Rio Grande Resources Announces Results from its Airborne Survey at Winston Gold/Silver Project, New Mexico and Announces New President

VANCOUVER, BC / ACCESS Newswire / April 30, 2026 / Rio Grande Resources Ltd. (CSE:RGR)(OTCQB:RGRLF) ("Rio Grande" or "RIO" the "Company"), is pleased to announce results from its recently completed airborne magnetic and radiometric geophysical surveys conducted at its Winston Gold-Silver Project (the "Winston Project" or the "Project") located in the Black Range Mountains of Sierra County, New Mexico. The survey grid and flight-line layout (see Figure 1) was conducted by Precision GeoSurveys Inc., ("Precision") and included 384 line km of survey lines at 50 m spacing (see table 1). It identified possible structural trends and areas of potential hydrothermal alteration that may suggest zones of mineralization. The results are being used by Rio Grande to refine surface sampling targets for an upcoming field program, as well as drill targets currently in the planning stage.

Figure 1. Winston survey block grid showing survey flight lines and tie lines.

The magnetic survey suggests both shallow, near-surface structures and deeper alteration zones that require follow-up evaluation. The radiometric data, when used in conjunction with existing field observations and historical mining data, suggest areas of potential alteration that have not yet been tested by modern sub-surface exploration. Ratio maps (see figure 2), including the uranium-to-thorium (U/Th) ratio, highlight areas that may indicate hydrothermal alteration when coupled with additional exploration data.

Survey Highlights include:

• Multiple linear magnetic trends that may represent faults or structural corridors

• Discrete zones of magnetic disruption that may reflect structural complexity

• Radiometric responses that suggest areas of potential hydrothermal alteration

• Areas that have not yet been tested by modern sub-surface exploration

• Geophysical features being evaluated in conjunction with previously reported high-grade surface sampling results

Figure 2. Map of the total magnetic intensity throughout the Winston claim block. The magnetic survey conducted by Precision suggests both shallow, near-surface structures and deeper alteration zones that require follow-up evaluation

"The results from our airborne survey provide an important new layer of data as we continue to refine our understanding of the Winston Project," said Jason Barnard, CEO of Rio Grande Resources. "The identification of possible structural trends and areas of potential alteration supports our ongoing work to prioritize targets and advance toward drill testing."

"I am pleased to transition the Interim President role to Christina Barnard on a permanent basis." adds Mr. Barnard, "Christina has been instrumental in the Company's development from the outset, and I am confident this transition provides continuity, stability, and strong operational leadership as we advance our exploration programs."

Integration with Surface Sampling

The airborne survey results build directly on the Company's previously reported surface sampling program, which returned gold values up to 41.2 g/t Au and silver values up to 1,435 g/t Ag (see news release February 19, 2026). Geophysical responses observed in the magnetic and radiometric datasets are being evaluated in conjunction with previously reported high-grade surface sampling results, including results from the Poverty Creek Trend and historically developed zones at Ivanhoe, Emporia, and Little Granite. The Company is using these datasets to refine areas for follow-up field evaluation and drill-target planning.

Next Steps

The Company will:

• Complete detailed interpretation of magnetic and radiometric datasets

• Integrate results with existing geological, structural, and geochemical data

• Conduct targeted ground validation and follow-up sampling in priority areas

• Refine drill targets focused on structurally favorable zones

The objective is to define and prioritize drill targets that demonstrate structural continuity, association with known surface mineralization, and favorable geometry for future testing.

New President Appointment

Rio Grande Resources is pleased to announce the appointment of Christina Barnard as its new President. Ms. Barnard has been closely involved with Rio Grande since its formation and was integral to the successful completion of the Plan of Arrangement with Foremost Clean Energy Ltd., creating Rio as a standalone public company focused on advancing the Winston Gold and Silver Property.

Ms. Barnard brings extensive experience in public company administration, regulatory compliance, project management, corporate governance, and multi-exchange coordination. As acting Chief Operating Officer of Foremost Clean Energy Ltd (Nasdaq: FMST, CSE:FAT), being involved with the company since 2020, she has played a key behind-the-scenes role in executing complex corporate initiatives, including the Company's successful Nasdaq listing in 2023. Her operational discipline, attention to detail, and experience coordinating legal, regulatory, exchange, and corporate workflows position her well to lead Rio Grande through its next phase of development. Mr. Barnard has stepped down from his role as interim president and will remain as CEO and director.

