August 3, 2018 – The U.S. Environmental Protection Agency is very engaged at the Iron Mountain Mine Superfund site near Redding, California, in response to the Carr Fire, which spread through the site from July 26 to July 28.

The centerpiece of the Iron Mountain Mine Superfund site is the Minnesota Flats Treatment Plant, which collects and treats acid mine drainage and discharges clean water to Spring Creek. The treatment plant was not harmed by the fire, but was shut down on Wednesday, July 25, in anticipation of losing power. Acid mine drainage was stored in on-site facilities while the plant was shut down. As of July 30, EPA is working with the site operator as the treatment plant is operating again, using generators for power. There has been no off-site release of acid mine drainage that would normally be captured and treated in the Minnesota Flats Treatment Plant.

EPA and its contractors are responding to extinguish small spot fires on the site as they are identified. A spot fire on a pipeline within the Richmond Mine adit started on the evening of July 26. EPA first evaluated the mine using remotely operated tools. After the evaluation, a firefighting team entered the mine to extinguish the fire in the early morning of August 2. Later that afternoon, a firefighting team re-entered the Richmond Mine, evaluated the conditions within the mine and confirmed that the fire was completely extinguished. The pipeline spot fire only impacted conditions within the adit, and did not pose a risk to the public. Although the 18-inch high-density polyethylene (HDPE) pipeline was damaged by the fire, an alternate drain collects the acid mine drainage and routes it to the Minnesota Flats Treatment plant.

EPA is in regular communication with stakeholders and incident responders, including the Federal Emergency Management Agency, the U.S. Bureau of Reclamation, the U.S. Geological Survey, the Bureau of Alcohol, Tobacco, Firearms and Explosives, the California Department of Forestry and Fire Protection, the California Governor’s Office of Emergency Services, the California National Guard 95th Civil Support Team, the California Department of Toxic Substances Control, and the Regional Water Quality Control Board, to ensure the site is secure and operations continue. EPA is working with the site operator to develop a timeline for replacement of any damaged resources.

Background on Iron Mountain Mine Superfund site:

From the 1860s through 1963, the 4,400-acre Iron Mountain Mine was periodically mined for iron, silver, gold, copper, zinc and pyrite. Though mining operations ceased in 1963, underground mine workings, waste rock dumps, piles of mine tailings and an open mine pit remain at the site.

Historically, underground and open pit mining caused daily discharges of acid mine drainage containing up to six tons of heavy metals into the Sacramento River. In recognition of the mine’s negative impacts on water quality and aquatic systems, the site was added to EPA’s Superfund National Priorities List in 1983. Site cleanup activities have controlled acid mine drainage discharges and the site has continuously met water quality standards in the Sacramento River for more than 14 years.