day, and have been granted in accordance with the company's omnibus stock incentive plan dated Dec. 20, 2024, and the policies of the Canadian Securities Exchange.

About Rio Grande Resources Ltd.

Rio Grande Resources is a burgeoning mineral exploration company focused on unlocking the high-grade gold and silver potential within its 3,000-acre drill-ready property in the Black Range of Sierra county, New Mexico. The company holds a 100-per-cent interest in the Winston project group, which includes the two patented historical Ivanhoe and Emporia claims, and Little Granite mines, all known for their past production of high-grade precious metals. Rio Grande Resources is led by a team of experienced professionals with expertise in mineral exploration and development, who are targeting large-scale precious metal discoveries within the property's well-documented low-sulphidation epithermal setting.

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