Mr. Rob McEwen reports

MCEWEN MINING ANNOUNCES POTENTIAL NEW SOURCE OF REVENUE AT THE BLACK FOX COMPLEX

McEwen Mining Inc. has provided an updated mineral resource estimate for the Tamarack gold and base metal deposit at the 100-per-cent-owned Black Fox complex in Matheson, Ont. The Black Fox complex comprises the Black Fox mine and the Tamarack, Gibson-Grey Fox, Froome and Stock zones. The base metal component of the Tamarack resource is being included for the first time.

"This is the first time that base metals have been in incorporated into a resource estimate for the Tamarack project. With further drilling, we are excited to see how the project develops into what could be an additional revenue stream at Black Fox," said Rob McEwen, chairman and chief owner.

The new resource estimate increased from 41,000 inferred ounces gold at a grade of 6.23 grams per tonne gold (previous resource effective Oct. 31, 2017) to 127,000 indicated ounces gold equivalent at a grade of 5.08 grams per tonne gold equivalent with the inclusion of silver, lead and zinc mineralization.

The updated resource estimate for Tamarack is the result of 46 new surface and underground exploration, delineation, and definition drill holes completed between October, 2017, and April, 2018, and already-existing base metal assays not considered in previous estimates.

                       TAMARACK MINERAL RESOURCE ESTIMATE
                  (SRK Consulting (Canada) Inc., May 18, 2018)
 
Classification      Cut-off    Quantity                   Grade                    
                      grade      tonnes     Gold   Silver    Lead    Zinc     AuEq
                    (g/t Au)      (000s)    (g/t)    (g/t)     (%)     (%)    (g/t)

Total indicated 
resource               3.00         778     1.83       26    1.08    3.29     5.08

                                     Contained metal
                       Gold      Silver       Lead      Zinc        AuEq   
                   (000s oz)   (000s oz)   (000s t)  (000s t)   (000s oz)

Total indicated 
resource                 46         663          8        26         127

The attached table outlines the mineral resource estimate for Tamarack reported at a cut-off grade of three grams per tonne gold equivalent to reflect an underground mining scenario. Mining operations at the adjacent Black Fox mine are currently 100 per cent underground operations. The drilling completed over the last six months has increased confidence in the estimate such that previously reported inferred resources have been upgraded to the indicated category.

Tamarack geology and mineralization

The polymetallic (gold/silver/lead/zinc) Tamarack deposit is centred on a north-south-striking quartz breccia that crosscuts the faulted contact between Tisdale-assemblage ultramafic-to-mafic volcanic flows and Porcupine group sedimentary rocks. The zone is characterized by an upper and lower lens; the upper lens measures approximately 300 metres along strike and 450 metres down dip from near surface and has an average true width of 4.5 metres. The lower lens measures approximately 200 metres along strike and 250 metres down dip from a depth of 500 metres and is open at depth. The lower lens has a true width of up to 5.4 metres. These lenses are separated by minor, narrow and discontinuous diabase dikes.

Lead, zinc and silver mineralization is preferentially located in the hangingwall of the quartz breccia, occurring as either: (i) stringers, disseminations, and semi-massive knots, clusters and bands of sphalerite and galena hosted within both the volcanic and sedimentary rock units; (ii) as clasts in quartz breccias; and (iii) as inclusions and fragments within adjacent diabase dikes. Gold mineralization is preferentially hosted within the quartz breccia, occurring as fine visible gold and in association with disseminated fine-grained pyrite.

Exploration drilling will continue to test possible southerly strike extensions of the upper lens, where a few narrow intercepts of gold-plus-or-minus-base-metal mineralization lie outside of the current mineralized envelope. The lower lens remains open along strike to the south and down dip.

