Copper price back at record’s edge as Grasberg smelter halt bites, aluminum surges

Metal Markets Abuzz as Supply Disruptions Fuel Price Rallies

Metal markets are experiencing a significant jolt as key supply disruptions push prices to multi-week and even record highs. Copper has dramatically closed the gap with its all-time zenith, propelled by an unexpected operational halt at a crucial Indonesian processing plant. This event exacerbates an already tight supply environment, keeping the benchmark London contract firmly above the $14,000 per tonne mark for an extended period. Simultaneously, the aluminum market is witnessing a substantial uplift, reaching a seven-week high following a drastic reduction in output from a major Brazilian alumina facility.

In the U.S. Comex market, September-delivery copper futures flirted with history, reaching $6.7005 per pound (equivalent to $14,772 per tonne). This level was merely four-tenths of a cent shy of the record $6.7045 per pound established on August 5. While it later pulled back to $6.6360, still marking a 0.3% gain for the session, the market sentiment remains bullish. Further out the curve, the December contract climbed to $6.7980, and contracts for the latter half of 2027 were trading hands above the psychologically significant $7 per pound level. This extended pricing suggests deep-seated supply concerns are influencing longer-term expectations.

On the London Metal Exchange (LME), three-month copper registered a more modest change, settling near $14,195.50 per tonne. This leaves the premium over the Comex contract at approximately $435, underscoring the strength of U.S. pricing dynamics. The physical scarcity is further evidenced by the cash metal settling $138 above the three-month contract on Monday, the widest such premium seen for near-term deliveries since October. This is a classic indicator of immediate demand outpacing readily available supply.

The catalyst for much of this copper price action is the operational suspension at the Gresik smelter in Indonesia. Buyers were notified that the plant would cease operations for an indefinite period of assessment and repair following a boiler leak on August 8. Gresik is a vital processor for ore originating from the massive Grasberg mine. The facility is a joint venture between Mitsubishi Materials and PT Freeport Indonesia.

Mitsubishi has confirmed the suspension, stating that no definitive restart date has been set. This development casts a shadow over immediate supply availability. While Freeport's own Manyar smelter in East Java is slated to restart production in September, the combined output of these two plants is expected to hover around 400,000 tonnes of cathode annually. Crucially, the Grasberg mine itself is still in the recovery phase following a devastating mudslide in September of the previous year, with full production not anticipated until the close of 2027.

Aluminum's Ascent Driven by Brazilian Output Shock

The aluminum market also saw a significant surge, with prices climbing as much as 1.9% in London and trading 1.7% higher at $3,373 per tonne. This rally was triggered by an announcement from Norsk Hydro. The company revealed that its Alunorte refinery in Brazil, recognized as one of the world's premier alumina sources, has slashed its operational capacity by half. The reason cited for this drastic measure is disruptions to the natural gas supply chain, impacting its key supplier.

Adding to the bullish sentiment for aluminum, alumina futures in Shanghai closed 1% higher at 2,724 yuan per tonne. The broader context includes ongoing geopolitical tensions in the Middle East, which have disrupted flows from a region accounting for approximately a tenth of global aluminum output. This has depleted LME inventories to around 255,000 tonnes, a level not seen since November 1990. Analysts at Hydro had previously cautioned that a global shortfall could exceed 900,000 tonnes annually if maritime traffic through the Strait of Hormuz remains compromised.

Yan Weijun, head of nonferrous metals research at Xiamen C&D, commented on the situation, noting that the lack of smooth progress in Middle East negotiations is likely to provide continued support for aluminum prices. Other metals on the LME showed mixed performance. Tin held near $55,750 per tonne, reflecting a substantial 37% gain for 2026. Zinc, however, slipped to $3,728, and lead remained relatively steady at $1,908. Nickel lagged behind, down 1% at $16,782, showing little change for the year.

Why This Matters Now

The current supply-side shocks impacting both copper and aluminum markets are creating a potent cocktail for investors and traders. The prolonged strength in copper prices, now testing record levels, is directly linked to the unexpected shutdown of the Gresik smelter. This event highlights the fragility of a supply chain already strained by the ongoing recovery at the Grasberg mine. The widening premium of cash copper over futures contracts is a clear signal that physical availability is severely constrained in the short term.

For traders, the implications are substantial. The market's reaction, particularly the extended Comex futures trading above $7 a pound for 2027 contracts, suggests that the supply deficit is perceived to be structural rather than temporary. This could encourage further price appreciation if the Grasberg mine's full recovery is delayed or if other supply disruptions emerge. The situation in aluminum, driven by the Alunorte refinery's output cut and Middle East transit issues, also points to persistent tightness. Investors should closely monitor inventory levels on the LME and Comex, as well as any further updates on the Gresik smelter's repair timeline and the geopolitical situation in the Strait of Hormuz.

The stark contrast between the soaring metal prices and the declining performance of major mining stocks like Freeport-McMoRan, Lundin Mining, and Vale is particularly noteworthy. This divergence suggests that while the underlying commodities are in demand, broader market sentiment or specific company-related challenges might be weighing on equities. Market participants will be watching how quickly these mining giants can navigate operational hurdles and benefit from the elevated commodity prices. The relationship between commodity prices and related equities can often decouple, presenting both risks and opportunities for astute observers.

The connected markets to watch closely include industrial metals ETFs, currency pairs sensitive to commodity export revenues such as USD/CAD and AUD/USD, and potentially broader equity indices like the S&P 500 Materials Sector, which saw a slight dip. The sustained high prices for copper and aluminum could also feed into inflation expectations, potentially influencing central bank policy discussions later in the year.