Ok Guys if this was Colorado I could tell you where the yellow is.This is Illinois,Well I did a lot of research and some panning here is some spots:
Gold in Gay,Fountain,Sugar Creek.Also in Creeks in Marchall,Lincoln along Salt Creek,along Kickapoo Creek.East fork of Spoon River in Noth East part of Stark County.
Rock River has bedrock,good place to pan.Green River near Amboy bears a good chance to pan.Kankakee River near Momence,Wilmington,and other points. Good Luck
May the bottom of your pan always be yellow.Remember if it is private property get permission.
Terry