The Bunker Hill Mine and Smelting Complex was the largest silver-lead smelter in the United States for much of the 20th century. The mine that Noah Kellogg's jackass allegedly found in 1885 became the anchor of a massive industrial operation that ran for nearly a century before closing in 1981. The smelter's stack — a distinctive chimney visible from much of the valley — remains standing as a monument to both the industry's scale and its legacy of contamination.
The site is now part of the Bunker Hill Superfund site, one of the largest environmental cleanup projects in US history. The contamination left behind — lead, zinc, cadmium, and arsenic in the soil — affected an area of over 21 square miles and required the replacement of topsoil in hundreds of residential properties. A small interpretive area near the site explains the history of both the mine and the cleanup.