Anaconda Smelter Stack

The Anaconda Smelter Stack is a radial brick smoke stack, once part of the Anaconda Company at Anaconda, Montana in the United States. The stack rests on a concrete foundation and measures 585 feet 1.5 inches (178.3 m) high. The inside diameter of the stack is 75 ft (23 m) at the bottom and 60 ft (18 m) at the top. The wall thickness ranges from six feet at the bottom to two feet at the top.

Construction of the stack was completed on May 5, 1919. The Stack was built by the Alphons Custodis Chimney Construction Company of New York. At the time it was built, it was the tallest masonry, brickwork structure and chimney of any kind in the world and it remains the world's tallest and possibly largest free standing masonry structure. An interesting note is that the Washington Monument would easily fit inside. It is commonly referred to as 'The Stack' and is a well known landmark in western Montana.

The stack was designed to discharge exhaust gases from the various roasting and smelting furnaces at the smelter. The stack is situated on the top of a hill. The smelter had a large network of exhaust flues from the furnaces that all fed a main flue. The main flue carried the combined smelter exhaust gases a half-mile up the hill to the stack. The flue system and stack combined to provide a natural draft to carry the smelter exhaust gases, and it was claimed to be capable of handling three to four million cubic feet per minute of gas.

The Anaconda Smelter was demolished after its closure in 1981, and the site underwent environmental cleanup. The stack alone, however, remains standing. After the smelter’s closure, citizens of Anaconda organized to “Save the Stack,” and in 1986 it was designated a state park. The site is known as Anaconda Smoke Stack State Park.