NEWS RELEASE, 19 OCTOBER 2022

Q3 2022 PRODUCTION REPORT

40% QUARTER ON QUARTER PRODUCTION INCREASE

Antofagasta plc CEO, Iván Arriagada said: "As we guided last quarter, production has significantly improved in the third quarter of the year due to greater water availability at Los Pelambres increasing throughput, the movement of the concentrates that were temporarily stockpiled in June, and the higher grades at Centinela Concentrates. Across the Group, copper production increased by 40%.

"In the first nine months of 2022 we produced 450,600 tonnes of copper at a net cash cost of $1.76/lb and we remain on track to achieve the lower end of our full year production guidance of 640-660,000 tonnes.

"Following the lifting of the suspension of the marine construction works at the Los Pelambres desalination plant project, its completion is now expected in H1 2023 and Group copper production in 2023 is estimated at between 670,000 and 710,000 tonnes."

HIGHLIGHTS

PRODUCTION

·    Group copper production in Q3 2022 was 181,900 tonnes, 40.1% higher than in the previous quarter with production nearly doubling at Los Pelambres, on improved water availability, and higher grades at Centinela

·    Group copper production for the first nine months of the year was 450,600 tonnes, 17.0% lower than in the same period last year mainly due to the temporary reduction in throughput (-23.8%) at Los Pelambres as a result of the drought and the reduced concentrate pipeline availability in June, and expected lower grades (-21.7%) at Centinela Concentrates

·    Gold production for the quarter was 46,900 ounces, 32.5% higher than in the previous quarter mainly due to higher throughput at Los Pelambres and higher grades at Centinela. The year-to-date production decreased by 35.6% to 120,700 ounces as a result of the expected lower grades at Centinela

·    Molybdenum production in the quarter was 2,600 tonnes, 30.0% higher than the previous quarter on increased throughput at Los Pelambres. For the year-to-date, production was 6,600 tonnes, 1,800 tonnes lower than in the same period last year due to lower throughput and grades at Los Pelambres

CASH COSTS

·    Cash costs before by-product credits in Q3 2022 were $2.12/lb, 28c/lb lower than in the second quarter reflecting the improved production during the period

·    Cash costs before by-product credits in the first nine months of the year were $2.27/lb, 29.7% higher than in the same period last year mainly due to the temporary decrease in production in H1 and higher input prices during the period, particularly for diesel and sulphuric acid. Other inflationary pressures were largely offset by the weaker Chilean peso

·    Net cash costs were $1.66/lb in Q3 2022 and $1.76/lb for the year-to-date, a 12.6% decrease compared with the previous quarter and 53.0% higher than the same period last year, respectively. This increase reflects the increase in cash costs before by-product credits and lower by-product credits due to lower by-product production

GROWTH PROJECTS UPDATE

·    As at the end of Q3 the Los Pelambres Desalination Plant and Expansion projects, including design, procurement and construction, were 88% complete

·    As previously reported, on 15 August unusually high sea swells overturned a construction platform working on the marine works of the desalination plant project and work was temporarily halted pending recovery of lost equipment and materials. This suspension was lifted on 3 October and as a result of this and adjusted working conditions for assumed continuing swells, it is now expected that completion of the desalination plant will be in H1 2023

·    Expected completion of the Los Pelambres concentrator plant expansion in Q1 2023 remains unchanged, as is the estimated total capital cost of the Los Pelambres Expansion project

·    Progress continues on the engineering and remaining project studies for the Centinela Second Concentrator project. In line with our disciplined approach to capital allocation, the decision on when to submit the project to the Board for approval during 2023 will consider the completion date of the Los Pelambres Expansion project as well as ongoing discussions on the tax reform and mining royalty bills

GUIDANCE

·    Copper production guidance for 2022 is unchanged at the lower end of the 640-660,000 tonnes range

·    The Cost and Competitiveness Programme is on track to achieve the targeted savings of over $50 million during the year

·    In 2023 copper production is expected to be between 670,000 and 710,000 tonnes, with completion of the Los Pelambres desalination and concentrator plants, and lower production at Centinela Cathodes

·    Sustaining and mine development capital expenditure are expected to average approximately $1 billion per year for the coming years with some larger projects being advanced such as the expansion of the Los Pelambres desalination plant and the replacement of its concentrate pipeline. Development expenditure in 2023 will include the residual expenditure on the Los Pelambres Expansion project and any expenditure of the Second Concentrator at Centinela if it is approved during the year. Capital expenditure guidance will be given in January 2023

SUSTAINABILITY

·    As previously announced, Antucoya has obtained the Copper Mark, for compliance with this independently verified responsible production standard, joining Centinela and Zaldívar who received it in 2021. In turn, Los Pelambres is in the final phase of verification following successfully completion of the site review

OTHER

·   Zaldívar submitted an Environmental Impact Assessment (EIA) in 2018 which included an application to extend its water extraction permit from 2025 to 2029 (with decreasing extraction levels in 2030-2031) together with the extension of the permit to mine, which expires in 2024. This application is still pending approval.

