RICO — An otter popped up in the once-toxic water.
Its appearance last winter — devouring a trout — has ignited hopes around an experiment to transform a scarred, mining wasteland into a naturalistic mountain valley.
This re-engineering along headwaters of the Dolores River requires replanting wetlands with native grasses and laying in soil to mimic natural processes — an innovative approach that may be deployed more widely across the water-challenged West, where tens of thousands of toxic mines foul rivers and streams. So far, the experiment is working, removing fish-killing zinc, manganese linked to birth deformities and cancer-causing cadmium from muck flowing from the Argentine Mine complex uphill from Rico.
“Mining is what brought communities to life at the turn of the 19th century, but now residents and visitors would like to see these scars restored as much as possible — especially focusing on water cleanup,” San Miguel County commissioner Hilary Cooper said from her perch in Telluride, 22 miles north of the mess. “For many of these areas, human intervention is required to initiate the cleanup. But planning, which ultimately allows native vegetation, restored natural floodplains and the engineering skills of beavers to assist with the cleanup is generally preferred when possible. In the end, we will find it is more effective.”
The cleanup near Rico stands out at a time when Colorado’s track record has been less than stellar in dealing with repeat mine disasters such as Summitville, where an ill-issued state permit left taxpayers perpetually burdened, and the Gold King, where an EPA mistake highlighted degradation of the Animas River. A state government survey completed last year found more than 140 toxic flows still unaddressed, poisoning more than 1,800 miles of waterways.
Wildlife, including river otters, may be reviving in Rico because multiple factors favor environmental recovery.
First, federal agencies enforced laws. The Environmental Protection Agency in 2011 issued an emergency order compelling action to stop contamination of Dolores headwaters after state regulators and mine owners failed to get a grip. Then, EPA officials swiftly identified and enlisted a private company legally responsible for the mess — something agency officials haven’t done at other sites, including the Gold King Superfund district, where a potentially responsible corporation is fighting the EPA in court.
And the company, Atlantic Richfield — now owned by global energy giant BP — resolutely embarked on a cleanup, investing tens of millions of dollars. This compares with less than $5 million that the EPA has mustered for cleanup of the 48-site Gold King district above Silverton. For another Superfund disaster that the EPA declared in 2008 in Creede, federal funds have been so scarce that cleanup has barely begun.
In 2012, Atlantic Richfield contractors at Rico faced rising water inside mine tunnels that threatened a ruinous blowout. The St. Louis Tunnel, within a few hundred yards of the Dolores River, had collapsed and was oozing as much as 1,300 gallons a minute of toxic muck. A lime water treatment plant installed to neutralize sulfuric acid in the flow, churning out thousands of cubic yards a year of waste solids, wasn’t working. (The acid, private contractors later determined, is mostly neutralized by natural calcium deposits inside the tunnel before the muck flows out.) Cleanup crews also had to deal with eroding, unlined tailings ponds where rain and melting snow leached toxic metals into the river.
“The Dolores was pretty severely impacted for a number of miles downstream of the mine effluent. There was no natural reproduction of trout and the density of trout was depressed,” said Colorado Parks and Wildlife aquatic biologist Jim White, whose agency continues to stock the river with fish.
The innovative cleanup by Atlantic Richfield modernizes the standard approach of installing water treatment plants in the high country along with bulkhead plugs to try to control leaks. Contractors scooped out and lined the old ponds, planted grasses interspersed with stones and put in a sediment mix of manure, hay, alfalfa and woodchips — all aimed at filtering out toxic metals.
This massive experiment now covers 55 acres, closed inside fences and berms, below the newly dammed St. Louis Tunnel. The toxic muck still flows at rates fluctuating from 700 to more than 1,000 gallons a minute but now is channeled through three black tubes that carry the muck through the engineered ponds and wetlands.
In one pond, the toxic mine water seeps down vertically 2.5 feet through sediment, where chemical reactions help break out the manganese, zinc and cadmium. Native sedge and rush grasses are starting to grow atop that sediment layer. In other ponds, water is pushed through wetlands created using stones and grasses that grow naturally in the San Juan Mountain to filter out and chemically extract toxic metals.
Once contractors figure out which method or combination works best, they say they’ll seek EPA approval and then fully install engineered wetlands, eventually removing fences and roads.
“That’s what a lime water treatment plant looks like,” Atlantic Richfield cleanup supervisor Chris Sanchez said last week at the site, pointing to the decommissioned water treatment plant, comparing it to patches of sandy-colored sedges and rushes.
“These grasses and rocks, similar to the river bed,” Sanchez said, “it seems less harsh on the eyes.”
Atlantic Richfield mining project operations supervisor Anthony Brown said the work has been costly, but the approach holds promise for mining cleanups elsewhere.
“The huge lesson learned at Rico is that you have to look at each site as a unique situation,” he said. “You have to be innovative. You have to bring the right technology to the site.”
