Exhibit 96.1

Table of Contents

List of Tables

List of Figures

The Los Azules Project is among the largest undeveloped copper deposits on the globe. Los Azules presents a multi-generational opportunity to design, build and operate a copper mine that is globally significant, technologically advanced, embraces regenerative design principles, and minimizes carbon footprint.

This report is a Technical Report Summary (TRS) which summarizes the findings of the Preliminary Study completed for the Los Azules Project in accordance with The United States Securities Exchange Commission (SEC) 17 CFR Part §229.1300 (S-K 1300) Standard Instructions for Regulation S-K subpart 1300 SEC S-K §229. 1304 and §229.601(b)(96). This TRS is intended to meet the requirements of S-K 1300 as considered for an Initial Assessment (IA) level of study and disclosure as defined in the regulations and supporting reference documents. The purpose of this TRS is to report the study results, updated mineral resources, additional technical work completed, and the subject project estimated costs and economic potential. The effective date of this report is May 9, 2023, concurrent with the updated final resource estimates published herein.

This TRS supersedes the current report on file titled: SEC S-K 229.1304 INITIAL ASSESSMENT INDIVIDUAL DISCLOSURE FOR THE LOS AZULES PROJECT, ARGENTINA, prepared by Mining Plus US Corporation with an effective date of April 01, 2021 (report revision date of February 25, 2022).

All currency shown in this report is expressed in May 2023 United States Dollars unless otherwise noted. Metric units of measure are used unless otherwise specified.

This Technical Report Summary is prepared for McEwen Mining Inc. (McEwen Mining) trading under the symbol NYSE/TSX: MUX for the purposes of disclosing current updates and information related to its 51.9% owned subsidiary McEwen Copper Inc. (McEwen Copper), which controls the Los Azules copper property located in Argentina. Los Azules is an exploration and development project presently consisting of a large porphyry copper deposit located in the Andes Cordilleran region of San Juan Province, Argentina near the border with Chile (the “Project”).

The Project is at the exploration stage of investigation; consequently, this study is preliminary in nature and includes Inferred mineral resources in one of the conceptual mine plans and mine production schedules presented. Inferred mineral resources are considered too speculative geologically and in other technical aspects to enable them to be categorized as mineral reserves under the standards set forth in S-K 1300. There is no certainty that the estimates in this IA will be realized.

McEwen Mining is obligated to report material information pursuant to its dual listings on the New York Stock Exchange (NYSE) and Toronto Stock Exchange (TSX). A corresponding Technical Report was also completed in accordance with Canadian National Instrument 43-101 (NI 43-101) based on the same information and data. Information related to the project described under the NI 43-101 reporting rules is included in this report for clarity and to avoid confusion between reports. Two open pit based mine plans were developed and are described in this TRS; one includes only material classified as Measured & Indicated Resources as required by S-K 1300 and a second mine plan including inferred resources within the pit comparable to what is reported in the corresponding NI 43-101 report.

This 2023 IA incorporates an updated development strategy with the following two phases: Phase 1 considers mining and processing resources associated with the oxide and supergene copper mineralization in the near surface portion of the deposit using heap leaching methods. Phase 2 of the project considers the continued development of the deposit’s primary copper mineralization found beneath the supergene copper layer. The focus of this 2023 IA is the initial Phase 1 project with limited concepts presented for Phase 2. For clarity, the economic outcomes for the cases presented in this report include only Phase 1.

The Phase 1 implementation scheme for the Project is an open pit mine initially processing materials with crushing, bio-heap leaching and solvent extraction and electrowinning (SX/EW) facilities to produce LME Grade A copper cathodes for sale in Argentina or for export. Phase 1 preliminary mining plans excluding Inferred Mineral Resources extract a total of 8.2 billion pounds (3,732 ktonnes) of contained copper from the Measured & Indicated resources, of which 6.0 billion lbs. (2,721 ktonnes) is recoverable to copper cathodes. The total copper recovery expected is approximately 73% and considers scale-up efficiencies and production distribution over a two-year timeframe from placement of material on the leach pad.

Based on consensus estimates and independent analysis, long-term metal pricing used in this report (except for mineral resource estimation) and project economic analysis are Copper (Cu) - $3.75/pound; Gold (Au) - $1,700/ounce; and Silver (Ag) - $20.00/ounce. The 2023 updated financial outcomes for the Phase 1 initial project mine and facilities are shown in Table 1.1 below (expressed in Q1 2023 United States Dollars, after taxes).

C1 cash costs are defined as the cash cost incurred at each processing stage, from mining through to recoverable copper delivered to the market, net of any by-product credits. C1 cash costs per pound of copper produced and all-in sustaining costs per pound of copper produced are non-GAAP ratios. If it were in production today, the average C1 cash costs at Los Azules would be in the lowest cost quartile among copper producers. Figure 1.1 shows global cost data from S&P Capital IQ and SE showing how the Los Azules Base Case and Alternative Case average C1 cash costs compare to producing copper mines in 2022.

(Source: S&P Capital IQ Mine Economics Market Intelligence 2022 Data, SE Analysis)

Figure 1.1: C1 Cash Costs by Current Producer and Selected Development Projects

The opportunity to process primary sulfides directly through a heap leach rather than building a traditional copper concentrator in the future is the envisioned approach to the Los Azules development plan. The primary sulfides are currently not considered economically suitable for commercial heap leaching operation.

Continuing the benefits of a hydrometallurgical approach is the preferred path of the project for Phase 2, along with ongoing development work efforts. Metallurgical work evaluating NutonTM bio-leaching technology is being developed to potentially replace the need for a future milling operation in favor of continued leaching and copper cathode production for the life of the mining operations. Potential scenarios for the future operations employing the NutonTM bio-leaching technology are presented and discussed in Section 22.2.1 of this report.

Although Nuton LLC, a Rio Tinto Venture, has completed larger scale testing at several global project sites and has developed proprietary modeling techniques to predict results, there are no commercial applications of the Nuton™ technology operating at the time of this report. Based on preliminary small-scale testing by Nuton and economic modeling inputs, these options provide the opportunity to extend the mine life to more than 50 years in some instances and increasing copper produced by more than 30% while adding significant additional value at lower LOM operating costs.

A significant testing program will be required to validate these preliminary estimates; therefore, these results are not considered suitable for inclusion at this time in the initial project phase cases presented and are only included as a demonstration of the potential future opportunity.

A conventional mill and flotation/concentrator option was considered to process primary copper mineralization to demonstrate economic viability employing conventional methods and support reserves estimation confidence. Details for this option can be found in Section 22.2.2.

The next steps for the Los Azules Project are continuing with infill resource drilling, variability and confirmatory metallurgical testing, environmental baseline studies, and commencing critical preliminary engineering such as hydrogeologic field investigations and geotechnical drilling at the heap leach pad site, tailings dam site and within the pit wall slopes to support a feasibility study.

A NEW VISION AND APPROACH

Copper is a key ingredient in the solutions to global climate change, including initiatives in the automotive sector as the industry transitions to electric cars and the energy sector as it moves to more renewable forms. Los Azules aspires to be the world’s first Regenerative Copper Mine, providing valuable materials for a renewably powered world.

Guiding regenerative principles were developed to reframe the approach to sustainable innovation within the mining industry and set forth high-reaching goals that are being explored for all facets of the mining processes considered for Los Azules. The project development seeks to significantly reduce the environmental footprint of mining operations and their associated greenhouse gas emissions by integrating the latest renewable and environmentally responsible technologies and processes. The project aims to obtain 100% of its energy from renewable sources (wind, hydro, and solar) in a combination of offsite and onsite installations. Where possible, the project is also seeking to have long-term net positive impacts on the greater Andean ecosystem, the lives of miners, and the citizens of nearby communities, while contributing positively to the local and national economy of Argentina.

The project concepts allow for early adoption of emerging technologies under development and are anticipated to be commercially viable over the mine life. By being ‘future ready’ the project will be poised to adopt newly emerging technologies and infrastructure opportunities

Key project initiatives aimed at achieving these goals are described below.

Respecting the Lands We Use

The Los Azules Project is committed to responsible stewardship of the land and minimizing disturbance of local glacial morphologies and wetlands (“vegas” in the local terminology) wherever possible. Careful consideration of how activities are conducted and where they are located is a key aspect to meeting these commitments, both in the short and long term. Minimizing land use and disturbance by consolidating uses to the extent possible is considered in the site layouts, individual site areas, facilities/buildings, and access to the mine site.

Although the vegas in the pit and leach pad areas will be impacted, minimizing the footprint of the site facilities, re-routing, and diverting water courses to downstream connections are key design feature for the mine and leaching areas water management plans to minimize these impacts. The leach pad design includes an underdrainage for non-contact water coming from upstream sources to flow through the same valley and to the Rio Salinas. Longer term, the water courses will be restored during reclamation of the mine site at the completion of activities to bring the area as close to its original state as possible.

Transforming Water Use and Quality

Climate change, population growth and the industrial and agricultural use of water are some of the factors that affect water availability. In addition, the expansion of urban infrastructure exerts pressure on the quantity and quality of natural water courses. Long-term water solutions must be flexible, adaptable, and environmentally sustainable, working within the ‘carrying capacity’ of its place and climate. Increasing the efficiency of water use is equivalent to increasing productivity or, in other words, reducing the intensity of use by maximizing the value of uses and, in this way, improving allocation among different competing utilization.

Selecting a hydrometallurgical process option for Los Azules could reduce effective water usage by 75% to 80% over a milling/concentrator alternative. Additionally, alternatives for improving precipitation/snow capture, site dust control, reuse/recycle and passive water treatment strategies are being developed at Los Azules.

Transforming the Energy/Carbon Nexus

An extensive review of power generation and supply options for the project was undertaken to consider the options for renewable energy. YPF Sociedad Anónima (“YPF S.A.” or “YPF”) owns and operates power generation facilities in Argentina based on wind, solar, geothermal, and hydroelectric sources through its subsidiary YPF-LUZ. YPF-LUZ has a rate structure based on 100% renewables sourced power generation that can be used as the project basis, eliminating hydrocarbon-based generation and associated emissions. The YPF-LUZ electric power supply option was selected for the Los Azules Project at a small premium over other hydrocarbon-based power options.

In addition to energy supply, the reduction of energy consumption is also a key aspect to regenerative mining.

Processing with the End Game in Mind

Given the context above, the most appropriate technology selection for Los Azules to minimize water usage is a hydrometallurgical approach, which is the basis for the Phase 1 project development. The hydrometallurgical option also provides lower overall project impacts from:

Moving Rock and Decarbonizing Mining Operations

Maximizing electrification, coupled with renewable power supply is aimed at significantly reducing environmental impacts.

The initial mining concepts will use trolley-assisted diesel-electric mine haulage and support equipment initially to significantly reduce diesel emissions. However, the project will select equipment and methods to rapidly transition to fossil fuel-free alternatives as rapidly as the technology and manufacturing capacities allow. The transition would also include in-pit conveying alternatives to minimize fleet requirements. The ultimate vision is a fully electric mine and the elimination of emissions associated with fossil-fuels.

A Mining Camp for Maximum Livability – the healthiest, greenest mine camp in the world.

The long-term permanent mine camp has been strategically located to optimize multiple variables. Worker safety, comfort, well-being, as well as the distance from the mine operations and access to the main road are major considerations. In addition, the specific layout and orientation have been selected to support passive heating and cooling strategies and solar energy generation, which are key considerations.

The Los Azules camp and mine will be forming a microgrid in a remote location, although Los Azules in closer to basic infrastructure than most other mines in the region. Even though the camp will be connected to offsite energy production, it is being sized for net-positive energy production, making it a candidate for International Living Future Institute’s (ILFI) Net Zero Energy certification (living-future.org), the world’s most rigorous green building standards. The camp will pursue ILFI certification based on the alignment with the Living Building Certification “Water Petal”.

The camp will also be designed to provide space for growing food in a self-sustaining environment. Finally, the camp will provide waste management systems to provide reuse of waste materials, either through direct reusing, recycling, composting, and eliminating single-use plastics and packaging.

Minimizing the Carbon Footprint from Mine to Market

Copper mining emits an average 2.3-2.5 tonnes of carbon dioxide equivalent per tonne of copper metal produced (t CO2-e/t Cu), while smelting adds another 1.65 tonnes (Source: “Metals recycling to be a key plank for cutting emissions” by Pratima Desai, Reuters, July 14, 2021). By employing modern, low emission technologies, the Los Azules Project intends to improve upon the standards set forth by “The Copper Mark” and set a new standard for CO2 emissions per unit of copper produced.