During the period, the company (as well as other named defendants) submitted a response contradicting the allegations made by the Consejo de Defensa del Estado (CDE), an independent governmental agency tasked with the defence of the interests of the State of Chile before the courts, who previously filed a claim against Minera Escondida, Albemarle and Zaldívar, alleging that their extraction of water from the Monturaqui-Negrillar-Tilopozo aquifer over the years has impacted the underground water level. Since the EIA remains unresolved and the litigation by the CDE is outstanding the company has been in discussions with the local environmental authority and is planning to submit a DIA⁽¹⁾, a limited scope and less detailed procedure than an EIA, requesting that the permit to mine be extended to 2025 in line with current water permit to achieve continuity while the water extraction permit is under review

·   On 4 September the proposed new Chilean constitution was rejected in a national referendum. Congress is now considering how to proceed, but is expected to propose an alternative plan for drafting a new constitution for the country

·   The Government presented a draft mining royalty bill to Congress in July. Following representations from the mining industry, academics, trade unions and other interested parties, the bill is expected to be simplified.  The bill will then be debated in the Senate before being passed to the lower house for its consideration, which is expected to be before the end of the year

·   Labour agreements were successfully concluded during the period with the supervisors' union at Zaldívar, and in October with the supervisors' union at Los Pelambres and the workers' union at Antucoya. Together with the earlier agreement with the supervisors' union at Antucoya, this completes the labour negotiations scheduled for 2022

(1) Declaración de Impacto Ambiental (Environmental Impact Declaration)

(2) Cash cost is a non-GAAP measure used by the mining industry to express the cost of production in US dollars per pound of copper produced.

There will be a Q&A video conference call today at 1:00pm BST hosted by Iván Arriagada - Chief Executive Officer and Mauricio Ortiz - Chief Financial Officer. Participants can join the conference call here.

Register on our website to receive our email alerts http://www.antofagasta.co.uk/investors/email-alerts/

MINING OPERATIONS

Los Pelambres

In the first nine months of 2022, copper production at Los Pelambres was 186,200 tonnes, 25.6% lower than in the same period last year. This decrease includes the impact of the reduced availability of the concentrate pipeline in June, but was mainly driven by the expected reduced throughput, which was down 23.8% compared with the prior year due to the lack of water due to the water scarcity in H1. The precipitation in recent months has allowed for a progressive increase in throughput.

As throughput increased by 46.0% during the quarter, copper production nearly doubled to 87,800 tonnes; including approximately 10,000 tonnes from copper in concentrates stockpiled at the plant in June.

Molybdenum production was 2,100 tonnes in Q3 2022, 700 tonnes higher than in the previous quarter. Production for the year-to-date decreased to 4,800 tonnes from 7,500 tonnes in the same period in 2021, due to lower throughput and grades.

Gold production for the first nine months of 2022 was 29,300 ounces, 12,100 ounces lower than in the same period last year due to expected lower throughput and grades.

Cash costs before by-product credits in Q3 were $1.75/lb, 15.0% lower than in previous quarter mainly due to higher production, and for the first nine months of 2022 were $1.89/lb, 22.7% higher than the same period last year. This increase was due to the lower copper production, higher input prices (mainly diesel and explosives) and general inflation, partially offset by the weaker Chilean peso.

Net cash costs in Q3 2022 of $1.19/lb decreased by 18c/lb compared to Q2 2022 reflecting the lower cash costs before by-product credits, partially offset by lower by-product credits. For the year to date, net cash cost increased by 53.7% to $1.26/lb due to the higher cash costs before by-product credits and lower by-product credits.

As at the end of Q3 the Los Pelambres Expansion project was 88% complete, and completion of the desalination plant is expected in H1 2023 and the concentrator expansion in Q1 2023.

The labour agreement with the supervisors' union was successfully concluded this month.

(1) Includes tolling charges of $0.17/lb in Q3 2022, $0.18/lb in Q2 2022, $0.17/lb YTD 2022 and $0.16/lb YTD 2021

Centinela

Centinela produced 62,500 tonnes of copper during the quarter, 12.4% higher than in the previous quarter on higher copper grades, slightly offset by lower throughput. Production for the year-to-date was 173,800 tonnes, 14.3% lower than in the same period last year, due to expected lower ore grades at Centinela Concentrates.

