Experts say options limited for mine site remediation
FARMINGTON — While experts continue to monitor conditions on the Animas River after a spill last week at the Gold King Mine in Colorado, federal officials are beginning to discuss solutions to the decades-old problem of pollution in the Upper Animas Mining District.
On Wednesday, a bipartisan coalition of U.S. lawmakers from Colorado and New Mexico called on President Barack Obama to consider devoting federal funds to building a water treatment plant on the Upper Animas River.
U.S. Environmental Protection Agency Administrator Gina McCarthy told The Daily Times Wednesday the EPA needed to take a "long-term view" of the crisis.
She pointed out the EPA has long sought a Superfund designation for the Upper Animas River watershed, but has been rebuked by locals and former mine operators.
Though the Upper Animas Mining District is not a Superfund site, it's long been the focus of remediation efforts by local, state and federal entities.
The EPA was in the process of plugging the Red & Bonita Mine when the Gold King Mine was inadvertently breached by an EPA team on Aug. 5.
The agency installed a concrete bulkhead at the Red & Bonita Mine, located upstream of the Gold King Mine, due to the threat the mine posed to human health and the environment, according to federal records.
The EPA determined in March 2013 the century-old mine was discharging approximately 300 gallons per minute of acidic water containing high concentrations of aluminum, cadmium, iron, lead, manganese and zinc, the records state.
Mark Williams, a specialist in mountain hydrology and acid mine drainage at the University of Colorado Boulder, explained Wednesday in an interview that water trapped within mines such as the Red & Bonita becomes acidic by interacting with exposed sulfide, or fool's gold. That acidic water then leeches metals from rock in the mine and that heavy-metal laden wastewater leaks into local rivers, Williams said.
Though acid drainage occurs naturally in some environments, its exacerbated by mining, which exposes the sulfide to oxygen.
Williams said he toured the Upper Animas Mining District with EPA officials in the early 2010s to discuss site remediation.
He said the EPA and its local partner, the Animas River Shareholders Group, has taken a "mine-by-mine" approach to remediation, which has made progress difficult.
Williams and other experts have said the plugging of the Sunnyside Mine in the late 1990s and early 2000s likely caused water to escape through fractures from the Sunnyside Mine into surrounding mines, including Gold King, Red & Bonita and Mogul.
The former operator of the Sunnyside Mine, Sunnyside Gold Corp., disputes that assertion, but the EPA notes in its regional risk assessment report that water discharge from the Gold King, Red & Bonita and Mogul mines increased dramatically in 2003, shortly after Sunnyside Gold Corp. finished plugging Sunnyside Mine.
Williams said environmental inspectors need to chart the pathways the water is using within the mountain to fully understand the ultimate source of the polluted waters.
He said understanding the source of water emanating from the mouth of the mine can lead to more holistic approaches that limit treatment costs.
Williams suggested that concrete bulkheads could be installed in the mine shafts, forcing the water to filter through more sediment before being discharged at a higher elevation.
Williams was skeptical that a water treatment plant would provide a long-term solution.
"Understanding the hydrology of these complicated systems is expensive, but in the long run, it's the only method that is viable," Williams said. "We can't treat water forever."
A water treatment plant operated by Sunnyside Gold Corp. was used to filter water in the Upper Animas River for years before it was shutdown in 2003 after the company prevailed in a lengthy legal battle.
Williams said any solution would take years to implement, partly because winter weather limits the work season in Silverton to the summer months.
Bill Simon is co-coordinator of the Animas River Shareholders Group, an organization formed by local residents, mine operators, public officials and others who opposed the Superfund designation in 1994.
The shareholders group has conducted several voluntary mine waste cleanup projects since its formation.
Simon lamented the lack of innovative solutions in mine remediation and said his group has offered financial incentives to find new ways to treat mine waste.
In regards to treatment plants, Simon said: "The present technology that exists, it's hundreds of years old," he said.
Marcie Bidwell, executive director of Mountain Studies Institute, a nonprofit environmental research organization, agreed that solutions are limited.
"One answer is to treat everything," she said. "Another solution is to reduce what we treat by holding it in the mine."
Simon said the lack of new solutions means he is in no hurry to embrace a Superfund designation in the Upper Animas Mining District.
"We don't have a viable approach either way," he said. "I think we should be finishing the characterization work and further exploration of innovative ways of treatment."
Martin Hestmark, the assistant regional director of EPA Region 8, said Monday a pilot program proposed at Captain Jack Mill in Boulder County, Colo., showed promise.
According to the EPA's website, the agency has proposed impounding water within the Big Five Tunnel through the installation of a concrete bulkhead.
A portion of the tunnel would be packed with crushed limestone, which, combined with a low-oxygen environment, would lower the pH and cause most metals to precipitate from the water as solids, the website states.
If additional pH adjustment is needed, sodium hydroxide could be injected into the tunnel, the website states. Water could also be recirculated through the crushed limestone to promote treatment.
Hestmark said the goal is to return the environment to pre-mining conditions.