The Greenhouse Gas (“GHG”) Protocol Corporate Standard classifies a company’s GHG emissions into three ‘scopes’. Scope 1 emissions are direct emissions from owned or controlled sources. Scope 2 emissions are indirect emissions from the generation of purchased energy. Scope 3 emissions are all indirect emissions (not included in scope 2) that occur in the value chain of the reporting company, including both upstream and downstream emissions.

Figure 1.2 Estimated Carbon Intensity versus Copper Equivalent Production Centiles 2022-2040 for mine site emission chart presents the relative estimated emissions for copper assets on an equivalent copper basis as obtained from the Emissions Benchmarking Tool – (Metals)™, a product of Wood Mackenzie Limited (“WoodMac”). The WoodMac database includes 394 individual global mining assets and covers Scope 1 and 2 emissions determined using the published methodology on their website. The highlighted assets represent comparable major Argentinian projects as included in the WoodMac modeled information. The Los Azules Project metrics in the WoodMac data (red line highlighted) reflects the estimated emissions for the prior project concept. The WoodMac average Scope 1 and Scope 2 emissions intensity for all 394 included assets the period between 2022 and 2040 is 1,980 kg CO2-e/t Cu Eq. (kilograms of Carbon Dioxide Equivalent per tonne of Copper Equivalent produced). Carbon Dioxide Equivalent means having the same global warming potential as any another greenhouse gas. For the 57 copper SX/EW assets included, the average Scope 1 and Scope 2 emissions intensity for the period between 2022 and 2040 is 1,723 kg CO2-e/t Cu Eq.

Based on the current project concepts considered for implementation at Los Azules, notably:

The carbon intensity per unit of copper equivalent production (Cu Eq) was estimated by Whittle Consulting Pty Ltd (“WCPL”) using the GHG Protocol Corporate Accounting and Reporting Revised Standard principles (published by the World Resources Institute (WRI), a U.S.-based environmental NGO, and the World Business Council for Sustainable Development (WBCSD), a Geneva-based coalition of 170 international companies) which provides requirements and guidance for companies and other organizations preparing a corporate-level GHG emissions inventory).

WCPL’s estimations based on the preliminary information developed, the predicted carbon intensity for the Los Azules initial Base Case project is estimated to be to be 670 kg CO2e/tCu Eq for Scope 1 & 2 emissions. The estimated Scope 1-3 emissions for the Base Cases is approximately 902 kg CO2e/tCu Eq, assuming transport of copper cathodes to port facilities in either Chile or Argentina.

Figure 1.2 also shows the relative position of the Los Azules base case developed in 2023 and the prior Los Azules 2017 Project concept against the WoodMac average Scope 1 & 2 emissions intensity for all 394 included assets. Of significant importance is the improvement in the project compared to the prior concept and the project position in the lower 10% range of projects globally. Full electrification could drive emissions even more towards the lowest in the industry.

Continued implementation of newer and less impactful technologies, fully electric mine and equipment, EV use for materials and supplies transport to site, and broader employment of regeneration applications throughout the mine site to further off-set carbon emissions is expected to deliver on McEwen Copper’s commitment to achieve net-zero carbon emissions from the Los Azules Project by 2038, well ahead of its peers.

Figure 1.2: Estimated Carbon Intensity vs Copper Equivalent Production Centiles 2022-2040 (Scope 1 & 2 Emissions) - Wood Mackenzie 2022

NOTE: “The data and information provided by Wood Mackenzie should not be interpreted as advice and you should not rely on it for any purpose. You may not copy or use this data and information except as expressly permitted by Wood Mackenzie in writing. To the fullest extent permitted by law, Wood Mackenzie accepts no responsibility for your use of this data and information except as specified in a written agreement you have entered with Wood Mackenzie for the provision of such data and information.”

This subsection was prepared by J. Sorensen, FAusIMM, Samuel Engineering (Source Q1 2023 public filings).

McEwen Mining was organized under the laws of the State of Colorado on July 24, 1979, and is listed on the New York Stock Exchange (NYSE) and on the Toronto Stock Exchange (TSX) under the symbol MUX. The Company’s head office is in Toronto, Canada. As of May 2023, the Company owns a 51.9% interest in the Los Azules copper deposit in San Juan, Argentina through its subsidiary, McEwen Copper Inc. (“McEwen Copper”) which owns a 100% interest in the Los Azules Copper Project in San Juan, Argentina, and the Elder Creek Exploration Project in Nevada, USA.

McEwen Copper has 28,885,000 common shares outstanding, and its shareholders are: McEwen Mining Inc. 51.9%, FCA Argentina S.A. (Stellantis) 14.2%, Nuton LLC (Rio Tinto) 14.2%, Robert R. McEwen 13.8%, Victor Smorgon Group 3.5%, and other shareholders 2.4%.

The Los Azules Project is a porphyry copper development project located in the Andes Cordilleran region of San Juan Province, Argentina along the border with Chile. The Project falls within the Calingasta Department of the San Juan Province. The Project is approximately 80 km west-northwest of the town of Calingasta, in the San Juan Province of Argentina at approximately 31° 06’ 25” south latitude and 70° 13’ 25” west longitude. The mine development is located approximately 6 km east of the border with Chile (Figure 1.3). Calingasta is located 173 km by road west of the city of San Juan along Route 12.

Figure 1.3: Location of Los Azules in the High Andes (Hatch, 2017)

The terrain elevation at the project site ranges between 3,200 meters above sea level (masl) at the proposed camp location and up to 4,500 masl on the high peaks in proximity to the Project. The proposed pit and facilities are located between 3,200 and 3,600 masl. The Project area is remote, and no infrastructure is present. There are no nearby towns, Indigenous residents, or settlements. Seasonal exploration work typically commences in October or November and terminates in April or May. Exploration operations are supported by means of two temporary camps within the Project site area.

The facilities and site arrangements contemplated for the Los Azules Project are shown in Figure 1.4. Facilities are located to stay within the surface and mining rights currently held by McEwen Copper.

Figure 1.4: Overall Site Plan (Samuel, 2023)

There are no covered or uncovered “white glaciers” (classic ice glaciers) in the Project, although there are several small rock glaciers (or cryogenic geoforms) near the Project area that are not impacted by exploration or the proposed future development activities.

A preliminary seismic risk assessment of the Los Azules site was completed in April 2019. The area where the Los Azules Project is located corresponds to Seismic Zone 4, considered very high. The highest seismic event recorded near the Project was magnitude 7.5 in 1977 affecting the entire province of San Juan.

Drill core storage and processing facilities are in the town of Calingasta. These facilities will be upgraded during the next phases of work to increase the storage capacity and provide for accommodations and staging of workers traveling to/from the project site.

The nearest mining projects to the Los Azules Project site are the Altar copper-gold project site owned by Aldebaran Resources Inc. located approximately 40 km south and the El Pachon copper-gold project site owned by Glencore plc located approximately 90 km south of Los Azules. To the north, the distance to Filo del Sol owned by Filo Corp. and Josemaria owned by Lundin Mining is approximately 300 km.

The information in this section relies upon a legal review and opinion report Re: “Incorporation and good standing status of Andes Corporación Minera S.A. (ACMSA) and of its mining rights” dated January 11th, 2023, by Abogado (lawyer) Jose Vargas Gei of Vargas & Galindez (V&G), a Mendoza based legal firm.

The Los Azules Project is comprised of properties (the “Properties”) owned by Andes Corporación Minera S.A. (ACSMA), an Argentine subsidiary of McEwen Mining through its ownership in McEwen Copper. ACMSA is duly registered before the Dirección de Personas Jurídicas of the province of Mendoza, by Resolution #2025 dated November 2nd, 2005.

There are two types of tenure under Argentine mining regulations: Cateos (Exploration Permits) and Minas (Mining Permits). Exploration Permits are licenses which allow the property holder to explore the property for a period following a grant that is proportional to the size of the property. Mining Permits are licenses which allow the holder to exploit the property subject to regulatory environmental approval. To convert an exploration permit (Cateo) to a mining concession (Mina), some or all the area of a cateo must be declared as MD (Manfestación de Descubrimiento) and then converted to a Mina. Minas are mining concessions which permit mining on a commercial basis.

McEwen Copper controls approximately 31,746 ha of mining rights (Minas) around the Los Azules deposit. In addition, McEwen Copper owns sufficient surface rights for the Project pursuant to an agreement with CCM S.A., on March 3rd, 2010, whereby ACMSA acquired the surface rights set out in Figure 1.5 (18,000 hectares in green outline).

The international border with Chile forms the limits of the owned property on the west side (shown as a black dashed line Figure 1.5). The surface rights limits of the property are represented by the green line in Figure 1.5. Based on the V&G review and opinion, ACMSA has good and valid, legal, and beneficial title to the mining rights shown in Figure 1.5.

Figure 1.5: Los Azules Project Property Limits (V&G Report, 2023)

Exploration at Los Azules commenced in the mid-1990’s and has included various studies of geology, geophysics, and geochemistry, as well as drilling with both reverse circulation and diamond core drills, sampling and analysis of surface and drill core samples, and road construction. Drilling programs have been undertaken at Los Azules between 1998 and 2023 by three different mineral exploration companies including BMG, MIM Argentina (now Glencore) and Minera Andes/McEwen Mining and McEwen Copper. Drilling included reverse circulation programs mostly for gold exploration and diamond drilling focusing on supergene and hypogene porphyry-style copper mineralization. Descriptions of these programs are detailed in the following sections. Table 1.2 provides a summary of the drilling information.

The mineral resources have been classified according to guidelines and logic summarized within disclosure requirements and policies for mining properties with current industry and global regulatory practices and standards, as embodied by the Committee for Reserves International Reporting Standards (“CRIRSCO”) referred to in S-K 1300. Resources were classified as Indicated or Inferred by considering geology, sampling, and grade estimation aspects of the model.

The extent of mineralization along strike exceeds 4 km and the distance across strike is approximately 2.2 km. The deposit is open at depth. Over the approximately 2.5 km strike length where mineralization is strongest, the average drill spacing is approximately 150 meters to 200 meters but there are localized areas where drilling is on 100-meter spacing. The assay database considers 162 drillholes and 56,528 meters of assay interval data. Resource estimation work was performed using Datamine Studio modeling software.

As of the date of publication, 47 holes and approximately 18,318 meters of drilling (mostly infill) have been completed but were not included in the database for resource estimation, data for which was cut off on date December 31st, 2022.

The Indicated and Inferred resources for the enriched and primary zones are presented in Table 1.3. Mineral resources are determined using an NSR cut-off value to cover the processing cost for each recovery methodology. For supergene and primary material going to the leach pile, the cutoff was $2.74/t. For supergene going to the mill, the cutoff was $5.46/t and primary material going to the mill was $5.43/t. The resource is further constrained by a pit shell that demonstrates the reasonable prospects of eventual economic extraction (RPEEE) of this material.

Generalized technical and economic parameters include a long-term copper price of $4.00/lb, and a variable resource pit slope between 20° and 42°, depending on depth. Other parameters used in the resource pit development are detailed in Section 11.13.

Resources are reported in two categories related to processing amenability: 1) materials that are suited for processing in a commercially proven conventional, ambient conditions, copper bio-leaching scheme (Leach); and 2) materials that are better suited to processing either in a more advanced bio-leaching scheme such as NutonTM technology or traditional milling/concentrator approach (Leach+ or Mill).

Note: Mineral Resources do have demonstrated economic viability. No values are presented where the process recovery method does not consider this aspect of the materials.

The Los Azules Deposit grades, geometry, and depth make it suitable for conventional, large-scale truck-shovel open pit mining methods. This includes the use of equipment such as blasthole drills, diesel hydraulic excavators, electric shovels, large off-highway haul trucks, and associated operations support equipment.

One copper cathode production rate case was assessed during the mine engineering and planning process. This 175k tpa Cu cathode production scenario is the ‘base case’.

The ultimate pit shell limit and intermediate pit shells (or phases) were developed with the use of Geovia Whittle™ pit optimization software. Using Net Smelter Return (NSR), surface restrictions / constraints, pit slope geotechnical parameters, mining parameters, and production rates resulted in a series of economic pit optimizations that were evaluated to define pushbacks and the ultimate pit. The Los Azules Deposit also contains mineralized material that may be economic for producing a milled copper concentrate product, but this material was not considered for base case pit optimization or mine schedule.

