Marimaca Copper: Pampa Medina's High-Grade Core Confirmed, Maiden Resource Target by October

• Marimaca's latest drilling extends the ultra-high-grade zone at Pampa Medina further to the west and south, confirming continuity of the mineralised system.
• Drill hole SPRD-15 delivered the company's best result yet at Pampa Medina, intersecting 216 metres at 1.0%+ copper including a high-grade zone of 62 metres at 2.2% copper.
• CEO Hayden Locke reframed Pampa Medina as a sediment-hosted copper deposit comparable to Kamoa-Kakula, rather than a Chilean porphyry.
• Marimaca has narrowed its MOD financing search to three lender groups now in final due diligence, targeting full construction during 2027.
• Management expects to deliver an initial maiden resource on a subset of Pampa Medina once current drilling concludes at the end of October.

Marimaca Copper Corp. (TSX:MARI) has released a fresh batch of drill results from its Pampa Medina discovery in northern Chile. According to CEO Hayden Locke, the results confirm the company's understanding of the deposit's increasingly large scale. Speaking from Marimaca's construction camp at the Marimaca Oxide Deposit (MOD), where he was preparing for lender site visits, Locke walked through a set of results that extend the deposit's ultra-high-grade zone further west and south, adding to a mineralised footprint the company now believes could rival some of the best sediment-hosted copper systems in the world.

For investors, the results arrive at a pivotal moment: Marimaca is simultaneously pushing its permitted MOD project toward a construction decision while its exploration team works to define just how large the Pampa Medina opportunity might become.

A Sediment-Hosted System

Locke was keen to correct what he described as a common misreading of the Pampa Medina story. Unlike the porphyry deposits more typically associated with Chilean copper, Pampa Medina is a sediment-hosted system, comparable to the Kupferschiefer basin of Poland and Germany and, more strikingly, to the Central African Copperbelt's Kamoa-Kakula deposit.

To illustrate the comparison, Locke referenced average grade thickness - true thickness multiplied by grade - as the key metric for sediment-hosted systems. Poland's Nova Sol project, by way of comparison, averages between 4-5% copper-metres, with a measured and indicated grade of around 1.2% copper plus 38 grams per tonne (g/t) silver. A historical KGHM-operated mine in the same basin averages around 1.9% copper plus 35 g/t silver over a true thickness of four to five metres, equating to roughly 8% copper-metres in its highest-grade zone.

Kamoa-Kakula, meanwhile, hosts zones exceeding 40% copper-metres at its core. Locke put Pampa Medina's simple average grade thickness across the drilling released to date at around 70% copper-metres plus roughly 10 g/t silver.

Headline Numbers From the Latest Results

The standout intercept was drill hole SPRD-15: 216 metres at 1.0% copper and 7 g/t silver, including a high-grade zone of 62 metres at 2.2% copper with 21.6 g/t silver.

"SPRD-15 would have to be the best drill hole we've released yet at Pampa Medina. It is an exceptional thick and highgrade drill, but it's not the only one. There are multiple repetitions where we delivered significant widths and grades." 

SPRD-17 returned 104 metres at 0.7% copper including a 30-metre zone at 1.0% copper. SPRD-12, further south-west in an area the company expected might be structurally discontinuous, instead returned 56 metres at 1.0% copper including a high-grade zone of 22 metres at 1.8% copper plus 10 g/t silver. Stepping east to west across the broader system, the company also highlighted a hole in the far north at 160 metres at 0.6% copper with multiple stacked mantos of 10 to 30 metres above 1% copper.

Taken together, the company now defines a broader drill-confirmed area of roughly 3km by 1.5km, with a central high-grade zone of approximately 1.3km by 1.3km.

Reading the Structural Controls

Locke addressed two separate structural questions that had puzzled the market: post-mineral dikes and faulting. The dikes, while not entirely barren, carry effectively zero grad- but drilling has shown their true thickness is significantly thinner than earlier intercepts suggested, since the dikes run on a similar orientation to the drill holes themselves. That's a positive for eventual resource tonnage, as it means less dilution than previously modelled.

On faulting, Locke said the company has a good handle on east-west, uplift-down-drop structures, and that a north-south mining orientation would encounter significantly fewer of them - though he acknowledged that geotechnical drilling would still be required before any underground mining decision.

Interview with Hayden Locke, CEO of Marimaca Copper

Financing the Marimaca Oxide Deposit

While Pampa Medina drives the exploration narrative, Marimaca's near-term catalyst remains the MOD, its permitted flagship project. The company has narrowed its financing process to three groups now in final due diligence, after which it will select one partner to negotiate exclusively. Locke was explicit about the company's approach to capital structure.

