Rio Grande Resources Completes 2025 Field Program and Advances Drill Targeting at the Winston Gold-Silver Project

Executive Summary

• Rio Grande Resources completed its 2025 geological field program at the Winston Gold‑Silver Project, conducting detailed mapping, surface sampling and historic work documentation.
• The program confirmed a well‑developed low‑sulfidation epithermal gold‑silver vein system with multiple mineralized trends and extensive historic mine workings, indicating a district‑scale target that remains open along strike and at depth.
• Rio Grande will integrate the new data into an updated geological model and pursue additional geophysical work and drill planning focused on high‑potential vein intersections and historic work zones.

Key Details

• Program Duration & Contractor: Field program carried out Dec 2–8, 2025 by Dahrouge Geological Consulting USA Ltd.
• Mapping Results: Confirmed mineralization hosted in low‑sulfidation epithermal veins with classic textures (bladed quartz, comb quartz, colloform banding, vugs, amethyst).
• Sampling & Outcrops: Collected 72 channel and rock‑chip samples; mapped 52 mineralized vein outcrops across the project area.
• Historic Work Identified: Documented 58 historic mine workings (shafts, adits, pits, trenches), many previously unrecorded in modern datasets.
• Vein Trends & Targets: Multiple intersecting vein trends mapped; identified priority zones – Ivanhoe‑Emporia, Little Granite Mine, Poverty Creek – based on structural complexity and vein density.
• Continuity & Open‑Ended Potential: Vein continuity extends hundreds of metres to >1 km along strike in several areas; system remains open both laterally and at depth.
• Next Steps:
• Integrate mapping and sampling data into an updated geological/structural model.
• Evaluate additional geophysical surveys (magnetic, gravity, induced polarization) to refine structural and alteration targets.
• Improve site access for expanded sampling and mapping.
• Develop targeted drill plans focusing on vein intersections, proximity to historic workings, and zones with strong epithermal textures.
• Qualified Person: Review and approval by Mr. Jacob Anderson CPG, MAusIMM (NI 43‑101 QP).

Notable Quotes

“The completion of the 2025 field program at Winston marks an important step in advancing the Project through a systematic, data‑driven approach… We are now focused on integrating this work into an updated geological model to guide the next phase of exploration and drill targeting.” – Jason Barnard, President & CEO

Materiality Assessment: Non‑Material – Positive (provides substantive operational update without immediate financial impact, but enhances project outlook).