High concentrations of heavy metals continue to flow directly into Silver Creek above Rico from a long-abandoned mine tunnel at levels that far exceed water-quality standards set by the Colorado Board of Health and Environment.

The ongoing contamination has left Silver Creek, a tributary of the Dolores River, essentially devoid of life downstream of the tunnel, and could threaten the health of the Dolores River watershed, the municipal water source for the towns of Dolores and Cortez.

The illegal discharge from the Blaine Tunnel prompted the federal government and the State of Colorado to file a civil complaint last year in U.S. District Court against the now-dissolved Rico Development Corporation, the supposed owners of the mines, for allegedly violating the federal Clean Water Act. The law was enacted in 1996 to protect the nation’s watersheds from dangerous levels of pollution.

The civil suit also alleges that RDC was derelict in operating a mine-runoff treatment system that filters wastewater from the nearby St. Louis Tunnel through a series of 11 settling ponds before emptying into the Dolores River. The operation has been abandoned since 1996, and is in disrepair, also a violation of the Clean Water Act.

In April, the EPA Emergency Response team was called in and successfully reinforced failing soil berms on two of the ponds draining the St. Louis Tunnel, which had been backing up and were leaking untreated wastewater directly into the adjacent Dolores River.

But because of exorbitant costs, the now-breached concrete barrier installed in the Blaine tunnel to prevent leakage there was not repaired. The Blaine tunnel is not considered a legal discharge point, and RDC’s former owners do not have a permit to allow the effluent spill into Silver Creek.

The EPA is seeking payment from the RDC owners named in the suit, Wayne Webster and Virginia Sell. The agency also is asking that the owners repair or find a solution to the Blaine Tunnel leak, continue to operate the St. Louis treatment plant in accordance with a permit, renew and comply with their now-expired discharge permit issued by the Colorado Department of Health and Environment for the St. Louis Tunnel, plus incur penalties of up to $25,000 per day."

According to a water-quality study ordered by the EPA, the illegal discharge from the Blaine tunnel is contaminated with toxic amounts of cadmium, copper, lead and zinc. A 1997 study by the Colorado Department of Health showed the waste flow out of the Blaine tunnel at 1-3 gallons per minute.

Last summer the EPA’s Denver office had water samples tested from nine sites at the Argentine mine site, including three involving the Blaine Tunnel — one upstream of the tunnel, one at the actual discharge, and one downstream of the leak.

The report reveals that the effluent from the Blaine tunnel has caused levels of copper and lead in Silver Creek to exceed water-quality standards that must be met for aquatic life to survive. And the unpermitted discharge has more than doubled the amount of zinc absorbed by Silver Creek after it flows by the mine tunnel.

Cadmium was diluted enough to stay below the threshold.

But the amounts of copper and lead, both toxic by-products of hard-rock mining, in the creek coming from the Blaine tunnel discharge clearly do exceed the allowable amount established for the mountain stream under Colorado water-quality standards, according to the EPA study, effectively killing off life in the creek downstream.

With copper, aquatic life in Silver Creek begins to die off at levels of 14 parts per billion, according to state standards. Below the Blaine tunnel, that level hit 66 parts per billion, or more than four times greater than water-quality standards allow.