Cleanup of the Red Arrow Mill site will begin June 9, the Environmental Protection Agency announced Tuesday.
The mill was closed last year after it was discovered mercury was being used to process gold. High levels of arsenic were also found in a building at 1000 West Grand Ave. and in waste materials and mill tailings on the site.
During the fall, all the potentially contaminated materials were contained, and in December, the EPA announced that no major immediate health risks existed.
The decontamination efforts are estimated to cost $429,600. Federal funding is anticipated to cover most of the project. The local community will not have to contribute to the project.
The EPA estimates decontaminating the buildings will take two to three weeks, and work on the soil and other waste materials make take three weeks, according to an EPA statement.
The EPA will start with the building in June and work on the soil and tailings will happen later in the summer. The entire project is estimated to be completed by Sept. 30, Chergo said.
"EPA does not anticipate any impacts to the local community or adjacent property owners. There will be air monitoring conducted at the mill building and at the property perimeter for the duration of the cleanup," EPA representative Jennifer Chergo said in a statement.
In the buildings, crews will recover all visible, free mercury from the building with mercury vacuums. Crews will also pump and treat liquids through granulated activated carbon.
The water may be taken to a water-treatment plant or an off-site disposal facility.
Equipment will be treated or disposed. Particularly large equipment may be cleaned with power washers or zinc powder, said Craig Myers, the EPA on-scene coordinator in a previous interview.
Tailings, and soil waste previously identified as being contaminated with mercury will be treated with a zinc compound to reduce its ability to leach. All mill tailings and other process wastes on-site will then be disposed of either by transporting them back to the mine site or to a local, permitted landfill. No matter the location, these materials would be stored in a container that would prevent leaching.
It would preferable to move it back to the mine site, Myers said, so it wouldn't fill up limited space in the landfill.
The EPA stated previously the cleanup process has been delayed by the bankruptcy proceedings in Texas concerning the former owner of the mill and the gold mine Craig Luikko.
Luikko has been embroiled in an ownership dispute with a bankrupt partner company and a New York hedge fund. The federal bankruptcy has been resolved, but there is still a case in county court pending, Chergo said.
When the work on the mill site is complete a public health consultation report is also set to be released. At a public meeting in December officials stated they were most concerned about employees of the mill who would have had the most exposure to the mercury and arsenic. Those employees had not come forward at the time.
The EPA plans to schedule a public meeting that will be attended by regulatory officials to discuss the cleanup efforts, but a date has not been set.