South32 (ASX:S32) has updated its Hermosa Taylor project with a number that will get investor attention. Growth capital expenditure has increased to approximately US$3,300 million, up by around US$1,100 million from final investment approval in February 2024.
First production has also moved from H2 FY27 to H2 FY28, and nameplate capacity from FY30 to FY31. The causes are not hard to understand.
Shaft contractor underperformance has been the dominant factor in the schedule slip. Materials cost inflation driven by steel, piping, concrete, and US tariffs has been the main driver of the capex increase. The company is being direct about both.
Approximately US$500 million of the capex increase reflects inflation and tariff impacts, approximately US$450 million reflects revised shaft construction costs, and approximately US$100 million reflects the addition of decline infrastructure from the Clark deposit.
The positive offset in this announcement is that the Taylor reserve base has grown meaningfully. The Ore Reserve increased by 52% to 99 million tonnes, and the initial mine life has extended by five years to approximately 33 years. The underlying project economics have held up better than the headline capex number suggests.
Why the Decline Access from Clark Changes the Production Profile
The most operationally significant development in this update is the decision to use the Clark exploration decline as an additional access route to the Taylor orebody. This was not part of the original design, but the completed Clark decline has turned out to offer a material benefit.
First ore from the decline access is expected in mid-FY28, giving South32 early production ahead of full shaft commissioning. Ore handling capacity also increases by approximately 25% once the decline is incorporated, creating potential to eventually push production above current nameplate design rates.
The ventilation shaft is approximately 75% complete and the main shaft is approximately 53% complete as at April 2026. The revised timeline builds in the reality that targeted improvement measures on contractor performance will only partially close the productivity gap.
Investors should read that as management giving themselves buffer rather than guiding to a scenario where construction stays at the current pace.
The Economic Case at US$3,300m Still Holds Under Long-Term Pricing
Steady-state EBITDA is expected at approximately US$650 million per annum over the FY31 to FY59 production window. At spot prices as at April 2026, that figure moves to approximately US$800 million per annum.
The post-tax NPV comes in at approximately US$3,100 million at a 7% real discount rate on the base case, rising to approximately US$4,500 million at spot prices. With US$2,100 million of capital remaining to be invested from 1 April 2026 to H2 FY28, the return profile still looks attractive on a risk-adjusted basis.
The post-tax internal rate of return on the base case is approximately 19%, rising to 22% at spot. That is not a marginal project. It is a meaningful return on a large asset, assuming the schedule and remaining capex hold.
The Peake copper deposit adjacent to Taylor also received a 32% resource upgrade to 33 million tonnes. Peake is not in the current mine plan, but its growth alongside Taylor is the mechanism by which South32 expects to extend mine life and add copper production in the medium to longer term. That option is increasingly well-defined.
Investors’ Takeaway for South32
The honest read here is that this announcement is a reset, not a disaster. The capex overrun and schedule delay are real, and investors who held South32 partly on a FY27 Taylor production story will need to re-anchor expectations to FY28. That repricing is likely already partially reflected given the guidance South32 provided in February 2026 flagging a review was underway.
The project still makes economic sense at long-term price assumptions. The reserve upgrade adds mine life. The decline access improves flexibility. And approximately 80% of Taylor’s growth capex is now invested, contracted, or subject to final pricing, which reduces the uncertainty around the remaining US$2,100 million.
The risk from here is that contractor performance does not improve to the degree assumed, or that further materials cost escalation adds to the remaining capex envelope. Both are plausible in the current construction environment. Investors should also note that South32 carries this project alongside a diversified portfolio of alumina, aluminium, manganese, copper, and zinc operations, which provides earnings support while Taylor moves toward production. Coverage of ASX-listed diversified resources and mining companies is available at Stocks Down Under.
