Superfund Information Systems: Site Profile

Superfund Site:


Cleanup Activities

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The 8,000-acre New Idria Mercury Mine site is located in and near the abandoned town of Idria, California. The mine operated from 1854 to the early 1970s. Mining activities contaminated surface water, groundwater, sediments and wetlands with metals, including mercury. Site studies of the contamination are ongoing.

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What Is Being Done to Clean Up the Site?

The site is being addressed through federal and state actions.

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What Is the Current Site Status?

Removal actions, or short-term cleanups, included re-routing the acid mine drainage, construction of a settling pool for acid mine drainage to allow metals to settle out of the groundwater before discharging it into San Carlos Creek, and construction of surface water diversions to control erosion. These actions finished in 2011. Additional investigations to determine the extent of the contamination are ongoing.

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EPA’s Involvement at the Site

The New Idria Mercury Mine operated from 1854 to the early 1970s. It was the second most productive mercury mine in North America and produced over 38 million pounds of mercury. The abandoned town of Idria contained dozens of dilapidated buildings until a fire in July 2010 destroyed nearly half of the historic structures in the northern part of the town.

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Operable Units

During cleanup, a site can be divided into a number of distinct areas depending on its complexity. These areas, called operable units (OUs), may address geographic areas, specific problems, or areas where a specific action is required. Examples of typical operable units include construction of a groundwater pump and treatment system or construction of a cap over a landfill.

View a list of all of the operable units at this site.

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Cleanup Progress

View the schedule for cleaning up this site.

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