A demolition team is making the final preparations for tomorrow's implosion of a ten-story office building in downtown Louisville.The structure, formerly owned by Humana, is coming down to make way for the new arena at Second and Main Streets.Demolition contractor Michael O'Rourke says the implosion, scheduled for 7:00am, will last just 12 seconds, but it will be at least an hour-and-a-half before traffic can resume moving through the area."We will not open the streets until we're 100 percent confident we can give the all-clear, we have to make there's no problems with neighborhood properties, obviously we don't anticipate that," O'Rourke said.A safety zone bounded by First, Fourth and Market Streets and River Road, will be in force starting at 6:00am.The public can watch the implosion from a parking garage at First and Main Streets.