Marimaca Copper Secures Environmental Approval for Chilean Project

• Marimaca Copper Corp. secured environmental approval (ICSARA) on February 28, 2025, from Chile's Superintendence of the Environment for its Marimaca Oxide Deposit in the Antofagasta Region, representing a significant de-risking event for the development-stage copper producer.
• The project demonstrates robust financial metrics with a post-tax NPV of US$709 million at US$4.30/lb copper price, 31% internal rate of return, and 2.5-year payback period, positioning it among the most capital-efficient copper developments globally.
• The deposit contains 748,000 tonnes of contained copper in proven and probable reserves, supporting a 13-year mine life with targeted production of 50,000 tonnes per annum of copper cathode.
• The project addresses global copper supply constraints as demand accelerates from electrification and energy transition initiatives, while new mine development remains constrained worldwide.
• Marimaca advances toward a Final Investment Decision in H2 2026 with approximately US$77 million in cash following a recent capital raise, providing financial runway for pre-development activities and detailed engineering work.

Introduction: Strategic Timing in a Copper-Constrained Market

Global copper markets face mounting supply pressures as the energy transition accelerates demand while new mine development stagnates. Against this backdrop, Marimaca Copper Corp.'s recent environmental approval for its Chilean oxide project represents more than a regulatory checkbox it positions the company to deliver critically needed copper production in a jurisdiction renowned for mining expertise. The approval arrives as copper prices trade above US$5.00 per pound on the London Metal Exchange, reflecting structural market tightness that analysts project will persist through the decade.

The February 28, 2025 approval from Chile's Superintendence of the Environment removes a key development risk for the Marimaca Oxide Deposit, located 25 kilometers from the port of Mejillones in the Antofagasta Region. The permit allows the company to proceed with detailed engineering and construction planning for a project that completed its Definitive Feasibility Study in August 2025, demonstrating compelling project economics even at conservative copper price assumptions.

For mining-focused investors seeking exposure to copper's structural bull market, Marimaca offers a development-stage opportunity with institutional-grade technical work, proven reserves, and now regulatory certainty in a Tier-1 mining jurisdiction. The company's advancement toward production by 2027-2028 aligns with anticipated copper supply deficits as electrification and grid infrastructure investments accelerate globally.

Company Overview: Chile's Newest Significant Copper Discovery

Marimaca Copper Corp. operates exclusively in Chile's prolific Coastal Copper Belt, approximately 40 kilometers from the regional capital of Antofagasta. The company controls three key properties in the Sierra de Medina region: the flagship Marimaca Oxide Deposit, the Pampa Medina exploration target, and the Madrugador acquisition. This consolidated land position provides both near-term development potential and long-term resource expansion opportunities in one of the world's premier copper-producing regions.

The Marimaca Oxide Deposit contains 213.5 million tonnes of measured and indicated resources grading 0.40% total copper, representing 854,000 tonnes of contained copper. The company converted 88% of these resources into proven and probable reserves totaling 178.6 million tonnes at 0.42% copper, supporting a 13-year mine life. This conversion rate significantly exceeds industry norms and reflects the deposit's favorable metallurgy, simple geology, and straightforward mining characteristics.

Beyond the oxide deposit, Marimaca's district-scale exploration portfolio includes compelling sulphide targets at Pampa Medina where drilling has intersected thick, high-grade mineralization. Notable intersections include 100 meters at 1.3% copper from 580 meters depth, including 26 meters at 4.1% copper and 6 meters at 12.0% copper. This exploration upside provides optionality for future production expansion through either satellite oxide deposits or larger-scale sulphide development, potentially transforming Marimaca from a single-asset developer into a multi-decade copper producer.

Key Development: Environmental Approval Unlocks Project Advancement

The ICSARA (Informe Consolidado de Solicitud de Aclaraciones, Rectificaciones o Ampliaciones) approval represents the completion of Chile's environmental review process for the Marimaca Oxide Deposit. This regulatory milestone enables the company to proceed with construction activities once financing is secured and a Final Investment Decision is made, targeted for the second half of 2026. The approval process, conducted under Chile's Declaration of Environmental Impact (DIA) framework, typically requires 18-24 months and involves comprehensive technical review by multiple government agencies.

Hayden Locke, Marimaca's CEO and President, emphasized the significance of this achievement, stating:

"Receipt of the ICSARA allows the Company to continue progressing the MOD Project towards a construction decision targeted for H2 2026."