Production of copper in concentrate was 37,600 tonnes in Q3 2022, 12.9% higher than in the previous quarter on higher grades, partially offset by lower throughput due to a major maintenance completed during the quarter. For the first nine months of the year, copper in concentrate production was 103,800 tonnes, 24.8% lower than in the same period last year, mainly due to expected lower copper grades which were 0.47% compared to 0.60%.

Copper cathode production during the quarter was 24,900 tonnes, 12.2% higher than in Q2 2022 primarily as grades increased by 17.7%. For the year-to-date, copper cathode production was 70,000 tonnes, 8.0% higher than in the same period last year primarily due to expected higher grades.

Gold production was 33,000 ounces in the quarter, 15.4% higher than the previous quarter on higher grades, and for the first nine months was 91,300 ounces, 37.4% lower than the same period last year as grades, which are correlated to copper grades, and recoveries decreased.

Cash costs before by-product credits were $2.47/lb, 7.1% lower than in the previous quarter. Cash costs before by-product credits for the first nine months of the year were $2.60/lb, 42.9% higher than the same period in 2021 primarily due to lower copper production and higher input costs, particularly for diesel, sulphuric acid and explosives. Other inflationary pressures were largely offset by the weaker Chilean peso.

By-product credits in Q3 were $0.55/lb compared with $0.63/lb in Q2. For the first nine months, by-product credits decreased from $0.72/lb in 2021 to $0.64/lb in 2022 due to lower gold production.

Net cash costs in Q3 2022 were $1.92/lb, 5.4% lower than the previous quarter. During the first nine months of the year net cash costs were $1.96/lb, 86c/lb higher than in the same period in 2021 reflecting the increase in cash costs before by-product credits and the slightly lower by-product credits.

(1) Includes production from ROM material

(2) Includes tolling charges of $0.15/lb in Q3 2022, $0.14/lb in Q2 2022, $0.14/lb YTD 2022 and $0.11/lb YTD 2021

Antucoya

Total copper production at Antucoya during the quarter was 21,000 tonnes, 11.1% higher than in the previous quarter reflecting higher grades, slightly offset by lower throughput due to major scheduled maintenance. Production in the first nine months of 2022 was 57,400 tonnes was very similar to the same period last year.

During the quarter, cash costs were $2.40/lb compared to $2.59/lb in Q2. For the year-to-date, cash costs were $2.47/lb, 20.5% higher than the same period last year due to increased input costs, particularly for sulphuric acid, diesel and explosives. Other inflationary pressures were largely offset by the weaker Chilean peso.

The labour agreement with the workers' union was successfully concluded this month.

Zaldívar

Copper production for the quarter was 10,600 tonnes, 3.6% lower than in the previous quarter due to lower grades and recoveries, partially offset by higher throughput. Production for the year-to-date was 33,100 tonnes, 4.7% higher than the same period last year due to higher grades, partially offset by lower throughput.

Cash costs during the quarter were $2.55/lb, $0.37/lb higher than Q2 2022 primarily due to lower production, higher sulphuric acid consumption and the payment of a one-off signing bonus following the successful completion of a new 3-year labour agreement.

Cash costs for the first nine months of the year were $2.27/lb, compared with $2.42/lb in the same period in 2021, mainly due to higher production partially offset by higher input prices.

(1) Metallurgical recoveries during the period. Prior periods have been restated

(2) Group's 50% share

(3) Includes production from secondary leaching

Transport Division

Total transport volumes in Q3 2022 were 1.7 million tonnes, 6.5% lower than the previous quarter, mainly due to customers' maintenance and lower demand for transport services.

For the first nine months of the year, transport volumes increased by 7.2% compared to the same period in 2021 as new rail transport contracts have ramped up during the period.

Commodity prices and exchange rates

Spot commodity prices for copper, gold and molybdenum as at 30 September 2022 were $3.47/lb, $1,672/oz and $18.3/lb respectively, compared with $3.74/lb, $1,815/oz and $17.1/lb as at 30 June 2022 and $4.40/lb, $1,820/oz and $18.7/lb as at 31 December 2021.

The provisional pricing adjustments for copper, gold and molybdenum for the quarter were negative $97.5 million, negative $3.2 million and positive $0.5 million respectively.

The provisional pricing adjustments for copper, gold and molybdenum for the year to date were negative $304.4 million, positive $0.5 million and negative $12.7 million respectively.

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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.