The extant smelter stack is the first of two identical stacks at the San Juan and New York Mining and Smelting Company (SJ&NY) plant in Durango. It stands at the south end of the site of the original plant. SJ&NY grew to become the largest smelting operation in the San Juan Mountain mining region, originally processing gold, silver, lead, and copper primarily for eastern manufacturing concerns. Beginning in the 1940s, the plant processed uranium for WWII research in Los Alamos, and post-war security programs. The stack, as part of the original smelter's operations, played and significant role in the industrial development of Durango and southwest Colorado.