SEC Form DEFA14A filed by McEwen Mining Inc.

Step 1: Go to www.envisionreports.com/MUX. Step 2: Click on Cast Your Vote or Request Materials. Step 3: Follow the instructions on the screen to log in. www.envisionreports.com/MUX Online Go to www.envisionreports.com/MUX or scan the QR code — login details are located in the shaded bar below. Shareholder Meeting Notice 045DLB Important Notice Regarding the Availability of Proxy Materials for the McEwen Mining Inc. Shareholder Meeting to be Held on June 19, 2025 Under Securities and Exchange Commission rules, you are receiving this notice that the proxy materials for the annual shareholders’ meeting are available on the Internet. Follow the instructions below to view the materials and vote online or request a copy. The items to be voted on and location of the annual meeting are on the reverse side. Your vote is important! This communication presents only an overview of the more complete proxy materials that are available to you on the Internet. We encourage you to access and review all of the important information contained in the proxy materials before voting. The 2025 proxy statement and annual report to shareholders for the year ended December 31, 2024 are available at: Obtaining a Copy of the Proxy Materials – If you want to receive a copy of the proxy materials, you must request one. There is no charge to you for requesting a copy. Please make your request as instructed on the reverse side on or before June 9, 2025 to facilitate timely delivery. 2NOT Easy Online Access — View your proxy materials and vote. When you go online, you can also help the environment by consenting to receive electronic delivery of future materials. Step 4: Make your selections as instructed on each screen for your delivery preferences. Step 5: Vote your shares. MMMMMMMMMMMM MMMMMMMMM 000001MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 ADD 5 ADD 6 ENDORSEMENT_LINE______________ SACKPACK_____________ 1234 5678 9012 345 C 1234567890 COY MMMMMMM

Here’s how to order a copy of the proxy materials and select delivery preferences: Current and future delivery requests can be submitted using the options below. If you request an email copy, you will receive an email with a link to the current meeting materials. PLEASE NOTE: You must use the number in the shaded bar on the reverse side when requesting a copy of the proxy materials. — Internet – Go to www.envisionreports.com/MUX. Click Cast Your Vote or Request Materials. — Phone – Call us free of charge at 1-866-641-4276. — Email – Send an email to [email protected] with “Proxy Materials McEwen Mining Inc.” in the subject line. Include your full name and address, plus the number located in the shaded bar on the reverse side, and state that you want a paper copy of the meeting materials. To facilitate timely delivery, all requests for a paper copy of proxy materials must be received by June 9, 2025. The 2025 Annual Meeting of Shareholders of McEwen Mining Inc. will be held on June 19, 2025 at 3:00 p.m. ET, virtually via the internet at meetnow.global/MYY6V4K. To access the virtual meeting, you must have the information that is printed in the shaded bar located on the reverse side of this form. Proposals to be voted on at the meeting are listed below along with the Board of Directors’ recommendations. The Board of Directors recommends that you vote FOR the election of each of the nominees for director, and FOR proposals 2, 3, and 4: 1. Election of Directors: Nominees: 01 – Robert R. McEwen 02 – Dalia Asterbadi 03 – Ian J. Ball 04 – Richard W. Brissenden 05 – Alfred Colas 06 – Nicolas Darveau-Garneau 07 – Steve Kaszas 08 – Michelle Makori 09 – Michael Melanson 10 – John Florek 11 – William M. Shaver 2. To approve on an advisory (non-binding) basis the compensation of the Company’s named executive officers. 3. To ratify the appointment of Ernst & Young LLP as the Company’s independent registered public accounting firm for the year ending December 31, 2025. 4. To approve the amendment to the Company’s Second Amended and Restated Articles of Incorporation to change its name to McEwen Inc. 5. Other Business; To transact such other business as may properly come before the meeting or any adjournment thereof. PLEASE NOTE – YOU CANNOT VOTE BY RETURNING THIS NOTICE. To vote your shares you must go online or request a paper copy of the proxy materials to receive a proxy card. If you wish to attend and vote at the meeting, please have the control number shown on the front of this notice available. Shareholder Meeting Notice