Jacob Snively began Castle Dome Mines in 1862. They were the second patented in Arizona. In 1864 Castle Dome City's population was 12. By the 1880's the population of what was then called Castle Dome City exceeded that of Yuma. By now there were 300 mines and they were the longest working mines in Arizona. From 1862-1979 the mines and the lives of those who worked them thrived. In 1979 when silver prices dropped to an all time low, the mines were closed. Castle Dome Mining District was left to the sun and forgotten. The Armstrong's purchased and restored the area, so people could learn of the rich history of Arizona mining. Looking at one of the many mines in the area.