McEwen Inc. — Proxy Solicitation & Information Statement 2021

Apr 30, 2021

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

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• Preliminary Proxy Statement

• Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

• Definitive Proxy Statement

• x Definitive Additional Materials

• Soliciting Material under §240.14a-12

McEwen Mining Inc.

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

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The Sample Company 000004 + MC 12M345M678M90 MMENDORSEMENT_LINE__SACKPACK_______ MR A SAMPLE DESIGNATION (IFANY) ADD 1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6 Online Go towww.envisionreports.com/MUX or scan the QR code — logindetails are located in the shaded bar below. Shareholder MeetingNotice1234 5678 9012 345 Important Notice Regarding theAvailability of Proxy Materials for the McEwen Mining Inc.Shareholder Meeting to be Held on June 28, 2021 Under Securitiesand Exchange Commission rules, you are receiving this notice thatthe proxy materials for the annual shareholders’ meeting areavailable on the Internet. Follow the instructions below to view thematerials and vote online or request a copy. The items to be voted onand location of the annual meeting are on the reverse side. Your voteis important! This communication presents only an overview of themore complete proxy materials that are available to you on theInternet. We encourage you to access and review all of the importantinformation contained in the proxy materials before voting. Theproxy statement and annual report to shareholders are available at:www.envisionreports.com/MUX Easy Online Access — View yourproxy materials and vote. Step 1:Go towww.envisionreports.com/MUX. Step 2:Click on Cast Your Vote orRequest Materials. Step 3:Follow the instructions on the screen tolog in. Step 4:Make your selections as instructed on each screen foryour delivery preferences. Step 5:Vote your shares. When you goonline, you can also help the environment by consenting to receiveelectronic delivery of future materials. Obtaining a Copy of theProxy Materials – If you want to receive a copy of the proxymaterials, you must request one. There is no charge to you forrequesting a copy. Please make your request as instructed on thereverse side on or before June 16, 2021 to facilitate timely delivery.MMMMMMMMM 03GAKB 2 N O T C O Y+

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Shareholder Meeting Notice The 2021 Annual Meeting ofShareholders of McEwen Mining, Inc. will be held on June 28, 2021at 4:00 p.m. ET, virtually via the internet atwww.meetingcenter.io/236635772. To access the virtual meeting,you must have the information that is printed in the shaded barlocated on the reverse side of this form. The password for thismeeting is — MUX2021. Proposals to be voted on at the meetingare listed below along with the Board of Directors’recommendations. The Board of Directors recommends that youvote FOR the following proposals: Election of Directors: Nominees:– ROBERT R. MCEWEN – ALLEN V. AMBROSE – MICHELE L.ASHBY – RICHARD W. BRISSENDEN – ROBIN E. DUNBAR –GREGORY P. FAUQUIER – DONALD R.M. QUICK – MICHAELL. STEIN To adopt an amendment to the Company’s SecondAmended and Restated Articles of Incorporation to increase thenumber of shares of common stock authorized to be issued from500,000,000 to 675,000,000. To adopt an amendment to theCompany’s Amended and Restated Equity Incentive Plan to increasethe number of shares authorized to be issued under the Plan from17,500,000 to 30,000,000 and to extend the expiration date of thePlan to April 15, 2031. TO RATIFY THE APPOINTMENT OFERNST & YOUNG LLP AS THE COMPANY’S INDEPENDENTREGISTERED PUBLIC ACCOUNTING FIRM FOR THE YEARENDING DECEMBER 31, 2021. Other Business To transact suchother business as may properly come before the meeting or anyadjournment thereof. PLEASE NOTE – YOU CANNOT VOTE BYRETURNING THIS NOTICE. To vote your shares you must goonline or request a paper copy of the proxy materials to receive aproxy card. If you wish to attend and vote at the meeting, pleasesave this notice and use the control number to access the meeting.Here’s how to order a copy of the proxy materials and selectdelivery preferences: Current and future delivery requests can besubmitted using the options below. If you request an email copy, youwill receive an email with a link to the current meeting materials.PLEASE NOTE: You must use the number in the shaded bar on thereverse side when requesting a copy of the proxy materials. Internet– Go to www.envisionreports.com/MUX. Click Cast Your Vote orRequest Materials. Phone – Call us free of charge at 1-866-641-4276. Email – Send an email to investorvote@computershare.comwith “Proxy Materials McEwen Mining Inc.” in the subject line.Include your full name and address, plus the number located in theshaded bar on the reverse side, and state that you want a paper copyof the meeting materials. To facilitate timely delivery, all requestsfor a paper copy of proxy materials must be received by June 16,2021.