Qualified Person

The scientific and technical information contained in this news release has been reviewed and approved by Mr. Jacob Anderson CPG, MAusIMM, a Qualified Person as defined under National Instrument 43-101. Mr. Anderson is independent of Rio Grande Resources.

Historical results referenced in this news release have not been verified by a Qualified Person and should not be relied upon as indicative of mineral resources or reserves. The Qualified Person has reviewed the sampling and mapping data disclosed herein but has not independently verified the data. Verification included a review of field procedures, sample locations, and consistency with historical records.

About Rio Grande Resources

Rio Grande Resources (CSE:RGR)(OTCQB:RGRLF) 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 100% interest in the Winston project group, which includes the 2 patented historic Ivanhoe & 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-sulfidation epithermal setting.

To view the company fact sheet and corporate presentation, please visit our website at www.riogranderesources.ca

Contact and Information

Company
Jason Barnard, CEO and Director
(604) 767-6598
jason.barnard@riogranderesources.ca

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Forward-Looking Statements

Except for the statements of historical fact contained herein, the information presented in this news release and oral statements made from time to time by representatives of the Company are or may constitute "forward-looking statements" as such term is used in applicable United States and Canadian laws and including, without limitation, within the meaning of the Private Securities Litigation Reform Act of 1995, for which the Company claims the protection of the safe harbor for forward-looking statements. Such forward-looking statements and forward-looking information include, but are not limited to, the proposed benefits of the Arrangement. These statements relate to analyses and other information that are based on forecasts of future results, estimates of amounts not yet determinable and assumptions of management. Any other statements that express or involve discussions with respect to predictions, expectations, beliefs, plans, projections, objectives, assumptions or future events or performance (often, but not always, using words or phrases such as "expects" or "does not expect," "is expected," "anticipates" or "does not anticipate," "plans," "estimates" or "intends," or stating that certain actions, events or results "may," "could," "would," "might" or "will" be taken, occur or be achieved) are not statements of historical fact and should be viewed as forward-looking statements. The Company cautions that the identification of structural features or geophysical anomalies does not necessarily indicate the presence of economic mineralization, and there can be no assurance that the Company's geological interpretation or exploration objectives will result in a discovery. Such forward-looking statements involve known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the Company to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. Such risks and other factors include, among others, the availability of capital to fund programs and the resulting dilution caused by the raising of capital through the sale of shares, continuity of agreements with third parties, the satisfaction of the conditions to the Arrangement, risks and uncertainties associated with the environment and delays in obtaining governmental approvals, permits or financing. Although the Company has attempted to identify important factors that could cause actual actions, events or results to differ materially from those described in forward-looking statements, there may be other factors that cause actions, events or results not to be as anticipated, estimated or intended. There can be no assurance that such statements will prove to be accurate as actual results and future events could differ materially from those anticipated in such statements. Although the Company believes that the expectations reflected in such forward-looking statements are based upon reasonable assumptions, it can give no assurance that its expectations will be achieved. Forward-looking information is subject to certain risks, trends and uncertainties that could cause actual results to differ materially from those projected. Many of these factors are beyond the Company's ability to control or predict. Important factors that may cause actual results to differ materially and that could impact the Company and the statements contained in this news release can be found in the Company's filings on SEDAR+. The Company assumes no obligation to update or supplement any forward-looking statements whether as a result of new information, future events or otherwise. Accordingly, readers should not place undue reliance on forward-looking statements contained in this news release and in any document referred to in this news release. This news release shall not constitute an offer to sell or the solicitation of an offer to buy securities. Please refer to the Company's most recent filings under its profile on SEDAR+ at www.sedarplus.ca for further information respecting the risks affecting the Company and its business.

The CSE has neither approved nor disapproved the contents of this news release and accepts no responsibility for the adequacy or accuracy hereof.

SOURCE: Rio Grande Resources