Anaconda in Deer Lodge County, Montana — The American West (Mountains)

Smelting the Ore

Photographed By Cosmos Mariner, July 18, 2016

1. Smelting the Ore Marker

Inscription. Extracting pure copper from the ores mined in Butte was a complex process. First, the useless waste rock was separated from the valuable ore, and the high-grade material was separated from the low-grade material. Next, the lower-grade ore was concentrated by crushing and mechanically separating the heavier metal particles from the lighter waste rock. Copper concentrates were “roasted” in furnaces to remove part of the sulphur. Roasted concentrates were then smelted in a blast or reverberatory furnace to further remove impurities. This process formed molten copper matte and slag, a waste material made up of iron oxide and silica (sand). Slag was poured off and run through water to cool and granulate it. Molten matte was smelted in converter furnaces to create crude “blister” copper and more slag. At this point slag itself contained copper and was recycled rather than discarded. Blister copper was further refined in the casting furnaces, cast into anodes, and shipped to Great Falls, where the remaining impurities, metals such as gold and silver, were removed. These valuable by-products were collected and marketed. The massive black hill near the entrance to Anaconda, directly east of this site, is a slag pile.

During the copper smelting process, the stack acted as a chimney to carry off the smoke and

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gases produced as by-products. Exhaust from the individual roasting, smelting, and refining furnaces traveled first through a series of dust chambers and flues and then up and out through the stack.

Research and development conducted at the smelter resulted in more efficient methods at each stage of the copper smelting process. The Washoe Smelter contributed to the growth of Montana's copper industry and ensured the name “Anaconda” was recognized as a world leader in metallurgy.

Erected by Montana Historical Society and Montana Department of Fish, Wildlife & Parks.

Topics. This historical marker is listed in these topic lists: Industry & Commerce • Natural Resources.

Location. 46° 7.379′ N, 112° 55.86′ W. Marker is in Anaconda, Montana, in Deer Lodge County. Marker is on Anaconda Smelter Road (East 4th Street), ¼ mile south of Park Avenue (Pintler Veterans Memorial Scenic Hwy) (State Highway 1), on the right when traveling east. Marker is located in Anaconda Smelter Stack State Park, along the circular walkway around the smelter stack exhibit, just east of the parking lot. Touch for map. Marker is at or near this postal address: 100 Anaconda Smelter Road, Anaconda MT 59711, United States of America. Touch for directions.

Other nearby markers. At least 8 other markers are within walking distance of this marker. Contributions of the Washoe Smelter (a few steps from this marker);

Marker photo: Overhead crane pouring a molten slag image. Click for full size.

Courtesy of Anaconda Historical Society Archives

2. Marker photo: Overhead crane pouring a molten slag

Overhead crane pouring a molten slag return in the reverberatory furnace. Cranes used in the operation weighed between 50 and 75 tons, rose 60 feet in the air, and traveled 600 feet of converter aisles while transferring molten materials between the reverberatory, converter, and copper casting furnaces. In 1976, a new electric furnace replaced the reverberatory furnaces.

Organized Labor (a few steps from this marker); Goosetown Historic District (a few steps from this marker); Washoe Stack Facts (a few steps from this marker); Marcus Daly - An Irishman with Vision (within shouting distance of this marker); Preserving the Washoe Smelter Stack (within shouting distance of this marker); Washoe Brewery (approx. 0.4 miles away); 801 East Third Street (approx. 0.6 miles away). Touch for a list and map of all markers in Anaconda.

More about this marker. Marker is a large, framed, laser-printed metal plaque, mounted horizontally on a waist-high metal post.

Related markers. Click here for a list of markers that are related to this marker. Butte-Anaconda National Historic Landmark District

Marker photo: "poling" image. Click for full size.

Courtesy of Anaconda Historical Society Archives

3. Marker photo: "poling"

Smeltermen “poling” the copper casting furnace. Pine logs were used to help burn off oxygen before the copper was cast into anodes. In the early 1970s, natural gas replaced the burning timber in this process.

Smelting the Ore Marker (<i>wide view</i>) image. Click for full size.

Photographed By Cosmos Mariner, July 18, 2016

4. Smelting the Ore Marker (wide view)

Anaconda Smelter Stack Exhibit (<i>marker is located along walkway, on east side of the ring</i>) image. Click for full size.

Photographed By Cosmos Mariner, July 18, 2016

5. Anaconda Smelter Stack Exhibit (marker is located along walkway, on east side of the ring)

Anaconda Smelter Stack State Park (<i>turn here to access exhibit and marker</i>) image. Click for full size.

Photographed By Cosmos Mariner, July 18, 2016

6. Anaconda Smelter Stack State Park (turn here to access exhibit and marker)

Credits. This page was last revised on December 20, 2020. It was originally submitted on January 2, 2019, by Cosmos Mariner of Cape Canaveral, Florida. This page has been viewed 239 times since then and 29 times this year. Photos: 1. submitted on January 2, 2019, by Cosmos Mariner of Cape Canaveral, Florida. 2, 3, 4, 5, 6. submitted on January 3, 2019, by Cosmos Mariner of Cape Canaveral, Florida. • Bill Pfingsten was the editor who published this page.