 At its peak in 1875, Caribou's population was estimated to be about 3,000 people.Caribou and its silver mines were completely deserted by the time 19-year-old geology student Tom Hendricks saw it in 1970, but Hendricks became convinced that the silver mines at Caribou could make a profit, and has made the mines his life work.After he got his geology degree, he acquired the old Cross mine in 1973, and began shipping silver concentrate in 1977.