The Zip Feed Mill (Sioux Falls, South Dakota)

 tower, mill, historical layer / disappeared object

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The Zip Feed Mill tower, at 202 feet tall, was the tallest building in Sioux Falls, South Dakota, and possibly the state. The mill had sat vacant for several years, and had not been used for its original purpose for much longer. To make way for ongoing development of the property it occupied, plans were made to demolish it.

A large media campaign was built around the demolition to raise money for charity. Tickets were sold for a raffle to decide who would flip the switch to detonate the explosives that would topple the building. An estimated 50,000 people showed up for the demolition, scheduled for 12:55 p.m. CST on 3 December, 2005.

When the switch was thrown, the explosives went off, but the building simply dropped about 20 feet into its own basement, tipped about 15 degrees to the east, and stopped. The company hired to demolish the building, Dykon Explosive Demolition of Tulsa, Oklahoma, failed to accurately assess what it would require to drop the building on its side. The plan was for the explosives to remove the supporting structure at the ground level on the east side first, creating a hinge point, and the building would simply topple to the ground and crush itself on impact.

What actually happened was that the explosives shattered the supporting structures on both sides of the building almost equally, which caused the concrete structure to fall almost vertically, which didn't allow sufficient velocity to tip it on its side. Following this most public failure, Dykon brought in a crane with a wrecking ball to finish the job, which took several weeks to complete.

Video can be found on YouTube youtube.com/results?search_query=zip+feed+mill&sear...
and on Google Video video.google.com/videosearch?q=zip+feed+mill

www.gadgetopia.com/post/4697

The imagery used by Google Maps seems to be from the winter months prior to the building's demolition; as the images are updated in the future, the mill tower will obviously not be seen; the office complex (Cherapa Place) that was built on the site will be visible instead. It may be worth noting that the concrete from the old mill tower was crushed on site and used as fill during construction.