Marimaca’s Oxide Deposit (MOD) in Chile is advancing through 2026 via multiple parallel workstreams ahead of a Final Investment Decision (FID). The company’s development approach links technical, regulatory, infrastructure, and financing steps that must align before construction approval. Progress reported for 2026 includes permitting submissions, power-grid approvals, engineering partner selection, early works, and debt financing initiation.
Project economics from the 2025 definitive feasibility study
The project’s investment case is based on a Definitive Feasibility Study completed in 2025. The company has not significantly revised its economic assumptions since that study was published. Reported metrics include a post-tax NPV of US$709 million, pre-production capital expenditure of US$587 million, and an IRR of 31%. The copper price assumption used is US$4.30 per pound, with capital intensity stated at US$11,700 per tonne of annual copper production capacity.
Permitting package submitted to SERNAGEOMIN
A key regulatory step occurred in April 2026 when Marimaca submitted its principal sectorial permitting package to Chile’s mining regulator, SERNAGEOMIN. The submission followed receipt of the project’s Environmental Qualification Resolution (RCA) in late 2025. The permitting package covers mine closure planning, open-pit mining operations, crushing and leaching infrastructure, and waste and storage facilities. Approval is expected during the fourth quarter of 2026, with any delay potentially affecting construction scheduling and major works timing into 2027.
Power connection approval for the El Lince line
In May 2026, Chile’s National Electric Coordinator approved Marimaca’s connection to the 110-kilovolt El Lince transmission line. The line is located approximately 13 kilometers from the project site. The approval is intended to reduce infrastructure risk related to power availability during development. It also addresses a common schedule constraint for mining projects when grid access remains unresolved after engineering progress has begun.
EPCM selection and early works activities
Marimaca has launched the selection process for a lead Engineering, Procurement and Construction Management (EPCM) partner. Several internationally recognized engineering firms have been invited to participate in the tender process. The future EPCM contractor will work with the company’s internal project team on detailed engineering and construction execution. Early works are also underway, including access road improvements, highway intersection upgrades, and site preparation initiatives.
Sulphuric acid supply evaluation linked to heap leach operations
The MOD development plan includes a sulphuric acid supply strategy because heap leach copper production depends on sulphuric acid for operations. The original feasibility study assumed acid would be sourced from external suppliers. To support supply security, Marimaca acquired the Dos Amigos Acid Plant (PADA) in 2025. In 2026, a memorandum of understanding signed with a major acid plant operator in Mejillones is evaluating refurbishing the plant, relocating facilities, integrating operations, and establishing a joint venture structure.
The evaluation process is expected to take approximately six months. The reported logistics consideration is that liquid sulphuric acid requires extensive storage infrastructure including specialized containment systems and safety measures. By contrast, elemental sulphur can be stored more simply and processed as needed, which may reduce both capital and operating costs relative to liquid storage requirements. These efficiencies are described as potential value beyond what was captured in the feasibility study.
Surface rights easements and land access approvals
Land access remains part of the development requirements for mine and supporting infrastructure. Marimaca has secured provisional easements covering surface rights needed for engineering activities, site preparation, and construction planning. Final easement agreements are still required because lenders typically require fully secured land rights before committing project financing. Negotiations with the Chilean government are ongoing, with final approvals targeted for the third quarter of 2026.
Debt financing process initiated by Endeavour Financial
Project financing is identified as the final major component required before a construction decision can be approved. Financial adviser Endeavour Financial formally launched the debt financing process in May 2026 to secure funding for estimated US$587 million pre-production capital requirements. Management expects to present a finalized financing strategy before the end of 2026. The company states that its strong economic profile is expected to support lender interest.
Exploration drilling at Pampa Medina and Madrugador properties
The current production plan targets approximately 50,000 tonnes of copper annually. Marimaca controls exploration properties including Pampa Medina and Madrugador, located roughly 25 kilometers from the MOD. An ongoing drilling campaign of 30,000 meters has identified oxide mineralization and higher-grade sulphide zones at depth. Additional resource development within an existing operating district is described as potentially reducing future permitting requirements, infrastructure costs, and development timelines through existing environmental data, community relationships, and transportation corridors.
Copper market timeline context for advanced greenfield projects
The reported global demand drivers for copper include electrification, renewable energy expansion, electric vehicles, data centers, and grid modernization. New copper supply is described as difficult to bring online, with industry studies suggesting many greenfield projects require between 15 and 20 years from discovery to production. Projects that have completed feasibility studies, secured major environmental approvals, and entered active financing discussions are characterized as occupying a highly valuable position within the development pipeline. Marimaca is described as belonging to this relatively small group of advanced projects as workstreams continue through 2026 toward a Final Investment Decision.
