Colorado water quality regulators this week finalized a $1.1 million penalty against the owner of a dormant mine west of Fairplay that has drained one million gallons a day of runoff containing cadmium and zinc into South Mosquito Creek.
The creek flows into the South Platte River in metro Denver’s watershed.
Administrative law Judge Robert Spencer approved the penalty by the Colorado Department of Public Health and Environment’s Water Quality Control Division against owners of the London Mine, according to a court document.
The mine has been inactive for more than a decade.
A tunnel at the mine discharges a number of pollutants, including zinc — toxic to fish — and cadmium, linked to cancer in humans.
Attorneys for the estate that owns the London Mine argued that the penalty was excessive, urging state regulators to consider an inability to pay and that third parties were responsible for violations of state discharge permits.
CDPHE officials couldn’t be reached.
The London Mine is one of many that leach toxic heavy metals into Denver’s watershed. Municipal water treatment plants keep contaminants from flowing out taps in homes, but the discharges hurt ecosystems.
State agencies and contractors for years have worked on a cleanup at the London Mine, including installation of a water treatment plant. The continuing discharges shows how difficult cleanup of old mines can be.
The London Mine is one of about 230 inactive mines statewide that drain into headwaters of the nation’s waterways. This toxic acid runoff has left thousands of miles of waterways statewide devoid of aquatic life.
Colorado lawmakers have been investigating the problem, and on Thursday, Colorado Gov. John Hickenlooper said in his annual State of the State address that the government was working on inventorying draining mines to prioritize them for cleanup.