Mirasol Advances Large Untested Target Towards Drilling at the Flagship Sobek Copper-Gold Project in the Vicuña District, Chile

• Geochemical soil survey defined a large (~1.0 × 0.7 km), prominent and coherent copper-gold-moly anomaly where structurally controlled hydrothermal and tourmaline breccias breach the surface
• The 46 South target lies on the southern margin of a district scale (~6 x 6 km) circular magnetic high
• Ground-based IP responses and coincident cylindrical shaped magnetic susceptibility and MT anomalies directly underlie the soil anomaly and breccias on surface
• Ahead of the drill program we anticipate launching in early November, a Deep Vector IP and MT survey will be deployed to refine geometry and enhance vectoring of the targets
• The 46 South target is located just 7 km west of Filo del Sol at the southern end of a parallel 3 km corridor of mineralization
• Webcast video presentation highlighting the potential of the 46 South target is available on our website

VANCOUVER, British Columbia, Sept. 16, 2025 (GLOBE NEWSWIRE) -- Mirasol Resources Ltd. (TSX-V: MRZ) (OTC: MRZLF) (the “Company” or “Mirasol”) is pleased to announce that the geochemical soil survey and IP ground geophysics reinforce 46 South as a high-priority drill target on the central block of the Company’s 100%-owned Sobek Copper-Gold-Silver Project (“Sobek” or “the Project”) in the Vicuña District of Chile . The grid-based soil survey outlined a prominent, large and coherent copper-gold-moly geochemical anomaly that coincidently overlays IP-PDP resistivity and chargeability responses from IP ground geophysics surveys completed late last season. Structurally controlled tourmaline breccias and hydrothermal breccias with porphyry-derived clasts were identified while prospecting and mapping in the target area. The 46 South target resides on the southern margin of a district-scale magnetic high where both the airborne MT and magnetics surveys outlined distinct cylindrical anomalies. To refine the maiden drill program at 46 South an innovative and proven geophysical system will be deployed to further delineate the geometry of both the shallow IP/Res domains and the deeper MT anomalies ahead of drilling.

The Sobek Project is located in Chile within the Vicuña District which hosts both the Filo del Sol deposit and the Lunahuasi discovery across the border in Argentina. The 46 South target lies at the southern end of a 3-km N-S trending corridor hosting alteration and mineralization that runs parallel to Filo del Sol which is only ~7 km to the east.

“Our Sobek central property in the Vicuña District hosts a 3 km N-S trending corridor of targets that have become more attractive as we progressed further to the south. At the southern end of the corridor, where we now have road access, the 46 South target represents the most compelling untested target that we have encountered to date at our Sobek project,” Mirasol’s President and CEO Tim Heenan stated. “The recent results from the IP ground geophysics and soil sampling survey combined with the coincident airborne magnetic and MT anomalies along with the hydrothermal and tourmaline breccias encountered on surface reinforce 46 South as a high-quality priority target. The deployment of the proven Deep Vector IP and MT geophysical survey at the outset of the exploration season will refine our targeting and improve the probability of a successful drill program which we anticipate launching in November of this year.”

Figure 1: Vicuña District - Sobek Property Package including the 46 South Target

Regional Airborne Magnetics and Airborne MT Surveys

Mirasol has completed 2,700-line kilometers of airborne magnetics and over 500-line kilometers of airborne MT across Sobek, which has provided a robust dataset when integrated with surface geological mapping and rock chip and soil grid geochemical sampling. These airborne geophysical surveys outlined a district-scale magnetic high and revealed an MT anomaly at depth at 46 South. These datasets have been critical in vectoring exploration towards 46 South, confirming that the target is not an isolated feature but part of a preserved, district-scale magmatic–hydrothermal system.

