Formosa Mine

BLM District	Roseburg (Oregon)	BLM Field Office	South River
Congressional District	Oregon 4th	AMLIS #	OR1058-00002
State Office Contact	John Barber	HUC # /Subbasin	17100302
Field Office Contact	Susan Lee	Specific Watershed	South Umpqua
Location		West side of Silver Butte (T30S, R6W, Sec. 23,SESW, NESW, Willamette Meridian, Lat. 42.857921, Long. -123.381888)
Land Ownership		Private & BLM-administered lands
Estimated Cost		$680,000 (BLM)
Other Agency Links		Oregon Dept. of Environmental Quality
Google Earth		Click here for map

The Formosa Mine, located within BLM's Roseburg District, is a mixed ownership National Priority Listed site which includes Bureau administered land. The site was listed on EPA's National Priority List (Superfund) in 2007. Acid mine drainage from adits tailings is leaching high levels of metals into local streams negatively impacting water quality and fisheries. BLM is working cooperatively with the Environmental Protection Agency (EPA), the U.S. Geological Survey (USGS), and the Oregon Department of Environmental Quality (ODEQ) on a remedial plan and interim actions to manage acid mine drainage and its impacts on local resources at this Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) site.

The objective of this project is to assist EPA in completing the investigations needed to design the final cleanup remedy for the Formosa mine site. The currently envisioned preferred alternative would recommend a phased, adaptive management approach that recognizes the extremely complex nature of the site to restore the affected watersheds to pre-mining conditions supportive of fish populations and aquatic life. The project is of significant community interest to Riddle and other communities in Douglas County and is one of the highest priority mine cleanup projects for ODEQ and BLM. The project has the support of numerous members of the public including state congressional officials, county commissioners, and local elected officials, as well as many local organizations as indicated through direct communications at public meetings and personal conversations. Easily implementable, low risk technologies will be applied to minimize the production and off-site migration of contaminants with the best chances of success at the lowest cost. The results will be closely monitored to determine the need, extent, and cost of any additional technologies needed to meet clean-up objectives.

The mine was most recently operated between 1990 and 1993 by Formosa Exploration, Inc., a Canadian mining company. In 1993, when mining operations terminated, the company and the Oregon Department of Geology and Mineral Industries began reclamation work. Formosa Inc., abandoned the site in 1994. By 1997, the system to handle mine drainage was no longer functioning; resulting in release of untreated acid mine drainage into the headwaters of Middle Creek directly affecting 18 miles of stream located on private timber land and on BLM-managed lands. Since 1994, the ODEQ and BLM have spent over $2 million on site investigations and interim cleanup actions. The total cost of implementing a cleanup remedy is still under review, but could exceed $20 million.

An interagency memorandum of understanding (MOU) between EPA and BLM is currently under development, and EPA is conducting a search for Potentially Responsible Parties (PRPs). EPA has asked BLM to enter into a cost sharing agreement for remedial actions at the Formosa site, because Superfund money cannot be utilized on Federal lands. BLM is providing both funding and work-in-kind to assist EPA in completing the Remedial Investigation/Feasibility Study (RI/FS), which includes ecological health hazards to the Middle Creek and South Fork of Middle Creek watersheds. Additionally, BLM will perform an Engineering Evaluation/Cost Analysis (EE/CA) for a removal action to address acid mine drainage from the Formosa #1 adit as part of a two unit task. Unit One will include completion of a RI/FS, project proposal, and record of decision (ROD) for surface features, waste rock, tailings piles, and surface water management. Unit Two tasks will focus on ground water sampling plans, installation of monitoring wells, and implementing RI/FS findings. BLM will also undertake an EE/CA and initiate a non-time-critical removal action to address the failing acid mine drainage diversion system and provide operation and maintenance funding for the system (AMLIS OR1058-00002).

	Precipitates from Mine Drainage
	Mine Drainage Collection System
	Existing Mine Drainage Treatment Boxes
	Mine Drainage Seeping from Backfilled Portal
	Existing Mine Drainage Collection System