Codelco is facing an extended stoppage at one of its smelters as the world’s largest copper producer struggles to complete an overhaul in time for the start of stricter emission standards in Chile. The duration of the smelting disruption at the Chuquicamata operation isn’t clear. One of the main unions said Thursday that it will be halted for 60 days starting Dec. 13, when the new rules kick in, while the Santiago-based company said some processes may be interrupted for 80 days. “We’re talking about 50-year-old machinery, for which there’s no replacements in the market, so our workers have been repairing it themselves for years," Union No. 3 president and smelter coordinator Rolando Milla said by telephone. "The time to invest in the smelter was many years ago and by not doing it they have let it die.” The smelter has been operating at a reduced capacity since mid-September, when the air blower in the thermal-electric sulfur plant broke down, Milla said. Copper futures pared losses as news of a likely stoppage emerged. Codelco embarked on an almost $1 billion smelting upgrade at Chuquicamata three years ago as Chile prepares to introduce rules that require plants to capture 95 percent of emissions. Seeking ‘Flexibility’ The state-owned company is having difficulties installing equipment while the smelter is operating, it said in an emailed response to questions. As a result, some “processes” could experience delays of about 80 days from mid-December, the company said. Maintenance and upgrading works that were scheduled for later in the year will be brought forward to this period, both the company and Milla said. Chairman Juan Benavides said Tuesday that there may be “a little delay” of 30 to 60 days in the Chuquicamata smelter upgrade and that the company is asking its customers for “flexibility” to be able to deliver concentrate rather than processed copper. The market is expected to post a deficit of 90,000 metric tons this year, theInternational Copper Study Group said earlier this month, more than double a forecast made in April. Some large producers are delaying investments as trade tensions cloud the outlook for global growth. More Clarity The Chuquicamata smelter -- the world’s 13th largest, according to Bloomberg Intelligence -- is operating at a capacity of 1,800 tons a day with a converter on maintenance, Codelco said. Repairs will continue through the first days of November, after which capacity will increase to 2,400 tons, it said. Codelco’s third-largest mine produced 137,000 tons in the first half of the year, 18 percent above the same period last year. Unions expect to have more clarity about the impact of the stoppage on output after an Oct. 16 meeting with management, Milla said. Emission standards are in the news in Chile right now following a series oftoxic gas leakages around the industrial town of Quintero, to the south. More than 1,200 people have sought emergency medical treatment since the first pollution episode on Aug. 21, the regional healthcare secretary said on Sept. 27. Operating in that area is Codelco’s Ventanas smelter, which has already been fully upgraded to new emission standards, as well as state oil refiner Enap and Copec SA. In the past month, authorities have charged GNL Quintero, Oxiquim SA, Gasmar SA and Enap for breaching environmental regulations.