Montero geochemical results confirm arsenic at Elvira

Dr. Tony Harwood reports MONTERO IDENTIFIES LARGE HYDROTHERMAL SYSTEM WITH EPITHERMAL AND PORPHYRY-STYLE CHARACTERISTICS AT ELVIRA GOLD PROJECT Montero Mining and Exploration Ltd. has released geochemical results from its Elvira gold project in Chile's Maricunga gold belt. This work forms part of the company's continuing integrated exploration program combining geological mapping, geophysical surveys, geochemical data sets and artificial-intelligence-assisted modelling to refine exploration targets within the Elvira hydrothermal system. Dr. Tony Harwood, president and chief executive officer of Montero, commented: "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." Geochemical results Sampling at Elvira was conducted between October and December, 2025. A total of 38 rock samples were collected and analyzed using four-acid digestion ICP-MS methods for high-sensitivity multielement analysis, forming the basis for geochemical vectoring work. In addition, 47 rock samples and 47 soil samples were collected and analyzed using fire assay for gold and silver, together with multielement ICP analysis (32-element suite), at ALS and AAA laboratories in Santiago, Chile. Geochemical results confirm widespread arsenic enrichment across the project area, with localized molybdenum anomalism, consistent with hydrothermal zoning patterns observed in porphyry-epithermal systems. The geochemical signature is interpreted to reflect high-sulphidation hydrothermal alteration that may overlie a porphyry source, consistent with patterns observed in high-sulphidation systems elsewhere in the Maricunga belt. Elevated arsenic values are spatially associated with areas of mapped advanced argillic alteration, consistent with a high-sulphidation epithermal environment, while localized molybdenum anomalism occurs within the central portion of the system and may indicate proximity to a deeper porphyry-style source. Multielement and ratio-based geochemical analysis Multielement and ratio-based anomaly mapping has been used to further evaluate geochemical zonation within the Elvira hydrothermal system. Epithermal signatures are highlighted by strong mercury anomalism, together with lead-to-arsenic and copper-to-arsenic ratios, as well as composite arsenic plus antimony plus mercury responses. Porphyry-oriented indicators include zinc, molybdenum-to-arsenic ratios and composite multielement responses including molybdenum plus bismuth plus tellurium plus mercury, which define discrete zones interpreted to represent potential higher-temperature centres and potential vectors toward a deeper porphyry-style source. The combined use of element distributions, ratios and composite anomaly mapping supports an interpretation consistent with a vertically zoned porphyry-epithermal system and helps identify vectors toward potential higher-temperature centres at depth. Analogue to Maricunga discoveries Multielement geochemistry has been an important exploration tool in high-sulphidation systems in the Maricunga belt and formed part of the discovery workflow at Salares Norte, where pathfinder element assemblages including As, Bi, Hg, Pb, Sb and Te were used in combination with alteration mapping and geophysical targeting to define drill targets (Brewer et al., 2017, and Gold Fields, 2021). At Salares Norte, the relative distribution of arsenic and antimony, together with multielement pathfinder geochemistry, was used to vector toward higher-temperature centres and guide drill targeting. The presence of strong high-sulphidation epithermal geochemical signatures at surface, including arsenic-antimony, and mercury-dominated anomalism and associated element ratios, is consistent with interpretations of the upper portions of hydrothermal systems. In comparable systems, including Salares Norte, such geochemical signatures have been used in analogous deposits to vector toward mineralized centres at both shallow epithermal levels and deeper porphyry-style zones. Next steps The company will continue integrating geological, geochemical and geophysical data sets using structural interpretation and artificial-intelligence-assisted modelling. Continued exploration work will focus on: Using geochemical data to refine exploration vectors; Continued integration of geological, geophysical and geochemical data sets; Refinement of 3-D exploration models; Prioritization of areas for potential drill target definition. The company intends to provide further updates as interpretation of the integrated data sets progresses. Qualified person The scientific and technical information contained in this press release has been reviewed and approved by Marcial Vergara, BSc, and Mike Evans, MSc, PrSciNat, each a qualified person as defined by National Instrument 43-101 (Standards of Disclosure for Mineral Projects) and a consulting geologist to the company. About Montero Mining and Exploration Ltd. Montero is a Canadian exploration company focused on gold and copper exploration in Chile. Montero holds a 100-per-cent interest in the Avispa copper-molybdenum project in the Palaeocene porphyry copper-molybdenum belt of northern Chile, and has an option to acquire the Elvira and Potrero gold projects in the Maricunga gold belt. These projects are currently being advanced through exploration. The company's board and management have experience in the discovery and development of precious and base metal projects. Montero is listed on the TSX Venture Exchange under the symbol MON and has 8,353,833 common shares and 835,383 stock options outstanding. We seek Safe Harbor.