McEwen Inc. — Proxy Solicitation & Information Statement 2023

May 2, 2023

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. )

Filed by the Registrant x

Filed by a Party other than the Registrant ¨

Check the appropriate box:

¨ 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)

Payment of Filing Fee (Check the appropriate box):

x No fee required.

¨ Fee paid previously with preliminary materials.

¨ Fee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11

Step 1: Go towww.envisionreports.com/MUX. Step 2:Click on Cast Your Vote or RequestMaterials. Step 3: Follow the instructionson the screen to log in.www.envisionreports.com/MUX OnlineGo to www.envisionreports.com/MUX orscan the QR code — login details arelocated in the shaded bar below. TheSample Company Shareholder MeetingNotice 03T4XD + + Important NoticeRegarding the Availability of ProxyMaterials for the McEwen Mining Inc.Shareholder Meeting to be Held on June29, 2023 Under Securities and ExchangeCommission rules, you are receiving thisnotice that the proxy materials for theannual shareholders’ meeting areavailable on the Internet. Follow theinstructions below to view the materialsand vote online or request a copy. Theitems to be voted on and location of theannual meeting are on the reverse side.Your vote is important! Thiscommunication presents only anoverview of the more complete proxymaterials that are available to you on theInternet. We encourage you to accessand review all of the importantinformation contained in the proxymaterials before voting. The proxystatement and annual report toshareholders are available at: Obtaininga Copy of the Proxy Materials – If youwant to receive a copy of the proxymaterials, you must request one. Thereis no charge to you for requesting a copy.Please make your request as instructedon the reverse side on or before June 16,2023 to facilitate timely delivery. 2NOTEasy Online Access — View your proxymaterials and vote. When you go online,you can also help the environment byconsenting to receive electronic deliveryof future materials. Step 4: Make yourselections as instructed on each screenfor your delivery preferences. Step 5:Vote your shares. MMMMMMMMMMMMMMMMMMMMM 1234 5678 9012 345 C1234567890 COY MMMMMMM MR ASAMPLE DESIGNATION (IF ANY) ADD1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6ENDORSEMENT_LINE__SACKPACK_______ 000001

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Here’s how to order a copy of theproxy materials and selectdelivery preferences: Current andfuture delivery requests can besubmitted using the optionsbelow. If you request an emailcopy, you will receive an emailwith a link to the current meetingmaterials. PLEASE NOTE: Youmust use the number in theshaded bar on the reverse sidewhen requesting a copy of theproxy materials. — Internet – Goto www.envisionreports.com/MUX.Click Cast Your Vote or RequestMaterials. — Phone – Call us freeof charge at 1-866-641-4276. —Email – Send an email toinvestorvote@computershare.comwith “Proxy Materials McEwenMining Inc.” in the subject line.Include your full name andaddress, plus the number locatedin the shaded bar on the reverseside, and state that you want apaper copy of the meetingmaterials. To facilitate timelydelivery, all requests for a papercopy of proxy materials must bereceived by June 16, 2023. The2023 Annual Meeting ofShareholders of McEwen Mining,Inc. will be held on June 29, 2023at 2:00 p.m. ET, virtually via theinternet atwww.meetnow.global/MMHG65D.To access the virtual meeting, youmust have the information that isprinted in the shaded bar locatedon the reverse side of this form.Proposals to be voted on at themeeting are listed below alongwith the Board of Directors’recommendations. The Board ofDirectors recommends that youvote FOR the following proposals:1. Election of Directors:Nominees: 01 – ROBERT R.MCEWEN 02 – ALLEN V.AMBROSE 03 – IAN BALL 04 –RICHARD W. BRISSENDEN 05 –ROBIN E. DUNBAR 06 – MERRISANCHEZ 07 – WILLIAMSHAVER 2. To adopt anamendment to the Company’sSecond Amended and RestatedArticles of Incorporation toincrease the number of shares ofpreferred stock authorized to beissued from 2 to 10,000,000 andto increase the total authorizedshares accordingly. 3. To ratify theappointment of Ernst & YoungLLP as the Company’sindependent registered publicaccounting firm for the yearending December 31, 2023. 4.Other Business To transact suchother business as may properlycome before the meeting or anyadjournment thereof. PLEASENOTE – YOU CANNOT VOTE BYRETURNING THIS NOTICE. Tovote your shares you must goonline or request a paper copy ofthe proxy materials to receive aproxy card. If you wish to attendand vote at the meeting, pleasesave this notice and use thecontrol number to access themeeting. Shareholder MeetingNotice

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