The May 2026 Kazzinc explosion and Cajamarquilla fire are the latest in a cascade of Western smelter disruptions that has removed more than 400,000 tonnes of annual refining capacity since early 2025. Collapsing treatment charges have broken the economics of Western zinc refining, and the attrition shows no sign of slowing.
The list of Western smelter closures and curtailments since early 2025 reads like a roll call of the industry's wounded. Toho Zinc permanently closed its Annaka smelter in Japan (120,000 tonnes per year). Korea Zinc temporarily suspended operations at its Seokpo smelter in South Korea. Nyrstar curtailed production at its Hobart smelter in Australia. Glencore shut its secondary zinc operations in Italy. And in May 2026, two of the West's largest remaining smelters — Kazzinc in Kazakhstan (250,000-300,000 tpy) and Cajamarquilla in Peru (~300,000 tpy) — were hit by accident and fire, respectively. (FACT: Reuters, Andy Home, January 27, 2026; Reuters, May 20, 2026; MINING.COM)
The cumulative impact: Western refined zinc production fell 2.2% year-on-year in 2025, even as global mine output surged 4.8-6.5%, according to ILZSG data. Every tonne of extra mine supply ran into a bottleneck at the smelting stage. Global refined zinc production grew only 1.7% in 2025, and all of that growth was Chinese. (FACT: ILZSG via Reuters, May 20, 2026)
The root cause is the collapse in treatment charges, the fee smelters charge miners to process concentrate into refined metal. The annual TC benchmark fell from $274 per tonne in 2023 to $165 in 2024 to $80 in 2025 — a 71% cumulative decline. The 2026 benchmark remains unsettled as of late May, with market participants discussing zero or negative numbers. At $80/t, a typical Western smelter cannot cover its operating costs, particularly in Europe where electricity prices remain 2-3x pre-2022 levels. (FACT: Fastmarkets, LME Week 2025; European Commission energy data; SMM)
Every unplanned outage therefore carries permanent closure risk. There is no economic incentive for a Western smelter operating at a loss to restart after a disruption. This dynamic was evident when Toho Zinc chose to permanently close Annaka in 2025 rather than restart. It threatens Kazzinc and Cajamarquilla as well — if the damage assessment reveals significant repair costs, the companies may elect to walk away from capacity that was already loss-making. (FACT: Reuters, SMM, 2025-2026)
LME stocks illustrate the severity of the attrition. Inventories fell from 230,325 tonnes at the start of 2025 to a crisis-level 34,700 tonnes (only 24,850 tonnes on-warrant) by October 2025 — barely one day of global consumption. While stocks have partially recovered to approximately 110,000-144,000 tonnes by May 2026, they remain less than half the level at the start of 2025 and critically low by historical standards. (FACT: SMM, LME, TradingEconomics, October 2025 through May 2026)
The International Lead and Zinc Study Group (ILZSG) has acknowledged the structural shift. In October 2025, the group forecast a 271,000-tonne surplus for 2026. By April 2026, that forecast had been revised to a 19,000-tonne deficit — a 290,000-tonne swing driven overwhelmingly by Western smelter attrition. And those April forecasts were made before the May accidents at Kazzinc and Cajamarquilla. (FACT: ILZSG, Kitco News, April 23, 2026; Reuters, May 20, 2026)
The Western smelter crisis is structural, not cyclical. Low TCs are not a temporary market condition — they are the direct result of a structural concentrate surplus meeting a structurally constrained Western smelting sector. Do not expect any of the closed or curtailed smelters to restart. Every additional outage carries permanent closure risk because the economics do not support reinvestment. Plan your 2026-2027 zinc procurement assuming that Western smelting capacity will continue to shrink. The only question is how fast and how much. Secure term contracts with Chinese or Middle Eastern suppliers to diversify away from Western smelter-dependent supply chains.
Action: The Western zinc smelter crisis is structural, not a temporary disruption. Do not wait for Kazzinc or Cajamarquilla to resume normal operations — their economics were already marginal before these incidents. Diversify your zinc supply chain immediately: negotiate term contracts with Chinese smelters (the only region adding capacity), lock in fixed premiums now before the deficit widens further, and establish secondary supply lines with Middle Eastern or Korean producers. A buyer purchasing 10,000 tonnes/year of SHG zinc who has relied on European or Latin American supply for 50% of that volume should assume that Western tonnage shrinks rather than recovers.
Horizon: Physical premiums are already rising — LME cash-to-three-month backwardation hit $85/mt and premiums in Europe are north of $400/mt. Expect further tightening through Q3 2026 as the full impact of Kazzinc and Cajamarquilla works through the supply chain. Chinese exports of refined zinc will partially fill the Western gap, but logistics (shipping, warehousing, quality certification) add 6-8 weeks. The ILZSG's 19,000-tonne deficit forecast was made before both May incidents — the actual deficit in 2026 could reach 100,000-150,000 tonnes.
Trigger: Watch two dates. First, Nexa's Cajamarquilla restart announcement — the company said it does not expect "material impact," but until a firm restart date is published, the market has priced in an extended outage. Second, Glencore's quarterly production report — if Kazzinc's reduced-capacity status extends beyond Q2, expect Glencore to signal force majeure on zinc deliveries, which would accelerate the price rally. LME on-warrant inventories falling below 80,000 tonnes (from ~88,750 currently) would be a third trigger for spot price spikes.