Copper prices bounce on US warehouse squeeze: supply and capex signals for mines
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Copper climbed 3.3% intraday to $6.8410/lb on Comex and $14,710.50/t on the LME as visible stocks tightened, with LME on-warrant inventory down to 133,725 t and cash copper flipping from an $86/t discount to a $26/t backwardation in a week. Comex warehouses now hold 696,204 t, about 69% of exchange-monitored copper, but storage at the Port of New Orleans is near capacity even as another 100,000 t from Africa and South America is due by October. Supply disruptions at Grasberg and Kamoa-Kakula have removed roughly 600,000 t from 2026 mine output, supporting prices less than 2% below record highs.
Technical Brief
- Of 255,900 t in LME warehouses, 115,450 t (45%) are cancelled warrants already scheduled for withdrawal.
- Yangshan copper premium reached $124/t, a near four‑year high, before easing slightly to $119/t.
- Planned maintenance at multiple Chinese refineries in October–November is expected to constrain domestic refined output into year‑end.
- Port congestion at Shanghai is obscuring arrival timing for seaborne copper cargoes into China’s main import hub.
- Comex copper stocks recorded their first weekly decline since April, slipping 65 t in the latest week.
- New Orleans, the primary Comex delivery hub, is reported “largely full”, constraining further physical inflows into US storage.
- Supply losses from Freeport’s Grasberg and Ivanhoe’s Kamoa‑Kakula operations total about 600,000 t versus prior 2026 expectations.
Our Take
The tight US warehouse situation for copper echoes the 9 September coverage of Comex and LME contracts trading near record levels, signalling that physical bottlenecks are now reinforcing the financial squeeze already visible in exchange spreads.
Our database shows multiple 2026 copper pieces linking constrained mined output at Grasberg, Kamoa-Kakula and Chilean operations with rising Yangshan and Comex premiums, suggesting that traders with flexible logistics between the US, China and Chile can arbitrage location and quality differentials more aggressively than in prior cycles.
With Comex now holding about 69% of exchange‑monitored copper and US‑listed majors like Freeport‑McMoRan, BHP and Southern Copper all featuring heavily in recent coverage, North American storage and port capacity (e.g. New Orleans) is becoming a strategic constraint that mine planners and marketers will need to factor into offtake and shipment scheduling by year‑end.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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