Platinum Group Metals Ltd. press release

Los Azules Feasibility Study Confirms Economically Robust Copper Project With Leading ESG Performance

2025-10-07

TSX - Toronto Stock Exchange · Platinum · Palladium · Rhodium · Gold · Copper · Nickel · Canada

TORONTO, Oct. 07, 2025 (GLOBE NEWSWIRE) -- McEwen Copper Inc. , 46.4% owned by McEwen Inc. (NYSE, TSX: MUX ) is pleased to announce positive results from the independent Feasibility Study (FS) for its 100%-owned Los Azules copper project in San Juan, Argentina.

The FS confirms Los Azules as a long-life, low-cost producer of high-purity copper cathodes with strong economic returns and sustainability . The project design advances Los Azules toward construction readiness within a framework that reduces its environmental footprint. Project risk has been further reduced through a strategic collaboration agreement with IFC to potentially lead debt financing and additional funding proposals for infrastructure and construction.

With these results, Los Azules is positioned to become a supplier of responsibly produced copper, critical to the global energy transition towards a low-carbon sustainable future.

“The Los Azules Feasibility Study is more than a technical milestone - it’s a blueprint for the future of copper mining. We have delivered a plan for a long-life asset that will play a role in the world’s clean-energy transition. Copper is the foundation of electrification and the modern world, and Los Azules is ready to contribute to that global supply chain - responsibly, efficiently, and profitably ,” said Rob McEwen, Chairman and Chief Owner of McEwen Inc.

“With this Feasibility Study, our team has transformed the geological potential of Los Azules into a clear, actionable development plan. This work gives us confidence in the project’s design, costs, and schedule, providing the foundation for the next stage of growth.

_“Having significant experience with large-scale construction and mining operations in Argentina, I am confident that we have the right plan, the right team, and the right partnerships to develop Los Azules. Together with our local communities and government partners, we aim to create Argentina’s first regenerative copper mine - a model for responsible and innovative mining,” __said Michael Meding, Vice President of McEwen Copper and General Manager of Los Azules. _

This press release starts with the FS Highlights below, followed by Footnotes , a Glossary of Terms, Units and Abbreviations and continues with a detailed account of the study in a Technical Appendix .

FS Highlights

Simple Takeaways

Economics After-tax (1) : NPV(8%) $2.9B IRR 19.8% Payback Period 3.9 yrs Initial Capital $3.17B

Copper Cathode Production (2) : Average Years 1–5 204,800 tonnes per year ( 451M lbs/yr ) Life of Mine 21 years Average Production 148,200 t/yr ( 327M lbs/yr )

Costs: C1 cash cost $1.71/lb AISC $2.11/lb

Scale – Reserves and Resources (3) : Mineral Reserves Proven & Probable 10.2B lbs Cu (1.02 B tonnes at 0.45% Cu)

Mineral Resources ( exclusive of Reserves) Measured & Indicated 5.4B lbs Cu (0.97 B tonnes at 0.26% Cu) Inferred 20.0B lbs Cu (4.24 B tonnes at 0.21% Cu)

Capital Intensity Using: LOM Capital & Production $1,600/t Cu Initial Capital & Avg. Annual Production $20,200/t Cu per yr

Designed for Low Impact

Leach + SX/EW process produces 99.99% copper cathodes ( LME Grade A) on site (no smelter required). Project design provides: 72% lower mine-to-metal carbon intensity than industry average for mine-to-metal 100% renewable power (4) (wind, hydro, solar) 74% less water use than conventional milling No tailings dam

Carbon-neutral (Scopes 1 & 2) goal by 2038.

De-risked Regulatory Status

Environmental Impact Statement EIA (Environmental Permit) for construction and operation was approved by the San Juan Provincial Government's Ministry of Mines in December, 2024. Accepted into Argentina’s Large Investment Incentive Regime (RIGI) in September, 2025, providing tax, foreign exchange and customs stability for 30 years, legal certainty, foreign exchange regulations allowing to leave export proceeds abroad in increasing steps that will reach 100% by the time the project starts exports and access to international arbitration in case of disputes.

Ownership & Partners

Ownership: McEwen Inc. 46.4%, Stellantis 18.3%, Nuton (Rio Tinto) 17.2%, Rob McEwen 12.7%, Victor Smorgon Grp 3%, Others 2.4% . Preliminary finance proposals from Tier-1 OEMs (Komatsu, Sandvik & others), YPF Luz , European ECAs , and a collaboration agreement with IFC (5) to align with IFC’s ESG standards and for potential financing. Indicative proposals could support $1.1B+ (6) in equipment and infrastructure financing.

