In 1880 the president of the Detroit Copper Mining Company at Morenci, William Church, asked Phelps, Dodge for financial assistance.

They next purchased the El Paso and Northeastern Railroad to secure delivery from their coal mines in Dawson, New Mexico to their smelting plants.

[2] He also served as vice president and director of the Copper Queen Consolidated Mining Company in Bisbee, Arizona.

[2] According to one historian, James was "a genuinely good man of impeccable character, a secret philanthropist, whom Charles Parkhurst said loved everything in the universe 'from God down to the newsboy.

James died at the Mount Washington Hotel, Bretton Woods, New Hampshire, in September 1907, one of the hundred wealthiest Americans, having left a large fortune estimated at $26 million (U.S. dollars).