"We've had a lot of discussions with our shareholders about this, and there is strong alignment that the strategy we're pursuing is the correct one, which is to move forward on a project that's very rare in the copper industry."

Management's stated philosophy is a conservative debt-to-equity ratio, an aversion to hedging, and a preference for traditional senior secured lenders over more complex financing structures. Once a lender is selected exclusively, legal due diligence is largely already completed through the company's public listing and prior capital raises, and long-form documentation would run into the middle of 2027, with full construction expected during 2027.

Piggybacking Infrastructure and Capital Discipline

Marimaca has already adjusted the MOD's design in anticipation of Pampa Medina's growth. Recognising that power and water availability would be the limiting factors if oxide material from Pampa Medina were processed through MOD infrastructure, the company has oversized its planned water pipeline to a capacity capable of supporting 100,000 tonnes of cathode production per annum. Any oxide material at Pampa Medina, regardless of ultimate scale, is expected to piggyback on MOD's infrastructure; a sufficiently large discovery could instead justify a standalone solvent extraction plant. The larger sulfide opportunity at Pampa Medina, by contrast, will require substantially more drilling before its development path becomes clear, and Locke was clear that decision won't be rushed.

With roughly $140 million in cash on hand, Locke states the company splits into separate development and exploration teams, the latter led by VP Exploration Sergio Rivera intending to keep drilling to demonstrate further upside for shareholders while remaining disciplined about preserving capital through to MOD construction.

The Investment Thesis for Marimaca Copper

• Pampa Medina's drill results continue to extend both scale and grade, with the company now defining a roughly 3km by 1.5km area and a 1.3km by 1.3km high-grade core.
• Management frames the deposit as a sediment-hosted analogue to Kamoa-Kakula and the Kupferschiefer basin rather than a Chilean porphyry, a distinction that matters materially for how investors should value the asset.
• The MOD remains the near-term catalyst: financing has been narrowed to three groups in final due diligence, with construction expected through 2027 on a permitted, de-risked project.
• Design work already links Pampa Medina's oxide potential to MOD infrastructure, creating built-in optionality without requiring separate capital commitments for smaller discoveries.
• The company holds approximately $140 million in cash, providing runway to keep drilling Pampa Medina while pursuing MOD financing in parallel.
• Watch for the initial maiden resource on a subset of Pampa Medina, expected once current drilling concludes at the end of October.
• The larger sulfide opportunity at Pampa Medina remains unquantified and will require significantly more drilling before a development pathway is defined - a multi-year, not near-term, catalyst.

Macro Thematic Analysis

Marimaca's Pampa Medina story sits inside a broader repricing of sediment-hosted copper systems as a distinct and increasingly valuable deposit style. For much of the past two decades, market attention - and premium valuations - concentrated on porphyry copper, the dominant style across Chile and Peru. Kamoa-Kakula's emergence in the Central African Copperbelt changed that calculus, proving that sediment-hosted, manto-style systems can host bonanza-grade zones at genuinely world-class scale, all while carrying different metallurgical and mining characteristics than porphyry ore.

"When I look at the Kupferschiefer, but particularly at Kamoa Kakula, which was world class in anyone's definition, we are comparing extremely favourably to one of the best copper discoveries made in the last two or three decades."

That framing matters for how investors should assess Marimaca. A sediment-hosted deposit with genuine scale offers a different risk-reward profile than a comparably sized porphyry project as often shallower, higher-grade in its core zones, and potentially more capital-efficient to bring into production. With copper prices supported by structural demand from electrification and grid infrastructure, and few large-scale, high-grade discoveries emerging globally in recent years, a project that can credibly invite Kamoa-Kakula comparisons even at an early, pre-resource stage is likely to draw increasing scrutiny from both generalist and specialist mining investors as the maiden resource takes shape.

TL;DR

Marimaca Copper's newest Pampa Medina results, headlined by SPRD-15's 216m at 1% copper (including 62m at 2.2%), extend the sediment-hosted system further west and south to a roughly 3km by 2km footprint. CEO Hayden Locke compares the deposit to Kamoa-Kakula and the Kupferschiefer basin rather than a Chilean porphyry. A maiden resource is expected by end-October, while the flagship MOD project moves toward a financing decision with three lenders in final due diligence and construction targeted for 2027.

FAQ (AI-generated)