SUMMIT COUNTY — A long-running effort to clean up the Blue River below Breckenridge culminates this week with the official dedication of a water-treatment plant in French Gulch.

The new facility will remove zinc and cadmium oozing out of the abandoned Wellington Oro mine, creating cleaner water for downstream trout.

The $1.2 million plant was built by BioTeq, a Canadian company that has built similar facilities for other highly polluted mine sites.

The acid mine drainage from the Wellington-Oro contributes significant levels of cadmium and zinc to the waters of French Gulch and, in turn, the Blue River, threatening the aquatic ecosystem downstream.

The goal of the treatment is to clean the water sothe Blue can support a self-sustaining brown-trout fishery below its confluence with French Gulch.

A pilot project showed that the treatment technology can remove significant quantities of zinc and cadmium.

The chemistry of the treatment mimics the function of a natural wetlands system.

Inside a “precipitation reactor,” a sulfide compound is added to the water, essentially causing the dissolved zinc and cadmium to solidify.

“It’s like taking dissolved sugar or salt in water and turning it back into a solid,” Bioteq engineer Mike Bratty said previously during a test run of the technology.

One advantage to BioteQ’s method is that it’s selective in terms of which metals it treats, focusing on the zinc and cadmium.

That reduces the amount of solid waste generated by the process, said Summit Couty open-space director Brian Lorch, who serves as the county’s lead on mine cleanups and river restorations.

The plan is to deliver the solid waste from the treatment project to a smelter, where the zinc and cadmium will be reprocessed for the manufacture of batteries, according to Bratty.

That helps solve the waste-disposal issue and also adds some economic value to the operation, he said.

In the long run, the Town of Breckenridge would take over day-to-day operations at an estimated annual cost of about $90,000.

Mine cleanup

The abandoned Wellington Oro silver and zinc mine was the largest in Summit County between the 1880’s and the 1930’s. The water draining from 12 miles of tunnels is contaminated with zinc, lead and cadmium.

The mine ceased operation in 1972 and later was identified as a site for potential Superfund listing by the U.S. Environmental Protection Agency. The Town of Breckenridge and Summit County purchased the site as part of an 1,800 acre open-space plan.

The goal of the mine cleanup is to lower the concentration of dissolved metals in the Blue River downstream of French Creek, to meet Colorado water-quality standards and protect the brown-trout fishery.

Plant opening Nov. 18

Where: 2001 French Gulch Road, Breckenridge (across from the Country Boy Mine)

What and when: Ribbon cutting and speeches: 1-2 p.m.

Open house and tours: 2-4 p.m.