Future Growth Opportunities Beyond the FS

Nuton® leaching technology (Rio Tinto venture) could allow processing of primary ores with the existing infrastructure (indicative recoveries >76%) , or a Conventional Concentrator could also provide higher copper recoveries, plus recover gold and silver as well. Either process could extend mine life by 30+ years by economically treating primary sulfides. Neither of these opportunities are included in the FS base case. Exploration has shown that there are four porphyry targets near the Los Azules deposit that could provide further extension to the mine life. Exploration of the newly identified targets will start in Q4 2025. High-priority targets near Los Azules include Tango, Porfido Norte, Franca, and Mercedes.

Timeline & Next Steps

FS NI 43-101 Technical Report to be filed: within 45 days (7) . Water concession: application under review. Construction target: 2026 → SX/EW startup: 2029 → First copper : 2030.

Footnotes to Highlights

(1) NI 43-101 feasibility study using a copper price of $4.35/lb or $9,592/ tonne for cash flow modeling.

(2) Average copper recovery is 70.8% over the life of mine.

(3) For additional details on the calculation of Mineral Resources and Mineral Reserves see Section 3 of the Technical Appendix, Mineral Resource & Reserve Estimates .

(4) Power supply 100% renewable, with 48% lower electricity demand than a conventional concentrator.

(5) Collaboration agreement signed with IFC to align with IFC’s ESG standards for potential future financing, an important milestone in McEwen Copper’s broader financing strategy.

(6) Preliminary financing proposals from Tier-1 OEMs, YPF Luz, and European ECAs could provide $1.1B+ in equipment and infrastructure support.

(7) The FS NI 43-101 Technical Report will be filed within 45 days on SEDAR and McEwen Inc.’s website at https://www.mcewenmining.com/investor-relations/reports-and-filings .

ABOUT MCEWEN INC. McEwen Inc. shares trade on both the NYSE and TSX under the ticker MUX .

It provides shareholders with exposure to a growing base of gold and silver production in addition to a very large copper development project, all in the Americas. The gold and silver mines are in prolific mineral-rich regions of the world, the Cortez Trend in Nevada, USA, the Timmins district of Ontario, Canada and the Deseado Massif in Santa Cruz province, Argentina. McEwen Inc. is considering reactivating a gold and silver mine in Mexico.

It has a 46.4% interest in the large, long-life, advanced-stage Los Azules copper development project in San Juan province, Argentina – a region that hosts some of the country’s largest copper deposits. The Los Azules copper project is designed to be one of the world’s first regenerative copper mines and carbon neutral by 2038.

Rob McEwen, Chairman and Chief Owner, has a personal cost basis for his investment in the companies of over $200 million and takes a salary of $1 per year, aligning his interests closely with shareholders. He is a recipient of the Order of Canada, a member of the Canadian Mining Hall of Fame and a winner of the Ernest & Young Entrepreneur of the Year (Energy) award. His objective is to build MUX’s profitability, share value and eventually implement a dividend policy, as he did while building Goldcorp Inc.

ABOUT MCEWEN COPPER McEwen Copper Inc. is a Canadian-based private company with a 100% interest in the Los Azules copper project in San Juan, Argentina and the Elder Creek copper/gold project in Nevada, USA.

Based on S&P Global data for 2024, Los Azules projected annual production would rank it as the 26 th worldwide, once in production, placing it in the top 6% of all 423 copper producers. The project also ranks 10 th globally in terms of total Mineral Resources among all undeveloped copper porphyry deposits (company disclosure).

Los Azules is being designed to provide a model to the industry for a more sustainable, low-carbon future and to help improve public perception of mining by fundamentally differing from conventional copper mines –substantially reducing water consumption and carbon emissions and operating on 100% renewable electricity once in production.

Glossary of Terms, Units and Abbreviations

AISC - All-In Sustaining Cost (C1 + sustaining capital + royalties + taxes)

Approx. - Approximately

B - billion

Blb - billion pounds

Copper cathode - High-purity (typically 99.99%) of refined copper sheets (LME Grade A) produced through an electrolytic refining process. This finished product serves as a primary raw material for high-quality copper products, such as wires, tubes, and various alloys.

CO₂-e/t Cu - Kilograms of CO₂ equivalent per tonne of copper

Cu - copper

C1 Costs - Direct cash costs of production

EIA - Environmental Impact Assessment

FS – Feasibility Study

GHG Emissions - Greenhouse gas emissions (CO₂-equivalent)

Heap Leach - Process of extracting metals by percolating acid through ore piles

Hypogene or Primary - Refers to mineralization formed by ascending hydrothermal fluids deep below the surface, usually at high temperature and pressure

IFC - International Finance Corporation

IRR (Internal Rate of Return) - Rate at which NPV = 0

ktpa - 1,000 tonnes per annum

km - kilometer

lb - pound (0.4536 kg)

leach project - project using heap leach process

LOI - Letter of Intent

LOM - Life of Mine

L/s - 1 liter per second

m - meter

M - million

MW – megawatt (1,000,000 watts)