Open pit mining would take place in phases from an initial starter pit, allowing for a shorter pre-strip and earlier access to mineralized material for leaching. For the 175k tpa Cu cathode production base case, the material mined over the two-year pre-production period is 115M tonnes of which 17.4M tonnes is mineralized material that is either stockpiled or crushed and placed on the heap leach pad. There is a ramp-up in annual production to year 5, when peak annual material movement is reached at 130M tonnes. Material movement tonnage stays at approximately 130M tonnes through to year 11 and declines to 50M tonnes in year 17.

Approximately 58.6M tonnes of lower grade mineralized material is stockpiled during these periods of which 41.8M tonnes is reclaimed and placed into the crusher feed in years 15-17. The remaining 16.8M tonnes is predominantly primary copper mineralization and will be processed in the Phase 2 project.

Copper mineralization is complex and varied at Los Azules, consisting primarily of chalcocite, chalcopyrite, bornite and covellite with little oxide mineralization, typically chalcocite dominant with some covellite in the supergene materials and chalcopyrite dominant with some bornite in the primary materials. Metallurgical characterization testing has been completed as part of this study in the form of sequential assay (sulfuric acid and cyanide steps) for the resources considered, column testing and bottle roll testing. The sequential assay method used at Los Azules for both the resource assay and metallurgical programs provides an indication of the copper mineralization present in the form of acid soluble copper (CuAS) and cyanide soluble copper (CuCN), both assays combined provide an approximation for leachable/soluble copper (CuSOL) component of the total copper assay (CuT).

Historical testing for McEwen Copper was conducted on samples from the resource in several phases. C. H. Plenge Laboratory (Plenge) in Lima, Peru, performed several scoping level investigations from 2008 to 2012. A mineral liberation analysis (MLA) was completed at Thompson Creek Metals Company in Challis, Idaho; in 2012 on rougher flotation samples from the Plenge lock-cycle testing. Additional samples from the resource were tested at the SGS Research Limited (SGS) to support a Preliminary Economic Assessment (PEA) by Hatch in 2017.

The current metallurgical program consists of three concurrent phases of work, aimed at supporting a feasibility study level of investigation in future. In the current Phase 1 program work, existing drill core was selected for testing by lithology and material type to reflect economically processable material in the resource for this study. Phases 2 and 3 will utilize new metallurgical core obtained from the ongoing drilling program to investigate the potential metallurgical variability of the deposit and focus on the initial 3-5 years of material to be mined.

As of the effective date of this report, the initial columns for the current Phase 1 program are still on-going pending final analyses. As such, results are considered preliminary until tail assays can be obtained to provide a calculated head assay and related recovery.

Heap leach copper extraction is derived by two (2) different methods, one for leachable/soluble copper (CuSOL) and residual copper (CuRES) as derived from sequential copper assay methodology. The projected extraction for CuSOL is 100% for leachable/soluble recovery and 15% for CuRES. Residual copper assay is the difference between total assayed copper (CuT) and CuSOL. For the 19mm column tests in the current program, the total copper extraction ranged from 86% to 72% in 180 days and averaged 80% overall.

Copper recovered to cathodes considers a heap efficiency and inventory factor of 90% of the long-term extractable copper extended over a two-year leach cycle period based on general experience. Soluble copper recovery exceeding 100% implies partial leaching of material which was not categorized as “soluble” based on the sequential assaying method and data available. Based on the resource assay data and column results, the apparent soluble copper (CuSOL) recovery to cathodes is approximately 107%, with total copper (CuT) recovery at 73%.

Based on current bottle roll results and the current column consumption, an average gross acid consumption is 18 kg/t of material. Net acid consumption is a function of recoverable copper with acid produced as a result of the electrowinning process and calculated in the process cost model annually.

The Phase 1 project Base Case option considers a processing facility to nominally produce 175,000 tonnes per annum (tpa) of copper cathodes from higher grade, highly leachable (soluble) copper content materials. An expansion of the mining rates and materials handling facilities is required by Year 4 to and again in Year 7 to maintain copper production as the copper grade drops. An additional solvent extraction train will be required in Year 8. This initial processing facility will function through to the completion of mining for the initial project phase in Year 15 with lower grade stockpile reprocessing and residual leaching operations to Year 18.

All Primary copper mineralized material mined during the initial project phases will be stockpiled for future processing routes that may include a mill/concentrator or alternative bio-leaching technologies.

Figure 1.6: Simplified Process Flowsheet (Samuel, 2023)

The project initial capital costs are based on budgetary cost quotations and regional contractor estimates for major equipment and facilities obtained in Q4 2022 and Q1 2023. The capital costs for the project are summarized below and should be viewed with an expected level of accuracy for a preliminary analysis at +40%/-20% consistent with AACE International Recommended Practice No. 47R-11 for an Estimate Class 5. Owner’s Costs include the initial mine fleet, preproduction stripping costs and preoperational costs for early crushing and material placement on the leach pad.

The project life of mine direct operating costs per tonne processed and per pound of copper produced are summarized below. Costs vary with open pit development, feed head grades, acid requirements in leaching, power consumption increases over time and actual copper production.

*Note: Numbers may not add exactly due to rounding

Based on consensus estimates and independent analysis, long-term metal pricing used in this report (except for mineral resource estimation) and project economic analysis are Copper (Cu) - $3.75/pound; Gold (Au) - $1,700/ounce; and Silver (Ag) - $20.00/ounce. The 2023 updated financial outcomes for the Phase 1 initial project mine and facilities are shown in Table 1.6 below (expressed in Q1 2023 United States Dollars). C1 cash costs are defined as the cash cost incurred at each processing stage, from mining through to recoverable copper delivered to the market, net of any by-product credits. C1 cash costs per pound of copper produced and all-in sustaining costs per pound of copper produced are non-GAAP ratios.

Notes:

A summary of the 8 Year and LOM Cash Cost can be seen in Table 1.7.

*Note: Numbers may not add exactly in every case due to rounding

This subsection was prepared by J. L. Sorensen, FAusIMM, QP, Samuel Engineering and reviewed by the respective QP for each area.

This report is a Technical Report Summary (TRS) that summarizes the findings of the Initial Assessment completed for the Los Azules Project in accordance with Securities Exchange Commission 17 CFR Part 229 Standard Instructions for Filing Forms Regulation S-K subpart 1300 (S-K 1300) and is intended to meet the requirements of S-K 1300 as considered for an Initial Assessment (IA) level of study and disclosure as defined in the regulations and supporting reference documents. The effective date of this report is May 9, 2023, concurrent with the updated final resource estimates published herein.

Based on the results of this preliminary assessment, contributing authors have identified important risks and opportunities related to the Los Azules Project development. Below are what is believed to be the most significant “key” risks and opportunities. A complete list and description of the interpretations, conclusions, and recommendations to advance the Project is provided in Sections 22 and 23.

Risks

Opportunities

This subsection was prepared by J. L. Sorensen, FAusIMM, QP, Samuel Engineering and reviewed by the respective QP for each area.

Based on the results of this Initial Assessment, contributing authors recommend that McEwen Copper complete additional work to further de-risk the Project, including more advanced stages of drilling to complete the work necessary for a Feasibility Study based on the findings reported. Key issues and items are included below. A complete list of these tasks and, summary of the interpretations, conclusions, and recommendations to advance the Project are provided in Sections 22 and 23.

Adequate work has been completed through the prior studies to define the project options going forward to select an option for Feasibility Study delineation, however metallurgical, geotechnical, geological, hydrological, and other aspects are not developed beyond a preliminary level of study at this time.

Given the resources developed to date, project technical options considered and permitting basis to date, a Preliminary Feasibility Study (PFS) is considered an optional step and a Feasibility Study (FS) level of project definition is recommended to expedite the project development timeline and to also comply with the requirements of the property ownership agreements with the Provincial Mining Ministry.

As of the effective date of this report, the initial Feasibility Study resource drilling, geotechnical, hydrogeologic and metallurgical test work programs were started and in progress. The recommended technical program to complete the work deemed necessary to support the completion of a Feasibility Study is as follows:

A Feasibility Study level of definition is estimated to take 18-20 months to complete from the effective date of this report and assuming continuance of the work areas in progress.

Based on current information from work in progress, the estimated cost is approximately $232 million including estimates for McEwen Copper/ACMSA costs. The study cost areas are broken out in the below Table 1.8 for the recommended program to complete the Feasibility Study and other expenditures planned during the same timeframe except where noted. As of the date of publication, approximately $43.4 million has already been incurred in 2023, which should be deducted from the 2023 total shown for a forward-looking cost estimate.

This report is a Technical Report Summary (TRS) which summarizes the findings of the Preliminary Study completed for the Los Azules Project in accordance with United States Securities Exchange Commission (SEC) 17 CFR Part 229 Standard Instructions for Filing Forms Regulation S-K. The report complies with 17 CFR Part §229.1300 (S-K 1300) Standard Instructions for Regulation S-K subpart 1300 SEC S-K §229. 1304 and §229.601(b)(96) and is intended to meet the requirements of S-K 1300 as considered for an Initial Assessment (IA) level of study and disclosure as defined in the regulations and supporting reference documents. The purpose of this TRS is to report the study results, mineral resources, and the subject project estimated costs and economic potential. The effective date of this report is May 9, 2023, concurrent with the updated final resource estimates published herein.

This TRS supersedes the current report on file titled: SEC S-K 229.1304 INITIAL ASSESSMENT INDIVIDUAL DISCLOSURE FOR THE LOS AZULES PROJECT, ARGENTINA, prepared by Mining Plus US Corporation with an effective date of April 01, 2021.

All currency shown in this report is expressed in May 2023 United States Dollars unless otherwise noted.

The Los Azules deposit is a classic Andean-style porphyry copper deposit. The large hydrothermal alteration system is at least 5 km long and 4 km wide and is elongated in a north-northwest direction along a major structural corridor. The altered zone surrounds and includes the Los Azules deposit area, which is approximately 4 km long by 2.5 km wide. The limits of the mineralization along strike to the North and at depth have not been entirely constrained by drilling. Primary or hypogene copper mineralization extends to at least 1,000 m below the present 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 trace amounts, but copper is by far the most important economic constituent at Los Azules.

The Project is at the exploration stage of investigation; consequently, this study is at the scoping level of accuracy, preliminary in nature, and includes Inferred mineral resources in the conceptual mine plan and the mine production schedule. Inferred mineral resources are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves under the standards set forth in S-K 1300. There is no certainty that the estimates in this updated IA will be realized.

This Technical Report provides information related to an updated resource estimation, revised processing flowsheet concepts and updated project economics since the last previously disclosed S-K 1300 Technical Report Summary in 2021. This report has been prepared in collaboration with McEwen Copper and other qualified contributors to assess the current potential economic viability of the Los Azules property.

This 2023 IA update supersedes the prior reports and reflects a revised development philosophy, processing flowsheet, updated resource model and estimations, metallurgical information, mine plans and economic parameters such as current capital and operating costs and associated new financial inputs and model. The main differences between this 2023 updated study and the most recent previously disclosed Technical Report Summary are:

This IA is triggered by McEwen Copper’s intention to publicly disclose the engineering and optimization studies completed by Samuel Engineering Inc. and Stantec Inc. in conjunction with McEwen Copper during 2021 - 2023. The results from the updated IA and the Los Azules property are material to McEwen Copper.

The quality of information, conclusions and estimates contained herein are consistent with the level of effort involved in the authors’ services based on: (i) information available at the time of preparation; (ii) data supplied by outside sources and (iii) the assumptions, conditions and qualifications set forth in this report. This report is intended to be read as a whole and sections should not be read or relied upon out of context.

This report was authored by the qualified persons (each a “QP” and collectively, the “QPs”) listed in Table 2.3. Each QP only assumes responsibility for those sections or areas of the report that are referenced opposite their name in Table 2-1. None of such QPs, however, accept any responsibility or liability for the sections or areas of this report that were prepared by other QPs.

The QPs believe the report complies with 17 CFR Part §229.1300 (S-K 1300) Standard Instructions for Regulation S-K subpart 1300 SEC S-K §229. 1304 and §229.601(b)(96) and meets the requirements of S-K 1300 as considered for an Initial Assessment (IA) level of study and reporting disclosure as defined in the regulations and supporting reference documents.

