Bob Lenon came from Nebraska to Yuma, in 1914, just two years after Arizona had become the 48th state. He remembers seeing the Colorado River when it had no highway bridges and traveling on a plank road across dunes where an Interstate Highway now runs. Because Bob grew up listening to neighbors' tales of gold in the hills, it was natural for him to make mining his life-as a prospector and as a mining engineer. He became an intrinsic part of the...