BILLINGS, Mont. – The following mining sites are affected by a U.S. Environmental Protection Agency decision to suspend investigations and some cleanup work at locations with similarities to a mine involved in a 3 million-gallon wastewater spill near Silverton, Colorado, in August:
— Leviathan Mine, near Markleeville, California. An open-pit sulfur mine that closed in 1962. Acid mine water drains from the 250-acre site and has killed off aquatic life in nearby creeks.
— Iron Mountain Mine, northwest of Redding, California. After operating for a century, the mine closed in 1963. Periodic uncontrolled spills have caused major fish kills in surrounding waterways.
—Standard Mine, near Crested Butte, Colorado. The former zinc, lead, silver and gold mine in the Gunnison National Forest shut down in 1966. Heavy metals including cadmium, zinc, lead and copper have contaminated Elk Creek, which drains into another stream that provides drinking water for Crested Butte.
— Southwest Jefferson County mining complex, near De Soto, Missouri. As many as 190 mines once operated in this 166-square-mile area first developed in the early 1800s. Lead has contaminated the soil and groundwater of residential properties in the area.
— Argonaut Mine, Jackson, California. A former gold mine that closed in 1942, Argonaut was the site of a 1922 fire that killed 47 workers. The 65-acre site contains highly contaminated soils and mine tailings.
— Flat Creek/Iron Mountain Mine, near Superior, Montana. It produced silver, lead, gold and other ores and closed in 1953. Mine tailings were used as fill and roadway material in Superior. Flooding has spread piles of contaminated waste throughout the Flat Creek flood plain.
— Upper Tenmile Creek mining area, southwest of Helena, Montana. Mining in the area, which is upstream of drinking-water sources for Helena, largely ceased in the 1930s. Surface waters and river sediments contain high levels of leads, arsenic, cadmium, copper and zinc that drained from the mines.
— Camp Bird Mine, near Ouray, Colorado. A former gold and silver mine that also produced other metals and operated from 1900 to 1990. Colorado health officials said they were not aware of any cleanup work being done.
— James Creek, 40 miles northwest of Denver. Colorado health officials said they were not aware of any cleanup work being done. No further information was available.
— Eagle River, central Colorado. No further information was available.
Sources: EPA, mindat.org