The statement underscores both the collaborative approach Marimaca has taken with Chilean regulatory authorities and the company's clear timeline toward development.

The approval process evaluated mining operations, processing facilities, water supply infrastructure, power transmission, and closure planning across the project's 13-year life. Chile's environmental review framework ranks among the most rigorous globally, requiring detailed baseline studies, impact assessments, and mitigation plans across environmental, social, and cultural dimensions. The timing of this approval provides Marimaca with operational flexibility as copper market fundamentals strengthen, allowing the company to engage engineering contractors for detailed design work, secure long-lead equipment orders, and finalize construction schedules while maintaining optionality on project financing timing.

Strategic Significance: Low-Cost Entry to Global Copper Supply

Marimaca's project economics position it favorably within the global copper development pipeline. The Definitive Feasibility Study, completed in August 2025, calculated a post-tax net present value of US$709 million using an 8% discount rate and US$4.30 per pound copper price conservative relative to current spot prices above US$5.00 per pound. The project's 31% internal rate of return and 2.5-year payback period rank in the top quartile of development-stage copper projects globally, according to third-party capital intensity benchmarks.

Initial capital requirements of US$587 million translate to capital intensity of US$11,700 per tonne of annual copper production capacity, among the lowest for greenfield copper developments worldwide. This efficiency stems from the project's low strip ratio of 0.8:1, proximity to existing infrastructure including the port of Mejillones, and conventional heap leach processing technology. First-quartile all-in sustaining costs of US$2.09 per pound position the operation to generate substantial free cash flow across commodity price cycles.

The project's operational simplicity reduces execution risk compared to more complex concentrator-based developments. Heap leach operations have proven track records in Chile's Atacama Desert environment, where several neighboring operations including Mantos Blancos and Lomas Bayas have operated successfully for decades. Marimaca's metallurgical test work, spanning seven phases of column testing including 4-meter height columns, provides high confidence in the recovery assumptions underpinning the feasibility study's 72% average copper recovery.

Current Activities: Advancing Toward Construction Decision

Following the environmental approval, Marimaca is progressing multiple workstreams toward a Final Investment Decision in H2 2026. Detailed engineering work continues with Ausenco and NCL, two prominent engineering consultants with extensive Chilean copper project experience. The company is also advancing long-lead equipment procurement, water supply agreements with the Bay of Mejillones, and power supply arrangements with renewable energy providers. These parallel work streams position Marimaca to commence construction rapidly once financing is secured.

The company's recent capital raise of A$80 million (approximately US$53 million) strengthened its balance sheet to approximately US$77 million in cash as of September 2025. This financial position provides runway for pre-development activities including detailed engineering, permitting compliance, stakeholder engagement, and exploration programs at Pampa Medina. Additional project financing will be required for construction, with management exploring various capital structures including project debt, equipment financing, streaming arrangements, and potential strategic partnerships.

Exploration activities continue at the Pampa Medina sulphide target, located 25 kilometers from the planned Marimaca Oxide processing plant. The company is currently executing a 10,000-meter drilling program to define the sulphide resource potential, with results anticipated in 2025-2026. This exploration work occurs in parallel with oxide development, reflecting management's strategy to build a multi-decade, district-scale copper operation rather than a single-asset mining company. Successful sulphide resource definition could support future production expansions leveraging the oxide project's infrastructure.

Management Perspective: Executing a Clear Development Strategy

Hayden Locke, who serves as CEO and President of Marimaca Copper, brings nearly 20 years of experience in mining and finance to the company's development strategy. His background includes serving as Head of Corporate Development for Papillon Resources and CEO of Emmerson Plc, providing him with direct experience navigating companies through the development phase. Under his leadership, Marimaca has systematically de-risked the project through comprehensive technical studies, stakeholder engagement, and regulatory advancement.

Locke's statement on the environmental approval reflects the company's methodical approach:

"This is a significant milestone for the Company and the culmination of many months of work by the Marimaca team in collaboration with highly experienced Chilean environmental consultants."

The emphasis on collaboration with experienced Chilean consultants highlights Marimaca's strategy of leveraging localexpertise rather than attempting to navigate Chile's regulatory environment independently an approach that has clearly yielded results.

The CEO's reference to the "highly experienced Chilean environmental consultants" also speaks to risk mitigation. Chile's environmental permitting process requires deep knowledge of local regulations, stakeholder dynamics, and technical requirements. By partnering with established Chilean firms including Jaime Illanes & Asociados for environmental work, the company has accessed institutional knowledge that would be difficult for an international junior to replicate. This collaborative approach has positioned Marimaca to advance toward its H2 2026 construction decision timeline with reduced regulatory uncertainty.

