NEWS RELEASE, 28 MARCH 2024

PUBLICATION OF 2023 REPORTING SUITE, 2024 NOTICE OF ANNUAL GENERAL MEETING AND CORPORATE UPDATE

Antofagasta plc ("Antofagasta" or the "Company") has today published the following reports: the 2023 Annual Report and Accounts, the 2024 Notice of Annual General Meeting, 2023 Sustainability Report, and a new Climate Action Plan. In addition, the Company has provided a corporate update on previous announcements regarding the Los Pelambres concentrate pipeline and investment in Compañía de Minas Buenaventura S.A.A.

2023 Annual Report and Accounts and 2024 Notice of Annual General Meeting

In compliance with LR 9.6.1, the Company has submitted the following documents to the Financial Conduct

Authority by uploading them to the National Storage Mechanism:

·    2023 Annual Report and Accounts

·    2024 Notice of Annual General Meeting

·    Form of Proxy for Ordinary Shareholders for Annual General Meeting

·    Form of Proxy for Preference Shareholders for Annual General Meeting

·    Letter to Shareholders regarding Electronic Communications

·    Statement of Reasons connected with PricewaterhouseCoopers LLP ceasing to hold office as Auditors

These documents will shortly be available for inspection in unedited full text at the National Storage Mechanism at data.fca.org.uk/#/nsm/nationalstoragemechanism.

The 2023 Annual Report and Accounts , 2024 Notice of Annual General Meeting and Statement of Reasons connected with PricewaterhouseCoopers LLP ceasing to hold office as Auditors are also available to view on the Company's website at www.antofagasta.co.uk.

This announcement is made in accordance with DTR 6.3.5R(1A).

Arrangements for 2024 Annual General Meeting

The Annual General Meeting will be held, in-person, at Church House Westminster, Dean's Yard, London SW1P 3NZ at 10:00am on Wednesday 8 May 2024. The formal notice of the Annual General Meeting and resolutions to be proposed are set out in the Notice of Annual General Meeting.

Mining Division's 2023 Sustainability Report and Climate Action Plan

The Mining Division's 2023 Sustainability Report and associated Databook, and Climate Action Plan have also been published today and are available to view on the Company's website at www.antofagasta.co.uk . The Climate Action Plan includes the decarbonisation strategy to accompany the emissions reduction targets that were released in February 2024.

Modern Slavery Statement

In compliance with the United Kingdom's modern slavery definition requirement, the Company's Modern Slavery Statement has been published today and is available to view on the Company's website at www.antofagasta.co.uk .

Corporate Update

·    Concentrate filtering resumed: As previously announced, on 31 January 2024, during regular cleaning activities prior to scheduled maintenance of the concentrate pipeline that connects the processing plant at Los Pelambres to the port at Los Vilos, concentrate material was detected that was stopping the normal transit of concentrate. This material was successfully cleared, and the filtering of concentrates at the port facilities resumed at the end of February. Mining and processing operations at Los Pelambres continued to operate unaffected throughout this process and concentrates were stockpiled at the processing plant in pre-existing stockpile locations. As a result, a portion of the Los Pelambres' concentrate filtered production and sales from Q1 2024, estimated to be approximately 27,000 tonnes of payable copper, will be rescheduled into future quarters. Following receipt of the relevant permit last year, Los Pelambres has initiated construction of a new concentrate pipeline. Until completion of this pipeline, Los Pelambres will continue to operate the existing concentrate pipeline under enhanced safety operating conditions and revised maintenance protocols. The Company confirms that production guidance for 2024 remains unaffected.

·    Buenaventura: In line with the Company's previous release in December 2023, when it was announced that the Company had entered into transactions in the secondary market to acquire beneficial ownership of shares of Compañía de Minas Buenaventura S.A.A. (Buenaventura), the Company can confirm that it now holds 48.1 million shares of Buenaventura, representing the equivalent of approximately 19% of Buenaventura's issued share capital. Following a meeting of Buenaventura's shareholders in March 2024, the Company can confirm that Iván Arriagada and Andrónico Luksic L. have now joined Buenaventura's Board of Directors.

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Cautionary Statement

This announcement contains certain forward-looking statements. All statements other than historical facts are forward-looking statements. Examples of forward-looking statements include, without limitation, those regarding the Group's strategy, plans, objectives or future operating or financial performance, reserve and resource estimates, commodity demand and trends in commodity prices, growth opportunities, and any assumptions underlying or relating to any of the foregoing. Words such as "intend", "aim", "project", "anticipate", "estimate", "plan", "believe", "expect", "may", "should", "will", "continue" and similar expressions identify forward-looking statements.

Forward-looking statements involve known and unknown risks, uncertainties, assumptions and other factors that are beyond the Group's control. Given these risks, uncertainties and assumptions, actual results, performance or achievements could differ materially from any future results, performance or achievements expressed or implied by these forward-looking statements, which apply only as at the date of this report. These forward-looking statements are based on numerous assumptions regarding the Group's present and future business strategies and the environment in which the Group will operate in the future. Important factors that could cause actual results, performance or achievements to differ from those in the forward-looking statements include, but are not limited to: natural events, global economic and financial conditions (which may affect our business, results of operations or financial condition); various political, economic, legal, regulatory, social and other risks and uncertainties across jurisdictions in which the Group operates; changes to mining concessions or the imposition of new mining royalties, or changes to existing mining royalties in the jurisdictions in which the Group operates; the Group's ability to comply with the extensive body of regulations governing the mining industry, as well as the need to manage relationships with local communities; the ongoing effects of the global COVID-19 pandemic; demand, supply and prices for copper and other long-term commodity price assumptions (as they materially affect the timing and feasibility of future projects and developments); trends in the copper mining industry and conditions of the international copper markets; the effect of currency exchange rates on commodity prices and operating costs; the availability and costs associated with mining inputs and labour; operating or technical difficulties in connection with mining or development activities; risks, hazards and/or events and conditions inherent to the mining industry, which may affect our operations or facilities; employee relations; climate change as well as the effects of extreme weather conditions; the outcome of any litigation arbitration, regulatory or administrative proceedings to which the Group is and may be subject in the future; and actions and activities of governmental authorities, including changes to laws, regulations or taxation.

Except as required by applicable law, rule or regulation, the Group does not undertake any obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise. Past performance cannot be relied on as a guide to future performance.

No statement in this announcement is intended as a profit forecast or estimate for any period. No statement in this announcement should be interpreted to indicate a particular level of profit and, as a consequence, it should not be possible to derive a profit figure for any future period from this report.