And so far, the water-cleaning systems seem to be working, judging from data provided to the EPA. Cadmium flowing out the St. Louis Tunnel at levels as high as 80 parts per billion has been reduced to traces. The systems cut iron from levels up to 60,000 ppb to around 10,000 ppb. Manganese has been cut from concentrations as high as 23,000 ppb to 2,000 ppb, still likely a problem. Zinc has been reduced to 100 ppb from 6,000 ppb.
It was at the lowest pond, near where treated mine waste is discharged into the Dolores River, that Atlantic Richfield contractor Ben Loomis saw something moving on the ice as he made maintenance rounds solo in his truck on Jan. 12.
Maybe it was a beaver. Or a coyote. Loomis said he was excited, got closer and determined it was a river otter, a species that in recent decades almost disappeared from western Colorado.
“He was sitting up on the ice, on his back, eating a fish,” Loomis said.
The photo he took was fuzzy. But in the absence of state data from sampling along the Dolores, it gave evidence that water quality may be improving.
Polluted water often is blamed for nearly driving river otters extinct in the early 1900s.
“River otters can be considered a sentinel species, indicators of acceptable habitat conditions that support the habitat and diet needs of otters,” said Eric Odell, species conservation program manager for Colorado Parks and Wildlife. “Seeing an otter, especially one eating a fish, indicates that there is a prey base that can support at least one individual otter. Seeing an otter there, especially since it is seen eating a fish, indicates relatively good water quality.”
How good remains unclear. Colorado Department of Public Health and Environment officials are legally required to take sufficient samples — where practical if they deem waterways accessible — to determine water quality. The agency’s mission includes protection of and restoration of water quality. But only one sample has been taken from the Dolores below Rico in recent years. An agency spokeswoman cited budget and staffing concerns as a factor and said sampling may be done in the future.
The CDPHE has not designated the river as “impaired,” although a tributary creek that enters at Rico is. CPDHE officials declined, through the spokeswoman, to discuss the situation at Rico. “No interviews,” she wrote in an email. She offered no comment on the otter, because “otters are not used” by CDPHE “as determinant of water quality health.”
Colorado residents increasingly may demand a more aggressive approach to protecting the environment from mining’s toxic legacy, said Jennifer Thurston, director of the Colorado-based Information Network for Responsible Mining, who has been tracking cleanups. Engineered wetlands may be a useful tool, she said.
“The bill is finally coming due for historic mining disasters. We are at the point where we really do need to start dedicating a lot more money and other public resources to addressing this problem that really is significant,” she said. “A lot of these mines have been left to fester in the mountains for a long time and are polluting creeks and rivers.”
At EPA regional headquarters in Denver, David Ostrander, the director of disaster response and preparedness, called the otter eating a fish “a pretty big indicator that water quality and natural biological activity are improving.”
Yet EPA officials have determined “we are still above the state’s ambient water quality standards for the Dolores River,” Ostrander said.
“(The cleanup so far) is really a great effort by Atlantic Richfield, and what they are doing is generating a lot of interest. A lot of industries — and we — are going to be looking at where we can adapt this to other sites,” he said. “It just doesn’t generate as much waste.”
Notions of harnessing natural filtration and break-down processes to clean water have been around for more than a decade. Proponents tout cost advantages over waste-generating water treatment plants and risky bulkhead plugs that can force leaks from other mine tunnels and holes. But environmental experts emphasize that engineered wetlands, while appearing “natural,” must constantly be monitored and maintained to keep removing toxic metals.
Atlantic Richfield crew leaders said they envision scooping out and recharging wetlands every three to 10 years depending on water-testing results.The metals-laced sludge collected in ponds would be placed in a lined repository adjacent to the tunnel that has the capacity to store 30,000 cubic yards before it would have to be emptied. Company officials said they’d commit to constant monitoring at the site.
“There is really no such thing as a passive treatment system that you get to leave to its own devices at this scale,” Ostrander said. “The hope here is that it is cheaper and easier to operate than more traditional systems.”
Nearly 11 months have passed since Loomis spotted the otter in the newly cleaned water below the mine. White, the parks and wildlife aquatic biologist, said he’s looking into conducting a fish survey on the Dolores River to determine the extent to which trout can reproduce naturally and check for invertebrates such as dragonflies, grasshoppers and beetles.
And environmental cleanup workers who monitor the wetlands daily said they’re hoping to see that same otter, or another, this winter.
CORRECTION: This story was updated on Dec. 19, 2017, to remove Robert Friedland’s name from a paragraph noting other mining disasters in Colorado. Friedland was chairman and CEO of Galactic Resources, which operated the Summitville Mine, but resigned from that company prior to a cyanide spill from the mine that was blamed severely degrading a 17-mile stretch of the Alamosa River system. The story also imprecisely referred to the aftermath. Although U.S. prosecutors considered Friedland a flight risk as they pursued a settlement in the case, a Canadian judge later rebuked them, noting that he had established permanent residence in Canada in 1988.