Mlb - million pounds

NPV (Net Present Value) - Present value of future cash flows discounted at 8%

NSR – (Net Smelter Return) - a royalty based on a percentage of metal produced based on the metal sale proceeds less the cost of refining at an off-site refinery (Metal Price × Payable Metal Content) − (Treatment Charges + Refining Charges + Penalties + Transport/ Insurance/ Marketing Costs)

NTP – Notice to Proceed

Nuton ® - Rio Tinto’s proprietary Nuton technology

OEM - Original Equipment Manufacturer

oz - troy ounce (31.1 grams)

Primary or Hypogene – Refers to the original ore minerals formed during the initial geological processes (e.g., magmatic or hydrothermal activity). Primary mineralization is typically found at depth and is unaltered by surface weathering.

RIGI - Argentina’s Large Investment Incentive Regime

SX/EW - Solvent Extraction / Electrowinning

Secondary - Refers to ore minerals or enrichment formed after the primary (hypogene) stage, usually by supergene processes (weathering, oxidation, and downward percolation of fluids near the surface).

Soluble Copper (CuSOL) – the amount of copper assayed using sequential methodology that includes acid soluble and cyanide soluble assayed components. Acid soluble copper generally represents readily acid dissolvable oxide, carbonate and similar copper minerals. Cyanide soluble copper generally represents secondary copper minerals that are readily leached with commercial bioleach technology (chalcocite, digenite, covellite)

Supergene - Secondary ore minerals formed near the Earth’s surface through weathering, oxidation, and groundwater movement. Metals are leached from upper zones and reprecipitated at depth, often creating an enriched zone of higher-grade mineralization.

Total Copper (CuT) – the amount of copper contained in all mineral forms in the deposit by conventional assaying methodology. Total copper includes the soluble copper component.

t - tonne (1,000 kg)

yr - year

Technical Appendix

The information in this appendix is provided for technical readers and analysts.

1. Project Overview Property Description Exploration Targets A Sustainable Approach

2. Copper Price Assumption

3. Mineral Resource & Reserve Estimates Updated Mineral Resource Estimate Maiden Proven and Probable Mineral Reserve Estimate

4. Metallurgy & Recovery

5. Economic Analysis Economic Metrics Sensitivity Analysis

6. Capital & Operating Costs Capital Costs Estimates YPF Funding Power Supply Operating Costs Estimates

7. ESG & Sustainability

8. Permitting & Regulatory Status

9. Development Timeline

10. Nuton ® Opportunity

11. Strategic Partnerships

12. Study Contributors and Qualified Persons

13. End Notes

1. Project Overview Property Description Located in Calingasta District, San Juan Province, Argentina, on the border with Chile. The Los Azules copper project is a classic Andean-style porphyry copper deposit. The large hydrothermal alteration system spans at least 5 kilometers (km) by 4 km, elongated along a north-northwest major structural corridor. The Los Azules deposit area itself is approximately 4 km long by 2.2 km wide and lies within the alteration zone.

The limits of the Los Azules mineralization along strike to the North and at depth have not yet been defined. Near-mine primary or hypogene copper mineralization extends to at least 1,000 m below the surface. Near surface, leached primary sulfides (mainly pyrite and chalcopyrite) were redeposited below the water table in a sub-horizontal zone of supergene enrichment as secondary chalcocite and covellite. Hypogene bornite appears at deeper levels together with chalcopyrite. Gold, silver, and molybdenum are present in small amounts, however copper is the economic driver at Los Azules.

Exploration Targets Porphyry exploration targets near to Los Azules include Tango, Porfido Norte, Franca, and Mercedes. They are a priority for next season’s exploration (see Figure 1 ). These targets offer the potential to enlarge the size of resources and extend the life-of-mine beyond that presented in this study.

The Franca target, with high-grade intercepts, shows the potential to extend the Los Azules resource to the northeast. The Mercedes target west of Los Azules has hydrothermal alteration and similar surface geology to Los Azules and has the indication to be another hidden porphyry, like Los Azules. Porfido Norte is a target that is located along the main Los Azules structural corridor with indications of a suitable intrusive suite of rocks with hydrothermal alteration. Finally, the Tango target will be mapped in detail to better understand the potential drill targets.

Figure 1 : Los Azules deposit (outlined in blue), and exploration targets Mercedes, Porfido Norte, Franca and Tango (black squares). Satellite image with Total Magnetic Intensity map.

