Anaconda Copper Mining Company

Anaconda Copper Mining Company (from 1899 to 1915, known as the Amalgamated Copper Mining Company) was an American mining company. It was one of the largest trusts of the early 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 to process copper mined in Butte, Montana. By 1910, Anaconda had expanded its operations and bought the assets of two other Montana copper companies. In 1922 it bought mining operations in Mexico and Chile; the latter was the largest mine in the world and yielded two-thirds of the company's profits. The company added aluminum reduction to its portfolio in 1955.

In 1960 its operations still had 37,000 employees in North America and Chile. It was purchased by Atlantic Richfield Company (ARCO) on January 12, 1977. Anaconda halted production in 1980, and mining ceased completely in 1982 when the deep pumps keeping the mine drained were shut off, allowing the mine to fill. It currently exists only as a massive environmental liability for Tesoro, the current owner of ARCO.

Anaconda Copper Mining Company was started in 1881 when Marcus Daly bought a small silver mine called Anaconda near Butte, Montana. At the time, Daly was working for the Walker Bros. (mining investors) of Salt Lake City, Utah as a mine manager and engineer of the Alice, a silver mine in Walkerville, a suburb of Butte. While working in the Alice, he noticed significant quantities of high grade copper ore. Daly obtained permission from the owner of the Anaconda and several other mines in the area, to inspect the workings. He was a geologist and knew the red mineral he was looking at. After Daly's employers refused to buy the Anaconda, Daly sold his interest in the Alice and bought it himself. Placer gold and silver lode mining had taken place at Butte, placer mining at Helena, Bannock and Virginia City, Montana territory. Daly asked George Hearst, San Francisco mining magnate, for additional support. Hearst agreed to buy one-fourth of the new company's stock without visiting the site. While mining the silver left in his mine, huge deposits of copper were soon developed and Daly became a copper magnate. When surrounding silver mines "played out" and closed, Daly quietly bought up the neighboring mines, forming a mining company. Daly built a smelter at Anaconda, Montana (a company town) and connected his smelter to Butte by a railway. Anaconda Company eventually owned all the mines on Butte Hill.