A summary of the QPs, as defined in S-K 1300, responsible for each section of the report and their respective company affiliation is provided in Table 2.1.

The author considers the foregoing personal inspections to constitute a “current personal inspection” in accordance with S-K 1300 for the current level of study.

Mr. Allan Schappert (CPG, SME-RM) of Stantec Consulting, QP, visited the Los Azules property during the period from 24 April – 15 May 2022. The purpose of the visit was to observe, review, and comment on all aspects of data collection, recording, and analysis in preparation of the Mineral Resource Estimate. Activities and discussions included the following: visit and inspection of operating drill sites; care, custody, and control procedures of core boxes; core logging facilities at Los Azules camp; core storage and sampling procedures at the Calingasta warehouse; a tour of the independent assay lab in Mendoza; review of historical and current QA/QC protocols with a review of recent results.

Mine Technical Services (MTS) conducted two phases of database audits (2021 and 2022) including a site visit by Todd Wakefield and Francisco Ramos between April 18 – 27, 2022. Discussions of their findings and a review of their recommendations were made. Stantec’s geological QP supported McEwen Copper’s decision to undertake an extensive re-assaying program of existing core to augment the database prior to the updated estimate.

A site visit was performed 08 April 2022 to 13 April 2022 with a team physically on the site 09 April 2022 through 12 April 2022 and attended by the following Stantec individuals.

SRK Geochemists Rob Bowell and Brooke Clarkson visited the Los Azules core warehouse facility in Calingasta, November 7-9, 2022, and were accompanied by Hugo Bracamonte from McEwen Copper. The focus of the visit was to examine the drill core from the intervals selected for geochemical characterization. Field logging included a description of the lithology, alteration, mineralogy, and structure.

Bruno Borntraeger, PE of Knight Piesold (KP), QP for the leach pad design visited the site January 29-31, 2023. The visit focused on leach pad site locations and field-testing requirements for the geotechnical design of the leach pad.

David Tyler (SME-RM) is the McEwen Copper Project Director for the Los Azules Project and has the responsibility for the study work. Mr. Tyler has visited the Los Azules site several times in 2022 and 2023.

The Los Azules Project is a porphyry copper development project located in the Frontal Andes Cordilleran region of San Juan Province, Argentina along the border with Chile. The project falls within the Calingasta Department of the San Juan Province. The Project is approximately 80 km west-northwest of the small town of Calingasta, in the San Juan Province of Argentina at approximately 31° 06' 25" south latitude and 70° 13' 25" west longitude. Calingasta is located 173 km by road west of the Provincial Capital city of San Juan along Route 12.

The terrain elevation at the project site ranges between 3,200 meters above sea level (masl) at the proposed camp location and up to 4,500 masl on the high peaks in proximity to the Project. The Project area is remote, and no infrastructure is present. There are no nearby towns, Indigenous residents, or settlements. Seasonal exploration work typically commences in October or November and terminates in May or early-June. Exploration operations are supported by means of two temporary camps within the Project site area.

The mine development is located approximately 6 km east of the border with Chile (Figure 1.3).

McEwen Copper controls approximately 32,700 ha of mining rights and 18,000 ha of surface rights around the Los Azules Project. Aerial photography and global positioning were utilized to locate the property in the field; the coordinates of the corners of the property are established in the government documents granting the mining rights.

The Los Azules Project is currently accessed by 120 km of unimproved road with eight river crossings and two mountain passes (both above 4,100 m elevation). This access is subject to snow accumulation and is passable only from November through to May. This 2023 update describes in Section 15 “Infrastructure” a potential future northern access route within McEwen Copper owned lands that is less affected by snow. Also described is an airstrip currently permitted for construction.

The laws, procedures, and terminology regarding mineral title in Argentina differ from those in the United States and in Canada. Mineral rights in Argentina are separate from surface ownership and are owned and administered by the provincial governments. The following summarizes some of the relevant provisions of the Argentine Mining Code and Argentinean mining law terminology to aid in understanding the McEwen Mining land holdings in Argentina.

The provinces are the owners of the natural resources located within their territories and each province retains the power to administer and regulate mineral rights according to the federal Mining Code and supplemental provincial laws and regulations.

Surface rights are separate from mineral rights, and they are treated separately under Argentine law. The Mining Code establishes that mining is in the public interest and therefore surface owners cannot prevent the granting of mining rights and properties or commencement and/or continuity of mining activities on their property, but surface owners have a right to collect an indemnity because of the use of the land by the miner and the damages derived from mining activities. Land over which a mining concession has been granted is legally subject to different types of easements (e.g., right of way, occupation of land, use of water, etc.), provided that an indemnity is paid to the owner of such land.

Mineral rights are considered forms of real property and can be sold, leased, or assigned to third parties on a commercial basis. “Cateos” (exploration permit) and “Minas” (mining concession) can be forfeited if minimum work requirements are not performed or if annual payments are not made. Generally, notice and an opportunity to remedy defaults are provided to the owner of such rights.

Grants of mining rights, including water rights, are subject to the rights of prior users. Further, the mining code contains environmental and safety provisions administered by the provinces. Prior to conducting operations, applicants must submit an environmental impact report (“Informe de Impacto Ambiental” or IIA in Spanish) to the provincial mining authority describing the proposed operation and the methods to be used to prevent undue environmental damage. When the provincial mining authority approves the IIA it issues a permit in the form of an official declaration (“Declaratorio de Impacto Ambiental” or DIA in Spanish). The IIA must be updated every two years, with a report on the results of the protection measures taken. If protection measures are deemed inadequate, additional environmental protection may be required. Mine operators are liable for environmental damage. Violations of environmental standards may cause exploration or mining operations to be shut down but without prejudice to mining title.

McEwen Mining was organized under the laws of the State of Colorado on July 24, 1979, and is listed on the New York Stock Exchange (NYSE) and on the Toronto Stock Exchange (TSX) under the symbol MUX. The Company’s head office is in Toronto, Canada. As of May 2023, the Company owns a 51.9% interest in McEwen Copper which owns a 100% interest in the Los Azules Copper Project in San Juan, Argentina, and the Elder Creek exploration project in Nevada, USA. The relevant ownership structure is shown in Figure 3.1, as provided by McEwen Mining.

The Los Azules Project is comprised of properties (the “Properties”) owned by Andes Corporación Minera S.A. (ACSMA), an Argentine subsidiary of McEwen Mining through its ownership in McEwen Copper.

ACMSA controls approximately 31,746 ha of mining rights (Minas) around the Los Azules deposit. In addition, ACMSA owns sufficient surface rights for the Project pursuant to an agreement with CCM S.A., whereby ACMSA acquired 18,000 ha in surface rights. In 2018, ACMSA filed a request to group all the Mining Permits together, file #1124.553-A-2018, in such way that, once all surveys are approved, all the Mining Permits be considered as one larger Mining Permit. This will allow investments to be distributed across the larger permit group and eliminate the need to spend on each individual Mina. It is expected that this request by ACMSA could be favorably resolved during 2023. These Properties are the subject of this Technical Report. Specific property details are discussed in Section 3 of this report.

FCA Argentina S.A., a subsidiary of Stellantis N.V. (“Stellantis”), invested ARS $30 billion in Argentina to acquire shares of McEwen Copper in a transaction that closed on February 24th, 2023. In connection with the Transaction, McEwen Copper and certain of its affiliates entered into an Investor Rights Agreement with Stellantis (the "Stellantis IRA”) and a Copper Cathodes and Concentrates Purchase Rights Agreement (the “CCCPRA”), which are described below.

The Stellantis IRA provides for the following principal terms:

The CCCPRA provides an option to Stellantis and its affiliates that, if exercised to its maximum extent, would allow them to purchase a percentage of the copper cathodes or copper concentrates or both produced from the Los Azules Project, in each case equal to their equity ownership percentage in McEwen Copper at the time of exercise.

Nuton LLC, a Rio Tinto Venture (“Nuton”), has invested a further USD $25 million to acquire shares of McEwen Copper in a transaction that closed on August 31st, 2022. In connection with the transaction, McEwen Copper entered into a collaboration agreement with Nuton (the "Nuton Collaboration Agreement”), to advance our understanding of the potential application of heap leach technology at Los Azules, including the testing of Nuton™ Technologies for compatibility with Los Azules copper mineralization. Leaching has many potential economic and environmental benefits over a conventional milling scenario, including lower water and energy consumption, no large tailings storage facility or dam, and typically lower capital and operating costs.

The principal terms of the Nuton Collaboration Agreement include:

Nuton has invested a further USD $30 million to acquire additional shares of McEwen Copper in a transaction that closed on March 15th, 2023.

In connection with the second Nuton transaction, McEwen Copper and certain of its affiliates entered into an Amended Collaboration Agreement (the "New Nuton Collaboration Agreement”) and a Copper Cathodes and Concentrates Purchase Rights Agreement (the “CCCPRA”), which are described below.

The New Nuton Collaboration Agreement provides for the following additional rights beyond those in the original Nuton™ Collaboration Agreement.

The CCCPRA provides an option to Nuton that is equivalent to that of Stellantis described above.

After closing the second Nuton Transaction, McEwen Copper has 28,885,000 common shares outstanding on a fully diluted basis, and its shareholders are: McEwen Mining Inc. 51.9%, Stellantis 14.2%, Nuton 14.2%, Robert R. McEwen 13.8%, Victor Smorgon Group 3.5%, and other shareholders 2.4%.

Figure 3.1: Los Azules Ownership Structure (McEwen Mining, 2023)

In 1994, Minera Andes S.A. (MASA), an Argentine subsidiary of Minera Andes, was granted the Cateo to explore the Cordon de Los Azules (file # 545.957-D-94). This cateo was divided and converted into two MDs on October 17, 1998, known as Azul 1 and Azul 2. These MDs cover part of the southern portion of the Project. In 2009 MASA transferred these two MDs to Andes Corporación Minera S.A. (ACSMA). The central portion of the Project is covered by MD Mirta and the northern portion by Escorpio II, all owned by ACSMA.

The Los Azules Project is comprised of properties (the “Properties”) owned by ACSMA, an Argentine subsidiary of McEwen Mining through its ownership in McEwen Copper. The information in the section relies upon a legal review and opinion report Re: “Incorporation and good standing status of Andes Corporación Minera S.A. (ACMSA) and of its mining rights” dated January 11, 2023, by Abogado Jose Vargas Gei of Vargas & Galindez (V&G), a Mendoza-based legal firm.

Based on the V&G review and opinion, the following conclusions were included in their memorandum.

The challenge by ACMSA for the peripheral properties under threat of forfeiture, Gina, Sofia, Torora II, and Marcela, was resolved in the company’s favor and the forfeited rights were returned by the Mining Council on December 29, 2022.

As of January 17, 2023, the powerline easement was granted by the provincial government.

A list of those land holdings is detailed in Table 3.1 and are also shown on Figure 3.2. The size of the property covered by those tenements, once actually granted, however, may differ from those set out below.

*NOTE: Escorpio IV was originally requested, by the previous owner, as a 4,411.71 hectares mining permit. However, mining law sets a limit to the size of the mining permits held by companies of 3,500 hectares. Consequently, Escorpio IV, when acquired by ACMSA, was 911.71 hectares above the legal limit. This led ACMSA to release the central area of Escorpio IV, as suggested by its geologists, as it being an area that does not affect ACMSA plans for Los Azules Project. The mineral claim locations are shown Figure 3.2.

By law, the released area is granted to Instituto de Exploraciones y Explotaciones Mineras (IPEEM, a provincial mining company), that, following certain procedures, can grant this area to private companies to be explored and exploited.

Figure 3.2: Map of Mineral Claims (Minas), Easements (Servidumbres) and Surface (Superficie) Ownership (Vargas & Galindez/McEwen 2022)

As for the mining right at the project center, labeled Soberania (File # 259,299-C-84), ACMSA and three other persons have claimed the right to this mine simultaneously. To date, the award of the mining right has not been resolved, but it is expected that to be resolved in favor of ACMSA, since the request and technical arguments of ACMSA are more relevant than those of the third parties.

The 21 mining rights have been grouped into a Mining Group, which is in process under file No. 1124.553-A-2018. According to Argentine laws, it is necessary to have approved measurements of each mining right to constitute a Mining Group, so these measurements are in process and this approval is expected during the year 2023.

