The Magma was the last industrial short line railroad to use steam power, dieselizing on September 4, 1968.

The railroad has since changed hands and is currently owned by Resolution Copper, a joint venture of Rio Tinto and BHP.

Exploration in 2001-2003 resulted in the discovery of a large copper ore body some 7,000 feet (2,100 m) beneath the surface of lands just three miles (4.8 km) east of Superior.

If the mine is eventually reopened, it is highly likely the Magma Arizona will be revived to transport the one billion short tons (910,000,000 t) of ore to off-site smelters.

Discussions with representatives of Resolution indicate the Magma Arizona name will be kept if the mine and railroad are both reopened, which may occur after feasibility studies are completed in 2009.