South32 Limited - Quarterly Report: September 2025

QUARTERLY REPORT

September 2025

South32 Chief Executive Officer, Graham Kerr: "We delivered another period of strong operating performance as we continued our focus on safe and reliable operations.

"Production highlights included a 12 per cent increase in payable copper equivalent production at Sierra Gorda and a 33 per cent uplift in manganese volumes, as we successfully executed the operational recovery plan at Australia Manganese.

"Our financial position remains strong as we continued our investment in growth at Hermosa, supported by US$117 million in net distributions from our Sierra Gorda and manganese equity accounted investments during the quarter.

"At Hermosa, we continued critical path shaft sinking for our Taylor zinc-lead-silver project, while the exploration decline for the Clark battery-grade manganese deposit remains on track to be completed in the December 2025 quarter.

"In addition to Hermosa, we continue to advance a pipeline of high-quality base metals development and exploration options.

"We welcome the decision of the US Government to support the establishment of the Ambler Access Road. This is a key step in unlocking the potential of the Ambler Mining District, where we hold high-grade copper and zinc options.

"Looking ahead, we remain focused on maintaining our operating momentum and capitalising on strengthening market conditions in base metals."

CORPORATE UPDATE

DEVELOPMENT AND EXPLORATION UPDATE

Hermosa project

Ambler Metals project

Greenfield exploration

Other exploration

WORSLEY ALUMINA (86% SHARE)

Worsley Alumina saleable production was largely unchanged at 934kt in the September 2025 quarter, supported by improved bauxite supply to the refinery, while planned calciner maintenance was completed. FY26 production guidance remains unchanged at 3,750kt.

Sales decreased by 12% in the September 2025 quarter following a drawdown of inventory in the prior quarter and the timing of shipments.

BRAZIL ALUMINA (36% SHARE, NON-OPERATED)

Brazil Alumina saleable production increased by 6% (or 20kt) to 354kt in the September 2025 quarter, as the refinery operated above nameplate capacity, driven by improved plant availability. FY26 production guidance remains unchanged at 1,360kt.

BRAZIL ALUMINIUM (40% SHARE, NON-OPERATED)

Brazil Aluminium saleable production decreased by 3% (or 1kt) to 37kt in the September 2025 quarter, reflecting a temporary reduction in amperage and pots in operation to manage the ramp up of all three potlines. The smelter's operating performance and production volumes improved towards the end of the September 2025 quarter, with FY26 production guidance remaining unchanged at 160kt.

Sales decreased by 37% in the September 2025 quarter due to the timing of export shipments.

HILLSIDE ALUMINIUM (100% SHARE)

Hillside Aluminium saleable production was unchanged at 181kt in the September 2025 quarter, as the smelter continued to test its maximum technical capacity, despite the impact of load-shedding. FY26 production guidance remains unchanged at 720kt⁴.

Sales decreased by 13% in the September 2025 quarter as a shipment slipped to the December 2025 quarter.

MOZAL ALUMINIUM (63.7% SHARE)

Mozal Aluminium saleable production increased by 3% (or 3kt) to 93kt in the September 2025 quarter, as the smelter operated near its maximum technical capacity, prior to our decision in August 2025 to stop pot relining due to the uncertainty of future electricity supply beyond March 2026¹. FY26 production guidance remains unchanged at 240kt⁴, based on operations continuing to March 2026, when the current electricity supply agreement expires.    

We are continuing to actively engage with the Government of the Republic of Mozambique, Hidroeléctrica de Cahora Bassa (HCB) and Eskom on securing sufficient and affordable electricity for Mozal Aluminium. Despite our efforts, negotiations have not progressed to provide confidence that Mozal Aluminium will secure sufficient and affordable electricity supply beyond March 2026. Without the required electricity supply, we expect that Mozal Aluminium will be placed on care and maintenance at the end of the current agreement.

SIERRA GORDA (45% SHARE, NON-OPERATED)

Sierra Gorda payable copper equivalent production² increased by 12% (or 2.6kt) to 24.9kt in the September 2025 quarter, due to higher planned copper grades, and a significant uplift in molybdenum recoveries in the current phase of the mine plan.   FY26 payable copper equivalent production² guidance remains unchanged at 85.7kt.

