An innovative mine reclamation project on Castle Creek has transformed a steep riverside slope from a potential public safety hazard filled with toxic mine debris into a green meadow of tall grass and daffodils — in one year’s time.
The experiment used biochar to successfully re-vegetate the area next to the abandoned Hope Mine, restoring soil ravaged by mine tailings. It is the first project of its kind in the world.
The pilot project at Hope Mine resulted from a partnership between local nonprofit For the Forest and the U.S. Forest Service, which owns the land on which the century-old abandoned silver mine rests.
Last fall they hired Carbondale’s Flux Farm Foundation to use biochar to attempt revegetating the area, in the hopes of pioneering a new, carbon-negative approach to mine reclamation projects.
With the slope of the mine revegetated, the partners are calling the experiment a success.
“This shows us that biochar is effective for forest health projects,” said Morgan Williams of Flux Farms.
The approach is scalable, he said, to the 23,000 abandoned mines in Colorado’s forests. Abandoned mines and the toxic debris left behind by the operations have contaminated 40 percent of the headwaters in the mountain west, according to forest officials.
Pitkin County alone holds 700 abandoned mine sites.
The Hope Mine site is on a steep slice of forest between Castle Creek and Castle Creek Road. The Forest Service identified it as a looming threat to Aspen’s water supply, which comes from the creek.
The city of Aspen’s water department has not found any dissolved mining materials spilling into Castle Creek from the mine in local drinking water, which is treated downstream of the mine. But forest officials believed the steep and rapidly-eroding bank on which the mine sat was vulnerable to sliding into the river.
“It’s pretty obvious why this was a concern to the Aspen water department,” said John Bennett, founder of For the Forest and former mayor of Aspen. “If a catastrophic event like a landslide occurred, it could close Castle Creek as a water source for Aspen for a couple of years.”
The reclamation project strengthened the soil there and has drastically cut the likelihood of a potentially calamitous slide.
“This reduces our risk so much it’s hard not to get excited about it,” said Scott Snelson, the Forest Service’s Aspen district ranger.
He said the Forest Service will closely follow results from ongoing monitoring of the soil at Hope Mine.
Biochar is a charcoal-like substance made from heated biomass. It is used to both increase the health of the soil it’s mixed with, and to sequester carbon emitted by grass, shrubs and trees.
For the Forest’s biochar order for this project — roughly 18,000 pounds — was the largest in the U.S. in 2010.
In all, the project cost For the Forest was about $88,000 and tackled a little less than an acre of forest.
Snelson said that a traditional reclamation approach, where the area would be excavated and mine tailings would be hauled away in trucks, costs about $1 million per acre.
“It’s a critical problem and we need to find a cheaper way to address it [than the traditional way],” Snelson said.
If For the Forest hadn’t spearheaded the project and picked up the tab, Snelson said, the feds would have let the site stay as it was and hope a catastrophic slide didn’t occur.
Snelson was hopeful that the Hope Mine model could potentially be transferred to communities throughout the West facing the dual forest health threats of bark pine beetles and toxic abandoned mining materials. Bennett added that it could also reduce carbon emissions and climate change impacts from the forest and mine reclamation projects.
If beetle-killed trees can be turned into biochar for local mine reclamation projects, forest officials could essentially use one forest problem to solve another.
Williams, the bio energy expert from Flux Farm, laid 42 different mixtures of compost, seed and biochar on the Hope Mine slope last October.
He found that areas without biochar didn’t revegetate, while those with it flourished. In a year, they’ve grown stronger, healthier and more resistant to erosion. From this point, he said, the root systems there will grow and naturally strengthen the riverbank through seasonal cycles.
Over the past year, as he’s assisted with the Hope Mine project, Williams also launched a for-profit private biochar company based in Carbondale. He has used the biochar research results from the Hope Mine to perfect his formula and market it to clients like tree companies. Biochar Solutions, based in Carbondale, Williams said, already has picked up clients throughout the U.S. and sold out of biochar through November.
The Hope Mine was founded in 1911 and apparently never turned a profit. Its ownership through the years included “Charlotte’s Web” illustrator Garth Williams and Given Institute founder Donald King, according to a history provided by For The Forest. Today, the mine entrance has been dynamited shut, but the tunnel is said to run nearly three miles into Aspen Mountain.