Copper price hits US record: sulphur constraints and tariff risks for mine planners
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Copper futures on Comex jumped 2.4% to a record $6.69/lb, widening the premium over LME contracts, which rose 1.6% to nearly $14,200/t, as traders priced in possible new US tariffs on refined copper imports. Supply risk is intensifying, with Gulf disruptions choking sulphur flows, threatening sulphuric acid availability for roughly one-fifth of global mined copper and potentially curbing up to 4.8 Mt of production if the Strait of Hormuz closes. Refined output is already reacting, with China’s April production down 3% and further declines expected, even as copper prices are up more than 10% year-to-date.
Technical Brief
- Comex futures moved 2.4% in a single session, versus 1.6% on the LME, signalling location-specific pricing stress.
- The LME benchmark is trading within roughly $300/t of its January all‑time high of $14,500/t.
- Price action follows a 40% copper price increase during 2025 driven by earlier mine disruptions.
- China’s refined copper output decline in April is already being linked to mine‑level raw material shortages.
- Arbitrage between US and LME contracts has reopened, encouraging metal inflows into US warehouses and altering regional inventory cover.
Our Take
Both this piece and the 12 May copper futures article flag sulfur and sulfuric acid as constraints, underscoring that any disruption through the Strait of Hormuz could hit not just Gulf-region smelters but also sulfur-dependent leach operations that our database shows are increasingly important for marginal copper supply.
With Comex copper at $6.69/lb and LME prices still $300/t off their peak, US-focused developers and recyclers are likely to lean on the upcoming 30 June Commerce Department report to argue for tariff or stockpile measures that lock in a domestic price premium relative to London benchmarks.
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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