In 2018, the Arizona Department of Environmental Quality (ADEQ) was alerted to polluted water pooling near Prescott. The agency discovered orange mine waste materials contaminating the water, flowing downstream into the Hassayampa River’s headwaters. The McKinley Mill Mine, active in the early 1900s, had left behind waste that polluted the surrounding water for decades.
In 2021, ADEQ initiated a remediation project at the McKinley Mill site. The steep waste pile was regraded, and a retention wall was built to limit the runoff to nearby creeks. The project cost $500,000, part of the $1.3 million annual budget for such efforts. Despite these successes, there are numerous abandoned mine sites in Arizona still in need of cleanup.
The ADEQ estimates that 40,000 to 100,000 abandoned mines exist across Arizona, though a full inventory has never been completed. With legal barriers preventing external groups from taking action, advocates hope a newly passed legislative fix will create a federal program to accelerate cleanup efforts.
The Good Samaritan Remediation of Abandoned Hardrock Mines Act, recently passed by Congress, aims to address the funding issues. The bill would establish a pilot program for 15 low-risk cleanup projects funded by non-government entities over seven years. Environmental groups believe the program will help clean up abandoned mine sites more efficiently.
The legislation also addresses liability concerns that have hindered organizations from participating in cleanup efforts. Under current law, groups could be treated as polluters, even if they reduce contamination by 95%. With the new bill, groups would be protected from liability, allowing them to focus on cleaning up sites without the fear of costly legal action. President Biden is expected to sign the bill into law soon.
