Willoughby: Ashcroft’s mini mineral lode
July 28, 2018
The Aspen mineral lode is located in what geologists call an inclined syncline. Sounding like an oxymoron, the term applies to sedimentary layers that first warped into a U shape, or syncline. Then forces tilted the U upward, or inclined them. The top of the tilt formed just south of Little Annie basin, and the bottom lies under the town.
A similar inclined syncline holds another mineral lode. In mining days, locals referred to it as the Columbia Mining District, east of Ashcroft. After you travel up Taylor Pass and reach the Markley Hut, you find yourself at the bottom of this syncline. If you stand downvalley from Ashcroft, at Elk Mountain Lodge, look south to view the entire syncline. As with the syncline on Aspen Mountain, you'll see edges of exposed rock, similar to Aspen Mountain's ridges on Shadow Mountain.
The Columbia lode is smaller than Aspen's, with more pronounced incline and warping. Largely devoid of trees, the bottom of the incline reveals more features.
To explore the edges, where warped geologic layers slowly slide downslope, plan to hike halfway up into the valley, follow the small stream that tumbles down the syncline, and then climb perpendicular to the stream up the west side of the valley. To understand what lies underfoot, build a model. Twist a few thick pieces of paper into a U shape and then examine the sheets' edges. A stair-step arrangement forms from the twisting. That same arrangement marks your path up the valley, in rock.
Dumps from former mines abound there. A frenzy of tunneling and shaft digging during 1883 supported mines with names like Snow Flake, Buckeye, and Last Dime. The Castle Peak Mining and Smelting Co. owned many of these mines' claims. Columbia District mines, plus those of the surrounding Ashcroft area, succeeded before Aspen's mines, due to scale. Miners found ore closer to the surface, where they could dig it out more easily than they could access Aspen's ore. But the veins were thin and miners quickly depleted them.
Owners changed often in the district, and each new set of owners sponsored more exploration. During 1895, Ole Larson found very profitable ore with 50 to 80 ounces of silver in a ton. Speculators took notice. By 1897, the claims changed hands again.
Recommended Stories For You
The largest operation sank a shaft about two-thirds of the way up the valley. Hikers can see it today because it operated on and off well into the 1900s. Not a deep shaft by Aspen's standards, the shaft never used a steam or electric hoist. Instead, a horse whim wound and unwound rope on a spool to pull up the ore.
A hermit operated a mine in the lode into the 1920s. He lived near the top of the west side of the valley, and unearthed just enough ore to provision him with tobacco and beans.
The Columbia silver lode lies contiguous to two other mineral areas. Southeast of the lode, at the top of the ridge, a gold mine offered some success. Situated above timberline, it could not operate with winter conditions. To the south, vast iron deposits below Taylor Peak stain the earth a rusty color.
The Castle Creek Fault system, a longitudinal fault with crosscutting faults, forms the geologic engine for these three mineral areas, and for Aspen Mountain as well. For each crosscut fault, a thrust of blocks opened areas for ore to intrude. In this way, extraordinary forces of nature endowed the area with a plethora of minerals. All cities may have their faults, but Aspen's are more valuable than most.
Tim Willoughby's family story parallels Aspen's. He began sharing folklore while teaching Aspen Country Day School and Colorado Mountain College. Now a tourist in his native town, he views it with historical perspective. Reach him at email@example.com.