In Kellogg, Idaho, construction crews are building a new facility that treats waste water that comes from the Bunker Hill mine. The goal is to reduce the pollution that makes its way into the south fork of the Coeur d’Alene River.
The historic Bunker Hill mine in Kellogg is no longer in production, but it still leaches water filled with heavy metals and other contaminants, often more than a thousand gallons per minute per day. That water flows downhill toward the south fork of the Coeur d’Alene River.
For more than 40 years, much of it has been captured and treated at a wastewater plant before it can make its way to the river. Some, though, gets there untreated and follows the current down all the way down to Lake Coeur d’Alene.
Rod Zion, an engineer for the U.S. Army Corps of Engineers, says the treatment system is getting an upgrade so that more of that polluted water can be intercepted.
“There’s two steps to doing that. One is to capture the groundwater with a series of extraction well pumps, 12 extraction pumps, that go along Interstate 90, east to west," he said. " Then the second part of that is a cutoff wall, basically an underground dam to retain the water so the extraction wells can capture it. Twenty-five to 35 feet deep and about 7,800 linear feet.”
That wall will catch the water before it gets to the river. What’s collected will be pumped through a new series of pipes back to the treatment plant, which will be upgraded with the latest technology. There, most of the metals and other undesirables will be pulled out, the water will be cleaned and piped down to the river. The solids will be trucked to the huge 270-acre central impoundment area west of Kellogg. Zion says that big repository is running out of room, so crews have dug new lined trenches to store that contaminated material. He says that water treatment system will continue to operate as long as water leaches from the Bunker Hill mine.
This is a multi-year project. Crews will stop work for the winter and pick up again next spring. The new water treatment plant is scheduled to begin operating in 2020.