Some representative assay results of the higher-grade base metal and silver intersections that were part of the data set used in the resource at Tamarack include:

• 12.45 per cent zinc, 7.78 per cent lead and 149.36 grams per tonne silver over 2.72 metres (true width) in hole 17BF-621;
• 12.10 per cent zinc, 3.20 per cent lead and 40.60 grams per tonne silver over 1.32 metres (true width) in hole 520-EX582-48;
• 25.24 per cent zinc, 4.53 per cent lead and 69.58 grams per tonne silver over 1.91 metres (true width) in hole 18BF-627;
• 5.95 per cent zinc, 4.56 per cent lead and 70.55 grams per tonne silver over 1.86 metres (true width) and 9.92 per cent zinc, 4.83 per cent lead and 58.96 grams per tonne silver over 5.95 metres (true width) in hole 17BF-625;
• 22.8 per cent zinc, 0.91 per cent lead, 16.90 grams per tonne silver and 1.01 grams per tonne gold over 0.42 metre (true width);
• 11.13 per cent zinc, 7.28 per cent lead, 127.71 grams per tonne silver and 0.81 gram per tonne gold over 4.21 metres (true width) in hole 520-EX582-47.

These intervals have been previously released in 2018 exploration news updates.

Further work

As part of the continuing exploration program, additional surface and underground drilling will test, refine and define possible strike and dip extensions at Tamarack.

Metallurgical test work on drill core samples from Tamarack is currently being conducted at an independent third party laboratory, the results of which will help determine what processing route potential future production will employ. The test work is under the direction of Dr. Nathan M. Stubina, PhD, PEng, FCIM, of McEwen Mining, who is a qualified person within the meaning of National Instrument 43-101. It is currently expected that the gold-rich quartz breccia mineralization will be processed at the existing mill facilities at the Black Fox Stock mill.

Further density testing of different lithologies, mineralized zones and host units will be used in future resource updates.

Exploration at the Black Fox complex

The exploration program across the Black Fox complex, which includes the Black Fox mine and the Tamarack, Gibson-Grey Fox, Froome and Stock zones, continues with a total exploration budget of $15-million for 2018. The company's primary goals are to extend mineralization around known deposits and to test targets close to its mine and mill. Recent highlights of the drilling campaign since the company's last exploration news release of April 30, 2018, include:

• 27.76 grams per tonne gold over 6.12 metres (true width), including 106.91 grams per tonne gold over 1.28 metres (true width) in hole 560-F098-05;
• 41.87 grams per tonne gold over 0.38 metre (true width) in hole 560-F098-06.

Both holes are located in the eastern Central zone of the Black Fox mine. Follow-up drilling is continuing and a full exploration update is planned for the end of Q2.

About McEwen Mining Inc.

McEwen's principal assets consist of the San Jose mine in Santa Cruz, Argentina (49-per-cent interest); the El Gallo gold mine in Mexico; the Black Fox mine in Timmins, Canada; the Gold Bar mine in Nevada, currently under construction; and the large Los Azules copper project in Argentina, advancing toward development.

Technical information

Black Fox complex drilling was conducted by Forage Asinii Drilling, Boart-Longyear, Major Drilling, NPLH and Norex Drilling and supervised by McEwen's geology department. All exploration drill core samples at the Black Fox complex were submitted as half core, and analyses reported herein were performed by the independent laboratories: ALS Laboratories, which is ISO 9001/IEC17025 certified; Activation Labs, which is ISO 9001/IEC17025 certified; and SGS Canada Laboratories, which is ISO 9001/IEC17025 certified. Samples from definition and select delineation drilling are assayed at McEwen Mining's on-site laboratory. McEwen's quality control program includes systematic insertion of blanks, standard reference material and duplicates to ensure laboratory accuracy. The internal lab also participates in the GeoStats round robin assay exercise as part of its quality control initiatives.

For further details about the Black Fox complex project, including Tamarack, please see the company's recent NI 43-101 technical report, titled "Technical Report for the Black Fox Complex, Canada," dated April 6, 2018, with an effective date of Oct. 31, 2017, available on SEDAR under the company's issuer profile.

Qualified person

The mineral resource estimate, with an effective date of March 31, 2018, was prepared by Dr. Aleksandr Mitrofanov, PGeo, who is a qualified person within the meaning of NI 43-101. Dr. Mitrofanov is an employee of SRK Consulting (Canada) and is considered to be independent of McEwen for the purposes of NI 43-101. The technical content in this press release, including geology, drilling, resource estimates and sampling, has been reviewed and approved by Luke Willis, PGeo, director, resource modelling, for McEwen, who is a qualified person within the meaning of NI 43-101.

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