 Its former headquarters office (built 1896) is now the Bisbee Mining & Historical Museum.His deep interest in transportation and mining were united in an essay he wrote in 1885 on "Historical and Geographical Features of the Rocky Mountain Railroads" which detailed the geological features of the land near the Union Pacific, Central Pacific, Denver and Rio Grand, Southern Pacific, Atlantic and Pacific, Northern Pacific, and the Canadian Pacific railroads.In the late 1880s early 90s, with the success of the Copper Queen and backing of Phelps Dodge partners, Dr Douglas acquired for them additional property and built up other spectacular copper mines, including the Detroit Copper Company at Morenci Arizona, the Moctezuma Copper Company at Nacozari, Sonora Mexico, and the United Globe-Old Dominion mines at Globe Arizona.