Mr. Rob McEwen of McEwen Mining reports

MCEWEN COPPER: LOS AZULES -- MORE POST-PEA ASSAY RESULTS

McEwen Copper Inc., 52 per cent owned by McEwen Mining Inc., has released additional assay results of the recently completed drilling season at its Los Azules project, located in San Juan, Argentina.

"These assay results include significant copper values over wide intercepts and demonstrate very good agreement between these new assay results and those predicted by the resource block model used in the 2023 preliminary economic assessment," said Rob McEwen, chairman and chief owner.

Los Azules is a large copper porphyry deposit with growth potential. It has many features comparable with world-class copper-gold deposits in South America, and its depth and lateral extent have yet to be determined. Infill drilling serves several purposes, including providing better data density to increase confidence in the mineral resources, along with providing material and data for metallurgical, geotechnical and hydrological studies.

An attached table provides an overview of the new assay results. This infill drilling has been designed to upgrade the copper resource estimate classification from inferred to measured or indicated.

Highlights:

• Hole GTK2320 intercepted an enriched zone of 386 metres grading 0.66 per cent copper (estimated true thickness) and includes a subinterval of 196 m grading 0.99 per cent Cu.
• Hole GTK2319 intercepted an enriched zone of 383.5 m grading 0.50 per cent Cu (estimated true thickness) and includes a subinterval of 120 m grading 0.67 per cent Cu.
• Hole AZ23237 intercepted an enriched zone of 308 m grading 0.69 per cent Cu (estimated true thickness) and includes a subinterval of 142 m grading 0.82 per cent Cu.
• Hole AZ23233 returned an enriched zone of 374 m grading 0.50 per cent Cu, including an enriched zone intercept of 206 m grading 0.65 per cent Cu.

This recently completed phase of drilling occurred between October, 2022, and June, 2023, and used up to 15 rigs to complete 39,900 m of drilling in 138 holes, to evaluate geotechnical, hydrological, resource and exploration-related parameters and opportunities. The Los Azules drill hole database now totals 126,000 m.

To test the performance of the resource model copper grades versus actual drilling results, approximately 30 infill holes completed subsequent to the data cut-off on Dec. 31, 2022, for the updated PEA model (released June 20, 2023) were utilized. The length-weighted average grade of the new drilling was 0.553 per cent Cu, compared with a resource model prediction of 0.515 per cent Cu. This limited test of the resource model's predictive capacity is encouraging, with actual grades 7.5 per cent higher than the model prediction. Over time, the company anticipates the local sensitivity of the model's predictive capacity to improve, as drilling increases the geologic confidence required to delineate a measured and indicated mineral resource estimate.

Technical information

The technical content of this press release has been reviewed and approved by Stephen McGibbon, PGeo, McEwen Mining's senior consulting geologist, a qualified person as defined by National Instrument 43-101.

All samples were collected in accordance with generally accepted industry standards. Drill core samples, usually taken at two m intervals, were split and submitted to the Alex Stewart International laboratory located in the province of Mendoza, Argentina, for the following assays: gold determination using fire fusion assay and an atomic absorption spectroscopy finish (Au4-30); a 39-element suite using ICP-OES analysis (ICP-AR 39); and copper content determination using a sequential copper analysis (Cu-Sequential LM-140). An additional 19-element analysis (ICP-ORE) was performed for samples with high sulphide content.

The company conducts a quality assurance/quality control program in accordance with NI 43-101 and industry best practices, using a combination of standards and blanks on approximately one out of every 25 samples. Results are monitored as final certificates are received, and any reassay requests are sent back immediately. Pulp and preparation sample analyses are also performed as part of the quality assurance/quality control process. Approximately 5 per cent of the sample pulps are sent to a secondary laboratory for control purposes. In addition, the laboratory performs its own internal quality assurance/quality control checks, with results made available on certificates for company review.

About McEwen Mining Inc.

McEwen Mining is a gold and silver producer with operations in Nevada, Canada, Mexico and Argentina. In addition, it has significant exposure to copper through its 52-per-cent ownership of McEwen Copper. The company's goal is to improve productivity and extend the life of its mines, with the objectives of increasing its share value and price as well as providing a yield. Rob McEwen, chairman and chief owner, has a personal investment in the company of $220-million (U.S.). His annual salary is $1 (U.S.).

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