I found information on Cranberry Magnetic Iron Mines while searching for decendents of Julius Dugger. William Dugger had interests in the mine. You will find a short history at www.crosswinds.net/~ruhi19/Genealogy/Dugger.html
I am the great, great, great, great (I believe) niece of William Dugger; descended from his brother James B. Dugger.
My great uncle, James Taylor Dugger, did extensive research on the Dugger family. He passed away in February, but I hope that some day his widow will pass along all of his information.
May be of interest to you:
Last Spring Dugger Mountain in Alabama was made a National Wildlife Preserve. The Duggers who lived on the mountain were of the same line.