An exploitation plan was filed in January 2023 and subsequently an Environmental Impact Statement for the exploitation was filed in April 2023 with the government of San Juan. This plan and EIS were in support of the maintenance of the ACMSA mining rights. The exploitation plan committed ACMSA to begin the development of the mine within 5 years, or before January 2028.

It should be noted that no facilities are foreseen in either the Soberania or the released area of the Escorpio IV mining rights. Figure 1.4 shows the layout of site facilities relative to the surface and mining rights.

In January 2010, Andes Corp. purchased 18,000 ha of surface rights in the Los Azules area. The purchase of this property, located near the Argentina/Chile border region, was subject to government approval. The approval was granted on August 31, 2010, by Resolution #907 of the Ministerio del Interior. Figure 3.3 shows the purchased surface rights. The surface rights currently held by ACMSA cover the area currently being explored by McEwen Copper. The area represented by the surface rights are also considered to be more than adequate for potential development of the mine, associated processing facilities and infrastructure considered in this technical report.

Figure 3.3: ACMSA Owned Propiedad Minera (Mining Rights) and Campo Superficiario (Surface Rights) (McEwen, 2022)

The green area in Figure 3.3 indicates the limits of McEwen Mining surface rights (land holdings) relative to the mining rights. The western boundary of the property is the border with Chile. Below, Figure 3.4 shows the surface right owners within and adjacent to the Los Azules Project, with the land held by Illanes Mery colored in orange, Campo Cortez Monroy to the south in yellow, Cortez Angel to the north in green, and the Estomonte property to the east in peach color.

Figure 3.4: Map of mineral concessions and surface rights (campos) within or adjacent to project area (Vargas & Galindez/McEwen, 2022)

None of the mineral concessions that are not owned by McEwen but that fall within the McEwen owned surface rights will have any impact upon the development of the Los Azules Project. All Los Azules facilities are located on lands where McEwen has both the surface and mining rights.

There are no outstanding royalties, payments, or other agreements or encumbrances to which the property is subject to other than a one-time USD $500,000 payment to be made to Hugo Bosque upon delivery of a feasibility study.

San Juan Province charges a 3% royalty based on the “mine head value”. The 3% is charged on the sale price less some costs (excluding depreciation of fixed assets and extraction costs). In other words, deductible expenses include: i) transport and freight costs; ii) crusher, milling and process (beneficiation) costs; iii) commercialization cost; iv) administrative cost (not related extraction cost) and v) smelting and refining costs. However, since July 2011, the Province of San Juan, through an agreement with the mining companies in operation, modified the calculation of the "mine head value" by a taxable base on gross sales, without any deductions. This change in the methodology has not been reflected in the legislation, and is implemented through agreements according to a series of conditions (e.g., metal prices, tax burden, etc.)

In addition, the Province of San Juan has an unlegislated practice of negotiating a voluntary contribution to a trust (“fideicomiso” in Spanish), usually 1.2% or 1.5% and on the same calculation basis as mining royalties (on gross sales, without deductions). These contributions are intended to finance infrastructure projects in the province, especially in the local area impacted by the mining operation.

TNR Gold Corp has a 0.4% NSR across the project, and McEwen has a 1.25% NSR.

There are no back-in rights.

At the present time, there are no known environmental liabilities at the Project site, since it is an exploration project. Reclamation activities are comprised of re-grading the drill pad sites, access roads at site and some portions of the main access road to the Project site.

There are two principal activities that have environmental impacts in the Project area. One is the overgrazing of pasture lands and the second is access roads and drill platforms on the property.

Seasonal grazing by “veranadas” from Chile takes place on sparse foraging resources and wetlands in the Project area. The “veranadas” with large animal herds (primarily goats) have affected:

There are numerous previously existing excavation areas for exploration roads in the Project and surrounding areas, including drilling platforms.

Argentine laws and regulations differentiate between prospecting, exploration, and exploitation activities. It is understood that exploration activities include mapping, sampling (including bulk samples), geophysics, trenching and drilling, whereas prospecting activities include only mapping and sampling.

There are different sectorial permits that are required to conduct mining activities, but the most relevant ones are the ones associated with environmental permits. The provisions related to environmental protection applicable to mining activity were established in 1995 by the General Environmental Law and have been incorporated in Title Thirteen of the Mining Code.

The federal government is empowered to issue Minimum Environmental Protection Standard Laws (MEPSL), applicable in the whole country by the respective local authorities. The provinces are allowed to supplement and regulate the MEPSL with more stringent local or provincial environmental regulations.

The main permit for the exploration phase at Los Azules is the Environmental Impact Declaration (Declaracion de Impacto Ambiental or DIA in Spanish), which must be updated at least every two years with the provincial mining authority. An EIA must be presented for each phase of the project development: prospecting, exploration, and exploitation (including industrialization, storage, transportation, and marketing of minerals). The last DIA renewal was received on June 2, 2021, and the resolution was issued on June 17, 2021.

Ancillary permits for water usage (domestic, drilling and dust mitigation), archeological research and investigation, hazardous waste, sewage, and domestic waste facilities are renewed on an annual basis before the commencement of the exploration season. The permit renewals are expected to be approved on time as per prior exploration seasons. All necessary permits have been obtained for the work currently being carried out on the Project.

There are five main legal requirements that impact the Project during the different stages of development: environmental regulation, mining regulation, hazardous waste regulation, health and safety regulation and the Mining Investment Law.

Environmental regulations applicable to mining have four sources:

Lack of compliance or other infringement of the environmental obligation may result in penalties ranging from fines to suspension of works or closure of the mine, but without effect upon title or ownership of the mining concession.

The acquisition, exploitation and use of minerals are regulated by the Mining Code (National Law 1919) and Provincial Law 688-M. In addition, the province of San Juan has adopted National Law 24585, environmental protection for mining activities.

Other regulations affecting the Project are related to Hazardous Waste regulations set forth in National Law 24051, adopted by the province of San Juan. This law regulates the generation, handling, transportation, treatment, and disposal of hazardous waste materials.

Health and safety regulations require that a mining company must hire an Occupational Hazard Insurer (ART, as per the acronym in Spanish) to identify and evaluate occupational hazards and to design preventive and emergency programs. For the mining sector, companies must give priority to riskier occupational activities and employee training.

Mining Investment Law 240196 includes article 23, which relates to the preservation of the environment. To prevent and correct any impacts to the environment due to mining activities, companies may establish a special accounting provision for that purpose. The annual amount shall be left to the criterion of the company but shall be considered deductible for income tax purposes up to a sum equivalent to 5% of the operational costs of material extraction.

Archeological sites are managed by the Ministry of Culture of the province of San Juan. Sites can be removed by applying to the Ministry for a permit that describes the tasks to be carried out, prepared by qualified professionals. A site plan of the proposed work area should also be submitted with the permit application. A permit is expected to take two months to obtain, and the work plan should be submitted one year in advance.

In 2010, Argentina passed Federal Legislation to protect its water resources contained in glaciers prohibiting activities that could affect these resources.

Following suit in July 2010, the province of San Juan enacted Provincial Law 8144, “Glacier Protection Law”, in a compromise with Federal Law, which, among other things, restricts disturbance of glaciers by mining activities. In addition, the Federal Congress issued a MESPL on the protection of glaciers and periglacial environment (Law 26639), which is separate from the provincial law.

Since 2011, several independent studies have been conducted by the Company.

The Los Azules exploration area was audited by a multi-agency environmental audit team in March 2013. There were no adverse findings and the audit results indicated that McEwen Mining is in full compliance in all areas protected by the provincial law.

In 2016, the Provincial Government began to catalogue the glaciers present in the provincial territory to determine if any impacts have taken place or if any glaciers could impede mineral development in the province.

Between 2007 – 2012 Ausenco Vector has monitored and collected environmental baseline data on surface and groundwater volumes and quality, soils, flora and fauna, archeology, and weather. Several other consultants have been involved for all environmental aspects. Ausenco Vector has also studied the boggy wetlands, locally referred to as “vegas”.

Ausenco Vector implemented a plan to relocate or compensate the vegas where they may be impacted by the project. The plan did not produce satisfactory results. Andes Corporación Minera S.A. requested to the provincial environmental authority to propose an alternative compensation criterion, however, there has not been any response from the authority to date.

Dr. Andres Meglioli, of Mountain Pass LLC, has been monitoring cryogenic geoforms in the project area since 2011.

The environmental baseline data on surface and groundwater volumes and quality as well as the flora and fauna data collection and additional studies on the vegas (including a compensation proposal) have been conducted since 2013 by the Instituto de Investigaciones Hidraulicas, a research center of the National University of San Juan, through their senior biologists Juan C. Acosta and Hector J. Villavicencio. These are ongoing studies contracted by McEwen Copper. After each drilling season, a report is prepared by the consultants and issued to McEwen Copper that summarizes the work completed through the season.

In late 2017 and throughout 2018, McEwen Copper, in conjunction with consultants and specialists, performed full-year baseline studies for fauna, flora, and hydrology that will require extended site access through all seasons and support using mules and helicopters. Geotechnical studies, such as water permeability tests, may also be performed to enhance the existing data set.

In 2022, additional environmental baseline work was undertaken with the objective of completing an IIA (Informe Impacto Ambiental) equivalent to the English EIA for exploitation of the mine. All of this and prior baseline data was included in the IIA documentation that McEwen Copper submitted to the authorities in April of 2023.

Access to the site is through provincial routes to mining access easements granted under Argentine law. The province of San Juan is bisected by RN 40, which extends the length of Argentina.

The main access to the Los Azules Project from Villa Calingasta (Calingasta Department – Province of San Juan), is through Provincial Route No. 437 from the intersection with Provincial Route No. 406 to La Alumbrera, an approximate distance of 25 km. From there, the mining road begins. This is the Exploration Road, which includes the Candadito support camp that is covered by an easement granted under file No. 1124.660-A-2012. The route has a length of 87 km and is covered by a road easement recorded in administrative file No. 520-0439-M-97 on behalf of ACMSA.

According to Argentine law, mineral rights supersede the overlying surface rights, and the holder of the latter is legally unable to impede access to the exploration or extraction of underlying mineralization. Fair compensation is provided to the surface rights holder for access and usage of the land in conjunction with exploration activities and mining operations. In January 2010, “Minera Andes”, a company 100% owned by McEwen Mining Inc., purchased 18,000 ha of surface rights covering the Los Azules Deposit and the associated surface facilities, as they are currently envisioned. The extent of surface rights and the proposed surface facilities are illustrated in the Los Azules General Arrangement in Figure 1.4.

Typically, the field season at Los Azules starts in December and runs through to the end of May due to limited access. However, last year, access to the site was maintained through mid-June, and depending upon the winter snowpack conditions, it is possible in some years to access the site as early as October as was the case in the last two drill seasons.

A weather station was installed near the camp site in mid-2010 to obtain local climatic information. The station is powered by a solar panel and collects meteorological parameters at 30-minute intervals. The station was manufactured by Coastal Environmental and is built around the ZENO® 3200 datalogger. Data communication is via an Iridium satellite modem. Data is downloaded using a companion base station located in the United States. The weather station uses a stand-alone tower with sensors to obtain the following parameters:

Two new weather stations were purchased and installed this season to provide better coverage over the site.

Considering the types of recorded parameters, the Los Azules meteorological station meets the World Meteorological Organization (WMO) standards for a Principal Climatological Station.

Figure 4.1, Figure 4.2 and Figure 4.3, which were obtained from the site meteorological station, present monthly weather data for temperature, total precipitation, and wind speed. Snowfall accumulations are recorded by the station as snow-water equivalent. Snowfall in the Project area is light, although heavy winter accumulations are common on the two high passes on the access road.

Figure 4.1: Monthly Temperature Data Apr-17-Jun-18, Nov-19 (McEwen 2022)

Figure 4.2: Monthly Total Precipitation Data – no data recorded Apr-17-Jun-18, Nov-19 (McEwen 2022)

Figure 4.3: Monthly Wind Speed Data – no data recorded Apr-17-Jun-18, Nov-19 (McEwen 2022)

The Project area is remote, and no infrastructure is present in the Project area. There are no nearby towns and/or settlements. Exploration operations are carried out by means of two-man camps within the Project development area.

