The Stibnite Mining District is one of the most historic mining districts in all of Idaho. The site is rich with minerals, including gold, silver, antimony and tungsten. Over the last hundred years, it has been home to thousands of miners, operated by several different mining companies and was critical to the U.S. war effort in the 1940s and 1950s. Mining activity stopped at the site in 1997. However, in 2009, a new company acquired the site and started to evaluate it for future mining potential.
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History
Miners first came to Stibnite during Idaho’s gold rush days in 1899. Over the next few years, the number of miners at the site continued to grow and several operators, including United Mercury Mining Company and Bradley Mining Company, started working in the area.
In 1938, miners started focusing their efforts on the Yellow Pine Pit. Miners were able to extract large quantities of gold from this area of the site. However, operations at the pit blocked fish passage and to this day fish in the East Fork of the South Fork of the Salmon River cannot swim upstream past the site.
During World War II, antimony became a mineral that was critical to the war effort. It was used to create bullets. Stibnite contained such large quantities of antimony that individuals were able to serve their country by working at the site. At one point, more than 1,500 people were working at the site. From 1941 to 1945 Stibnite mined and milled more tungsten and antimony than any other mine in the United States. During this wartime period Stibnite produced 40 percent of the nation's domestic supply of tungsten and 90 percent of its antimony
After World War II, operations at the site slowed down and many miners moved out of the area. Mining continued in the area sporadically from the 1970s to the late 1990s.
Geography
Stibnite is located in the mountains of central Idaho. It is approximately 10 miles outside of Yellow Pine and 39 miles east of McCall.
Geology
The Stibnite Mining District sits atop the Idaho Batholith, one of the signature features of Idaho’s unique geology. The Idaho Batholith is nearly 14,000 square miles of granite, formed from the collision of the oceanic plate and the North American plate around 100 million years ago during the Cretaceous period. Continental drift pushed the denser oceanic plate under the North American plate, where immense heat, pressure and superheated water caused the rocks to melt, rise and then slowly cool, creating the vast expanse of crystalline granite underneath most of central Idaho.
Some 50 million years later, an enormous volcanic complex erupted through the granite and left behind volcanic ash, lavas and crystalline rocks. The volcanic activity pumped hot fluids into the cracks and pores of the Idaho Batholith. These hot fluids contained gold, silver, antimony and sulfur which, as the waters cooled, left behind minerals like pyrite, stibnite and scheelite. The partnership of the Idaho Batholith cooling and interacting with volcanic forces, and mineral-rich fluids, created a geologic region that has captured the attention and imagination of geologists and prospectors for more than 100 years.