Mr. Carl Hansen reports

ATERRA METALS COMMENCES PREPARATION OF MAIDEN MINERAL RESOURCE ESTIMATE FOR THE TOTORA CU/AU PROJECT

Aterra Metals Inc. has commenced preparation of the company's maiden independent mineral resource estimate (MRE) for its Totora Cu/Au (copper/gold) project. The maiden MRE will define Totora's initial mineral inventory and establish the technical foundation for future economic studies. Aterra has engaged SRK Consulting (Chile) SpA, a leading international mining consultancy, to prepare the independent MRE. The project is located in the Dos Amigos mining district, 15 kilometres south of Tintina Mines' Domekyo sulphuros development project.

The MRE will be prepared in accordance with Canadian Securities Administrators' National Instrument 43-101 -- Standards of Disclosure for Mineral Projects and will incorporate the results from Aterra's recently completed phase I drill program together with historical drilling completed on the project. The estimate will focus on the company's three principal copper-gold porphyry systems -- Frontera, Totora and Clinton -- which collectively represent the most advanced exploration targets on the property. It is anticipated that the MRE will be available for release during September, 2026.

Carl Hansen, chief executive officer of Aterra, commented: "Our objective is to establish the first independently verified mineral resource at Totora by integrating the results from a number of historical drill programs with our successful phase I drilling. A maiden resource will provide investors with the first quantitative assessment of the scale of the project and guide Aterra's future exploration and development plans. This work marks an important step toward unlocking the value of the Totora project."

Mr. Hansen continued: "Recent investments by multiple companies in the Dos Amigos mining district underscore renewed industry interest in the region's copper-gold potential. We believe this increasing activity highlights the strategic position of the Totora project within an emerging mining district."

Phase I Totora drilling highlights

The mineral resource estimate will incorporate the results of Aterra's recently completed phase I drill program at Totora, the highlights of which were previously disclosed in the company's news release dated July 16, 2026. Selected drill highlights previously reported include:

• Frontera (AFROD01): 284 metres grading 0.64 per cent CuEq (copper equivalent) (0.41 per cent Cu and 0.27 g/t Au) from surface, including 180 metres grading 0.71 per cent CuEq (0.48 per cent Cu and 0.28 g/t Au);
• Totora (ATOD01): 194 metres grading 0.41 per cent CuEq (0.35 per cent Cu and 0.11 g/t Au) from 254 metres downhole.

National Instrument 43-101 disclosure

Qualified person: As defined by NI 43-101 of the Canadian Securities Administrators, the qualified person for Aterra Metals is Francisco Bravo, a resident of Santiago, Chile. As Aterra's chief geologist, Mr. Bravo is considered "not independent" as the term is defined by NI 43-101. Mr. Bravo, a public registered person for reserves and resources in Chile (N degrees 515) and registered with the Colegio de Geologos de Chile (N degrees 725), has reviewed and approved the technical information contained in this press release.

About Aterra Metals Inc.

Aterra Metals is a mineral exploration company focused on advancing high-quality copper and gold assets in the Americas. The company's flagship Totora Cu/Au project is located within Chile's highly prospective Dos Amigos mining district and hosts multiple copper-gold porphyry systems with significant exploration and development potential.

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