Marimaca Copper & Pampa Medina's SPRD-06: 8 Things You Need to Know

Project Overview

Pampa Medina sits in Chile's coastal Atacama Desert at low altitude, approximately 28 kilometres east of the Marimaca Oxide Deposit. The project has a documented exploration history dating back to 1993, when Doña Isabel and Rayrock conducted the first exploration programmes, including geochemistry surveys and short Track Drill wells; Apoquindo Minerals Inc. subsequently completed drilling programmes in 2007 and 2008. Marimaca Copper (TSX: MARI | ASX: MC2) consolidated the project area and surrounding land packages in 2024, then updated the geological model to redirect drilling at the lower sedimentary units that earlier programmes had not fully tested.

The current programme, a step-out and infill campaign targeting 30,000 to 35,000 metres, is testing a 3 by 1.5-kilometre area of interest. What began as a satellite oxide feed for the Marimaca Oxide Deposit, which currently holds Proved and Probable Reserves of 179 million tonnes at 0.42% total copper, supporting a 50,000 tonnes-per-annum copper cathode operation over a 13-year mine life, has since been reframed as a system with its own resource-scale potential.

1. What SPRD-06 Actually Returned

Hole SPRD-06 delivered a 424-metre intercept grading 0.58% copper and 2.2 grams per tonne silver, starting from 424 metres depth and drilled to a total depth of 904 metres. The hole was positioned as a 150-metre step-out between previously released holes SMRD-16 and SMRD-20.

Within the broad intercept, five distinct high-grade mantos were identified across oxide and sulphide domains. The shallowest returned 32 metres at 1.02% copper and 3.1 grams per tonne silver from 432 metres. The second intersected 8 metres at 2.54% copper and 21.0 grams per tonne silver from 494 metres, sitting within a 22-metre envelope grading 1.23% copper and 11.8 grams per tonne silver. The third returned 12 metres at 2.23% copper and 19.7 grams per tonne silver from 568 metres, within a 22-metre interval at 1.53% copper and 13.6 grams per tonne silver from 564 metres. The fourth and fifth mantos, both in the sulphide domain, returned 10 metres at 1.38% copper and 4.4 grams per tonne silver from 698 metres, and 8 metres at 1.29% copper and 10.8 grams per tonne silver from 752 metres, respectively.

2. The Architecture Behind the Intercept

The five mantos are not a single, broad mineralised body; they are independently mineralised sedimentary units stacked vertically within a single drill hole. Marimaca's management identifies this configuration as a key difference between Pampa Medina and other globally known sedimentary-hosted copper deposits. Pampa Medina's vertical stacking adds grade and tonnage across multiple horizons, which management notes allows tonnage to build rapidly per drill hole.

Chief Executive Officer of Marimaca Copper, Hayden Locke, is direct about what the current drilling has done to management's understanding of the system:

"It completely changes the thinking, and also the drilling on the edges changes our thinking. What we're seeing now is through that centre zone, which trends northeast-southwest from the original discovery hole way up in the north down a couple of kilometres to the south. There is a very coherent, thick, high-grade zone."

The coherent, thick, high-grade centre zone traces that northeast-southwest axis from the original discovery hole to a point approximately 2 kilometres to the south, establishing a structural spine that the current programme is systematically testing with tighter spacing.

3. The Host Rock Sequence

Mineralisation at Pampa Medina is hosted in Jurassic-Triassic sedimentary units comprising sandstones, conglomerates, tuffs, and black shales. These units are overlain by andesitic volcanics and underlain by an Upper Palaeozoic complex of metamorphosed sediments, volcanics, and intrusions, a stratigraphic configuration that positions the mineralised sediments within a clearly defined column.

The scale of the sedimentary package is directly relevant to the system's resource argument. The mineralised sediment at Pampa Medina reaches 26 metres thick in some areas. That figure is nearly six times the 4.5-metre average thickness of the Kupferschiefer, the European sediment-hosted copper system to which management draws comparisons. Sediment thickness is not merely a geological observation here; it is the physical basis on which the tonnage argument rests.

4. How the System Has Been Reframed

Pampa Medina was added to Marimaca's portfolio as a satellite oxide feed intended to supplement the Marimaca Oxide Deposit's cathode output. Drilling has since revealed a system extending well below the oxide-primary transition, dominated by leachable bornite and chalcocite in the sulphide domain.

The strategic sequencing has been adjusted to reflect this. Any oxide resource discovered at Pampa Medina is intended to be developed first, expanding the Marimaca Oxide Deposit's cathode production from 50,000 to 75,000 tonnes per year. That production expansion provides the time needed to continue drilling and understanding the scale of the larger underlying sulphide opportunity, while management evaluates the most economically viable long-term development scenarios.

5. What the Comparisons to Kamoa-Kakula & the Kupferschiefer Are Claiming

Management's comparisons of Pampa Medina to Kamoa-Kakula and the Kupferschiefer are not made casually. Both analogies rest on specific technical attributes, such as coherent sediment thickness and consistent grade, though management notes that Pampa Medina's vertical stacking geometry is a key difference from those systems. These are measurable characteristics, and the current drilling provides a direct basis for comparison.

