For nearly 10 years, Atlantic Richfield Co. has been cleaning up the Rico-Argentine Mine site along the Dolores River as part of a 2011 Environmental Protection Agency removal order.
Now, Arco seeks more than $63.7 million in cleanup costs from the mine’s previous owners, which it claims is part of NL Industries Inc.
The suit was filed Jan. 28 in U.S. District Court in Colorado under the Comprehensive Environmental Response, Compensation and Liability Act.
“In this action, Atlantic Richfield seeks to recover certain costs it has incurred and will incur in the future, responding to releases and threatened releases of hazardous substances at certain facilities and locations within the Rico-Argentine site, near Rico,” the company states in the complaint.
From 1927 to 1943, the Rico-Argentine Mine was owned and operated by NL Industries’ predecessors and subsidiaries, the lawsuit claims.
Arco alleges the defendant is responsible for mitigating hazardous mine drainage from mining operations by its predecessors.
“Although disposals and releases of hazardous substances by NL defendants’ predecessors contributed to the conditions that are being addressed by the Removal Action, to date NL defendants have refused requests from Atlantic Richfield to bear any of the costs,” the lawsuit states.
In its cleanup order, the EPA alleged that Arco, which now owns the Rico-Argentine Mine site, is a successor to previous mine owners and operators.
Mining at the site began in the late 19th century and produced silver, zinc, lead, gold and pyrite from a network of hard rock tunnels.
In 1925, the Rico Mining and Reduction Co. owned and operated the mine, according to the lawsuit. In 1927, the St. Louis Smelting and Refining Co. acquired Rico Mining’s assets and liabilities and conducted mining operations for two decades.
Arco claims that in 1927, St. Louis Smelting and Refining became a wholly owned subsidiary of the National Lead Co., which changed its name to NL Industries Inc. in 1971.
Arco reports it has spent $63 million in reclamation and pollution controls at Rico-Argentine Mine since the 2011 EPA cleanup order. It seeks a declaratory judgment to hold NL Industries defendants liable for past, present and future mitigation and cleanup costs.
Mine reclamation progresses
After mining ceased in the early 1970s, water containing heavy metals drained through the tunnels and was directed to exit at the St. Louis tunnel, located adjacent to the Dolores River and just north of the town of Rico.
From there the mine runoff — which accumulates unnaturally high levels of heavy metals hazardous to humans and wildlife — went through a water treatment plant and into a series of settling ponds before being released into the Dolores River.
The Dolores River provides agricultural and municipal water for the Ute Mountain Ute Tribe and 28,000 people in Montezuma and Dolores counties.
In 1996, the water treatment system and settling ponds fell into disrepair, triggering lawsuits and state and federal cleanup orders. By 2000, EPA emergency teams were at the site to keep settling ponds from overflowing into the river.
In 2011, an EPA Superfund order initiated a reclamation program that includes new relief wells, more advanced water treatment, real-time monitoring and a new waste disposal site.
A pilot water treatment system that uses biological controls has worked better than expected and will be scaled up to treat higher volumes of mine drainage year-round. The Enhanced Wetland Demonstration Treatment System is one of two in the nation and the only one at such a high elevation.
In 2016, two new relief wells were installed at the St. Louis Tunnel that will help drain the tunnel and prevent a blowout. Mine and EPA officials estimate 1.7 million to 2.2 million gallons of water is backed up in the mine.
Critical systems are wired to be monitored in real time, and live cameras monitor the plant. Mine managers and the EPA are notified remotely about the water level and pressure behind the collapsed tunnel, and about flow rates from the mine into the water treatment facility. An automated system alerts county and emergency managers, irrigation managers and sheriff’s offices if the Dolores River is threatened.
“We get real-time readings that ping us on the conditions,” said Paul Peronard, EPA’s cleanup coordinator at the mine in 2016. “It’s an impressive system that continuously tracks and monitors operations.”