Figure 2: Sobek Central - 46 South Target District Scale Magnetic High

The regional airborne magnetic data delineates a broad circular ~6 x 6 km magnetic high, interpreted as an underlying intrusive center. The 46 South target is positioned on the southern margin of this intrusive complex, where the magnetic gradient coincides with mapped hydrothermal breccias and alteration. At surface, both tourmaline-bearing breccias and typical High Sulphidation (HSE) type breccias containing porphyry fragments showing pervasive sericite alteration with a quartz–alunite overprint have been identified. These breccia exposures, located precisely on the southern edge of the highly magnetic body, highlight the structural and geological significance of this margin for focusing hydrothermal activity.

The Airborne MT data defined an underlying sharp resistivity contrast coincident with a strong cylindrical magnetic susceptibility anomaly directly below 46 South, starting at an elevation of ~4,600–4,500 masl and extending to depth. This anomaly aligns with the strongest part of the soil geochemical footprint. Comparable MT conductors in the Vicuña District have been reported at NGEX`s Lunahuasi discovery, where porphyry-related mineralization begins at ~4,600 masl and strengthens between ~3,800–3,900 masl and also at Mogotes Filo Sur project (at ~4,500 masl, interpreted as a porphyry target). The alignment in elevation and style suggests that the MT anomaly at 46 South may represent the upper levels of a porphyry system.

Figure 3: Sobek Central - 46 South Target Coincident MAG and MT Anomalies

Structural Interpretation

Mapping shows NS and NE-trending structures are crosscut by NW-trending faults, with these intersections localizing breccias and alteration. The strongest soil anomalies coincide spatially with these intersections, reinforcing the interpretation that structural controls are critical in the localization of mineralization at 46 South.

Soil and Rock Geochemical Results

Systematic soil sampling has defined a strong, widespread and very coherent copper-gold-molybdenum footprint with dimensions of ~1.0 × 0.7 km. This is clearly the largest and strongest geochemical anomaly yet identified on the Sobek property. Maximum values in soils reach 275 ppm copper, 37 ppm molybdenum and 88 ppb gold. Although outcrop is scarce within the colluvial cover, select rock chip samples returned values up to ~1.0 g/t gold, 420 ppm copper and 508 ppm molybdenum from sheeted quartz ± sulfide veinlets, local stockworks and breccias, confirming the presence of mineralization where structures and alteration coincide.

Figure 4: Sobek Central - 46 South Target Prominent Copper-Moly-Gold Soil Anomalies

Coincident Underlying Ground IP-PDP Geophysical Anomaly

An Induced Polarization (IP), Pole-Di-Pole (PDP) geophysical survey defined a robust anomaly underlying and coincident with the soil grid anomaly. Chargeability increases markedly from ~150m down to >600m, while resistivity values highlight a well-defined core exceeding 5,000 ohm-m. These coincident anomalies reinforce the interpretation of a vertically extensive mineralized system.

Figure 5: Sobek Central - 46 South Target Underlying IP Geophysical Anomaly

New Proven Geophysical Survey to Refine Drill Targets

To further resolve the geometry of these shallow IP/Res domains and the deeper MT responses, an innovative and proven Deep Vector IP and MT geophysical survey will be deployed at the outset of the exploration season. This survey is designed to refine the characterization of the existing resistive/chargeable domains at shallow levels and the deeper MT response, providing the vectoring required to define final drill targets. Comparable approaches at projects such as APEX´s Valeriano, directly south of Sobek in Chile, and Aldebaran’s Altar in Argentina have demonstrated the effectiveness of this technology in telescoped porphyry-epithermal systems.

Advancing Towards Drilling

The integration of airborne magnetics and MT, ground IP resistivity and chargeability, structural mapping and geochemistry establishes 46 South as a very compelling undrilled target within the Vicuña District. A first-pass drill hole is being designed to test the overlapping soil anomaly with the underlying resistive and chargeable bodies while also penetrating the deeper MT response interpreted as the possible roof zone of a porphyry system. Drill positioning is planned to be slightly offset from the chargeability center to maximize the chances of intersecting mineralization in both the near surface and deeper targets. We expect to complete the Deep Vector IP and MT geophysical survey by mid-October and anticipate launching the 2025 drill program in early November.

