By the early 1900s Arizona had become the copper king of America. America was beginning to use electricity so copper was a much needed resource. Hard rock miners were brought in to the mines to get the copper. There were copper mines in Jerome, Bisbee, Clifton, Morenci and Ajo and they were in operation through World War I. But, like the other mining towns, these towns started to come upon hard times once all of the copper was mined. The copper boon towns managed to stay around a lot longer than the gold and silver boon towns. Many of the towns are still there today but others have turned into ghost towns.