The Sioux City Ball Corporation plant is closing and consolidating its operations into the Ball plant in Ames. Patty Heagle, the head of the Sioux City economic development division, says the consolidation of the plastic container maker is part of an ongoing process.Heagle says the closing of the Ball plant is not an indication that the economy of the area is experiencing a downturn.The closing of the Sioux City plant will put 75 people out of work. The company will offer them a severance package.