Heap Leach SX/EW — The Preferred Path Forward

The FS is based on a heap leach process using solvent extraction-electrowinning (SX/EW) to produce 99.99% copper cathodes (LME Grade A equivalent) for sale in Argentina or international markets. There are three principal reasons why the implementation strategy remains a leach project, as in the 2023 PEA (11) :

1. Environmental Footprint : Process water consumption is 74% lower than a milling operation (158 L/s LOM average vs. 600 L/s). Net electricity demand is 48% lower than a concentrator (119 MW vs. 230 MW). GHG emissions are 72% lower than the average mining operation (1,082 vs. 3,930 kg CO 2 -e/t Cu for Mine-to-Metal (12) , with a roadmap to achieve further reductions through new technologies, with the ultimate goal of reaching net-zero carbon by 2038 with some offsets. Los Azules copper cathodes will thus be attractive to end-users seeking to measurably reduce their upstream environmental impacts. 2. Reduced Permitting Risk : With the approval of our Environmental Impact Assessment on December 3, 2024, and the approval of our application for the Large Investment Incentive Regime (RIGI) on September 26, 2025, and the expected approval of our Water Concession permit for operations, Los Azules is well positioned to begin construction. The project uses heap leach technology that is well accepted in the San Juan Province today. It also eliminates tailings and tailings dams, conserves scarce water resources, and reduces the overall complexity of the mine, optimizing the permitting process. 3. Producing Cathodes : The leach process will produce LME Grade A copper cathodes, which can be used directly in the fabrication of copper products, both within Argentina and internationally. The production of copper cathodes eliminates reliance on third party foreign smelters for the processing of concentrates into refined copper products. It also eliminates significant GHG emissions associated with transportation, and pollution associated with smelting. Counterparty and pricing risks are also reduced.

A Sustainable Approach

The FS marks another significant step toward our goal of reducing our environmental footprint . Greater environmental and social stewardship sets our project apart from other potential mine developments, which appropriately justifies certain economic trade-offs. Trade-offs to achieve the environmental benefits of heap leaching are lower overall copper recovery, slightly higher unit costs, and less immediate cashflow due to extended leach cycles. Nevertheless, the leach project remains economically attractive. Furthermore, McEwen Copper believes that some of these drawbacks can be mitigated by implementing developing technologies such as the Nuton ® Technology, discussed below. Additionally, trolley-assist haulage, conveyor waste haulage, and In-Pit Crush and Convey (IPCC) will be further evaluated during the detailed engineering stage to continue to reduce the mine’s carbon footprint. Additionally overall CAPEX is lower than comparable concentrators.

The team has also worked safely with 1,848,632 man-hours worked since our last Lost Time Incident and since January of 2022 we have worked a total of 2,367,891 man-hours to achieve this study result.

We developed regenerative guiding principles to frame our approach to sustainable innovation and set high-reaching goals addressing all facets of the mining and processing options considered for Los Azules. The project development seeks to significantly reduce the environmental footprint of mining operations and their associated GHG emissions by integrating the latest renewable and environmentally responsible technologies and processes. The project has letters of intent (LOIs) to obtain 100% of its energy from renewable sources (wind, hydro, and solar), primarily from YPF Luz, using a combination of off-site and onsite installations. The project is also seeking to have long-term net positive impacts on the greater Andean ecosystem, local flora and fauna, the lives of miners, and citizens of nearby communities, while contributing positively to the local and national economy of Argentina. Refer to the full FS NI 43-101 Technical Report for more information about our regenerative approach.

2. Copper Price Assumptions The copper price used for mineral reserves in the FS was $4.25 per pound and $4.80 per pound for mineral resources, in line with analysts’ consensus projections for long-term copper prices that range between $3.55 and $5.00 per pound, with a median price of $4.25 per pound. The mineral resource price was set at 113% of the mineral reserve price.

Economics in the cashflow model were analyzed at $4.35 per pound copper. This reflects analysts’ consensus at the time of publication of the feasibility study.

3. Mineral Resource & Reserve Estimates The FS includes an updated independent Mineral Resource and a maiden Mineral Reserve estimate , which contains a Mineral Resource of 5.4 B lbs Cu Measured and Indicated (965.5 million tonnes at grade 0.255% Cu) and 20.0 B lbs Cu Inferred (4,239.3 million tonnes at grade 0.214% Cu) (exclusive of Reserves), and a maiden Mineral Reserve of 10.2 B lbs Cu Proven and Probable (1,023.1 million tonnes at grade 0.453% Cu).

This study provides an update on the work done for the 2023 Los Azules PEA. Drilling more than 120,000 meters with more than 2.3 M man-hours worked in the last three seasons has upgraded the resource categories to allow us to present a Mineral Reserve in the FS similar to the 1.182 B tonnes of mineable Mineral Resources containing 10.9 B lbs Cu in the 2023 PEA. This achievement included a campaign during the 2023/2024 season with 70,000 meters drilled and up to 23 rigs operating simultaneously at site.