George Hearst was an American businessman, politician, and patriarch of the Hearst business dynasty. After growing up on a small farm in Missouri, he founded many mining operations, and is known for developing and expanding the Homestake Mine in the late 1870s in the Black Hills of South Dakota. In 1879, he listed it on the New York Stock Exchange and went on to other pursuits. The mine's gold production continued uninterrupted until 2001.

Marcus Daly was an Irish-born American businessman known as one of the four "Copper Kings" of Butte, Montana, United States.