The Formosa Mine Superfund Site is located on Silver Butte, about 10 miles south of the town of Riddle, in Douglas County,Oregon. The site was added to the National Priorities List (NPL) in 2007.
The acid rock drainage flowing from the mine has severely degraded 13 miles of Middle Creek and the South Fork of Middle Creek, affecting macroinvertebrates, resident fish, coastal steelhead trout, and Oregon coastal coho salmon. EPA is completing complete a remedial investigation and feasibility study that will lead to a final cleanup plan for the site.
Source: EPA
Narrative summary.
[url]http://www.epa.gov/superfund/sites/narr/nar1761.pdf[/url]