Headwaters Economics, a nonprofit research group, found that more than 68,000 documented abandoned or inactive mines are in flood-prone areas. In the Mountain West, that includes sites in Colorado (4,300), Utah (5,100), New Mexico (1,700), Montana (1,600), and Idaho (2,200).
When heavy rains hit, abandoned mines can leach toxic metals, like arsenic, into rivers and groundwater. Report authors say it’s unclear how big the threat is, since mine inventories are scattered and incomplete. This makes it difficult to know which sites pose the greatest danger.
That’s why more urgency is needed to clean up these mines, said Bridget Mitchell, who leads community assistance for Headwaters Economics’ FloodWise program.
“We need to make it a bigger priority so that we can better protect our people, our waters, and our local economies when the next flood happens,” Mitchell said. “When mines are not reclaimed, they degrade our ecosystem, they endanger our public, and they create economic liabilities for our communities.”
Cleanup makes a difference, she added. In southwestern Montana, years of reclamation paid off, keeping mine waste out of nearby waterways during a massive flood in 2022.
The report urges Western states to build better mine databases, secure steady cleanup funding, and fold these hazards into local flood plans, which are steps that could help communities avoid costly disasters.
This story was produced by the Mountain West News Bureau, a collaboration between KUNR, Wyoming Public Media, Nevada Public Radio, Boise State Public Radio in Idaho, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio, KJZZ in Arizona and NPR, with additional support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
