Mr. Jason Barnard reports

RIO GRANDE RESOURCES ADVANCES WINSTON GOLD-SILVER PROJECT WITH SECOND PHASE OF FIELD SAMPLING AND MAPPING IN SUPPORT OF PHASE 1 DRILL PROGRAM

Rio Grande Resources Ltd. is planning a second phase of field sampling and mapping in support of planning efforts for its upcoming phase 1 drill program at the Winston gold-silver project, located in the Black Range Mountains of Sierra county in New Mexico. The field program is being carried out by Dahrouge Geological Consulting USA Ltd., and is expected to include approximately seven days of detailed structural mapping and surface sampling during the second week of May, 2026.

The upcoming fieldwork represents the next step in a systematic exploration approach following the company's recent high-grade surface sampling results, which returned up to 41.2 grams per tonne (g/t) gold and 1,435 g/t silver from the Poverty Creek area (see news release dated Feb. 19, 2026), as well as the completion of an airborne magnetic and radiometric survey that identified key structural corridors and zones of potential hydrothermal alteration across the property. The program is designed to integrate and groundtruth these data sets through detailed structural mapping and systematic sampling, with the objective of refining and prioritizing high-confidence drill targets for the phase 1 drill program.

Field program focus and objectives

The field program will focus on the Poverty Creek area, the Ivanhoe and Emporia patented claims, and additional target areas identified through interpretation of the recently completed airborne geophysical survey. These areas were selected to follow up on previously reported high-grade surface sampling results and geophysical responses interpreted to reflect structural corridors and potential zones of hydrothermal alteration. Detailed structural mapping of vein orientations, fault systems and alteration zones will be carried out alongside systematic sampling of in situ vein exposures.

Jason Barnard, Rio Grande's chief executive officer, commented: "This next phase of fieldwork is a key step in advancing the Winston project toward drilling and unlocking the broader potential of the property. By integrating our recent high-grade sampling results with airborne geophysical data, we are focusing on structurally controlled targets that we believe offer strong discovery potential. This program is designed to refine and prioritize those targets, allowing us to move toward our phase 1 drill program with a disciplined, data-driven approach while continuing to build value for shareholders."

Channel sampling will be the primary method used to evaluate vein continuity and grade distribution, with rock chip samples collected where channel sampling is not feasible. This approach is consistent with the company's December, 2025, field program, where channel and rock chip sampling were used to evaluate exposed in situ veins, vein outcrops, subcrops and historical workings. Data collected during the current program will be used to refine the company's understanding of structural controls on mineralization and to finalize priority drill targets for the upcoming phase 1 drill program.

Next steps

The data collected during the program will be integrated with previously reported surface sampling results and the recently completed airborne geophysical survey to refine the company's understanding of structural controls on mineralization across the property. This integrated data set will be used to prioritize high-confidence drill targets based on structural continuity, association with known mineralization and favourable geological characteristics ahead of the phase 1 drill program.

Qualified person

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

The qualified person has reviewed the sampling procedures, analytical methods and results disclosed herein, and is satisfied that the information has been accurately presented. Verification included a review of field procedures, sample locations and consistency with historical records.

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 in New Mexico. The company holds a 100-per-cent interest in the Winston project group, which includes the two patented historic 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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