Grant, Iowa and Lafayette counties were once the center of a lead-mining boom. Indians had sold lead to early traders, but there were few white miners there in 1820. Mining brought in a large part of the 37,000 population credited to the three counties in 1850. Prospecting was done by practical men with little aid from mineralogical experts, using tools such as the shovel, pick, gad or crowbar, hand-drill and blasting powder. Mines were lighted by candles set in gobs of fire-clay that would stick to any part of the rock wall. Some miners spent the winters in caves or hurriedly prepared dug-outs and were nicknamed "Badgers." Many of the once thriving mining centers are now ghost towns, with only their refuse dumps and pock-marked land bearing evidence of the old mining days.