|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 and mine materials have 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 has completed a remedial investigation for Operable Unit 1 of the site. A feasibility study to evaluate cleanup alternatives will be available in 2013.
Final OU1 Feasibility Study Report (PDF) (451 pp, 12MB) - January 31, 2013
Final Remedial Investigation for Operable Unit 1 (PDF) (265 pp, 10MB)
Download appendices, tables, figures, etc. for the RI report from our FTP file repository: ftp://ftp.epa.gov/reg10ftp/sites/formosa