Riverside completes phase 1 drilling at Union project

Executive Summary

• Riverside Resources Inc. has completed Phase One drilling at its Union Project in Sonora, Mexico, in partnership with Questcorp Mining Inc.
• The program involved 12 diamond core holes totaling over 1,600 meters across six priority targets, with more than 700 half-core samples shipped for assay.
• The company is currently awaiting assay results to refine its geological model and scope a Phase 2 exploration campaign, which is expected to potentially occur in the first half of 2026.

Key Details

• Drilling Program Scope: 12 diamond core holes completed for a total of just over 1,600 meters.
• Targets Drilled: Six priority targets were tested: Union mine, Union Norte, Cobre, Luis, Famosa, and Famosa Mag.
• Strategic Focus: Drilling was oriented at angles and near-vertical to cut stratigraphy and structures typical of Carbonate Replacement Deposit (CRD) systems, focusing beneath oxidized horizons generally less than 150 meters deep.
• Sampling Volume: Greater than 700 half-core samples shipped for analysis.
• Laboratory Processing:
  • Samples from the first eight holes were delivered to Bureau Veritas (Hermosillo, Sonora) for gold fire assay, with pulps forwarded to Vancouver, Canada, for ICP-MS analysis.
  • Samples from the final four holes were shipped to ACT Labs Zacatecas, Mexico, for preparation, gold assay, and multielement ICP.
• Target-Specific Observations:
  • Union Mine: Three holes targeted manto horizons and chimney/feeder structures adjacent to historic underground workings to evaluate continuity.
  • Famosa Mine Area: Four core holes tested a west-dipping dolomite manto target. Logging noted intrusive dikes and breccias. Historical small-scale mining left surface dumps reported with gold grades >0.5 oz/t Au (>15 g/t) in a Questcorp NI 43-101 report (May 7, 2025). An inclined shaft dipping ~70 degrees to the west parallels the favorable horizon.
  • Union Norte: Two initial holes tested the manto horizon within dolomitic carbonate strata to evaluate continuity and geometry along favorable trends mapped near historic workings.
  • Cobre and Luis: Each target was tested to assess style, structure, and controls on mineralization, showing sulfides and intrusions aligned with a carbonate-hosted metals system.
• Partnership Structure: Work is funded through partner Questcorp Mining Inc. under an option agreement announced earlier in 2025, with Riverside acting as operator.
• Next Steps: Upon receipt of assays, the company will integrate results (assays, core logging, geophysics, geochemistry) to refine the CRD model. Phase 2 exploration, likely involving more extensive drilling, is planned for H1 2026, contingent on permit status and target definition.
• Qualified Person: Freeman Smith, PGeo, reviewed and approved the scientific and technical data.

Notable Quotes

• "This first exploration phase accomplished initial drill holes into six target areas. We tested multiple shallow gold and base metals targets, confirmed the key carbonate host units recognized by historic mining at Union and Famosa, and gathered the structural and alteration data to further progress efficient mineral exploration," said Dr. John-Mark Staude, president and chief executive officer of Riverside Resources.
• "This historically mined CRD district, validated by new drilling and improved data sets, advances our geologic model and supports the potential for a large-scale discovery. With six targets advanced and more than 700 samples at the lab, once results are received, we will scope the next exploration program and focus on the most prospective trends indicated by assay results, stratigraphy, structure and geophysics."