Marimaca Copper Corp. company history: the story so far

History

Marimaca Copper listed on the ASX in 2025, won environmental approval for its Chilean copper project, raised heavily to fund it, and by October 2026 was nearing construction readiness.

2025: Listing, discovery and a feasibility study

Marimaca Copper, already listed in Toronto, was admitted to the ASX on 31 March 2025, with CDIs (tradable receipts standing in for shares) quoted from 2 April. A small prospectus offer drew no applications, so no money was raised. The real news was in the ground. Re-interpreting more than 77,000m of old drilling plus five new holes, the company outlined a linked oxide copper system across about 5km by 4km at Pampa Medina, 25km from its main deposit. Hole SMD-01 then hit 68m at 1.20% copper, confirming the earlier SMR-01 discovery hole and finding sulphide mineralisation deeper down.

In June Marimaca raised US$17.7 million (C$24.4m) by issuing 5,311,416 shares at C$4.60, with insiders Assore and Ithaki taking 2,250,000 each. Drilling kept improving: SMRD-13 returned 6m at 12.0% copper within 26m at 4.1%, and the Pampa Medina economic study (a PEA) was paused. In August the company took a binding option on a used sulfuric acid plant in Chile for US$2.5m, which could supply 30-40% of the main deposit's acid needs.

2025: Feasibility study and environmental approval

On 26 August the feasibility study for the Marimaca Oxide Deposit set out 50,000 tonnes a year of copper cathode over 13 years, US$587m of pre-production capital, a post-tax NPV8 of US$709m and a 31% IRR at US$4.30 a pound. A maiden reserve of 178.6Mt at 0.42% copper was declared. Days later Marimaca raised about A$80m (C$72.1m) by placing 8,247,423 CDIs at A$9.70, with demand well above the target. Insiders Assore and Ithaki took part.

On 12 November the company received its formal environmental approval, resolving the main open question. Sectoral permits were next. Final Pampa Medina results from the 10,000m program showed mineralisation spanning 1.6km by 1.4km and still open, and a 30,000m Phase II program with five rigs began. In December the company filed a preliminary Canadian base shelf prospectus for up to $500m of securities, with no offering set.

2026: A large raising and a build-out team

Phase II drilling found new north-east oxide, prompting a re-think of the paused PEA for a larger scale. In February Marimaca launched a C$409m global offering at C$10.00 a share (A$10.35 a CDI). Of this, C$136.5m was new money for the company (13,650,000 shares), and the rest was existing shares sold by holders. Greenstone's stake fell from 18.58% to 6.44%. The proceeds were to fund engineering, early site works and Pampa Medina drilling. Mitsubishi was given notice of its right to buy additional shares, but the outcome is not recorded, and final TSX approval was still pending.

The company then built up its team. Joshua Watson became Project Director and Nico Cookson President from 1 March, with Hayden Locke staying as CEO. On 31 March Giancarlo Bruno Lagomarsino replaced Michael Haworth as Chair, and Zenon Wozniak joined the board.

2026: Toward construction

Drilling expanded to 10 rigs, targeting 100,000m in 2026. Results were strong: SPRD-06 hit 424m at 0.58% copper, SPRD-05 hit 96m at 1.19% including a 4m core at 11.32%, and SPRD-15 hit 216m at 0.96% including 62m at 2.20%. SPRD-08B found mineralisation in basement rock for the first time. Northern scout holes missed their target layer, and diamond drilling was extending them. The area of interest reached 3km by 1.5km, with a maiden resource estimate to follow once delineation drilling ends.

Sectoral permits were lodged in April, with approvals expected in the fourth quarter. A grid connection was authorised and upheld on 22 September after a challenge. A preliminary power agreement was signed at a price close to the study's US$93 per megawatt-hour. A non-binding agreement was also signed in May on a possible acid-plant joint venture in Mejillones, and engineering on the acid plant began.

As of 9 October 2026, the latest net working capital, at 30 June, was US$150.9m with no debt. Early site works were due to start in the fourth quarter, and a debt adviser was working on a funding strategy due by then. Peter Garner-Winship was promoted to CFO that day.

Written from the 30 story beats below (2025 to 9 Oct 2026), which come from the company's own announcements and filings.

Beat by beat

The events that changed the company's story, in plain English, each written against everything known about the company at the time. The dot shows whether it was good, bad or neutral for shareholders.

