Gold Hill Mill
NPS photo by Neal Nurmi
The mercury amalgamation mill was in use from the 1930s through the 1950s in Warm Springs Canyon in the southern end of the park. The mill site includes a well-preserved mill and arrastra. It is easily visited via the unpaved Warm Springs Road and is near a perennial stream.
Environmental analysis shows high levels of arsenic, lead, mercury, zinc, and antimony in the waste piles and the soils at the mill’s foundation. The site can pose a health risk for people who visit repeatedly or spend more than a passing amount of time there. It provides a greater risk to wildlife, exceeding wildlife’s safe exposures to lead by 130 times, zinc by 202 times, and antimony by 327 times.
The NPS proposes to remove about 50 cubic yards of contaminated soils from the mill foundation and waste piles. The materials would be disposed of in an appropriately licensed landfill. If this action is selected, more detailed design will be necessary to minimize risk of impacts to historic structures, such as the mill.
Public comments are welcome through December 26, 2021. To learn more about the project, or to comment, visit parkplanning.nps.gov/GoldHill.
Source: NPS
