Alta Copper Corp. — Proxy Solicitation & Information Statement 2025

Dec 24, 2025

Alta Copper Corp.

(the "Company")

Special Meeting

January 26, 2026 at 10:00 a.m. (Canada/Pacific)

Gowling WLG (Canada) LLP

Suite 2300 - 550 Burrard Street, Vancouver, British Columbia, Canada V6C 2B5

(the "Meeting")

LTA

COPPER

Proxy Voting – Guidelines and Conditions

1. THIS PROXY IS SOLICITED BY OR ON BEHALF OF THE MANAGEMENT OF THE COMPANY.
2. THIS PROXY SHOULD BE READ IN CONJUNCTION WITH THE MEETING MATERIALS PRIOR TO VOTING.
3. If you appoint the Management Nominees indicated on the reverse to vote on your behalf, they must also vote in accordance with your instructions or, if no instructions are given, in accordance with the Voting Recommendations highlighted for each Resolution on the reverse. If you appoint someone else to vote your securities, they will also vote in accordance with your instructions or, if no instructions are given, as they in their discretion choose.
4. This proxy confers discretionary authority on the person named to vote in their discretion with respect to amendments or variations to the matters identified in the Notice of the Meeting accompanying the proxy or such other matters which may properly come before the Meeting or any adjournment or postponement thereof, in each instance, whether or not the amendment, variation or other matter that comes before the Meeting is routine and whether or not the amendment, variation or other matter that comes before the Meeting is contested.
5. The securityholder has a right to appoint a person or company to represent the securityholder at the Meeting other than the Management Nominees indicated on the reverse. Such right may be exercised by inserting, on the reverse of this form, in the space labeled "Please print appointee name", the name of the person to be appointed, who need not be a securityholder of the Company.
6. To be valid, this proxy must be signed. If this proxy is given on behalf of joint holders, it must be executed by all of them and may be revoked by any of them. If this proxy is given on behalf of a body corporate, set out the full legal name of the body corporate, the name and position of the person authorized in writing to give the voting instructions on behalf of the body corporate and the address for service of the body corporate. Please date the proxy. If the proxy is not dated, it is deemed to bear the date of its mailing to the securityholders of the Company.
7. To be valid, this proxy must be filed using one of the Voting Methods and must be received by TSX Trust Company before the Filing Deadline for Proxy, noted on the reverse or in the case of any adjournment or postponement of the Meeting not less than 48 hours (Saturdays, Sundays and holidays excepted) before the time of the adjourned or postponed meeting. Late proxies may be accepted or rejected by the Chair of the Meeting in their discretion, and the Chair is under no obligation to accept or reject any particular late proxy.
8. If the holder is a corporation, the proxy must be executed by an officer or attorney thereof duly authorized, and the holder may be required to provide documentation evidencing the signatory's power to sign the proxy.
9. Guidelines for proper execution of the proxy are available at www.stac.ca. Please refer to the Proxy Protocol.

Electronic Delivery

If you are a registered securityholder and wish to enroll for electronic delivery for future issuer communications including meeting related materials, financial statements, DRS, etc., where applicable, you may do so:

1) After you vote online at www.voteproxyonline.com using your control number.
2) Through TSX Trust's online portal, Investor Insite. You may log in or enroll at https://www.tsxtrust.com/investor-login

For details go to www.tsxtrust.com/consent-to-electronic-delivery

VOTING METHOD
INTERNET	Go to www.voteproxyonline.com and enter the 12 digit control number
FACSIMILE	416-595-9593
MAIL or HAND DELIVERY	TSX Trust Company
301 - 100 Adelaide Street West
Toronto, Ontario, M5H 4H1

Investor inSite

TSX Trust Company offers at no cost to holders, the convenience of secure 24-hour access to all data relating to their account including summary of holdings, transaction history, and links to valuable holder forms and Frequently Asked Questions.

To register, please visit: https://www.tsxtrust.com/t/investor-hub/forms/investor-insite-registration and complete the registration form

For assistance, please contact TSX TRUST INVESTOR SERVICES.

Mail: 301 - 100 Adelaide Street West Toronto, ON, M5H 4H1

Tel: 1-866-600-5869

Email: tsxtis@tmx.com

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TMX
TSX TRUST

FORM OF PROXY ("PROXY")

Alta Copper Corp.
(the "Company")

Special Meeting
January 26, 2026 at 10:00 a.m. (Canada/Pacific)
Gowling WLG (Canada) LLP
Suite 2300 - 550 Burrard Street, Vancouver British Columbia, Canada V6C 2B5

CONTROL NUMBER:

SECURITY CLASS: [Option Holders]
RECORD DATE: December 15, 2025
FILING DEADLINE FOR PROXY: January 22, 2026 at 10:00 a.m. (Canada/Pacific)

APPOINTEES

The undersigned hereby appoints Giulio T. Bonifacio, President and CEO, or failing him, Dale Found, Vice President and CFO (the "Management Nominees"), or instead of any of them, the following Appointee

Please print appointee name

as proxyholder on behalf of the undersigned with the power of substitution to attend, act and vote for and on behalf of the undersigned in respect of all matters that may properly come before the Meeting and at any adjournment(s) or postponement(s) thereof, to the same extent and with the same power as if the undersigned were personally present at the said Meeting or such adjournment(s) or postponement(s) thereof in accordance with the voting instructions, if any, provided below.

• SEE VOTING GUIDELINES ON REVERSE -

RESOLUTIONS - VOTING RECOMMENDATIONS ARE INDICATED BY HIGHLIGHTED TEXT ABOVE THE BOXES

1. Arrangement Resolution

To consider, pursuant to the Interim Order, and, if deemed acceptable, to pass, with or without variation, a special resolution, the full text of which is set forth in Appendix A to the accompanying management information circular of Alta Copper dated December 19, 2025, approving an arrangement involving, among others, the Company, Fortescue Ltd ("Fortescue") and Nascent Exploration Pty Ltd, a wholly-owned subsidiary of Fortescue (the "Purchaser"), pursuant to a statutory plan of arrangement under Division 5 of Part 9 of the Business Corporations Act (British Columbia) whereby Fortescue will, among other things, indirectly through the Purchaser acquire all of the issued and outstanding Company Shares (other than those held by the Purchaser and its affiliates) and all of the outstanding Convertible Securities will be exchanged for the applicable consideration and cancelled, all in accordance with the terms of the arrangement agreement dated December 13, 2025 among the Company, Fortescue and the Purchaser.

FOR
AGAINST
☐
☐

This proxy revokes and supersedes all earlier dated proxies and MUST BE SIGNED

PLEASE PRINT NAME

Signature of registered owner(s)
Date (MM/DD/YYYY)