Lead and Zinc Mining in the Dubuque Area
Lead and Zinc Mining in the Dubuque Area by Greg A. Ludvigson and James A. Dockal This small cave, along Catfish Creek valley, is an example of cavern development in an oxidized lead ore deposit and may have been one of Julien Dubuque''s "Mines of Spain." Photo by Jim Dockal, University of North Carolina at Wilmington.