Alliant Energy officials are giving residents in a small, north central Iowa town tours of a new dome constructed over a huge pile of coal. Residents of Williams have complained of coal soot and noise from the Alliant Energy coal pile, and in mid-May, there was a fire on the site. A new “air-inflated” dome, similar to those constructed over golf practice facilities, now covers the coal. Dave Marshall of Alliant Energy is leading some of the tours. He says trucks enter an airlock at the end of the bubble that allows them to go in without deflating the dome. The trucks then load up with coal and leave via the same airlock. All the coal conveyors are enclosed in the dome to cut down on outside dust. The coal is being hauled to Ames. Residents of Williams are touring the site from four to six this afternoon. The dome was opened for media tours at mid-day. Williams is located about 20 miles east of Webster City, right off of Interstate-35.