Mr. Hayden Locke reports

MARIMACA APPOINTS PETER GARNER-WINSHIP AS CFO

Marimaca Copper Corp. has promoted Peter Garner-Winship to chief financial officer, effective immediately. Mr. Garner-Winship joined Marimaca in March, 2026, as vice-president, finance, after spending 17 years with Anglo American, holding senior roles in corporate finance, strategic planning and capital allocation. His experience also includes serving as financial controller for the $5.5-billion (U.S.) Quellaveco copper project in Peru, where he helped build the project organization and finance function through construction and the transition into operations. Jose Antonio Merino will continue in his role as managing director (Chile) where he will provide a key role in the advancement of the Marimaca oxide deposit (MOD) and the regional development and permitting strategy.

Hayden Locke, chief executive officer and director of Marimaca Copper, commented:

"As we transition to developing the Marimaca oxide deposit, we are excited to appoint Peter Garner-Winship to the role of CFO. Peter was heavily involved in the set-up of the finance function for the successful Quellaveco construction in Peru and will leverage this experience to develop our own financial controls and systems. He also brings broad experience in financial reporting, capital allocation and risk management from his time at Anglo American. This is an important appointment as we prepare to progress the MOD through construction into production.

"Jose Antonio has been an integral member of the Marimaca management team since 2022, leading the team that delivered numerous derisking milestones, including our environmental permits, securing water supply, power connections and commercial negotiations, our self-produced sulphuric acid strategy, and other commercial initiatives. He will continue as managing director (Chile), with the transition of CFO responsibilities allowing him to focus on leading all in-country aspects of the development of the MOD and the company's broader operational, permitting and growth strategy in Chile."

About Marimaca Copper Corp.

Marimaca is a Toronto Stock Exchange- (MARI) and Australian Securities Exchange-(MC2)-listed copper company focused on the development of high-quality copper assets in northern Chile. The company's flagship asset is the Marimaca oxide deposit project (MOD), located in Chile's prolific Antofagasta region. It is one of the few globally significant greenfield copper discoveries made in the last decade and represents a low-risk development opportunity, given the proximity to the city of Antofagasta and port of Mejillones, with substantial exploration upside. The company also controls additional exploration properties at Pampa Medina and Madrugador within the Sierra de Medina region, located 30 kilometres from the MOD, where recent drilling has identified both oxide extensions and high-grade sulphide mineralization at depth.

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