March 1998

The Butte Copper Mines

Copper Applications in Mining & Extraction


In the late 19th century, Montana was the largest producer of copper in the world. However, the mining history of what is now Montana did not begin with copper, but with the discovery of gold.

In the mid-1900's, prospectors in the area found gold and silver in placer deposits composed of sand and heavy minerals that eroded from underground rock. Found on or near the surface of the earth, the metals were separated from the rock by washing. After these were mined, it was necessary to dig further underground so shafts were dug for hard rock mining. Along the way, copper was found in many of the veins.

By the 1860's, southwest Montana was the second largest producer of gold and silver in the country. Merely a byproduct of silver mining, copper was incidental to mines whose primary concern was silver. At the time, there was not a big demand for copper and the native copper mines in Michigan provided an ample supply of copper for the nation. Gold and silver mining was more profitable than copper mining. Their deposits were easier to mine because they were located closer to the surface of the earth. Large capital investment and experienced miners were needed to produce Montana copper because the copper ore was a mixture of complex copper sulfur minerals that were located deep underground. The complex sulfide ores also required processing technology that was not available in Montana. Most of the ore was sent to Baltimore or Swansea, Wales for processing. Shipping the ore was expensive and time consuming. It was difficult for the copper mines in Montana to compete with the established copper mines in the Lake Superior region of Michigan that were mining native or pure copper.

By 1880 there were three primitive smelters in Butte for silver and copper, but most of the copper was still sent to Wales for processing. Marcus Daly played a major role in changing the outlook on copper mining in Montana. While working for a silver mining company in Butte, Daly discovered pure copper or copper glance at the end of a silver vein. Unknown at the time, this deposit was the largest copper sulfide deposit in America. In 1882 he decided to mine the copper ore and increase production. Daly's decision to mine copper coincided with two major industrial advances--the dawning of the electrical age and the invention of the telephone.

Prior to 1880, electricity was considered a fad, but in that decade, electrical technology was rapidly advancing. A broad range of electrical applications were developed for both the home and industry. In 1880, Edison patented the invention of the incandescent lamp. He was also experimenting with electric trolley cars. He set up the first electric power generation station in New York in 1882. The Pearl Street Generating Station supplied power for the electric street lights of New York City. The station used over 64 tons of copper for wire and equipment. Eventually, it was expanded to supply electrical power to the residents of New York and it was not long before electricity was wanted in every home.

In 1876 at the Centennial Exposition in Philadelphia, Alexander Graham Bell introduced the telephone. He demonstrated that speech could be transmitted through a copper wire. The telephone would eventually have everyone's home connected with copper wire.

Copper production in Montana was also spurred by drop in copper production outside the United States in the early 1880's. Copper production in Great Britain dropped from 16,000 tons in 1860 to 3,800 tons in 1880. Chile's production decreased from 50,000 tons to 38,000 tons. There was an increased need for domestic copper. With the support of a syndicate that was willing to make a major capital investment, Daly developed the Butte area with the primary goal of producing copper. The technology for processing the copper was now needed in Butte. The copper ore was hand roasted and concentrated with roller mills. By 1883 Daly had built his smelter 26 miles west of Butte in Anaconda. The smelter used the latest processing technology from England. He contracted with Union Pacific Railroad to build a railroad for taking the ore to the smelter and the purified copper to market. In response to the dropping price of copper in 1886, Daly updated the processing equipment to increase productivity. The crusher rollers in the concentrator were replaced with steam stamps. Bruckner roasting furnaces were builtwhich, alone, doubled the roasting capacity of the area to 1000 tons per day. By December 1887 the Butte mines surpassed those of Lake Superior and became the number one copper source in the country. By the end of the 19th century, The Butte copper mines became the largest copper producers in the world. Copper continued to be mined in Montana through the first half of the 20th century.


  1. Morris, Patrick, R., Anaconda Montana, Copper Smelting Boom Town on the Western Frontier, Swann Publishing, MD, 1997, p. 5.
  2. Marcosson, Isaac F., Anaconda, Dodd, Mead & Co., NY, 1957, p. 5.
  3. Marcosson, Isaac F., Anaconda, Dodd, Mead & Co., NY, 1957, p. 49.

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