Driving from Laramie to Walden, Colorado in the 1980s and 1990s, travelers passed a stockpile of white material filling long trenches perpendicular to Highway 125 just a few miles north of Cowdrey. This material was fluorspar, the industrial name given to the mineral fluorite, a mixture of calcium and fluorine. Then, in the summer of 1996, the stockpile disappeared. Both the opening of the fluorspar mines and the vanishing stockpile are related to the Laramie, Hahn’s Peak and Pacific Railroad (LHP&P).

The LHP&P Railroad helped move the ore

Driving from Laramie to Walden, Colorado in the 1980s and 1990s, travelers passed a stockpile of white material filling long trenches perpendicular to Highway 125 just a few miles north of Cowdrey. This material was fluorspar, the industrial name given to the mineral fluorite, a mixture of calcium and fluorine. Then, in the summer of 1996, the stockpile disappeared. Both the opening of the fluorspar mines and the vanishing stockpile are related to the Laramie, Hahn’s Peak and Pacific Railroad (LHP&P).

Laramie: gateway to the North Park of Colorado

Today the North Park area advertises itself as “removed from civilization but easily accessed by civilized folk in search of solitude.” No one would have said North Park was easily accessed in the 19th and early 20th century. It was a remote place, connected to Laramie by a wagon road via Kings Canyon, a narrow passage between Sentinel and Pinkham Mountains at its north end.

The LHP&P Railroad arrived in North Park in 1911. The railway was originally intended to run west from Laramie to gold mines in the Medicine Bow Mountains but before the line reached Centennial the mines were playing out and so the tracks were rerouted south towards North Park. When completed, the rails extended a total of 111 miles from Laramie to 26 miles southwest of Walden. There the railroad syndicate opened a coal mine at Coalmont, Colorado. Not until 1926 did State Highway 14 connect Walden with Fort Collins.

Discovery of fluorspar in North Park

The fluorspar veins on Pinkham Mountain near Kings Canyon were first discovered about 1900 by prospectors looking for copper. They found something, not copper but a mineral identified in 1918 as fluorite when Frank Heaton and Charles Baker staked the “Feldspar” claim on what is now known as the Fluorspar-Gero-Pember vein zone. Feldspar is a different mineral than fluorspar, although the names are similar.

When four additional claims were staked in 1921, the name of the claims was corrected to “Fluorspar.” These were sold to the Colorado Fluorspar Corp. in 1922 and the claims were patented (granted)in 1924. This group of claims became known as the Northgate district because of their location at the northern gateway to North Park.

Why mine fluorspar?

Fluorspar is an important additive used in steel making to reduce the melting point and remove impurities such as sulfur and phosphorus. It is also used in aluminum, ceramics and glass production. Fluorspar is the source of fluorine used in the production of refrigerants, propellants, insulating foams, non-stick coatings (Teflon), fluoridated mouthwashes, and toothpaste, and various pharmaceuticals. Fluorspar can be converted to hydrofluoric acid, which is used in production of high-octane gasoline, in processing uranium, in glass etching, and in the electronics industry.

From World War II to 2006, fluorspar was one of the strategic minerals stockpiled by the U.S. Government. Today it remains on the Department of the Interior’s list of “35 minerals deemed critical to U.S. national security and to the economy.”

How did fluorspar form?

Most fluorspar forms from calcium and fluorine dissolved in warm water deep in the Earth’s crust. As the water rises towards the surface along faults, fissures and shear zones it cools and the mineral precipitates. In the Northgate district, two large faults are filled with veins of fluorspar up to around 10 feet wide.

Mining operations consisted of both underground workings and large, linear open cuts. The deep, narrow open cut at the Fluorspar mine pictured indicates the flat sheets of the fluorspar vein-filled faults. The faults are related to the Rio Grande rift, a long, narrow region where the crust has been stretched and faulted. This rift zone runs north-south through New Mexico and Colorado, narrowing and terminating near the Wyoming border.

The rift enabled deep heat to rise and warm the solute-rich waters that precipitated the fluorspar deposits around 12 million years ago. Today warm and hot springs still occur along the rift, including Steamboat Springs and Saratoga Hot Springs at its northern end.

