Why Freeport’s Grasberg Delay Keeps Copper Supply Tight Through 2027

The delay follows a 2025 mudflow or mud-rush incident that disrupted underground operations. Project Blue reported that Freeport-McMoRan declared force majeure on supply contracts tied to the Grasberg Block Cave after a Sept. 8 incident ^[12]. Local reporting also said the 2025 mudflow damaged underground infrastructure and operating systems, with the overall mine operating at only about 40%–50% of capacity ^[3].

That does not mean Grasberg is completely shut. Freeport-McMoRan said in November 2025 that production had resumed from the unaffected Deep Mill Level Zone and Big Gossan underground mines in late October, while remediation continued for a phased restart and ramp-up of the Grasberg Block Cave beginning in the second quarter of 2026 ^[5]. The key change is the time needed to restore the full complex to normal production.

Why one mine can move the copper market

Grasberg’s scale is the reason the timetable matters. Project Blue reported that Grasberg accounted for about 3% of global mined copper and ranked as the world’s second-largest copper mine by 2024 production ^[12]. The Business Times also described Grasberg as the world’s second-biggest copper producer before operations were hampered by the mudflow ^[2].

Earlier estimates already showed a significant production hit. Project Blue said 2026 output could fall by as much as 35% after the force majeure ^[12]. Fastmarkets similarly reported that copper and gold output was expected to be 35% lower in 2026, with a phased recovery previously expected to bring operations back toward pre-incident levels in 2027 ^[13]. The new early-2028 full-production target extends that recovery window by another year ^[2].

Another measure of the disruption’s scale came from Mining.com, which reported that Goldman Sachs lowered its global copper supply forecasts for 2025 and 2026 and estimated as much as 525,000 metric tons of lost copper mine supply from the Grasberg disruption ^[15].

The supply impact: less recovery in 2027

The immediate effect is not that Grasberg disappears from supply entirely; it is that the expected recovery comes later. If full output had returned by early 2027, the market could have treated 2026 as the main disruption year. With full production now aimed at early 2028, the supply risk stretches across both 2026 and 2027 ^[2].

That matters for copper balances because a mine of Grasberg’s size can change the difference between a comfortable market and a tight one. Reports on the new timetable described the delay as worsening supply constraints already affecting the global copper market ^[1][2]. Any forecast that assumed a 2027 normalization now needs either lower Grasberg supply assumptions or offsetting gains from other mines.

What it means for copper prices

On supply alone, the delay is supportive for copper prices because it postpones the return of a major source of mined copper. But it should not be read as a complete price forecast. Copper prices will also depend on demand, inventories, scrap flows and whether other mines add or lose production during the same period.

The practical conclusion is narrower but important: Grasberg does not guarantee a global copper deficit by itself, but it raises the probability that 2026–2027 balances are tighter than forecasts built around a 2027 recovery ^[2][13].

What to watch next

The most important near-term signal is capacity utilization. If the overall mine remains near the reported 40%–50% range rather than steadily moving toward normal output, the market has less buffer against other disruptions ^[3].

The next updates to watch are Freeport’s progress on the Grasberg Block Cave ramp-up, any changes to the early-2028 full-production target, and revisions to 2026 and 2027 mine-supply forecasts ^[2][5]. Until those improve, the delayed Grasberg restart keeps the copper supply side fragile for longer.