Marimaca Secures Grid Access & Renewable Power Terms for Chile Copper Project

• On September 22, 2026, Chile's Panel of Experts upheld its approval of the Marimaca Oxide Deposit (MOD) to connect to the 110-kilovolt El Lince Line, about 13 kilometers from the project area.
• Marimaca signed a preliminary power purchase agreement framework for 100% renewable power from the national grid. The estimated all-in cost is close to US$93 per megawatt-hour, as used in the Definitive Feasibility Study (DFS).
• The power contract has no take-or-pay provisions during ramp-up and an initial 5-year term after ramp-up.
• Site early works are scheduled to start in the fourth quarter of 2026. Access road upgrades are targeted for completion by the end of 2026.
• Marimaca received an "A" rating in its 2025 Digbee assessment. It is the company's 3rd consecutive "A" and its first under the more rigorous Development Phase framework.

Company Overview

Marimaca Copper Corp. (TSX: MARI | ASX: MC2) is a copper company focused on developing copper assets in northern Chile. Its flagship asset is the Marimaca Oxide Deposit  (MOD) Project in the Antofagasta region, one of the few globally significant greenfield copper discoveries of the last decade. The project is close to the city of Antofagasta and the Port of Mejillones. The company also controls the Pampa Medina and Madrugador exploration properties in the Sierra de Medina region, 30 kilometers from the deposit, where drilling has identified oxide extensions and high-grade sulfide mineralization at depth.

Grid Connection Approved for 110-Kilovolt El Lince Line

Marimaca Copper Corp. received authorization to connect the MOD to Chile's national grid. On September 22, 2026, after a review and challenge period, the Panel of Experts upheld the National Electric Coordinator's approval of the connection application. The connection point is the 110-kilovolt El Lince Line, about 13 kilometers from the MOD project area.

Chief Executive Officer and Director of Marimaca Copper, Hayden Locke, described the approval as a step in de-risking the project:

"The approval of our grid connection is an important de-risking milestone for the Marimaca Oxide Deposit. Together with the preliminary Power Purchase Agreement framework, it provides a clear pathway to securing 100% renewable power at a cost closely aligned with the assumptions in our Definitive Feasibility Study. Importantly, the proposed commercial structure provides the flexibility required during commissioning and ramp-up."

Power Purchase Agreement Framework Targets 100% Renewable Supply

Marimaca signed a preliminary power purchase agreement (PPA) framework with a well-known Chilean energy provider. Under the framework, the provider will supply the MOD with 100% renewable energy from the national grid. The parties agreed on long-term pricing that yields an estimated all-in cost of approximately US$93 per megawatt-hour in the MOD Definitive Feasibility Study (DFS).

The PPA allows a ramp-up period to commercial production with no take-or-pay provisions. Once ramp-up is complete and the MOD is constructed, an initial 5-year term begins.

Access Road, Early Works & Permitting

Upgrades are underway on the primary MOD access road, which branches off Ruta B-12, a paved national highway. Marimaca is targeting completion by the end of 2026. Site early works remain scheduled to start in the fourth quarter of 2026, and contractor packages are out for tender. These works will establish facilities, roads and utilities to support full-scale construction. A separate workstream will bring forward preparatory work on the seawater pipeline route so that pipeline construction can begin in 2027. Permitting is progressing to plan. Further permits needed for full construction are targeted for early October 2026.

Detailed Engineering & Procurement

Marimaca selected a globally recognized engineering, procurement, and construction management firm as lead engineer, working alongside the company's Owner's team. The current priorities are optimizing the site layout from the DFS and advancing detailed engineering for core project areas.

Marimaca is targeting award of the major engineering procurement packages in the first half of 2027. These include the Dry Area, which is the crushing plant, and the Wet Area, which covers heap leaching and the solvent extraction-electrowinning (SX-EW) plant.

Dos Amigos Acid Plant Study

Under its non-binding memorandum of understanding with a leading local acid producer, first announced on May 20, 2026, Marimaca has started a conceptual engineering study for the Dos Amigos Acid Plant (PADA). The study will define the best development pathway for the PADA plant. The study focuses on developing the PADA plant to supply the MOD with self-produced acid. Self-supply could reduce the project's exposure to sulfuric acid price volatility.

3rd Consecutive "A" Rating from Digbee

Marimaca completed its 5th independent environmental, social and governance (ESG) assessment through the Digbee reporting framework and received an overall "A" rating, its 3rd in a row. The 2025 assessment was the first under Digbee's Development Phase framework, which reflects the MOD's progress since the DFS was released in 2025. The Development Phase framework has a stricter disclosure standard than earlier submissions. It focuses on closure planning, community development commitments, workforce planning, and water management.

The ESG factors Marimaca cites for the MOD start with location: the project is within 25km of the Port of Mejillones, and recycled seawater from the port is secured for life-of-mine water requirements, with no impact on local water supply. The approved grid connection and PPA framework give a pathway to 100% renewable energy. Heap leaching removes the need for a wet tailings storage facility, and producing copper cathode through SX-EW avoids the Scope 3 emissions from smelting and refining copper concentrates.

Locke linked the rating to the project's development progress:

"Our third consecutive 'A' rating from Digbee, achieved under the more rigorous Development Phase framework, further reinforces the MOD's strong sustainability credentials. These achievements reflect the team's disciplined approach to planning and commercial execution as we advance the MOD."

Next Steps

Marimaca is targeting further permits for full construction in early October 2026. Site early works are scheduled to start in the fourth quarter of 2026, with contractor packages currently out for tender. The company is targeting completion of the primary access road upgrades by the end of 2026.

In 2027, Marimaca is targeting the start of seawater pipeline construction. It is also targeting the award of the Dry Area and Wet Area engineering procurement packages in the first half of that year. Two items have no target dates yet: the PPA framework still needs to be finalized, and the Dos Amigos Acid Plant study is at the conceptual stage.

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