Copper has posted its longest run of weekly gains since 1994 as shrinking exchange inventories, mine disruptions and uncertainty over potential U.S. tariffs heighten pressure on the physical market. LME benchmark prices recorded a 10th consecutive weekly advance through last Friday, trading near $14,300 a ton and approaching January's record of $14,527.50. Comex prices exceeded $6.70 a pound in August, setting a record. LME warehouse stocks declined for 42 consecutive days through mid-August, while nearly half the remaining inventory was already designated for withdrawal. The supply concerns intensified after roughly 800,000 tons of wet material flooded Freeport-McMoRan's Grasberg mine in Indonesia on Sept. 8, 2025, killing two workers and triggering a force majeure (contractual relief after extraordinary disruption) that continues to affect the supply chain. Freeport reduced its 2026 production guidance for the complex by about one-third, with full recovery not expected before 2027 or 2028. Global mine output fell 1.1% in the first half of the year, according to International Copper Study Group data, while Codelco and Freeport reported double-digit declines. Chile cut its 2026 production forecast twice, to a 2.6% decline, after recording its weakest second quarter in at least 19 years. Codelco's Andes Norte expansion at El Teniente is not expected to begin production until 2029. Congo's early-August ban on copper and cobalt concentrate exports, intended to encourage domestic processing, affected only a small share of the country's copper trade but still lifted LME prices 1.8% on the day it was announced. U.S. tariff uncertainty has also redirected metal: about 200,000 tons of refined copper entered the country in July, a record monthly inflow, taking Comex inventories above 1 million tons as buyers sought to get ahead of a possible 15% duty that could begin as soon as January. The market does not yet show an immediate shortage of refined metal. Morgan Stanley expects refined production to rise nearly 1% this year as smelters use more scrap, even while mine output declines. The larger concern is mine supply. Citigroup sees copper reaching $15,000 a ton by year-end and potentially $17,000 if artificial-intelligence demand or a manufacturing recovery outpaces available supply. BlackRock's Evy Hambro said existing operations face declining grades and aging assets, while Anglo American's Ruben Fernandes said supply will come but questioned how quickly. Reuters columnist Andy Home said the market's reaction to Congo's export measure suggested further volatility could follow.