Calls for a commercial water treatment facility near the Gold King Mine have intensified following the mine waste spill on Aug. 5. However, a treatment facility in the remote part of Colorado that sits above 11,000 could be costly.

The Denver Post reported that while experts agree a treatment plant would be the best cleanup option — removing 99.9 percent of contaminants — such facilities can cost up to $20 million to build and must run as long as a mine is leaking, or forever. Heavy snowstorms can also render such facilities ineffective.

A previous effort to treat water near Gold King failed when its operators ran out of money in 2005, a year after the treatment system was damaged by a winter storm.

“That’s definitely the trade-off,” Mary Boardman, a Colorado Division of Public Health and Environment project manager, said of the cost. “It is expensive to run, but it's also the most effective (option).”

Boardman oversees operations of an Idaho Springs mine wastewater treatment plant, which hugs the banks of Clear Creek. Whirring machinery is busy at all hours, siphoning 950 pounds of metals from runoff each day.

Orange, contaminated sludge from turn-of-the-century mining makes its way into the facility, called the Argo Tunnel Water Treatment Plant, and enters a complicated series of filters, water tanks and pipes. The byproduct, after a process that costs $1 million a year, is a steady, pristine trickle.

The treatment system that existed below Gold King a decade ago cleaned water from the nearby American Tunnel and other area mines whose waste flowed into Cement Creek, a headwater of the Animas River. In the winter of 2004, a severe snowstorm knocked out electricity and access to the site for days, rendering it useless.

Within a year of the storm, the treatment system was cited with a technical violation. Funds ran dry and the plant — as well as the corporation that owned it — went under.

When the treatment stopped, water quality below Gold King in Cement Creek and the Animas River — which had been improving for years — declined “significantly,” according to the Environmental Protection Agency. There were no fish in the Animas below its confluence with Cement Creek for about two miles, and trout populations began declining as far as 20 miles downstream.

After the EPA-triggered Aug. 5 Gold King spill, which sent 3 million gallons of contaminants into the Animas River basin, members of Congress and locals called for a new treatment plant in the area. The EPA says it is considering building a temporary plant, among other options.

Todd Hennis, who currently owns Gold King, says in his talks with EPA officials about their treatment plans, the agency has said it needs to construct its treatment apparatus before Oct. 1, when serious snowfalls typically start.

The EPA has said its current treatment system — several settling ponds — will not work in freezing temperatures.

But Ron Cohen, an associate professor of civil and environmental engineering at the Colorado School of Mines, says commercial treatment plants are the best option.

“The conventional technology in these mine water-treatment plants is very well-developed and can be very effective,” he said. “The issue, as everything else, is an issue of money.”

Cohen said such facilities often cost between $5 million and $20 million and typically cost more than $1 million a year in upkeep.