Grasberg makes
$FCX go. The move seems understated,
Freeport has declared force majeure at Grasberg — and with good reason.
This will shake both copper and gold balances. Let me explain why.
Grasberg is a giant. One of the largest mines on earth, producing ~1.7bn pounds of copper (≈2% of global supply) and ~1.6Moz of gold pa (≈1.5% of global supply).
Think of it as a vast underground city: 28,000 employees, 250 km of tunnels across dozens of levels. Each year, 35–40 km of new tunnels are added — roughly the length of Switzerland’s Gotthard Base Tunnel (57 km), the world’s longest rail tunnel.
At its heart lies the Grasberg Block Cave (GBC), which accounts for ~70% of reserves and output. Other sections include Big Gossan and Deep MLZ.
On Sept 8, disaster struck: ~800,000 tons of wet material suddenly rushed in, flooding multiple underground levels. The mud hit GBC directly — the very core of Grasberg’s production.
A catastrophic failure. How was this even possible?
Block caving itself may become central to the story. Out of more than 12,000 active mines worldwide, only ~20 have ever used block caving — a handful do so today - El Teniente in Chile; Oyu Tolgoi in the desert in Mongolia; Cadia East & Northparks, both Australia; Palabora, SA; who else? That’s <0.1% of all mines.
None do so or did in the past within a similar rainy climate as Grasberg does.
Block Caving is an extremely rarely applied mining method, reserved for very large, low-grade underground ore bodies which themselves are exceptionally rare. Most mining is open-pit, stoping, or cut-and-fill.
Block Caving has economic appeal — low cost per ton — but the geotechnical risks are likely immense. Once caving starts, the process is essentially an engineered collapse of the mountain. What could possibly go wrong?
That’s why this accident isn’t just a local disaster IMHO. It could become a case study for the entire mining method. Perhaps it wasn’t well understood how block caving behaves under Indonesia’s heavy rainfall and complex geology? I don’t know — but I wouldn’t be surprised if that proves decisive.
My view? By year-end, Freeport will be fortunate just to understand the mechanics of this accident. Until then, production forecasts are pure guesswork.
Such a failure should (a) have been impossible, and (b) means operations can only restart once it’s crystal clear why it happened and how it can be prevented from happening again.
Analysts say full recovery is likely by 2027. That’s total nonsense. Nobody really knows. A true “known unknown.”
What is known: any company with less strength and brainpower than Freeport McMoRan would likely go bankrupt from this. Think Victoria Gold — a minor heap leach pad slide sank it within weeks.
Mining companies get hit twice: revenues vanish while capital costs to fix the damage soar, and regulators delay re-issuing permits until safety is proven. And this accident involves death. It’s a total nightmare.
My view? This is no quick fix. With infrastructure damaged, safety paramount, at least two confirmed dead and five still missing, investigations ongoing, potential class actions looming, and permitting hurdles ahead, the road back for Grasberg will be long and uncertain.
The only good news: Grasberg adds too much to the GDP of Indonesia to not fix this nightmare.