When Anson G. Phelps died, his sons-in-law purchased his portion of the company, but retained the name, and the import-export business. In 1880, the company invested in the
Detroit Copper Company of
Clifton, Arizona, at the time a very small copper camp in the eastern
Arizona Territory. Phelps-Dodge interested
Dr. James Douglas of
Phoenixville, Pennsylvania to inspect the property and make recommendations. Dr. Douglas inspected the Detroit Copper Co of
Morenci and also ventured south to the
Warren District. On his advice, Phelps-Dodge began its own mining operations in the Warren District with the purchase of the Atlanta Copper Mine in 1882, neighboring the
Copper Queen Mine. When both mines discovered the same ore body, instead of fighting over it, they merged in 1885, creating the Copper Queen Consolidated Mining Company. The Copper Queen Mine in
Bisbee, Arizona Territory, became one of the most productive in the state of the early 20th century. The company focused largely on providing copper wire and cables to industry, products that were in high demand as the
Industrial Revolution took hold. As the company diversified, it began investing in new railroads, essential in the company's efforts to keep costs as low as possible, especially in
Arizona Territory. It used its own lines to transport products to and from major railroads for its markets on the eastern/northeastern shores. In 1895, the first contract was signed by Phelps Dodge and Company and the
Nichols Copper Company (which was renamed from
G. H. Nichols and Company in 1891) to have Phelps Dodge deliver a minimum of of blister copper over three years. This economically symbiotic relationship lasted until 1922, in which Phelps Dodge provided 90% of the blister copper Nichols Copper Company used to produce 100% pure copper. In 1908, with the Phelps Dodge owners no longer alive, the company was re-organized as a public company and the name changed to Phelps Dodge Corporation, a holding company for all of the various properties and operations. Dr. Douglas was its first president. ==Labor relations==