the inside surface. It takes 20 minutes to ascend the stack, although workers only need to travel up to the 300-foot level each day, to service the air-sampling station. The Garfield Smelter Stack is the tallest free-standing structure west of the Mississippi River, the fourth tallest smokestack in the world and the fifty-ninth tallest free-standing structure on earth. It is the only operating smelter chimney left in Utah. See also List of chimneys List of tallest freestanding structures in the world References External links Kennecott Utah Copper A comparison with other large stacks of the world can be seen at skyscraperpage Buildings and structures in Salt Lake County, Utah Chimneys in the United States Towers completed in 1974 Towers in Utah 1974 establishments in Utah