Entry No. 75 — the Boulder file — filed under: history
Burlington Mine
Operating from 1920 to 1973, the Burlington Mine was once a premier fluorspar-producing site in the western United States. Following its closure, underground collapses created a massive 300-foot-deep surface pit, which has since been backfilled and capped during extensive ecological reclamation. Today, while the main shafts are sealed, colorful whitish-tan and purple-tinted mine tailings remain visible along the hillsides.
The story
You don't head up James Canyon Drive looking for pristine wilderness; you go to see what happens when an entire mountain gets hollowed out from the inside. From 1920 to 1973, the Burlington Mine was a monster operation—one of the premier fluorspar producers in the western United States, sending shafts plunging down over 1,400 feet into the rock near Jamestown. Miners carved out thousands of tons of calcium fluoride for steel production and chemical refining, leaving a honeycombed labyrinth underground.
When the machinery went quiet in 1973, the mountain started collapsing into itself. Underground failures eventually breached the surface, forming a terrifying 300-foot-deep crater that threatened the entire hillside. It took an extensive voluntary cleanup and ecological remediation effort to seal those deep shafts, backfill the massive sinkhole, and cap the site to prevent toxic runoff into the local watershed.
Today, the mine site itself is fenced off and heavily posted with 'No Trespassing' warnings, but you didn't hear it from us: you don't need to cross the property line to get a fix of mountain history. Staring down from the public right-of-way along County Road 87, you can trace the engineered contours of the reclamation site and spot pale, whitish-tan tailings streaked with purple—remnants of the fluorite veins that built this canyon.
What it's like
Expect a slow pull-off along a narrow dirt canyon road where pale mine dumps spill toward the tree line behind heavy fencing. There are no signs, no visitor centers, no restrooms, and zero cell reception—just a quiet roadside view of an engineered reclamation site. You'll spend your time safely on the public right-of-way along County Road 87, scanning the gravel near your shoes for small, translucent crumbs of purple fluorite caught in the high-altitude sun.
The move: Take a scenic drive up James Canyon Drive to County Road 87, where you can park and safely view the historic mine tailings from the roadside while searching for small fragments of purple fluorite.
📍 Before you go The mine site itself is private property, heavily remediated, and marked with 'No Trespassing' signs, but the historic tailings and geological features are easily visible from the public right-of-way along County Road 87.
- 📍 Boulder
- 💸 Free
- ⚡ Low-key
- 🌗 Outdoors
Where: Boulder, CO 80302, USA
Hours: Added 2026-07-20 — confirm current access before you go.
Pair it with
- Blue Jay Mine — Drive just a mile and a half over to Blue Jay Mine Open Space to explore another historic Jamestown fluorspar site with accessible trails.
- Jamestown Mercantile — Head a mile down the canyon to this 1890s general store turned community hub for a hot meal and live music.
- Gold Hill Historic District (Colorado's First Mining Town) — Take the back dirt roads four miles south to wander Colorado's oldest permanent mountain mining camp, established in 1859.
- Ward Townsite & Derelict Car Collection — Continue west toward Ward to compare Burlington's clean reclamation against an eccentric high-country town packed with 19th-century boomtown ruins and rusting classic cars.
Good to know
Can I walk onto the Burlington Mine property or enter the shafts?
No. The entire mine footprint is private property, remediated, and marked with 'No Trespassing' signs. Access is strictly limited to viewing the site from the public right-of-way along County Road 87.
Is roadside rockhounding allowed here?
You must stay within the public road right-of-way along County Road 87 and cannot step past private property lines, but scanning the public roadside gravel for loose purple fluorite fragments is a popular roadside activity.
What minerals were extracted at the Burlington Mine?
The site was primarily mined for fluorspar (fluorite), a mineral valued for industrial metallurgy and chemical manufacturing, which gives the tailings their distinct purple hue.
How do I reach the site from Boulder?
Drive up James Canyon Drive from Boulder toward Jamestown, then turn onto County Road 87, where the tailings dumps are visible along the hillside from the road.
Plan a visit & invite your people →
Further reading: Westword · Reddit
last checked: 2026-07-20