Alta Copper Corp. — Proxy Solicitation & Information Statement 2025

Dec 24, 2025

Notice of Special Meeting of Shareholders and Optionholders

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DATE
January 26, 2026

TIME
10:00 a.m.
(Vancouver Time)

LOCATION
Gowling WLG (Canada) LLP
Suite 2300 - 550 Burrard Street, Vancouver, British Columbia, Canada V6C 2B5

NOTICE IS HEREBY GIVEN that, pursuant to an order of the Supreme Court of British Columbia (the “Court”) dated December 19, 2025 (the “Interim Order”), a special meeting (the “Meeting”) of holders (“Shareholders”) of common shares (“Company Shares”) of Alta Copper Corp. (the “Company” or “Alta Copper”) and holders (“Optionholders”) of options to purchase Company Shares (“Company Options”) will be held at the offices of Gowling WLG (Canada) LLP located at Suite 2300 - 550 Burrard Street, Vancouver, British Columbia, Canada V6C 2B5, on Monday, January 26, 2026, at 10:00 a.m. (Vancouver Time), subject to any adjournment or postponement thereof.

The Meeting will be held to (i) consider, pursuant to the Interim Order, and, if deemed acceptable, to pass, with or without variation, a special resolution (the “Arrangement 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 (the “Circular”), approving an arrangement (the “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) (the “BCBCA”) 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 (as amended, supplemented or otherwise modified from time to time, the “Arrangement Agreement”); and (ii) transact such further or other business as may properly come before the Meeting and any adjournment or postponement thereof.

Specific details of the matters proposed to be put before the Meeting are set forth in the Circular which accompanies this Notice of Meeting. The Arrangement Agreement has been filed under Alta Copper’s issuer profile on SEDAR+ at www.sedarplus.ca.

The board of directors of Alta Copper (the “Board”), with the two directors having disclosable interests abstaining from voting, after receiving the recommendation of the special committee of the Board (the “Special Committee”), unanimously recommends that Shareholders and Optionholders vote FOR the Arrangement Resolution.

Pursuant to the Interim Order, the record date is Monday, December 15, 2025 (the “Record Date”) for determining Shareholders and Optionholders who are entitled to receive notice of and to vote at the Meeting. Only registered

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Shareholders shown on the shareholder register of the Company ("Registered Shareholders") and Optionholders, or their duly appointed proxyholders, at the close of business on the Record Date are entitled to receive notice of the Meeting ("Notice of Meeting") and to vote on the Arrangement Resolution at the Meeting. This Notice of Meeting is accompanied by the Circular, an applicable form of proxy and a letter of transmittal for Registered Shareholders (a "Letter of Transmittal").

Each Company Share entitled to be voted at the Meeting will entitle the holder thereof to one vote at the Meeting. The Company Shares underlying the Company Options entitled to be voted at the Meeting will each entitle the holder thereof to one vote at the Meeting.

In order to become effective, the Arrangement Resolution must be approved by at least (i) 66½% of the votes cast on the Arrangement Resolution by Shareholders present in person or represented by proxy and entitled to vote at the Meeting, (ii) 66½% of the votes cast on the Arrangement Resolution by Shareholders and Optionholders present in person or represented by proxy and entitled to vote at the Meeting, voting as a single class, and (iii) a simple majority of the votes cast on the Arrangement Resolution by Shareholders present in person or represented by proxy and entitled to vote at the Meeting, excluding for the purposes of (iii) the votes in respect of Company Shares held or controlled by persons described in items (a) through (d) of section 8.1(2) of Multilateral Instrument 61-101 – Protection of Minority Security Holders in Special Transactions. It is a condition to the implementation of the Arrangement that the Arrangement Resolution be approved at the Meeting. If the Arrangement Resolution is not approved at the Meeting, the Arrangement will not be completed.

Registered Shareholders, Optionholders and duly appointed proxyholders, including Shareholders who hold their Company Shares through a broker, investment dealer, bank, trust company, custodian, nominee or other intermediary ("Beneficial Shareholders") who have duly appointed themselves or a third-party as proxyholder, may attend, participate and vote at the Meeting. Beneficial Shareholders who have not duly appointed themselves as proxyholder may be able to attend the Meeting as guests but will not be able to vote at the Meeting.

Registered Shareholders and Optionholders are requested to read the enclosed Circular and are requested to date and sign the enclosed proxy form promptly, as applicable, and return it in the self-addressed envelope enclosed for that purpose or by any of the other methods indicated in the proxy form. Registered Shareholders and Optionholders may also vote in advance of the meeting by mail or on the internet. Pursuant to the Interim Order, proxies to be used at the Meeting must be received by TSX Trust Company by no later than 10:00 a.m. (Vancouver time) on Thursday, January 22, 2026 (or, if the Meeting is adjourned or postponed, by the time that is 48 hours prior to the Meeting, excluding Saturdays, Sundays and holidays). The time limit for deposit of proxies may be waived or extended by the Chair of the Meeting at his discretion, without notice. To vote online at www.voteproxyonline.com, you will need to enter your 12-digit control number (located on the bottom left corner of the first page of the form of proxy) to identify yourself as a Registered Shareholder or Optionholder on the voting website. Alternatively, a proxy can be submitted to TSX Trust Company either by mail or courier, to TSX Trust Company, 301-100 Adelaide Street West, Toronto ON M5H 4H1, or by fax to 1-416-595-9593, as instructed in the form of proxy. If a Registered Shareholder or Optionholder receives more than one proxy form because such Registered Shareholder or Optionholder owns securities of the Company registered in different names or addresses, each proxy form needs to be completed and returned or voted online.

