Montero geochemical results confirm arsenic at Elvira

Executive Summary

• Montero Mining and Exploration Ltd. has released geochemical results from its Elvira gold project in Chile, identifying a large hydrothermal system with both epithermal and porphyry-style characteristics.
• The findings are based on sampling conducted between October and December 2025, utilizing rock and soil samples analyzed for gold, silver, and multielement suites.
• The company plans to integrate these geochemical data sets with geological, structural, and geophysical data using artificial-intelligence-assisted modeling to refine drill targets.

Key Details

• Project Location: Elvira gold project, located in Chile's Maricunga gold belt.
• Sampling Period: October to December 2025.
• Sample Types and Methods:
  • 38 rock samples analyzed via four-acid digestion ICP-MS for high-sensitivity multielement analysis.
  • 47 rock samples and 47 soil samples analyzed via fire assay for gold and silver, plus multielement ICP analysis (32-element suite).
  • Laboratories used: ALS and AAA in Santiago, Chile.
• Geochemical Findings:
  • Widespread arsenic enrichment across the project area.
  • Localized molybdenum anomalism, consistent with hydrothermal zoning in porphyry-epithermal systems.
  • Geochemical signature interpreted as high-sulphidation hydrothermal alteration, potentially overlying a porphyry source.
  • Elevated arsenic values spatially associated with mapped advanced argillic alteration, indicating a high-sulphidation epithermal environment.
  • Localized molybdenum anomalism in the central portion suggests proximity to a deeper porphyry-style source.
• Multielement and Ratio Analysis:
  • Epithermal Signatures: Strong mercury anomalism, lead-to-arsenic and copper-to-arsenic ratios, and composite arsenic plus antimony plus mercury responses.
  • Porphyry Indicators: Zinc, molybdenum-to-arsenic ratios, and composite multielement responses (molybdenum plus bismuth plus tellurium plus mercury) defining discrete zones interpreted as potential higher-temperature centers.
• Analogue Context: The geochemical signatures are comparable to high-sulphidation systems in the Maricunga belt, such as Salares Norte, where similar pathfinder element assemblages (As, Bi, Hg, Pb, Sb, Te) were used to define drill targets.
• Next Steps:
  • Refine exploration vectors using geochemical data.
  • Continue integration of geological, geophysical, and geochemical data sets.
  • Refine 3-D exploration models.
  • Prioritize areas for potential drill target definition.
• Qualified Persons: Marcial Vergara, BSc, and Mike Evans, MSc, PrSciNat.

Notable Quotes

• "Geochemistry at Elvira highlights a large hydrothermal system with strong geochemical vectors consistent with shallow epithermal mineralization and deeper porphyry-style target concepts. This work will be integrated and interrogated using artificial-intelligence-assisted modelling, together with alteration, geological, structural and geophysical data sets, to develop a drill target model." — Dr. Tony Harwood, President and CEO