Galena, Illinois for mayor and aldermen on May 24, 1841, replacing the board of trustees; Charles S. Hempstead was elected the first mayor with 185 of the 356 votes cast. The first census was also held that year, finding 1,900 inhabitants. By 1845 Galena was producing nearly 27,000 tons of lead ore and Jo Daviess County was producing 80 percent of the lead in the United States. Once one of the most important cities in the state, Galena was a hub on the Mississippi River between St. Louis and St. Paul. Due to erosion, the Galena River is now inaccessible to steamboats.
Iron oxide copper gold ore deposits named as IOCG, by discovery and study of the supergiant Olympic Dam copper-gold-uranium deposit, and South American examples. IOCG deposits are classified as separate to other large intrusive related copper deposits such as porphyry copper deposits and other porphyry metal deposits primarily by their substantial accumulations of iron oxide minerals, association with felsic-intermediate type intrusives (Na-Ca rich granitoids), and lack of the complex zonation in alteration mineral assemblies commonly associated with porphyry deposits. The relatively simple copper-gold +/- uranium ore assemblage is also distinct from the wide spectrum of Cu-Au-Ag-Mo-W-Bi porphyry deposits, and there is often no metal zonation within