Beneficial Shareholders are requested to complete and return the request for voting instructions in accordance with the instructions provided to you by your broker or such other intermediary. Failure to do so may result in your Company Shares not being voted at the Meeting. In such instance, the Beneficial Shareholder will receive the

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consideration for their Company Shares, as applicable, pursuant to the terms of the Arrangement through the intermediary.

If you wish that a person other than the management nominees identified on the form of proxy or voting instruction form ("VIF") attend and vote at the Meeting as your proxy and vote your Company Shares and/or Company Options, including if you are not a Registered Shareholder and wish to appoint yourself as proxyholder to attend and vote at the Meeting, you MUST submit your form of proxy (or proxies) or VIF, as applicable, in accordance with the instructions set out in the Circular. If submitting a proxy and appointing a person other than the management nominees identified, you must return your proxy in accordance with the instructions set out in the Circular by 10:00 a.m. (Vancouver time) on Thursday, January 22, 2026 (or, if the Meeting is adjourned or postponed, by the time that is 48 hours prior to the Meeting, excluding Saturdays, Sundays and holidays).

If you are a Registered Shareholder (other than a Dissenting Shareholder (as defined in the Circular)), in order to receive the Consideration, you must duly complete and execute the Letter of Transmittal in accordance with the instructions included therein, and deliver it to the depository, TSX Trust Company (the "Depository"), together with the certificate(s) or the direct registration system statement(s) ("DRS Statements"), as applicable, representing your Company Shares, and such other documents and instruments as the Depositary or the Purchaser may reasonably require. If you are sending certificates, it is recommended that you send them by registered mail. The Letter of Transmittal contains complete instructions on how to exchange your Company Shares for the Consideration. You will not receive your Consideration until after the Effective Date, and only if you have returned your properly completed documents, including each Letter of Transmittal, the certificate(s) or DRS Statement(s), as applicable, representing your Company Shares, and such other documents and instruments as the Depositary or the Purchaser may reasonably require, to the Depositary. The Letter of Transmittal is also available under Alta Copper's issuer profile on SEDAR+ at www.sedarplus.ca.

Only Registered Shareholders are required to submit a Letter of Transmittal. The exchange of Company Shares for the Consideration in respect of any Beneficial Shareholder is expected to be made with the Beneficial Shareholder's intermediary account through the procedures in place for such purposes between CDS Clearing and Depository Services Inc. or the Depository Trust Company and such other intermediary, as applicable, with no further action required by the Beneficial Shareholder. Beneficial Shareholders who hold Company Shares registered in the name of an intermediary should contact that intermediary if they have any questions regarding this process and to arrange for such intermediary to complete the necessary steps to ensure that they receive the Consideration in respect of their Company Shares.

Pursuant to the Interim Order, Registered Shareholders as at the close of business on the Record Date have the right to dissent with respect to the Arrangement Resolution and, if the Arrangement becomes effective, to be paid the fair value of their Company Shares (which fair value shall be the fair value of the Dissenting Shareholder's Company Shares as of the close of business on the business day (as defined in the Circular) before the passing by the Shareholders of the Arrangement Resolution) in accordance with the provisions of Sections 237 to 247 of the BCBCA, as modified by the Interim Order, the Final Order and the Plan of Arrangement. A Registered Shareholder as at the close of business on the Record Date wishing to exercise rights of dissent with respect to the Arrangement must send to the Company a written objection to the Arrangement Resolution, which written objection must be sent to the Company c/o Gowling WLG (Canada) LLP, 550 Burrard Street, Suite 2300, Bentall 5, Vancouver, BC V6C 2B5, Attention: Jonathan Ross, by no later than 4:00 p.m. (Vancouver time) on Thursday, January 22, 2026 (or by 4:00 p.m. (Vancouver time) on the date that is two business days immediately preceding the date that any adjourned or postponed Meeting is reconvened), and must otherwise strictly comply with the dissent procedures set forth in Sections 237 to 247 of the BCBCA, as

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modified by the Interim Order, the Final Order and the Plan of Arrangement. The Registered Shareholders' right to dissent is more particularly described in the Circular. Copies of the Plan of Arrangement, the Interim Order and the text of Sections 237 to 247 of the BCBCA are set forth in Appendix B "Plan of Arrangement", Appendix C "Interim Order" and Appendix G "Dissent Provisions of the BCBCA", respectively, of the Circular. Anyone who is a beneficial owner of Company Shares and who wishes to exercise a right of dissent should be aware that only Registered Shareholders as at the close of business on the Record Date are entitled to exercise a right of dissent. Accordingly, a Beneficial Shareholder who desires to exercise a right of dissent must make arrangements for the Company Shares beneficially owned by such holder to be registered in the name of such holder prior to the time the written objection to the Arrangement Resolution is required to be received by the Company or, alternatively, make arrangements for the Registered Shareholder of such Company Shares to exercise the right of dissent on behalf of such Beneficial Shareholder. A Registered Shareholder wishing to exercise a right of dissent may only exercise such rights with respect to all Company Shares registered in the name of such Shareholder. It is recommended that you seek independent legal advice if you wish to exercise a right of dissent. Failure to strictly comply with the requirements set forth in Sections 237 to 247 of the BCBCA, as modified by the Interim Order, the Final Order and the Plan of Arrangement, may result in the loss of any right of dissent.

Please review the accompanying Circular before voting as it contains important information about the Meeting. It provides additional information relating to the matters to be dealt with at the Meeting and is deemed to form part of this Notice of Meeting. Any adjourned or postponed meeting resulting from an adjournment or postponement of the Meeting will be held at a time and place to be specified either by the Company before the Meeting or by the Chair at the Meeting.

DATED at Toronto, Ontario this 19th day of December, 2025.

BY ORDER OF THE BOARD

(signed) "Steven Latimer"

Chair of the Special Committee