The silver and lead mines that once flourished in Burke Canyon are a distant memory, but a negative aspect of their legacy lives on in the metals that wash down the narrow canyon near Wallace.
Piles of old waste rock – left over from Burke’s boomtown days in the early 1900s – leach cadmium, lead, arsenic and zinc into Canyon Creek. Decades after the mines closed, parts of the creek remain too toxic for fish.
As the U.S. Environmental Protection Agency charts the next phase of Superfund cleanup in the Coeur d’Alene basin, agency officials are focusing on historic mine waste’s role in polluting rivers and streams.
“As water flows through those areas, it’s continually exposed to contamination,” said Bill Adams, a Superfund program manager.
At a meeting Thursday in Kellogg, EPA officials will discuss plans for improving water quality. The work is part of a proposed expansion of Superfund cleanup that would cost $1.3 billion over the next three decades.
By tackling upstream pollution, the cleanup would improve downstream water quality in Lake Coeur d’Alene, said Anne Dailey, who’s also an EPA Superfund manager.
Thursday’s meeting will give local residents a taste of what’s in the proposal and how they can be involved in the decision-making. A formal 45-day comment period starts in mid-July, with another public meeting scheduled for August.
The plan targets the upper portion of the south fork of the Coeur d’Alene River, where more than 300 old mining sites have been identified, including the Burke Canyon waste rock piles. The plan also looks at ways to keep polluted groundwater from mixing with cleaner surface water and identifies areas where water treatment is needed.
Part of the challenge is the sheer prevalence of mine tailings. Until 1968, waste rock was dumped into the south fork of the Coeur d’Alene River after most of the minerals were removed. Tailings were also used as construction fill. Parts of Interstate 90 are built on waste rock.
EPA wouldn’t try to remove tailings from underneath the freeway or buildings, Dailey said. That isn’t practical, she said.
The second phase of Superfund cleanup expands on earlier work. Removing polluted soil from residential yards was an early priority to reduce children’s risk of lead exposure. Some communities still need yard remediation, and that work will continue, Adams said.
“Human health continues to be our first priority,” Daily said.
A settlement with Asarco will help pay for the cleanup. In December, the mining company agreed to pay the federal government $1.8billion for cleanup of 80 toxic sites across the nation. About $500million will be spent on Superfund work in the Coeur d’Alene Basin, Dailey said.