Forest service plans to clean up contaminated Snoqualmie Valley mine
December 31, 2008
By Michael Rowe
An abandoned copper mine in the Valley that is contaminated with heavy metals is scheduled to be cleaned up by the U.S. Forestry service next year.
The Rainy Mine and an associated mill site are twelve miles northeast of North Bend in the Snoqualmie National Forest. No one lives near the Rainy Mine and mill. The Forest Service report on the mine cleanup indicates that there are no residences within four miles of the area. Groundwater is not used for drinking near the site, and there are no plans to use groundwater as a future source of potable water.
The risk that toxic heavy metals like arsenic from the mine will threaten the health of area communities is practically nil, according to Rod Lentz, who is managing the cleanup project with the Forestry Service.
The Forest Service report states that hikers in the area of the mine may have some risk of exposure to arsenic and other heavy metals through physical contact with contaminated sediment or waste rock or from drinking from Quartz Creek.
The volcanic quartz deposits in the area have naturally occurring heavy metals. Mining operations create waste materials, piles of rubble, quarried from the mine while attempting to extract minerals. This waste rock containing the naturally occurring heavy metals was left on the site after mining operations ceased. Rain and other natural processes that break down and erode the waste rock causes the heavy metals to leech into the environment, contaminating soil, surface and groundwater.
The Rainy Mine site has approximately 2,200 cubic yards of contaminated waste rock that will be disposed of in the cleanup process, according to the final report on the mine cleanup.
Lentz said that the plan is to dispose of the waste rock at the mine site and to cover the entrance to the mine. This option costs less than the alternative of moving the materials off site to be stored somewhere else.
When the cleanup begins, workers will construct a repository on the site to hold the waste rock and contaminated sediment. The repository will be covered with an impermeable cap. Lenz hopes this will keep rainwater out of the waste repository and prevent further contamination.
After the waste is safely stored, workers will likely bring in new topsoil to the area and begin restoring natural vegetation. The Forest Service will also continue monitoring water quality at Quartz Creek. Quartz Creek is a tributary of the Taylor River and the Middle Fork of the Snoqualmie River.
The project is estimated to cost $508,150. Public comments on the cleanup project are being accepted through mid-January. The project will go out for bids after the public comment period is finished and the cleanup could begin in the spring.
Rainy Mine was active in the 1950s and there are several active mining claims on the site, but no mineral extraction operations, according to the final report on the mine cleanup. The final report is available at the North Bend public library or at the Forest Service Ranger Station in North Bend.
Reach reporter Michael Bayless Rowe at mrowe@snovalleystar.com or 392-6434.
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