During the September 2025 quarter, Sierra Gorda advanced the feasibility study for the fourth grinding line project, including additional engineering work on the tailings thickeners. An update on the fourth grinding line project will be provided with our December 2025 half year financial results.

CANNINGTON (100% SHARE)

Cannington payable zinc equivalent production³ decreased by 19% (or 11.2kt) to 48.3kt in the September 2025 quarter, as anticipated, with improved underground mining performance more than offset by lower average metal grades. FY26 payable zinc equivalent production³ guidance remains unchanged at 200.6kt, supported by higher average metal grades across the remainder of the year, in accordance with the mine plan. 

CERRO MATOSO (99.9% SHARE)

Cerro Matoso payable nickel production decreased by 3% (or 0.3kt) to 9.4kt in the September 2025 quarter, as improved plant availability was more than offset by lower planned nickel grades. Payable nickel production guidance for the December 2025 half year remains unchanged at 16.0kt.  

The divestment of Cerro Matoso to a subsidiary of CoreX Holding B.V. remains on track to be completed in the December 2025 quarter, subject to the satisfaction of remaining conditions precedent¹¹. 

AUSTRALIA MANGANESE (60% SHARE)

Australia Manganese saleable production increased to 854kwmt in the September 2025 quarter, as we successfully executed the operational recovery plan and ramped up export shipments as planned. FY26 production guidance remains unchanged at 3,200kwmt, subject to potential impacts from the wet season.

Sales increased to 944kwmt in the September 2025 quarter, as shipping rates reached full capacity following the commissioning of new wharf infrastructure.

SOUTH AFRICA MANGANESE (54.6% SHARE)

South Africa Manganese saleable production decreased by 7% (or 42kwmt) to 551kwmt in the September 2025 quarter, reflecting underground development activity at Wessels. FY26 production guidance remains unchanged at 2,000kwmt, with planned maintenance scheduled in the December 2025 quarter.

NOTES

The following abbreviations have been used throughout this report: US$ million (US$M); US$ billion (US$B); grams per tonne (g/t); tonnes (t); thousand tonnes (kt); thousand tonnes per annum (ktpa); million tonnes (Mt); million tonnes per annum (Mtpa); ounces (oz); thousand ounces (koz); million ounces (Moz); thousand wet metric tonnes (kwmt); million wet metric tonnes (Mwmt); million wet metric tonnes per annum (Mwmt pa); dry metric tonne unit (dmtu); thousand dry metric tonnes (kdmt).

Figures in italics indicate that an adjustment has been made since the figures were previously reported. The denotation (e) refers to an estimate or forecast year.

OPERATING PERFORMANCE

Forward-looking statements

This release contains forward-looking statements, including statements about trends in commodity prices and currency exchange rates; demand for commodities; production forecasts; plans, strategies and objectives of management; capital costs and scheduling; operating costs; anticipated productive lives of projects, mines and facilities; and provisions and contingent liabilities. These forward-looking statements reflect expectations at the date of this release, however they are not guarantees or predictions of future performance. They involve known and unknown risks, uncertainties and other factors, many of which are beyond our control, and which may cause actual results to differ materially from those expressed in the statements contained in this release. Readers are cautioned not to put undue reliance on forward-looking statements. Except as required by applicable laws or regulations, the South32 Group does not undertake to publicly update or review any forward-looking statements, whether as a result of new information or future events. Past performance cannot be relied on as a guide to future performance. South32 cautions against reliance on any forward-looking statements or guidance.

FURTHER INFORMATION

Approved for release to the market by Graham Kerr, Chief Executive Officer
JSE Sponsor: The Standard Bank of South Africa Limited

21 October 2025

South32 Limited

(Incorporated in Australia under the Corporations Act 2001 (Cth))

(ACN 093 732 597)

ASX / LSE / JSE Share Code: S32; ADR: SOUHY

ISIN: AU000000S320