Historically, Villa Calingasta was a mining town whose economy was supported by the exploitation of alum deposits, which is used in water purification and gold mining at the Casposo mine. The United Nations Development Program (UNDP) and other national and international agencies have established programs to help remediate certain environmental liabilities associated with the alum mining activity.

The current principal economic activity of the area is agriculture with fruit trees (apple and walnut) as the principal activity, in addition to employment in the public sector. Lesser activities include the following:

According to the Argentine National Census Bureau (INDEC) 2010 census, the population of the Calingasta Department (subdepartment) was 8,453 people. In 2015, the population was estimated to be 9,151 and was projected to be 9,641 by 2022. The 2022 census was not available at the time of writing this report.

The 2022 PEA considers the cost of connection at the existing Calingasta substation and routing a 220 kV powerline parallel to the Exploration Road. A study by Energía Provincial Sociedad del Estado (Provincial Energy Society of the State, EPSE), a state-owned company, showed that the province was well suited to support the development of projects providing renewable energy to the province and projects.

For the initial phase of the project, an indicative price was received by YPF Luz that could provide 100% renewable power to the project for a cost of $67 per MWh for a 5-year contract.

Surface water is available on the property in adequate amounts for McEwen Mining’s exploration activities. Preliminary hydrological evaluations conducted by Ausenco Vector have indicated that there are sufficient sources of water to operate the Los Azules mining and processing facilities and to provide the necessary fresh water needed to house employees at the mine site.

The Project is in a broad valley, formed by faulting and glaciation, and is bounded by steep ridges to the east and west. The deposit is centered on La Ballena Ridge (English translation: the whale), a low NNW-SSE trending ridge. The Project area is rugged and ranges in elevation from 3,500 to nearly 4,500 masl. Vegetation is sparse and is absent at higher elevations.

Long, narrow vegetated areas (“vegas” in Spanish) occupy the valley floors on either side of La Ballena. The vegas areas are fed by ephemeral spring-water and snowmelt, but also reflect the groundwater regime as well, with standing water levels at approximately 3,600 m in elevation. Springs are noted at approximately 3,790 m in elevation upstream of the vegas along the west side of La Ballena Ridge. Groundwater-fed springs and marshes are also noted around the range to the west of La Ballena between 3,800 and 3,900 m in elevation and along the eastern flank of the Cordillera de la Totora. The vegas areas feed the westerly flowing Rio La Embarrada, which joins the Frío River to the west before turning south into the Rio de las Salinas, a main tributary to the San Juan River.

Deposits of glacial debris (morainal materials) and scree account for much of the surface area covering the Los Azules Deposit and adjacent mountainsides. In the area of the deposit, these materials locally exceed 60 m in thickness, but on La Ballena Ridge, the cover is less, starting at 10 m thickness.

The area around Los Azules provides limited options for siting of the Heap Leach Facility (HLF), Filtered Tailings Storage Facility (FTSF), Mine Rock Storage Facility (MRSF), low-grade process stockpile, the processing facilities and other infrastructure needed. All facilities and permanent infrastructure considered in this PEA are located within areas where ACMSA has both mining and surface rights, or a current easement at this time.

The exact location of the project development surface facilities is yet to be finalized and requires hydrogeologic and geotechnical site investigations to support detailed design work to be performed.

The proposed Site General Arrangement of the various project facilities is presented in Figure 1.4. This is further described in Sections 13, 14, and 15.

There are no formal records of exploration in the Project area prior to 1980. The only important active project in the area prior to 1980 was the El Pachón Porphyry Copper Project, now owned by Glencore plc (Glencore), which is located approximately 90 km south of Los Azules. Evidence of prospecting (small trenches or pits) exists on some of the concessions.

In 1994, Minera Andes, through its subsidiary Minera Andes S.A. (MASA), acquired lands in the southern portion of the Los Azules area. Battle Mountain Gold Company (BMG) acquired lands immediately to the north through an option from Solitario Argentina S.A. (SASA). For the next couple of years, both companies independently explored for gold on their respective land holdings.

In 1998, a new access road was constructed by BMG while it conducted airborne geophysical surveys, mapping, trenching, and drilling several reverse circulation (RC) holes. A large hydrothermal alteration zone associated with dacite porphyry intrusions and stockwork structural zones was recognized in the Project area and Minera Andes signed a Letter of Intent with BMG to form a joint venture to explore the combined land package.

In 1999, Minera Andes and BMG signed a definitive joint venture agreement. BMG subsequently drilled additional RC holes and porphyry copper mineralization was intersected close to the property boundary; however, no drilling was done on the Minera Andes properties.

In 2000, BMG merged with Newmont Mining Corporation (NMC). No further work was done by BMG/NMC, and the joint venture was allowed to dissolve without BMG earning any interest in the Minera Andes or Solitario lands. At that time, capitalizing on a surveying error, Mr. Hugo Bosque, an attorney from San Juan, acquired a small strip of land between the Minera Andes and Solitario lands.

In 2003, MIM Argentina S.A. (MIM) optioned the Bosque and Solitario lands and began exploration work. Independently, Minera Andes began exploration on its own lands at Los Azules.

In 2005, a Letter of Intent was drafted between Minera Andes and Xstrata Copper (successor to MIM) for earn-in rights on the combined land package. More exploration occurred over the next couple of years.

International Copper Mining, Inc was incorporated in British Columbia, Canada on March 2, 2006, to hold ownership of exploration properties including the Los Azules property.

On November 2, 2007, Minera Andes Inc. entered into an Option Agreement with Xstrata whereby the exclusive right was granted to Minera Andes to explore and evaluate the area called “Los Azules” which included several properties owned by Xstrata as defined in the Option Agreement.

On May 15, 2009, the parties to the Option Agreement, together with Andes Corp. and Los Azules Mining, Inc. (LAMI), each wholly owned subsidiaries of Minera Andes, signed an Assignment and Amending Agreement whereby Minera Andes properties “Azul 1” and “Azul 2” were transferred to Andes Corp. together with the right to acquire from Xstrata 100% interest in and to the Los Azules properties (as defined in the Option Agreement). In addition, Minera Andes S.A. assigned and transferred to LAMI all of MASA’s right, title, benefit, and interest in, to and under the Option Agreement (as defined in the Assignment and Amending Agreement).

On May 29, 2009, Los Azules Mining Inc., exercised the option, by delivery of an Earn-in Notice (pursuant to the Option Agreement as amended by the Assignment and Amending Agreement) to acquire 100% interest in Los Azules properties (as defined in the Option Agreement). Therefore, Xstrata subsequently transferred to Andes Corp. all its properties located in the Los Azules area.

On September 30, 2009, Xstrata elected not to exercise its option to acquire a 51% interest in the Project and has no remaining interests in Los Azules.

In January 2012, Minera Andes Inc., was acquired by US Gold Corporation, which was subsequently renamed McEwen Mining.

Certain portions of the northern part of the Project that were formerly held by Xstrata and transferred to Minera Andes following the termination of the Option Agreement were subject to an underlying option agreement between Xstrata and a subsidiary of TNR Gold Corp. This agreement was the subject of litigation in the Supreme Court of British Columbia, Canada.

The final Transfer Agreement between TNR Gold Corp (along with Compañia Minera Solitario Argentina S.A.), and McEwen Mining (including Los Azules Mining Inc. and Andes Corporacion Minera S.A.) was executed on October 16, 2014, superseding the prior settlement agreement and transferred all rights on the Solitario Properties from TNR to McEwen Mining in exchange for an NSR royalty of 0.4% and TNR relinquishing the back-in right. The NSR terms are subject to a Net Smelter Returns Royalty Agreement executed on October 29, 2014, between Compañia Minera Solitario Argentina S.A. and Andes Corporacion Minera S.A.

International Copper was continued from the province of British Columbia to the province of Alberta on December 31, 2012, as International Copper ULC. The Corporation was converted to a limited liability corporation and changed its name to McEwen Copper Inc. by way of articles of amendment dated August 20, 2021. At the creation of McEwen Copper Inc., the company held a 100% interest in the Los Azules Copper Project. McEwen Mining Inc. also transferred a 100% interest in the Elder Creek Exploration Project to McEwen Copper to create a copper investment vehicle.

In 2018, ACMSA filed a request to group all the Mining Permits together, file #1124.553-A-2018, in such a way that, once all surveys are approved, all the Mining Permits be considered as one larger Mining Permit. If successful, this would allow investments to be distributed across the larger permit group and eliminate the need to spend on each individual Mina.

In July 2021, a private placement financing was initiated for McEwen Copper seeking to raise USD $80 million at a price of USD $10.00 per common share. This financing, subsequently closed in full, in three tranches on August 23rd, 2021, June 21st, 2022, and August 31st, 2022, respectively. On August 23rd, 2021, a company controlled by Robert R. McEwen (Chairman and Chief Executive Officer of McEwen Mining) purchased 4,000,000 shares for USD $40,000,000. On June 21st, 2022, the Victor Smorgon Group purchased 1,000,000 shares for $10,000,000 and other investors purchased 500,000 shares for an additional $5,000,000. On August 30th, 2022, Nuton LLC (a Rio Tinto Venture) purchased 2,500,000 shares for USD $25,000,000 and other investors purchased 185,000 shares for an additional USD $1,850,000. In total, 8,185,000 shares were sold in the private placement for gross proceeds to McEwen Copper of USD $81,850,000.

During 2022, a 1.25% net smelter return (NSR) royalty was created encumbering the Los Azules Project, which is held by McEwen Mining Inc.

As of December 31, 2022, McEwen Copper had 25,685,000 common shares issued and outstanding on a fully diluted basis, of which 17,500,000 common shares were owned (68.1%) by its parent company McEwen Mining Inc., and 8,185,000 common shares were owned by third parties and some affiliates.

The challenge by ACMSA for the peripheral properties under threat of forfeiture, Gina, Sofia, Torora II, and Marcela, was resolved in the company’s favor and the forfeited rights were returned by the Mining Council on December 29, 2022.

FCA Argentina S.A., a subsidiary of Stellantis N.V. (“Stellantis”), invested ARS $30 billion in Argentina to acquire shares of McEwen Copper in a two-part transaction that closed on February 24th, 2023.

Nuton invested $55 million to acquire shares of McEwen Copper in two transactions which closed on August 31, 2022, and March 15th, 2023.

Both the Stellantis and Nuton investments included investor rights and product purchase rights, discussed in detail in Section 1.1.

As of 2023, ACSMA/McEwen Copper continues to hold 100% of the Los Azules development, associated land holdings and mineral concessions and easements, while continuing to perform seasonal infill drilling and studies with a view to eventual project development.

This section relies heavily on geological studies conducted by Richard Sillitoe (2014) and Vázquez (2015) as well as other references cited in the section. A description of the techniques used in the geological modelling used as a base for the mineral resource estimate is provided later in Section 11.3.

Los Azules is a porphyry copper deposit located in western San Juan Province in west-central Argentina. This region is characterized by a series of north-south elongated mountain ranges that rise in altitude from east to west to form the rugged Andean Cordillera along the border between Argentina and Chile. Los Azules lies within the highest altitude Cordillera Principal at an elevation of about 3,700 masl (Figure 6.1).

The Cordillera Principal is composed of strongly folded, faulted, and elevated Paleozoic-Mesozoic sedimentary and volcanic lithologies (Gondwanide orogeny) overlain by extensive Upper Miocene ignimbrites (Andean orogeny) as shown in Figure 6.2. Eocene to early Miocene volcaniclastic strata in the region accumulated in an extensional basin followed by plutonic intrusion and contractional deformation from 19 Mya to 16 Mya. These units were overlain and intruded by 16 Mya to 7 Mya volcanic flows and pyroclastic units with comagmatic 12 Mya to 8 Mya plutons and porphyry systems. This was followed by a compressional event at 8 Mya to 5 Mya with important crustal shortening, thickening, and regional uplift (Sillitoe and Perello, 2005). Figure 6.2 also shows the relative locations of other major mining projects in the area.

Figure 6.1: Physiographic features of San Juan Province, Argentina (Rojas 2010)

Figure 6.2: Regional geology of the Andean Cordillera of Argentina and Chile (Rojas 2010)

Los Azules has been geologically mapped on at least four separate occasions (Rojas, 2007; Zurcher, 2009; Almandoz, 2010; Pratt, 2010). The entire area comprising the Los Azules Deposit is covered by thick scree or valley fill, so none of the rocks or structures are exposed in outcrop, although some near-surface exposures have been exposed in shallow trenching at the crest of the La Ballena Ridge. Consequently, the interpretation of the structures and intrusive bodies is based almost entirely upon drill hole data.

