Toronto, Ontario – September 16, 2026 – Rosa Ventures Ltd. (“Rosa” or the “Company”) is pleased to announce that it has retained Mr. Gustavo Delendatti, PhD, MAIG (8009), as independent Qualified Person (“QP”) under National Instrument

43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”) to prepare Technical Reports on the Company’s Polanco Porphyry Cu-Au Project and San Lázaro Porphyry Cu-Au (Mo) Project in northern Chile.

The reports will support a proposed Qualifying Transaction on a Canadian stock exchange and will include compilation and verification of historical exploration data, site visits as required for QP sign-off, geological interpretation, assessment of exploration potential, and recommendations for further work.

About the Projects

The Polanco project is located in the Paleocene (Tertiary) porphyry copper belt of northern Chile, approximately 115 km east of the port of Iquique and 23 km northeast of BHP’s Cerro Colorado copper mine. The property comprises 12 mining concessions totaling about 2,800 hectares at an elevation of 3,700 metres and is accessible year-round. Prior work by Teck (2018) and subsequent programs identified a semi-outcropping porphyry system with a 2 km by 1 km alteration footprint zoned from potassic-altered dacitic porphyry to phyllic-altered Jurassic sandstones. Age dating (K-Ar and U-Pb zircon) places the system in the same Paleocene window as Cerro Colorado. Relict-sulphide studies of A-veins indicate the encapsulated sulphides are dominated by chalcopyrite with minor bornite, chalcocite and covellite.

Surface rock samples have returned values up to 0.84 g/t Au and 851 ppm Cu, principally from the partially leached potassic zone. A drone magnetic survey outlined a roughly 2 km-diameter magnetic feature interpreted as the potassic core, much of which is covered by post-mineral volcanics. The project remains undrilled and is considered ready for an initial diamond-drill program.

The San Lázaro project lies in the Upper Eocene–Oligocene porphyry belt approximately 15 km south of the Collahuasi district, at 4,000 metres elevation and about four hours’ drive from Calama. The property covers approximately 1,600 hectares. Historical work by CODELCO/ASARCO and a 2015 Rio Tinto IP survey and 4,725-metre diamond-drill program at the Yuma target (on the current concessions) intersected long intervals of low-grade copper-gold mineralization hosted in propylitic Cretaceous volcanics and a phyllic-altered Paleozoic porphyry under roughly 100 metres of gravels. Reinterpretation of the district model—where Paleozoic and Eocene–Oligocene porphyries commonly occur in clusters sharing large chargeability anomalies—has outlined an undrilled 2 km by 1 km Tertiary target immediately east of the previous holes, under 70–100 metres of cover and within a moderate-to-strong IP chargeability anomaly. The target is of sufficient scale to host a significant porphyry system and can be tested with a modest number of 500–800 metre vertical diamond holes.

Qualified Person

Mr. Delendatti is a Qualified Person as defined by NI 43-101 and a Competent Person under the JORC Code, with more than 30 years of experience evaluating porphyry, epithermal and related systems in South America, North America and Australia. He previously served as Exploration Project Manager for Exeter Resource Corporation at the Caspiche porphyry gold-copper deposit in Chile’s Maricunga belt, where he planned and supervised the deep drilling that first outlined a world-class system and completed 3D geological and mineralization modelling. He has also managed and reviewed porphyry projects in Chile and Argentina, reinterpreted large historical datasets, designed drill programs on outcropping and covered targets, and co-authored NI 43-101 and JORC technical reports.

The Company and Mr. Delendatti will finalize a work schedule and delivery milestones consistent with the timeline of the proposed Qualifying Transaction. All work will be performed in accordance with NI 43-101 and applicable Canadian stock exchange requirements.

About Rosa Ventures Ltd.

Rosa Ventures Ltd. is a junior mineral exploration company focused on the acquisition and advancement of base metal projects in the highly prolific Andes region. The company is actively building a portfolio of copper porphyry opportunities in tier-one mining jurisdictions and is pursuing a reverse takeover transaction to become a publicly listed company.