The Zip Feed Tower was a grain elevator

Grain elevator

A grain elevator is a tower containing a bucket elevator, which scoops up, elevates, and then uses gravity to deposit grain in a silo or other storage facility...

 and feed mill in Sioux Falls, South Dakota

Sioux Falls, South Dakota

Sioux Falls is the largest city in the U.S. state of South Dakota. Sioux Falls is the county seat of Minnehaha County, and also extends into Lincoln County to the south...

. At 202 feet (62 meters) it was the tallest occupiable structure in South Dakota

South Dakota

South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...

 from its construction in 1956-1957 until its demolition in December 2005. The mill closed in 2000 and in 2005 was scheduled for demolition to make way for office and retail space.

Attempted demolition

On December 3, 2005 workers unsuccessfully attempted to implode

Building implosion

In the controlled demolition industry, building implosion is the strategic placing of explosive material and timing of its detonation so that a structure collapses on itself in a matter of seconds, minimizing the physical damage to its immediate surroundings...

 the building. The concrete tower fell into its own basement

Basement

__FORCETOC__A basement is one or more floors of a building that are either completely or partially below the ground floor. Basements are typically used as a utility space for a building where such items as the furnace, water heater, breaker panel or fuse box, car park, and air-conditioning system...

, leaning to one side but still standing. Demolition crews had attempted to drop the structure by cutting reinforcing bars throughout the structure then placing explosive charges in a ring around the base and up between the vertical silos. However, the integrity of the structure was such that, as the base was sheared off, the main structure dropped straight down crashing through the damaged base into the lower chambers (i.e. the basement).

A review of the demolition project proved that the crew had seriously underestimated the amount of cutting explosive required to "break" the structure's vertical integrity. Over the next two weeks a crane

Crane (machine)

A crane is a type of machine, generally equipped with a hoist, wire ropes or chains, and sheaves, that can be used both to lift and lower materials and to move them horizontally. It uses one or more simple machines to create mechanical advantage and thus move loads beyond the normal capability of...

 and wrecking ball

Wrecking ball

A wrecking ball is a heavy steel ball, usually hung from a crane, that is used for demolishing large buildings. It was most common during the 1950s and 1960s. Several wrecking companies claim to have invented the wrecking ball...

 were used to complete the demolition. The tallest building in Sioux Falls today is the 11-story Qwest Tower

Qwest Tower (Sioux Falls)

Qwest Tower is an office building located in Sioux Falls, South Dakota. It is 174 feet tall and has 11 stories, and is the tallest building in the state of South Dakota. Previously the 202-foot Zip Feed Tower was the tallest building in Sioux Falls, as well as South Dakota...

.