Union Pacific headquarters building auction nearly ready to roll.

By Stacie Hamel, Omaha World-Herald, Neb. Knight Ridder/Tribune Business News

Feb. 9--Tanner Hernandez enjoys digging into a modern-day archaeological site for 14 hours a day.

Since November, the latest dig for Hernandez and a crew of 20 has been the 12-story, 575,000-square-foot former headquarters of Union Pacific Corp. in downtown Omaha.

"I feel like a historian," he said.

The first of more than 10,000 items will go up for auction Thursday, the start of a three-day sale down the street from the U.P. building in a ballroom of the Doubletree Hotel, 1616 Dodge St. The sales total could reach $500,000, said Hernandez, general manager …