Superfund Sites in Reuse in Nevada
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Anaconda Copper Mine
The Anaconda Copper Mine site covers more than 3,400 acres in the Mason Valley, near Yerington, Nevada. Mining operations in the area date back to 1918. From about 1952 to 1978, Anaconda mined and milled copper on site. Mining operations generated 400 acres of waste rock, 900 acres of contaminated tailings and 300 acres of disposal ponds. In the late 1970s and early 1980s, sampling by the Nevada Division of Environmental Protection (NDEP) found that mining activities had contaminated area groundwater. NDEP and EPA took several emergency removal actions at the site, including stabilization of the leachate containment system, new leachate evaporation ponds, groundwater containment, monitoring and supplying bottled water to residents. EPA proposed adding the site to the Superfund National Priorities List (NPL) in 2015. At NDEP’s request, EPA deferred the listing in 2018 and transferred responsibility for investigations to the state. The site consists of eight areas, or operable units (OUs). An OU8 ROD was jointly signed by EPA and NDEP in 2017, and NDEP is overseeing the remedial action being performed by the PRP. Two more RODs are planned for the site, each consisting of several of the remaining OUs. EPA is leading remedial investigations and risk assessments on tribal lands at the site. NDEP oversees all other investigation and cleanup activities. Current site uses include a historical landmark with site information and an area that overlooks the 180-acre Pit Lake, which formed after mining operations and groundwater pumping from the pit stopped.
Last updated December 2023
As of December 2023, EPA did not have economic data related to on-site businesses, or economic data were not applicable due to site use. For additional information click here.
For more information:
Carson River Mercury Site
The Carson River Mercury Superfund site covers about 330 square miles and more than 130 river miles in northwest Nevada. Contamination at the site resulted from gold and silver mining in the late 1800s. Miners used about 14 million pounds of mercury to process gold and silver ore. Over several decades, the milling process released mercury, lead and arsenic into the environment. Mercury-contaminated tailings built up in the mine and mill sites. Over time, the tailings washed into the Carson River and farther downstream to the floodplain and wetlands, causing widespread contamination. In the early 1970s, the United States Geological Survey reported high levels of mercury in the Carson River’s sediment and water. EPA added the site to the National Priorities List (NPL) in 1990. EPA investigations found mercury in soil, sediments, fish and wildlife. To manage the cleanup, EPA divided the site into two operable units (OUs). OU1 includes the old mill sites and tailings and OU2 includes the Carson River and adjacent floodplain. As part of the OU1 remedy, EPA removed mercury-contaminated tailings from high-exposure risk areas such as parks. Cleanup included the removal of contaminated soils from five residential areas in Dayton and Silver City. EPA also restored infrastructure and landscaping disturbed by cleanup activities. EPA and the Nevada Department of Environmental Protection (NDEP) developed a Long-Term Sampling and Response Plan in 2006 and finalized it in 2018. The plan requires sampling and, if needed, cleanup, on properties slated for residential use. The plan relies on institutional controls that enable continued residential use on site throughout the cleanup process. Since the 1990s, EPA and NDEP have reviewed more than 70 property development proposals. NDEP has also done detailed soil sampling at 28 residential developments. EPA and NDEP worked with developers to help prevent the spread of mercury contamination by covering or capping contaminated soils. The Virginia City Historic District, where many of the historic mill sites are located, depends heavily on tourism. Areas surrounding the Carson River are mostly agricultural, although the area is experiencing rapid housing growth to support high-tech businesses along the nearby USA Parkway. EPA and NDEP work with developers and homeowners in the affected towns to identify and prevent unacceptable risk of exposure to contamination. EPA coordinates closely with the counties’ building and planning departments. OU2 includes surface water, bedded sediments, bank and lake sediments, the banks of the Carson River and adjacent floodplain soils. EPA is selecting an interim cleanup plan for OU2. The proposed interim cleanup plan includes land use restrictions and monitoring. EPA is also doing public outreach, recommending that people not eat fish in certain areas and stay away from mercury-contaminated soils. EPA’s Superfund Redevelopment Program is collaborating with state and federal agencies and The Nature Conservancy to identify areas well suited for solar and other renewable energy development on site. These areas will be explored further as part of a statewide effort called “Mining the Sun”. This collaboration between The Nature Conservancy and the Nevada Mining Association supports the development of renewable energy plants at historic mining sites in Nevada. Several parks, refuges and wildlife management areas surround the Carson River. Due to high mercury levels in fish, the Nevada State Health Division issued a health advisory to strongly recommend that people not eat fish from the Carson River from Dayton to the Lahontan Dam and from all waters in the Lahontan Valley. Catch-and-release fishing, swimming and other recreation activities are safe. In 2023, the site was added to those selected by EPA to receive cleanup funding under the Bipartisan Infrastructure Law (BIL). With this funding, EPA is already initiating work on backlogged remedial construction projects and accelerating cleanups at NPL sites.
Last updated December 2023
As of December 2023, EPA had data on 66 on-site businesses. These businesses employed 388 people and generated an estimated $32,552,393 in annual sales revenue. For additional information click here.
For more information:
- Renewable Energy Reuse Assessment: Carson River Mercury (PDF)
- Site Redevelopment Profile: Carson River Mercury Site (PDF)
- Superfund Site Profile Page