In many respects, the Los Azules Deposit is a classic Andean-style porphyry copper deposit. In the bedrock below the surface cover, a barren leached zone overlies a zone of secondary supergene enrichment of variable copper grades and thickness, and primary hypogene mineralization extends to at least 1,000 m below the present surface. The Los Azules hydrothermal alteration system is at least 5 km long and 4 km wide and is elongated in an NNW direction along a major structural corridor. The system disappears below volcanic cover to the north, so the overall extent is unknown. The altered zone surrounds the Los Azules Deposit, which is approximately 4 km long by 2.5 km wide. The limits of the mineralization along strike and at depth have not been entirely constrained by drilling. In fact, many of the holes in the core resource area have been terminated in mineralization that exceeds the resource cut-off grade.

Hypogene minerals include chalcopyrite, lesser bornite, chalcocite-digenite, idaite and trace molybdenite, magnetite and lesser hematite, usually deposited on igneous mafic minerals. Chalcopyrite is the most important hypogene copper mineral in the upper levels of the deposit, and hypogene bornite appears at deeper levels together with chalcopyrite. Copper sulfides rarely exceed 2% to 3% of rock volume. Intervals of 0.1% to 0.35% copper are common in hypogene mineralization. Silver (approximately 1 gram/tonne), anomalous gold (up to approximately 150 parts per billion) and molybdenum (up to approximately 600 parts per million) are reported in some intersections.

Circulation of meteoric ground water leached primary sulfides (mainly pyrite and chalcopyrite) from the host rocks over the past several million years, and the leached copper was redeposited below the water table in a sub-horizontal zone, or blanket, of supergene enrichment as secondary chalcocite and covellite. The intensity of secondary enrichment diminishes with depth, except along major structures where it may extend to great depth.

Starting at the boundary between the barren leached zone and the supergene mineralization, secondary enrichment mineralization gradually transitions to predominately hypogene mineralization at depth.

Sillitoe (2014) examined about 9,000 m (approximately 25% at the time) of the available drill core and proposed a revised geologic interpretation for Los Azules, which is shown in Figure 6.3.

Vázquez (2015) subsequently relogged 44,000 m from 98 drill holes representing essentially all the drill core available at that time. Vázquez confirmed Sillitoe’s interpretation, and he also refined the temporal sequence and spatial distribution of distinct phases of alteration and mineralization.

Figure 6.3: Model for Los Azules (pink: potassic alteration, green: chloritic alteration, blue: sericitic alteration, yellow: advanced argillic lithocap), (Sillitoe, 2014)

Sillitoe recognized the presence and importance of an early mineralized porphyry dike phase of igneous intrusion. Much of the hypogene mineralization as well as the supergene mineralization is associated with this phase; later dikes are not as well mineralized. Sillitoe referred to the later dikes as “inter-mineral” stage dikes.

Vásquez established the following chronological sequence of igneous and hydrothermal events at Los Azules, and these will be described in the following sections.

The most relevant geologic features to the current project considered are briefly discussed in the following sub-sections.

Supergene mineralization at Los Azules comprises a sub-horizontal chalcocite-covellite supergene blanket (“enriched” zone) that grades downwards through a partially enriched zone of incomplete replacement (mixed hypogene-supergene sulfides) into underlying hypogene sulfide mineralization. A sterile oxidized leached cap overlays the supergene blanket. Sillitoe considered that the enriched zone is immature because of the relative youthfulness of the supergene processes, which was probably active only since about 4 Mya –5 Mya.

The leached cap ranges from 0 m to 180 m thick and consists of oxidized and argillic-altered rock. Limonitic boxworks and disseminated spots of jarosite, goethite, and hematite are common. Hematite is more abundant in the southern structural block; jarosite is best developed over the central block, while goethite appears more widespread in the northern block (Zurcher, 2008a). Primary magnetite is altered to hematite, and ferrimolybdite also occurs (after molybdenite), but copper minerals and sulfides are mostly absent (Rojas, 2008). Copper oxides are reported from the margins of the leached zone and include brochantite, minor cuprite, copper pitch, and copper wad. Copper grades in the leached cap range between 0.01% and 0.10%.

Beneath the leached cap, a thin mixed sulfide-oxide zone gives way to a supergene sulfide zone where hypogene sulfides are replaced by chalcocite and minor covellite. The supergene copper blanket is best developed in the central and central-northern structural sectors and is characterized by a more jarositic oxide cap in the pyritic phyllic-altered zone located directly above the potassic alteration zone. Supergene (earthy) chalcocite and minor covellite partially (or rarely) completely replace hypogene sulfides, but pyrite usually survives. Traces of native copper and gypsum after anhydrite occur in the underlying potassic alteration zone.

The thickness of the supergene chalcocite blanket typically varies between 60 m and 250 m but can penetrate to more than 400 m down structures. The intensity of supergene mineralization gradually decreases with depth from the top of the zone, and there is typically no distinct lower limit or boundary to the zone of enriched mineralization (Sim and Davis, 2015). Also, see Section 14 for a geostatistical review and explanation.

Copper values in the supergene enriched zone vary between 0.4% Cu to greater than 1.0% in the north-central part of the system and decrease to 0.2% to 0.4% Cu in the south and peripheries. Supergene mineralization is the most important mineralization of economic interest at Los Azules.

Cyanide soluble copper data is used to interpret the distribution of supergene enrichment mineralization. Mineralization with a ratio of cyanide soluble copper content to total copper content >50% is “enriched”. See Section 11.3.6 for further details on the Copper Mineral Zonation Model. The limits may be modified slightly in places to match mineralization observed in the drill core. Figure 6.4 shows the enriched mineralization and the early mineralized dike. Lithology, alteration zones, and structures have been removed from the illustration for clarity, except the early mineralized porphyry dike. Supergene mineralization penetrates all lithologies and alteration types, and supergene mineralization appears to extend to greater depths along fault structures.

Figure 6.4: Early Mineralized Porphyry (magenta) with supergene enrichment zone (red) defined as the Soluble Cu ratio >50%. (McEwen Copper, 2022)

Triassic volcanic country rocks at Los Azules are deformed into an anticline or monocline with the steep limb in west and the flat limb in the east (Pratt, 2010). The anticlinal axis strikes north and may coincide with the NNW-striking structural corridor that controlled the locations of volcanic-intrusive centers in the region during the upper Miocene (Rojas, 2008). Near Los Azules, this structural corridor appears to control the locations of porphyry dikes, hydrothermal alteration, and mineralization zones along a seven-kilometer strike length including the Los Azules Porphyry System (Rojas, 2008).

The porphyritic dikes at Los Azules were emplaced along numerous, strong north-northwest and northwest striking faults (Zurcher, 2008a). Based on the few surface exposures, Zürcher proposed a steep easterly dip for most of the north-northwest striking faults. Sillitoe and Vásquez both noted that evidence from diamond drill core indicates that these structures were active as faults during as well as after the deposition of the mineralization because post-mineral movement is evidenced by slickensides in areas with supergene mineralization.

Pratt (2010) interpreted a kinematic structural model of the Los Azules Porphyry Copper Deposit. The Piuquenes Fault is part of the north-northwest striking “Vegas” fault system described by Rojas (2008). The northwest-striking faults were named Azules by Rojas (2008). Porphyry-related quartz veins (blue) and deeper level and older (than epithermal) alunite and vuggy quartz silicified ribs (red) are shown in Figure 6.5.

Figure 6.5: Kinematic structural interpretation of Los Azules porphyry copper deposit (Pratt 2010)

Battle Mountain Gold explored Los Azules during 1998-1999 for gold and drilled three at La Hoya in the extreme northwest of the area, without significant success. The company may have been attracted by hydrothermal breccias with associated kaolinite-illite-dickite-quartz-alunite alteration that are reported in volcanic lithologies intruded by small intrusions and dikes of feldspar porphyry in the Cerros Centrales (Cerro Oeste) area.

Indications of potential gold-silver mineralization around the Los Azules porphyry copper system include late-stage, intermediate-sulfidation epithermal quartz veins described by Pratt (2010).

The existence of a thick leached cap and supergene chalcocite blanket at Los Azules indicates that oxidation, dissolution, vertical transportation and redeposition of copper occurred in the system. Copper may also have been transported laterally away from the deposit and redeposited to form so-called “exotic” copper mineralization (Sillitoe, 2010). No exploration for this style of mineralization has yet been undertaken in the vicinity of Los Azules.

Los Azules is located within the Central Chile segment (400 km-long) of the Miocene-early Pliocene porphyry copper belt (6,000 km-long) of the North and Central Andes as shown in Figure 6.6. The figure also shows locations of the major porphyry copper and related epithermal deposits, limits of the porphyry copper belt and permissive northwest-trending structural corridors that influence the location of mineralization along the porphyry belt. Porphyry copper deposits in this sub-belt include the world-class Los Pelambres (Cu-Mo), Rio Blanco-Los Bronces (Cu-Mo) and El Teniente (Cu-Mo) Porphyry Deposits, the Maracunga Belt Porphyries (Cu-Au) in Chile and El Pachón (Cu) and Bajo de la Alumbrera (Cu-Au) in Argentina, as well as numerous other porphyry and related deposits (Sillitoe and Perello, 2005).

Panteleyev (1995) describes the common features of porphyry deposits as large zones of hydrothermally altered rock containing quartz veins and stockworks, sulfide-bearing veinlets, fractures, and lesser disseminations in areas up to 10 km2 in size. These are commonly associated intrusion breccias and/or dike swarms.

Deposit boundaries are determined by economic factors that define mineralized zones located within larger areas of low-grade, often concentrically zoned mineralization. Important geological controls on porphyry mineralization include igneous contacts, cupolas and the uppermost, bifurcating, parts of stocks and dike swarms. Intrusive and hydrothermal breccias and zones of intensely developed fracturing, respectively due to intersecting or parallel multiple mineralized fracture sets, commonly coincide with the greatest metal concentrations.

Surface oxidation commonly modifies porphyry deposits in weathered environments. Low pH meteoric waters leach copper from the oxide zone, which is then transported and redeposited as secondary chalcocite and covellite, usually immediately below the water table to form sub- horizontal, tabular zones of supergene copper enrichment. This process forms a copper-poor leached cap above a relatively thin, but often high-grade, zone of supergene copper enrichment that itself caps a thicker zone of often moderate grade hypogene copper mineralization at depth.

Figure 6.6: Part of the Central Chile Segment of the Miocene-early Pliocene Porphyry Copper Belt (Rojas 2008)

Other deposit styles often spatially, temporally, and genetically associated with porphyry deposits include:

The figure shows the spatial relationships between a porphyry copper system and its surrounding environment, including host rocks and peripheral styles of mineralization such as skarns, carbonate replacement (chimney-manto), sediment-hosted disseminated sulfides, mesothermal polymetallic veins, and higher-level high/intermediate/low sulfidation epithermal gold-silver veins and disseminated deposits.

Figure 6.7: Diagram Showing Spatial Relationships between a Porphyry Copper System and the Surrounding Environment (Sillitoe 2010)

Exploration at Los Azules commenced in the mid-1990s and has included various studies of geology, geophysics, and geochemistry, as well as drilling with both reverse circulation and diamond core drills, sampling and analysis of surface and drill core samples, and road construction. Exploration was conducted successively, and sometimes in cooperation, by Battle Mountain Gold, MIM-Xstrata, and Minera Andes/McEwen Mining and McEwen Copper, principally by the latter company.

The most comprehensive and up-to-date geological map of Los Azules was produced by Pratt and Bolsover in 2010, as described in Section 6.2. An earlier detailed geological map, with cross sections, was compiled by Rojas (2007); Almandoz (2010b) produced a geological map at a 1:5000 scale, and Zürcher (2008a) made a detailed map of the central portion of the north-northwest-trending La Ballena Ridge that focused on hydrothermal alteration and mineralization.

Petrographic studies of polished sections collected by Zurcher from drill cores, and surface samples were initially studied by DePangher (2008) in Oregon, and then by GEOMAQ in Santiago de Chile (Rojas, 2010). Zurcher (2008b) reported a series of U-Pb age dates for the igneous intrusions.

