Aspen-area mine to see pilot effort in reclamation
October 7, 2010
ASPEN – A tailings pile perched on the edge of Aspen’s water supply will be the focus of a pilot project that could not only further a new approach in mine reclamation, but also create a market for Colorado’s beetle-killed trees.
White River National Forest Supervisor Scott Fitzwilliams and John Bennett, executive director of the local nonprofit For the Forest, stood atop the Hope Mine tailings pile Wednesday to outline the project, a cooperative effort between the two entities, along with the Carbondale-based Flux Farm Foundation.
The U.S. Forest Service and For the Forest, brainstorming on possible partnerships, came up with reclamation of the mine site, which sits on Forest Service property off Castle Creek Road, south of Aspen.
The site “is very typical … of the history of mining in Colorado and the West,” said Fitzwilliams, gazing at the massive tailings pile – dirt hauled from inside the back of Aspen Mountain and dumped outside the now-closed-off Hope Tunnel entrance. “We have, I don’t know how many of these, all over the forest.”
The silver mine was apparently started in 1911, and the tunnel reportedly stretches back some 3 miles, connecting with the Little Annie Mine tunnel, according to For the Forest’s research.
The tailings pile looks innocuous enough – bare rock and dirt dotted with clumps of grass and other vegetation that has managed to take hold on its surface – but tailings piles are laced with heavy metals, Fitzwilliams said. And this one plunges nearly straight down to the edge of Castle Creek, a major source of Aspen’s municipal water.
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It appears some of it slid at some point during the summer, Bennett noted.
Tests of the water at the base of the pile indicate elevated levels of heavy metals, though downstream, the city has not recorded any increase in dissolved metals at its water plant, Bennett stressed.
The mitigation project will be preventative – an effort to stabilize the pile and prevent potential future problems, Fitzwilliams said.
The project will make use of biochar, a carbon-rich product created when biomass is heated in a closed container with limited air, according to For the Forest. Mixed with soil – hopefully even the challenging dirt of a tailings pile – biochar increases its ability to retain both moisture and nutrients, according to Denver-based soil scientist Andrew Harley, a consultant on the project.
“If this works here, this gives us a template we can use elsewhere,” he said.
Along with cleaning up a “toxic mine dump site” and helping protect Aspen’s water supply, Bennett said, the goal is demonstrating the qualities of biochar and, potentially, creating a market for dead trees left around the state by the advance of the bark beetle. The trees could be converted into biochar, a product that offers the added advantage of locking in the carbon from organic materials, keeping it out of the atmosphere. In that sense, the project addresses climate change, as well, he said.
“This is an experiment in several different ways,” Bennett said.
The $90,000 project, funded by For the Forest through donations, will involve the placement of stabilizing netting on the steep slopes of the tailings pile, according to Harley. Guys affixed to ropes will do that work, starting next week. Then, a high-speed conveyor will spread a mix of about 400 cubic yards of compost and eight tons of biochar, including a seed mix, over the netting. Mulch will cover the mixture.
The hope is a revegetated hillside, covered in native grasses and other plants, that stabilizes the slope and locks in the metals.
The Flux Farm Foundation is interested in the project in connection with its own mission of advancing the viability of agriculture in the West. Biochar could have role in that effort, as well.
The Aspen Water Department, which has been sampling the water below the tailings pile in advance of the work, will continue to do so in order to monitor any changes that occur.
The Hope Mine is one of more than 23,000 hazardous mines impacting 1,300 miles of streams in Colorado, according to For the Forest. The Aspen project could be a model for cleanup efforts elsewhere, according to the organization.
On Sunday, during the Aspen Climate Action Party, the creation of test plots atop the tailings pile is among the project options for volunteers. Individuals looking to sign up for a project should come to the Gondola Plaza at 1 p.m.