PHOENIX — Any way you look at it, Superior is a town down on its luck. Since the mines closed in the 1980s, most of the community's businesses have folded and more than half of its residents have moved away. But in the struggling community that has seen its share of booms and busts, another boom could be on the horizon. At the old Magma Mine's Shaft No. 9, east of town, geologists are swooning over ore samples taken from more than 7,000 feet below the surface. They show a huge deposit of high-grade copper ore that geologists believe could...