In 2014, Sillitoe examined about 9,000 m (approximately 25% at the time) of the diamond drill core and proposed a revised geologic interpretation for Los Azules, which is described in Section 6.2. Sillitoe recognized the presence and importance of an early mineralized porphyry dike phase of igneous intrusion. Much of the hypogene mineralization as well as the supergene mineralization is associated with this phase; later dikes are not as well mineralized. In 2015, Vázquez relogged 44,000 m from 98 drill holes representing essentially all the drill core at the time. Vázquez confirmed Sillitoe’s interpretation, and he also refined the temporal sequence and spatial distribution of distinct alteration phases and mineralization zones as described in Section 6.2.

Various geophysical studies were conducted at Los Azules by Battle Mountain Gold and by MIM-Xstrata respectively in 1998-1999 and 2004 and by Minera Andes (Quantec) in early 2010 and McEwen Mining (Quantec) in 2012. Work done and results for these surveys are described in the following section.

GEODATOS, a Chilean geophysical company, conducted an airborne geophysical survey in early 1998. The survey covered a 20 km by 10 km area elongated east-west including the Los Azules and Paso de la Coipa areas.

Results suggested the existence of a structural corridor striking northwest and structures striking east- northeast associated with strong to moderate magnetic low signatures in the Los Azules mineralized body. A total field magnetic plot identified a magnetic high anomaly surrounding a central magnetic low that extended 6 km north-northwest and 3 km northeast as shown in Figure 7.1. Battle Mountain Gold interpreted the magnetic low as altered rocks associated with the mineralized body.

Four lines of induced polarization (IP) were oriented east-west averaging two kilometers long and spaced at 600 m to 900 m apart. The lines were positioned to cross the locations of mineralized drill holes LA04-98, LA-06-98, and LA-08-98. IP results indicated high chargeability and low resistivity corresponding with the location of the Los Azules porphyry copper deposit.

Two ground magnetic surveys totaling 103 km were conducted in the Los Azules mineralized porphyry and the nearby Sector Mantos, which is 1 km west of Cerro Oeste.

Lines were oriented east-west at 100 m spacing and 10 m stations. Results confirmed the existence of north-northwest- and north-northeast-striking structures as indicated by aeromagnetics. Results also confirmed the presence of a magnetic low anomaly in the vicinity of drill holes LA-98-04, LA-98-06 and LA-98-08 and suggested the presence of a magnetic low along the alteration system of La Ballena Ridge as shown on Figure 7.1.

Figure 7.1: Magnetic Map of Los Azules (Reduced to Pole) and IP lines. (Rojas, 2008 after Xstrata, 2003).  Note: Red box indicates the mag low across the Ballena Ridge.

During 2003-2004, MIM-Xstrata carried out a magnetic survey of approximately 70 km at Los Azules. Lines were oriented east-west across the area controlled by the company at that time. In addition, MIM-Xstrata ran six lines of MIMDas (MIM-Xstrata proprietary IP system) east-west totaling 11.8 km. At the request of Minera Andes, MIM-Xstrata extended their geophysical lines south into Minera Andes ground completing five additional lines for a total 11.3 km in 2004. Total surveying by MIMDas was 23.1 km.

Magnetometry indicated a magnetic low beneath the Los Azules porphyry copper system and suggested that it extended north-northwest towards the La Hoya Zone (Cerros Oeste and Este). The total field plot identified a magnetic high anomaly surrounding the magnetic low. The magnetic low extends 7 km to 8 km north-northwest and up to 2 km east-northeast confirming the interpretations made by Battle Mountain Gold.

MIMDas IP surveying (2003-2004) indicated high resistivity in the north-northwest zones at Los Azules with much lower resistivity within the porphyry copper system. Chargeability is relatively low to the north but becomes much lower at the porphyry although it increases significantly at depth. These results reflect the occurrence of more superficial sulfides in the Lagunas area of the system (north of the porphyry deposit) and a thicker leached cap in the more altered part of the system.

Titan-24 DCIP-MT data were acquired at Los Azules during April and May 2010 by Quantec Geoscience Ltd., on behalf of Minera Andes Inc. The survey consisted of twelve parallel lines and each line comprised one single spread of 3.6 km, except for L63450 N that was 3.3 km long. Full MT tensor data was acquired in all the lines and DCIP was collected in all but two of the lines. In total, ten spreads of DC and IP data were acquired covering 35.7 km and twelve spreads of MT covering 42.9 km.

Over 130 IP anomalies were identified. Of these, 20 were classed as priority 1, 20 as priority 2, and 12 as priority 3. The priority 1 anomalies are larger targets, at least 200 m across, and described by Quantec as being consistent with the porphyry and near- porphyry mineralization model.

Two large, deep resistivity anomalies, one high to the east, under the Los Azules mineralization, and one low to the west are well defined by the MT survey. The width of the anomalies is 800 m to 1 km for the resistivity low and 500 m to 800 m for the resistivity high. Quantec postulated that the deep anomalies are most likely related to conductive sulfides, perhaps in a disseminated pyrite/sulfide shell surrounding a concealed porphyry intrusion. These anomalies, which are referred to as the “Southwest Target”, are the targets that were tested in Hole T-01B in 2011 and Hole 1279 in 2012 (Figure 7.2).

Figure 7.2: Section 58,400N Showing 2D IP Inversion Anomaly (Southwest Target) (McEwen 2012).

During January 2012, Quantec Geoscience Argentina S.A. performed a ground magnetic survey on the southwest portion of the Project. The data was presented as maps of the Total Magnetic Field, Reduction to the Pole transform, Analytic Signal, Tilt Derivative and First Vertical Derivative.

Figure 7.3 is the Total Magnetic Field map for the 2012 survey overlain on the image shown in Figure 7.1. The 2012 magnetic data shows a discontinuous north-northwest trending magnetic low southwest of and roughly parallel to the prominent magnetic low that corresponds to the location of the main Los Azules Deposit.

Areas of high magnetic response indicate the presence of elevated levels of magnetic minerals, such as magnetite, pyrrhotite, and hematite, whereas areas of low magnetic response may be caused by alteration processes such as magnetite destruction or may simply indicate rock types with no magnetic minerals. This anomaly was tested with one drill hole during the 2012 season and intersected only traces of copper mineralization.

Figure 7.3: Total Magnetic Field Map of Los Azules. (Quantec, 2012).  Note: Dashed red box indicates the mag low across the Ballena Ridge seen above in Figure 7.1 – the solid red box indicates the discontinuous mag low to the southwest.

Mineral exploration at Los Azules has been carried out successively by Battle Mountain Gold, MIM-Xstrata and Minera Andes-McEwen Mining, McEwen Copper and/or professional consultants or contractors employed by these companies.

In 2017, McEwen Mining engaged consultant Rodrigo Diaz to conduct an evaluation of remote spectral geology (RSG) over a 17 km by 20 km area at Los Azules and later extended to include an area 38 km by 42 km. Spectral data of Landsat 8 (30-15 m pixel and 16-bit radiometric resolution), spectral data of Aster (30-15 m pixel and 8-bit radiometric resolution) were selected and used; additionally, spectral data of the Sentinel 2 (20-10 m pixel and 16-bit radiometric resolution) and Sentinel 1-Radar (10 m pixel).

In 2022, McEwen Copper undertook a program of continuous hyperspectral scanning and high-resolution core photography on the entire available archive of drill core completed in 2022 and previous programs stored at Calingasta. By July 2022, this represented some 64,000 m of scanned material available to augment completion of an updated geological model and support the design of the ongoing metallurgical program. This work is expected to be a protocol for all future drill programs.

Also in 2022, McEwen Copper engaged the services of Murphy Geological Services to complete a structural interpretation of Sentinel-2 and high-resolution imagery of the Los Azules property and immediate surrounding area. Sentinel-2 is a new earth observation sensor with 13 spectral bands having resolutions up to 10 m which was launched by the European Space Agency in June 2015 and is a significant improvement on the 15 m resolution pan-sharpened Landsat-7 and ASTER data and allows more detailed structural analysis. An interpretation of a 45 km (E-W) by 35 km (N-S) Sentinel-2 extract centered on Los Azules was undertaken at up to 1:10,000 scale and a more detailed structural analysis of high-resolution satellite imagery for Los Azules Project area at up to 1:2,000 scale.

Completion of the Diaz work in 2017 and Murphy work in 2022 is foundational to designing and re-establishing more regional reconnaissance exploration at Los Azules.

The goals of future exploration at Los Azules include the establishment of upside potential on the property, ongoing geological model refinements, deposit growth, resource category upgrades, and identification/discovery of new porphyry mineralization as extensions of the Los Azules Deposit, as well as new porphyry systems.

Future exploration work programs should carry out reconnaissance study, field mapping, geophysical surveying, and core drilling to achieve these goals. More specifically, these activities should include:

Drilling programs have been undertaken at Los Azules between 1998 and 2023 by four different mineral exploration companies including BMG, MIM Argentina (now Glencore), Minera Andes/McEwen Mining and McEwen Copper. Drilling included reverse circulation programs mostly for gold exploration and diamond drilling focusing on supergene and hypogene porphyry-style copper mineralization. Descriptions of these programs are detailed in the following sections. Table 7.1 provides a summary of the drilling information.

The drill plan showing collar locations by the year drilled is shown in Figure 7.4.

Figure 7.4: Plan Showing Locations of drill holes at Los Azules (CRM 2022)

Drilling by McEwen Mining Inc. was contracted to various drilling companies including Connors Drilling, Patagonia Drill Mining Services, Adviser Drilling, Boland Minera, Major Drilling, Foraco Argentina, HG Perforaciónes, Conosur, and Boart Longyear. Drilling conditions have been particularly difficult, especially in faulted intersections or in areas of unconsolidated surface scree/talus.

Over the period of two drilling seasons from January 2022 to May 2023, McEwen Copper completed 40,815 m of core drilling in 99 holes. The primary purpose of the drilling was for mineral resource upgrading from Inferred to Indicated (66 holes for 28,221 m) and metallurgical purposes (33 holes for 12,594 m). A further 59 holes for 5,588 m drilled by RC, core and sonic drilling methods were used for geotechnical, hydrological, and ground investigation work in the area. Figure 7.4 shows the location and distribution of Los Azules drill holes based on core and RC drilling methods.

Samples taken from drill holes at Los Azules are logged at the Project camp by geologists employed or contracted by McEwen Copper. Sampling procedures are described in Section 8.2. Emphasis is given to recording rock-types, alteration associations, types and distribution of mineralization, and the presence of various types of veinlets and structures. These features are logged onsite (Figure 7.5) and then transferred to a digital database.

Figure 7.5: Logging and inspection of drill core

Geotechnical observations and parameters are recorded, including percentage of core recovery, RQD, Schmidt Hammer hardness determinations, point load testing, fracture density and angle relative to the length of the hole, as well as fracture fill material (Figure 7.6). This information is transferred to the digital database.

Figure 7.6: Geotechnical logging and data collection

Log sheets are coded, and details recorded for interval depth, interval width, lithology, alteration types, alteration intensities, alteration minerals, structure, percentage vein quartz, percentage total disseminated sulfides, mineralization minerals, mineral zone (hypogene or supergene), including observations of jarosite, goethite, hematite, covellite, chalcocite, pyrite, chalcopyrite, bornite among others.

According to McEwen Copper staff, downhole surveying is done on drill holes by the drilling contractors using REFLEX and/or Sperry-Sun tools. Density determinations were made for 915 drill core samples prior to the 2022 drill program. During the 2022 campaign, a program of hyperspectral scanning of the entire available core archive of some 64,000 m was completed.

There are a total of 439 drill holes in the Los Azules database, with a cumulative length of 116,664 m. A summary of the significant drilling results is found in Table 7.2 for campaigns prior to 2018, while Table 7.3 displays results for the 2022 drilling campaign.

Drilling has confirmed the presence of a hypogene porphyry copper deposit in a continuous body, as well as the presence and continuity of an overlying supergene chalcocite enrichment blanket. The extent of the mineral resource measures approximately 4 km north-south by 1.5 km west-east. Many of the drill holes in the central and northern parts of the deposit have been terminated in mineralization that exceeds the 2017 IA base case cut-off grade of 0.20% Cu. Drilling during the 2012-2013 campaign extended the depth of the mineralized system in the southwestern part of the deposit to at least 1,000 m.

Source: McEwen Copper press release dated August 4, 2022