Grasberg Delay Pushes Freeport’s Flagship Copper Recovery Into 2028

Freeport-McMoRan’s Grasberg recovery has become one of the defining operational stories in copper, with the company now facing a longer rebuild at the underground mine that underpins one of the world’s most important copper-gold districts.

PT Freeport Indonesia has adjusted the production recovery schedule for the Grasberg Block Cave underground mine in Central Papua, pushing a return to full operations into 2028. The revised timetable follows the September 2025 mudflow incident and the additional underground logistics and ore-handling work now required to restore safe, reliable production.

Mining in unaffected areas of the Grasberg Block Cave partially restarted in April 2026, but overall output remains in recovery mode at around 40% to 50% of normal capacity.

The revised ramp-up is commercially significant because Grasberg is not a marginal operation. Freeport describes the Grasberg minerals district as one of the world’s largest copper and gold deposits, with underground production expected to continue through 2041 under current operating rights. The district includes the Grasberg Block Cave, Deep Mill Level Zone and Big Gossan underground mines, supported by long-term development work at Kucing Liar.

The technical problem is centred on underground material handling. Following the shutdown after the mudflow, groundwater and wetter-than-expected ore conditions created additional constraints in moving ore through the system. Freeport has been modifying equipment used to load ore onto trains, including specialised chute technology designed to reduce mud-rush risk.

The issue has shifted the recovery profile from a fast restart to a more complex staged return governed by underground water control, chute performance, rail loading and safe drawpoint management.

The production impact is material. Freeport previously expected a stronger recovery profile through 2026, but now expects around 65% of Grasberg production to be restored in the second half of the year. The company also lowered its 2026 mine output expectations to 800 million pounds of copper and 700,000 ounces of gold, compared with earlier expectations of 1.1 billion pounds of copper and about 800,000 ounces of gold.

That delay lands in a copper market already struggling to match long-term demand growth. Copper’s role in power networks, motors, batteries, computing equipment and industrial wiring gives Grasberg’s recovery a direct bearing on the supply side of electrification, grid expansion and data-centre growth. The significance lies in the scale of the lost timing: tonnes that were expected to return sooner are now tied to engineering modifications in one of the most technically complex underground mining systems in the world.

For Indonesia, Grasberg remains a national strategic asset as well as a global copper source. PT Freeport Indonesia is majority Indonesian-owned, with 51.24% held collectively by state-owned MIND ID and PT Indonesia Papua Metal Dan Mineral, while Freeport-McMoRan holds 48.76% and manages the mining operations.

The operating structure gives Indonesia direct exposure to the timing of recovery, production volumes and downstream supply into its domestic processing strategy.

The next operational marker is not simply whether ore continues to move but whether the modified underground handling system can lift output safely and consistently through the remainder of 2026 and into 2027. Grasberg’s geological scale remains intact, but its near-term contribution to copper and gold supply now depends on the reliability of a staged underground recovery under wetter, more complex operating conditions than previously planned.