The fluorspar mines

The Northgate district fluorspar mines operated sporadically for more than fifty years. Production began in 1922 and continued until 1926 when a drop in the price of fluorspar forced the mine to close. About 15,000 tons of fluorspar were produced during this early mining period. Except for minor development and maintenance work, the mines were not worked from 1927 to 1941.

Mining activity in the Northgate district was renewed during World War II when Western Fluorspar Corp. leased the holdings and rehabilitated the Fluorspar mine and mill in 1941. The mill burned in December 1942 after about 5 months of production. A new 450-ton capacity sink-float mill was constructed by the Defense Plant Corporation. Meanwhile Western Fluorspar Corp. purchased the Fluorine block of claims and the U.S. Forest Service constructed a graveled road across Pinkham Mountain providing access to the Fluorine-Camp Creek vein zone. Production was resumed at the mill in November 1943 and continued until August 1945.

The United States was the world’s leading producer of fluorspar until the mid-1950s. In 1950-51, the Ozark-Mahoning Company purchased the Northgate fluorspar properties and produced up to 100 tons daily until closing down in 1959. The settlement was torn down, but the mines reopened in 1969 and were under full production for several years.

Consumption of fluorspar in the United States peaked in the early 1970s, which was also the peak period of U.S. steel production. The North Park mines closed in 1973 when Congress eliminated federal subsidies for fluorspar. Since then, U.S. fluorspar consumption has decreased substantially. Fluorspar mining in the U.S. ceased in 1996. Today, ore is imported mainly from Mexico, with lesser amounts from China and South Africa.

End of an era

The LHP&PRailroad transport of ore made fluorspar mining at Northgate economically possible. Ore was taken to Northgate station some 3 miles south of the mines where it was loaded onto trains and transported to Laramie, then on to market.

But from the start, the railroad had its own troubles. It relied on freighting coal, timber, livestock and fluorspar ore but was never profitable. It went into receivership and was sold in 1914, was reorganized again in 1924, and in 1936 was taken over by the Union Pacific, which operated the line until 1987. The Wyoming Colorado Railroad continued freight service and operated a tourist train until 1996.

Throughout the spring and summer of 1996 prior to abandonment of the line, the last coal was shipped out of Coalmont and stockpiles of fluorspar were removed from Northgate. Starting in October the rails were taken up and both the railway and the fluorspar mines became history.

If you visit

The fluorspar mines are on private property but there are several points of interest that can be viewed from Colorado highways 127 and 125.

Stop 1. Pull-off on the west side of Highway 127 5.4 miles south of the Wyoming-Colorado line, 300 feet north of a cluster of homes at the intersection with County Road 6E. Here you can inspect the Kings Canyon loading station for lumber onto the LHP&P. According to Wyoming Tales and Trails, the Otto Lumber Company, which was headquartered in Laramie, had several camps in the vicinity. The Baxter/Union Pacific tie plant in Laramie was a major destination for lumber, but not all was transported by rail. Much was driven down tie flumes and various creeks to the Big Laramie River during high water each spring.

Stop 2. Pull-off at a driveway on the north side of the highway, 8.1 miles south of the Wyoming-Colorado line, 1 mile before the intersection of Colorado 127 and 125. At this point just north of the road are earthen berms that impounded water and sediment below the Fluorspar-Gero-Pember fluorspar mines, which are located farther up the hill, just below the skyline.

Stop 3. 2.1 miles south of the junction with Colorado 127 on Colorado 125 is the Northgate loading station, where fluorspar was transferred from the trenches on the east side of the road (now empty) onto traincars. Satellite images and old topographic maps show the railroad “wye” immediately east of the trenches that allowed trains to reverse direction. From Northgate, the railway continued on the west side of highway 125 south to Cowdrey and Walden, and then on to its terminus at Coalmont.

To see mineral specimens of fluorite, visit the fluorescent mineral room in the UW Geological Museum. If you’d like some exercise, you can bicycle or walk the old LHP&P railroad grade between Lake Owen and Pelton Creek.

Carol Frost is Professor Emerita of Geology at the University of Wyoming. She notes that while there were several different name changes for the Laramie-Coalmont railroad line, she consistently uses the name under which it was first organized.