Investor Takeaway: Catalysts and Risk Considerations

Marimaca presents a compelling risk-reward profile for investors seeking leveraged exposure to copper price appreciation through a near-term development asset. The environmental approval removes a key permitting uncertainty, while the company's technical work demonstrates robust project economics across various copper price scenarios. Sensitivity analysis shows the project maintains positive economics at copper prices as low as US$3.50 per pound, providing downside protection while offering significant upside leverage if prices remain at current levels above US$5.00 per pound.

Near-term catalysts include the Final Investment Decision in H2 2026, project financing announcements, detailed engineering completion, and Pampa Medina exploration results. Construction commencement would mark a significant de-risking event, while first copper production in 2027-2028 would transform Marimaca from a developer into a producer generating substantial free cash flow. The company's location in Chile's established mining region provides access to skilled labor, experienced contractors, and proven supply chains, reducing execution risks compared to frontier jurisdictions.

Investment risks warrant consideration alongside the opportunity. Construction capital requirements of approximately US$587 million will necessitate additional financing, potentially including equity dilution, debt obligations, or streaming agreements that impact economics. Copper price volatility could affect project returns, though current market fundamentals suggest sustained price strength. Operational risks include potential cost overruns, schedule delays, or lower-than-expected metallurgical recoveries, though extensive test work and engineering mitigate these concerns. Geopolitical factors affecting Chile's mining sector, including potential tax or royalty changes, represent broader sector risks applicable to all Chilean operators.

The Investment Thesis for Marimaca Copper

• Environmental approval removes key development uncertainty in a jurisdiction with clear permitting pathways and established mining regulations.
• US$11,700 per tonne production capacity ranks among lowest globally; consider position sizing at 3-5% for development-stage exposure.
• 50ktpa copper production captures structural market tightness; reassess if copper sustains above US$5.00/lb through 2026.
• 31% IRR and 2.5-year payback support rapid capital return post-production; evaluate streaming deals if offered 15-20% upfront capital.
• Pampa Medina sulphides offer 50-100% production upside; allocate 25% of position to exploration optionality.
• US$77 million cash supports pre-development without immediate dilution; monitor debt-to-equity ratio targeting below 1.0x at construction decision.

Marimaca Copper's environmental approval represents a pivotal milestone in transforming a significant copper discovery into a producing mine in Chile's premier mining region. The combination of proven reserves, robust project economics, regulatory certainty, and strong copper market fundamentals positions the company as a compelling investment opportunity for investors seeking exposure to copper's structural supply-demand imbalance. With a clear pathway to production by 2027-2028 and substantial exploration upside at Pampa Medina, Marimaca offers both near-term development catalysts and longer-term growth optionality.

For mining investors, the company presents an opportunity to invest at the development stage of a project that has completed institutional-grade technical studies, secured critical permits, and demonstrated compelling economics across copper price scenarios. The 88% resource-to-reserve conversion rate, first-quartile capital intensity, and second-quartile operating costs reflect the deposit's favorable characteristics and management's technical execution. As CEO Hayden Locke noted, the environmental approval represents "the culmination of many months of work" and positions the company to "continue progressing the MOD Project towards a construction decision targeted for H2 2026."

The investment case ultimately rests on copper's indispensability to electrification, grid expansion, and renewable energy deployment trends that appear structural rather than cyclical. Marimaca's ability to deliver meaningful production by decade-end positions it to participate in what many analysts forecast as a multi-year copper price appreciation cycle driven by supply scarcity rather than demand speculation. With regulatory risks now substantially reduced and project financing the primary remaining milestone, investors have clarity on the pathway to production and the metrics for evaluating management execution through construction and commissioning.

TL;DR

Marimaca Copper secured environmental approval for its Chilean copper oxide project featuring 748kt contained copper, US$709M NPV, 31% IRR, and industry-leading capital efficiency at US$11,700/t capacity. The permit enables progression toward H2 2026 construction decision with first production by 2027-2028, targeting 50ktpa copper cathode output over 13-year mine life. With US$77M cash, 88% resource-to-reserve conversion, and district-scale sulphide exploration upside at Pampa Medina, the company offers leveraged copper exposure through near-term development catalysts in a Tier-1 jurisdiction. Investment risks include construction financing requirements, copper price volatility, and execution challenges, though extensive technical work and simple heap leach operations mitigate operational concerns.

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