One of those mines has an environmental impact here in the Valley.
The New Idria Mercury Mine is located about twenty miles northwest of Coalinga in San Benito County, but it affects waterways leading to the San Joaquin River.
Superfund is the federal program that investigates and cleans up the most complex, uncontrolled or abandoned hazardous waste sites in the country.
Past mining operations at New Idria have resulted in mercury contamination and acid mine drainage.
With all superfund sites, the EPA tries to identify and locate the parties potentially responsible for the contamination.