High Copper Prices and Holidays Prompt Production Cuts, SMM Predicts 10.77% Drop in Operating Rate

Two unions representing workers at Antofagasta Minerals' Centinela copper mine in Chile have called a strike vote after collective bargaining negotiations with the company reached an impasse.​ The Trabajadores de Minera Esperanza and Trabajadores Distrito Centinela unions said they received the company's latest offer on September 23 as part of their joint collective bargaining process. After reviewing the proposal, the unions called on their members to vote on whether to strike, with voting scheduled to take place between September 26 and September 28.​ The unions said the latest proposal failed to resolve their concerns over differences in benefits and remuneration between workers performing similar functions. The two organizations have been conducting a joint bargaining process and have called for greater alignment in employment conditions.​ However, a strike has not yet begun and operations at Centinela have not been reported as disrupted. Under Chilean labour procedures, if workers vote to reject the company's offer, the parties must still undergo a mandatory five-day government mediation period before a legal strike can begin. The mediation period can be extended by another five days if both sides agree.​ Antofagasta Minerals declined to comment on the ongoing collective bargaining negotiations. The company had previously disclosed that two collective bargaining processes involving workers' unions at Centinela were scheduled for the second half of 2026.​ The strike vote introduces a near-term supply risk at Centinela, although there has been no reported impact on copper production at this stage. The immediate focus will be on the September 26–28 vote and, if workers approve strike action, whether the subsequent mandatory mediation process results in an agreement. Any escalation into an actual work stoppage could increase supply-side uncertainty in Chile's copper sector, while an agreement during mediation would limit the operational impact.

[SMM Copper Cathode Rod Flash] High copper prices and high premiums kept downstream buyers on the sidelines, with new orders pulling back notably. Only end-users in wire and cable and enamelled wire saw operating rates rebound, driven by stockpiling. Inventories: Tight spot copper cathode supply combined with pre-holiday restocking pushed raw material inventories up MoM. Downstream cargo pick-up slowed, leading to a passive increase in finished product inventories MoM.

Gunnison Copper announced that its Johnson Camp Mine in Arizona achieved commercial production in September 2026, following record monthly copper cathode production in August and sustained operations above the company's required operating threshold during the first half of September.​ Johnson Camp produced 1.30 million lb, or approximately 592 mt, of copper cathode in August, marking its highest monthly production since operations restarted. The mine subsequently produced another 894,767 lb, or approximately 406 mt, of copper cathode between September 1 and September 17.​ Gunnison said the sustained operating performance in September supported its determination that Johnson Camp had reached commercial production. The operation is continuing to ramp up toward its nameplate production capacity of up to 25 million lb/year, equivalent to approximately 11,340 mt/year, of copper cathode.​ Johnson Camp produces 99.999% pure copper cathode directly from ore mined in Arizona, with copper processed into finished cathode at the site without requiring external smelting and refining. The operation is fully funded by Nuton LLC, a Rio Tinto venture.​ The achievement of commercial production follows the restart and subsequent ramp-up of Johnson Camp, while Gunnison continues to advance its larger flagship Gunnison Copper Project in Arizona.​ The achievement of commercial production at Johnson Camp marks a further step in the ramp-up of US domestic copper supply. August production reached a record level since the restart, while sustained output through the first half of September supported the company's declaration of commercial production. Attention will now turn to the pace of the remaining ramp-up toward the mine's nameplate copper cathode capacity of approximately 11,340 mt/year.