Figure 6: Sobek Central - 46 South - Compelling Undrilled Target

High-Profile Vicuña Copper-Gold-Silver District

Mirasol staked the Sobek Project in 2016 based on prospective local geology and attractive structural architecture prior to the 2021 discovery of the high-grade feeder zone at the Filo del Sol gold-copper deposit and the 2023 discovery of Lunahuasi. The consolidated Sobek Project is located on the same regional N-S trending structural corridor and just 7km to the west of the Filo del Sol deposit and 3km to the southwest of NGEx Mineral’s discovery at Lunahuasi.

Sobek is located within a prospective geological environment with a compelling north-northeast trending mineralized structural corridor crosscut by a north-northwest trending deep-seated trans-cordilleran lineament. This is a common structural configuration hosting numerous Andean metal deposits in both Chile and Argentina.

Webcast Video Presentation Highlighting the 46 South Target

Mirasol recently presented at the 2025 Precious Metals Summit Beaver Creek. The video is available to view here on our website: www.mirasolresources.com.

About Mirasol Resources Ltd

Mirasol is a well-funded exploration company with more than 20 years of operating, permitting and community relations experience in the mineral rich regions of Chile and Argentina. Mirasol is currently self-funding exploration at the flagship Sobek Copper-Gold project located in the Vicuña Copper-Gold-Silver District of northeast Chile and controls 100% of the high-grade Virginia Silver Deposit in the province of Santa Cruz, Argentina. Mirasol also continues to advance a strong pipeline of highly prospective early and mid-stage projects.

For further information, contact:

Tim Heenan, President & CEO
or
Troy Shultz, Vice President Investor Relations

Tel: +1 (604) 602-9989
Email: contact@mirasolresources.com
Website: www.mirasolresources.com

Qualified Person Statement: Mirasol’s disclosure of technical and scientific information in this press release has been reviewed and approved by Tim Heenan (MAIG), the President for the Company, who serves as a Qualified Person under the definition of National Instrument 43-101.

QAQC: Mirasol applies industry standard exploration sampling methodologies and techniques. All geochemical rock chip, soil, and stream sediment samples are collected under the supervision of the company’s geologists in accordance with industry practice. Geochemical assays are obtained and reported under a quality assurance and quality control (QA/QC) program with insertions of controls (standards, blanks and duplicates) submitted to the laboratory. Samples were dispatched to ALS Global - Geochemistry Analytical Lab, in Santiago, Chile, an ISO 9001:2015 accredited laboratory, which is independent from the Company. Rock chip samples (1-3kg) were prepared with PREP31, and analysed by Au_ICP21 and ME-MS61. The soil samples were prepared with PUL-31, analysed by Au_ICP21 and ME-MS61. Assay results from rock chip, soil stream sediment, channel, trench, and drill core samples may be higher, lower or similar to results obtained from surface samples due to surficial oxidation and enrichment processes or due to natural geological grade variations in the primary mineralization.

Forward Looking Statements: The information in this news release contains forward looking statements that are subject to a number of known and unknown risks, uncertainties and other factors that may cause actual results to differ materially from those anticipated in our forward-looking statements. Factors that could cause such differences include: changes in world commodity markets, equity markets, costs and supply of materials relevant to the mining industry, change in government and changes to regulations affecting the mining industry and to policies linked to pandemics, social and environmental related matters. Forward-looking statements in this release include statements regarding future exploration programs, operation plans, geological interpretations, mineral tenure issues and mineral recovery processes. Although we believe the expectations reflected in our forward-looking statements are reasonable, results may vary, and we cannot guarantee future results, levels of activity, performance or achievements. Mirasol disclaims any obligations to update or revise any forward-looking statements whether as a result of new information, future events or otherwise, except as may be required by applicable law.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this release.

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