The Anaconda Copper Mining Company, part of the Amalgamated Copper Company from 1899 to 1915, was an American mining company. It was one of the largest trusts of the early 20th century and one of the largest mining companies in the world for much of the 20th century. Founded in 1881 when Marcus Daly bought a silver mine, the company expanded rapidly based on the discovery of huge copper deposits. Daly built a smelter in Anaconda to process copper mined in Butte. Daly sold his assets in 1899 to H H Rogers and William Rockefeller.