Freeport’s delayed Grasberg restart to 2028: production and risk notes for mine engineers
Reviewed by Joe Ashwell
First reported on MINING.com
30 Second Briefing
Freeport Indonesia has pushed back Grasberg’s full production restart to early 2028, after a September mudflow in the Grasberg Block Cave killed seven workers, halted underground mining and triggered force majeure on shipments. The complex, which previously supplied about 3% of global copper (1.7 billion lb/year) and 1.4 million oz/year of gold, is currently operating at roughly 40–50% capacity, with copper output for 2026 now guided at 700 million lb versus a prior 1‑billion‑lb target. Ramp-up targets have been reset to 65% capacity in H2 2026 and 80% by mid‑2027, as additional logistics and ore-handling infrastructure work proceeds.
Technical Brief
- September mudflow in the Grasberg Block Cave underground mine is described as a “severe” event impacting ore-handling and logistics systems.
- Recovery sequencing prioritises Deep Mill Level Zone and Big Gossan underground mines, which resumed ahead of affected GBC panels.
Our Take
With Grasberg in Indonesia accounting for about 3% of global copper supply and 1.7 million lb of annual copper output, any multi‑year ramp‑up delay tightens the market just as other large copper projects in Chile, such as Freeport’s El Abra expansion, are still in the permitting and study phase.
Freeport-McMoRan’s move comes after it recently crossed the $100 billion market capitalisation mark in our coverage, so prolonged sub‑50% production at Grasberg could increase investor scrutiny on how the group balances safety upgrades with sustaining high‑margin copper and gold volumes.
Given Freeport’s identification by Morgan Stanley as a key supplier of copper and rare earth-related inputs for space hardware, reliability issues at high‑volume assets like Grasberg may push the company to diversify more aggressively into US assets such as the Shiloh exploration district in Georgia to underpin long‑term supply commitments.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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