2026

9 Oct
Peter Garner-Winship promoted to CFO, effective immediately. He joined in March 2026 as VP Finance after 17 years at Anglo American. José Antonio Merino stays as Managing Director (Chile), no longer CFO. Marked as a finance leadership change as the company moves toward construction.
director officer appointment
2 Oct
Grid connection to the 110kV El Lince line upheld on 22 September after challenge. A preliminary power agreement is signed at pricing close to the DFS's US$93/MWh. Early site works are to start in Q4, a lead engineer is chosen, and acid plant engineering has begun. Also an 'A' Digbee sustainability rating.
regulatory community update
9 Sept
Pampa Medina hole SPRD-15 hit 216m at 0.96% Cu and 7.2g/t Ag, including 62m at 2.20% Cu. Step-out holes extended mineralisation 300m south and west. Northern scout holes missed the target layer, and diamond drilling is now extending them. Continues the 150m delineation ahead of the maiden resource.
drilling result
8 July
SPRD-07 extended the ultra-high-grade bornite zone 300m south, with 20m at 2.65% Cu and 104m at 1.01% Cu. SPRD-08B found mineralisation in basement rock for the first time, to 1,052m depth. Webinar set for 14 July.
drilling result
9 June
Pampa Medina hole SPRD-05 hit 96m at 1.19% Cu and 11.7g/t Ag, including 16m at 5.70% Cu and a 4m ultra-high-grade core at 11.32% Cu. Continues the 150m-spacing delineation; company says a maiden resource estimate will follow once this campaign ends.
drilling result
20 May
New Pampa Medina step-out results show continuity at 150m spacing; SPRD-06 returned 424m at 0.58% Cu and 2.2g/t Ag with five stacked mantos. The area of interest is now 3km x 1.5km, extending the March western step-outs.
drilling result
20 May
Marimaca's Marimaca Oxide Deposit permitting is on schedule: sectoral permits were lodged in April, with approvals expected Q4 2026, and the power connection was authorised. A non-binding MOU covers a possible acid-plant joint venture in Mejillones. The debt adviser has started financing talks, with the funding strategy due by Q4 2026.
regulatory community update
31 Mar
Giancarlo Bruno Lagomarsino, a director since 2023 and former Mantos Copper CEO, became Chair, replacing Michael Haworth, who stays as director and Audit Committee chair. Zenon Wozniak (ex-First Quantum) joined the board; Alan Stephens and Clive Newall retired on 27 March 2026.
director officer appointment
12 Mar
Pampa Medina west step-out holes hit high-grade copper-silver, best SWRD-02 74m at 1.21% Cu and 7.9g/t Ag from 520m, about 600m west of earlier drilling. Marimaca will expand from five to 10 rigs, targeting 100,000m in 2026, subject to stage-gates.
drilling result
3 Mar
Joshua Watson, formerly of Teck, Barrick and Rio Tinto, appointed Project Director to lead development of the Marimaca Oxide Deposit. Nico Cookson became President from 1 March 2026; Hayden Locke remains CEO. The announcement says Marimaca is moving to the next development phase.
director officer appointment
27 Feb
Australian leg closed, completing the C$409m (about A$423m) global offering. 15,200,913 existing CDIs sold at A$10.35 (A$157m) with no proceeds to the company. Greenstone drops from 18.58% to 6.44% of shares and CDIs.
capital raising announcement
27 Feb
Canadian leg closed: C$257m, including C$136.5m of new shares for Marimaca. Insiders Assore (AIH) and Ithaki took 4,170,000 and 3,412,500 shares. Mitsubishi was given notice to buy additional shares under its existing agreement; outcome is cut off in the text. TSX final approval still pending.
capital raising announcement
19 Feb
Bookbuild completed for the C$409m offering: C$136.5m new shares (13,650,000 at C$10.00) to the company, C$272.5m existing shares sold by holders. Greenstone's stake falls from 18.58% after sale. Pro forma cash before costs is C$227m (about A$235m).
capital raising announcement
18 Feb
Marimaca launched a C$409m (about A$423m) global offering: about C$136m new shares from the company and about C$273m sold by Greenstone and others. Priced at C$10.00 per share and A$10.35 per CDI. Company proceeds fund pre-construction engineering, early site works and Pampa Medina drilling.
capital raising announcement
28 Jan
Phase II Pampa Medina results show new north-east oxide: SMRD-30 162m at 0.61% Cu, SMR-29 116m at 0.51% Cu, about 800m from the known oxide area. The company is re-evaluating the paused PEA for a larger oxide scale. Four deep sulphide holes await assays.
drilling result

