Approximately 0.5 mile hike from Jamestown. There is no formal parking near the site. Map and directions.
The Blue Jay Mine contained fluorspar, also known as fluorite, which was used for iron smelting. Although it was a relatively short-lived mine, with its peaks in production during World Wars I and II, it was crucial to the American war effort.
Blue Jay was mostly inactive for its first 30 years of operation because there was little demand for fluorspar and, although Blue Jay did contain silver, there was not enough to make mining worthwhile. Blue Jay's first boom was from 1914 to 1920, during World War I, when fluorspar ore was extremely lucrative, quadrupling in price within four years. The demand did not last long. Following the war, less fluorspar was needed, and the mine idled. The Great Depression of the 1930s made matters worse, driving fluorspar prices to lows not seen since 1900.
With the war came a corresponding spike in fluorspar prices. The mine shaft was extended 150 feet and was covered by a hoisting house. The miners communicated with the hoisting operators through signal bells, similar to Morse Code: 1 ring of the bell meant "stop," 2 rings meant "elevator descending," 3 rings meant "hoisting," and 4 rings meant "blasting." The mine also had air compressor powered rock drills, a ventilation system, and electric pumps to keep the mine dry.
Having trouble finding quality ore, Blue Jay's miners eventually sunk the shaft to a depth of 500 feet in hopes of having better luck deeper underground. Although better ore was found, another decrease in fluorspar prices closed the mine for good in 1954. Today the mine is part of Boulder County Parks and Open Space. The now-closed mine shaft, hoisting apparatus, and hoist house remain among the most intact fluorspar mines in Boulder County.
Did you know?
Fluorspar is often used in manufacturing products such as aluminum, gasoline, insulating foams, refrigerants, steel, and uranium. Blue Jay Mine was one of the largest fluorspar producers in the Jamestown Mining District, which was the most significant fluorspar mining district in the Western U.S. Most other fluorspar is mined in the East and Midwest.
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