Copper concentrate treatment charges slipped to $8-12/t in June, down from $18-22/t a year ago and approaching the crisis levels of 2024. The TC is the fee smelters charge miners to process concentrate into refined copper. A falling TC means fewer smeltable tons are available relative to capacity.
The current TC compression has two drivers. First, mine supply disruptions at Freeport-McMoRan's Grasberg operation in Indonesia and Ivanhoe Mines' Kamoa-Kakula complex in the DRC have removed an estimated 180,000t of concentrate from the 2026 supply pipeline. Second, new Chinese smelting capacity came online in 2025-2026, increasing competition for available concentrate.
Historically, TC sustained below $15/t for more than three months has preceded refined output cuts. The last comparable episode in 2024 drove a 3% reduction in Chinese refined production. The International Copper Study Group (ICSG) has flagged the risk of non-discretionary smelter curtailments in the fourth quarter if the TC environment does not improve.
The bull case for copper builds on this mechanism: tight concentrate limits refined output, which eventually draws down the elevated LME stocks. The bear case is that Chinese demand weakness persists long enough for inventories to absorb the supply shock without a price response.
TC compression is a leading indicator for copper supply. When TCs fall below $15/t, the probability of smelter cuts within 3-6 months increases significantly. For Q4 delivery, consider fixing at least partial volumes at current levels around $13,500/mt. If TCs remain below $10/t through August, the case for Q4 supply tightening strengthens.