2025

23 Dec
Marimaca filed a preliminary base shelf prospectus in Canada for up to $500m of shares, warrants, units or subscription receipts over 25 months. It is a flexible filing with no offering, price or size set yet, and it is not offered in Australia.
capital raising announcement
12 Nov
Final results from the 10,000m Pampa Medina program: SMRD-22 hit 48m at 2.05% Cu, SMR-19 16m at 2.29% Cu, 900m south of earlier drilling. Mineralisation now spans 1.6km x 1.4km and is open. A 30,000m Phase II program with five rigs has started.
drilling result
12 Nov
Marimaca received its formal environmental approval (RCA) for the Marimaca Oxide Project, filed December 2024, resolving the open thread expected before end-2025. Sectoral permits come next, with the project targeted construction-ready in the second half of 2026.
regulatory community update
12 Sept
Placement closed: 8,247,423 CDIs issued at A$9.70 for about A$80m, with allotment on 12 September, subject to final TSX approval. Insiders Assore (1,376,289 CDIs) and Ithaki (1,226,805) took part. Mitsubishi (about 4.4%) has 30 business days to top up pro rata.
capital raising announcement
8 Sept
Bookbuild completed: binding commitments for 8,247,423 CDIs at A$9.70, about A$80m (C$72.1m). Demand significantly exceeded the targeted amount, and new institutional investors join the register. Completion expected about 11 September, subject to TSX approval.
capital raising announcement
5 Sept
Marimaca launched an A$80m placement of about 8.25m CDIs at A$9.70 (about C$72.1m), after the feasibility study. Funds go to detailed engineering at the main deposit, Pampa Medina and sulphide exploration, and general purposes. Trading halted pending the raise.
capital raising announcement
26 Aug
Feasibility study for the Marimaca Oxide Deposit: 50ktpa copper cathode over 13 years, US$587m pre-production capital, post-tax NPV8 US$709m and 31% IRR at US$4.30/lb. Maiden reserve 178.6Mt at 0.42% copper (750kt). Environmental approval is expected by end-2025; debt partners targeted by year-end.
resource reserve update
22 Aug
Marimaca signed a binding option to buy a used 150,000 tonne-a-year sulfuric acid plant in Chile for US$2.5m (US$1.0m paid upfront, US$1.5m after a three-month review). It could supply 30-40% of the main deposit's acid needs.
asset acquisition disposition
18 Aug
Hole SMRD-16 extended Pampa Medina's high-grade copper 300m west, with 70m at 1.0% copper including 10m at 4.2%. The mineralised area is now 1.2km x 1.2km and still open, with three rigs on site in the 10,000m program.
drilling result
4 July
Pampa Medina drilling hit 6m at 12.0% copper within 26m at 4.1% (SMRD-13) and 40m at 2.1% (SMD-02), building on the earlier SMD-01 and SMR-01 results. A second rig and 14 holes are planned; the Pampa Medina PEA is paused. The main-deposit feasibility study is said to be near-complete.
drilling result
16 June
Second tranche closed, completing the private placement: 811,416 shares at C$4.60 to a new institutional investor. In total 5,311,416 shares were issued for about US$17.7 million (C$24.4m). Mitsubishi has been offered a pro-rata top-up.
capital raising announcement
5 June
Marimaca proposes a US$17.7 million (C$24.4m) private placement of 5,311,416 shares at C$4.60. Insiders Assore (AIH) and Ithaki take 2,250,000 each, with an institutional investor taking the rest. Funds go to exploration and the Marimaca project. This is new dilution for shareholders.
capital raising announcement
16 May
Hole SMD-01 at Pampa Medina Norte hit 68m at 1.20% copper and 40m at 1.07%, confirming the oxide discovery hole SMR-01 (Dec 2024) and finding new sulphide mineralisation at depth. Assays from 600-950m and two more deep holes are pending.
drilling result
16 Apr
Re-interpretation of 77,000m+ of historical drilling and five new holes indicate a linked oxide copper 'manto' system across about 5km by 4km at Pampa Medina, 25km from the main deposit. Best new hole SMR-05 hit 32m at 0.81% copper. Expanded 2025 drilling is being considered.
drilling result
31 Mar
Marimaca Copper, already listed on Toronto's exchange, was admitted to the ASX on 31 March 2025, with CDIs quoted from 2 April 2025. The 100-CDI A$600 prospectus offer drew no applications or funds, so no new money was raised.
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