Locke puts the grade and width comparison with the Kupferschiefer in precise terms:

"If you compare us to the Kupferschiefer, which we have a lot of analogous items in comparison to, we're drilling and delivering grades and widths that are exceeding the Kupferschiefer deposits in every single drill hole, so that adds up very quickly now. The real question is how well does it hang together, how much bigger could it be, and when we start to put a resource around this, how much are we going to capture in that eventual resource?"

Management characterises Pampa Medina as a potential Tier-1 discovery, defined as a system capable of producing 100,000 tonnes of copper annually for over 20 years, a scale described as attractive to almost any major copper producer in the world. That framing sets the threshold that the company believes the system may meet. Whether the drill programme confirms it at the resource-estimate stage is the open question the current campaign is designed to answer.

6. Two Mining Scenarios, One Economic Logic

The thick, coherent, high-grade centre zone created by vertical stacking offers genuine optionality at the project scale. The same geological configuration that generates the Kupferschiefer comparison supports either an enormous bulk-tonnage open pit or a competitive underground operation targeting a 20 to 50-metre mining horizon. The density of stacked mineralisation means that tonnage builds rapidly per drill hole, a direct consequence of the architectural arrangement established earlier.

Locke frames the economic logic across both scenarios:

"The question is whether it's 400 metres of 0.5% copper, in which case you try and do an enormous open pit, or whether it's an underground opportunity where you're taking 20 to 50 metres of underground mining horizon. Either way, the unit cost per tonne of ore that we deliver to the plant is going to be very competitive against the other sediment basins that we're looking at."

The economic argument does not depend on resolving which scenario the project will follow. Management's position is that the sediment-hosted stacking geometry delivers competitive unit economics under either configuration.

7. Where the Drilling Programme Stands

The 30,000 to 35,000-metre campaign is advancing from an initial 300-metre scout-hole spacing down to 150-metre spacing across the 3 by 1.5-kilometre area of interest. The tighter 150-metre infill phase is now underway.

Core-cutting delays that affected earlier result cadence have been resolved, and the company expects results to be released more rapidly as the programme approaches its September conclusion. Regional exploration activities, including step-out drilling to test the northern and western extensions of the system identified in previously completed geophysical work, are also planned alongside the main campaign.

8. The Resource Estimate Timeline & What It Will Capture

A maiden inferred resource for Pampa Medina, based on 150-metre drill spacing, is targeted for completion six to seven months after the current drill programme concludes. That timing, set against a September programme end, would place the resource estimate in the first half of 2027.

Locke is precise about what that resource will and will not represent:

"We'll take six to seven months to put together an initial resource, and that initial resource will be over a very small snapshot of what we think we've delineated. It's not going to be everything, but it'll be something that allows people to start looking at it and going, okay, this is actually a real opportunity."

The qualification is analytically material. A resource based on 150-metre spacing will capture the portions of the system where drill density meets the standard threshold for an inferred classification, not the full extent of what has been delineated to date. The maiden resource is therefore best understood as an entry-point figure, not a ceiling.

Key Takeaway for Investors

• Hole SPRD-06 returned a 424-metre intercept averaging 0.58% copper and 2.2 grams per tonne silver, with five discrete high-grade mantos spanning oxide and sulphide domains and true widths estimated at 80% to 90% of reported downhole lengths.
• The five mantos are independently mineralised sedimentary units stacked vertically within a single drill hole, a configuration that management identifies as a key difference between Pampa Medina and other globally known sedimentary-hosted copper deposits.
• Management's comparison of Pampa Medina to the Kupferschiefer rests on measurable attributes, grade, width, and sediment thickness, and the company states that current drill holes are exceeding Kupferschiefer deposits on both grade and width in every single drill hole to date.
• The thick, coherent centre zone creates genuine optionality between a bulk-tonnage open pit and a 20 to 50-metre underground mining horizon, with management stating that unit cost per tonne of ore delivered to the plant will be competitive against other sediment-hosted basins under either scenario.
• A maiden inferred resource estimate based on 150-metre drill spacing is targeted six to seven months after the programme concludes in September, and management has explicitly qualified that it will represent only a partial snapshot of the system delineated to date, not a full capture of the deposit's known extent.

Bottom Line

SPRD-06 is significant not because of its aggregate intercept length but because it confirmed that five independent high-grade mantos can coexist within a single vertical column at Pampa Medina. That structural characteristic, vertically stacked, independently mineralised sedimentary units across oxide and sulphide domains, is the mechanism by which the deposit differs architecturally from conventional Chilean manto systems, and it is the mechanism on which the resource-scale argument depends. The 30,000 to 35,000-metre programme now advancing to 150-metre spacing across a 3 by 1.5-kilometre area of interest will determine whether that architecture holds at system scale. The maiden resource estimate, when it arrives, will be a partial answer to that question.