Contractor Weston Solutions did not cause the 2015 release into several rivers of an estimated 3 million gallons of toxic wastewater, including 880,000 lb of heavy metals, from the abandoned Gold King Mine near Silverton, Colo., which eventually contaminated large areas in the state, New Mexico and Utah, a federal district court judge ruled Nov. 21. The court added that the company also is not responsible for cleanup costs related to the spill under the federal CERCLA law.

New Mexico and its environment agency filed a lawsuit against the U.S. Environmental Protection Agency and its remedial contractors and the owners of the mine for damages caused by the spill. But they did not establish that Weston Solutions “possessed, owned, or controlled the water impounded in the Gold King Mine,” chief district court Judge William Johnson said.

The release occurred as EPA, Weston Solutions and contractor Environmental Restoration were working at the mine site. Weston Solutions was the agency's Superfund Technical Assessment and Response Team contractor there. The firm ranks at No. 69 on ENR's list of the Top 200 Environmental Firms, reporing about $201 million in environmental services revenue.

The problem began when a tunnel that carried contaminated water from a nearby mine to a treatment plant was plugged when the mine was shut down in the 1990s by then owner, Sunnyside Gold Corp.

“Sunnyside Gold plugged the American Tunnel using two bulkheads—massive plugs in the mine openings designed to hold back the reservoir of toxic waste that would inevitably accumulate within the mine behind them,” the New Mexico complaint said.  

“By plugging the Sunnyside mine with bulkheads, the owners and prior owners of the Sunnyside Mine recklessly caused the Gold King Mine, among others, to fill with toxic, contaminated water, without regard to the effect it would have on nearby mines, the environment, or the downstream communities,” the complaint said. Sunnyside Gold has disputed that contention but it remains a "potentially responsible party" in site remediation.

Colorado safety officials recognized the risk of a large release of contaminated water from inside the Gold King mine In 2009, corroborated officially by EPA and its contractors five years later.

In its suit, New Mexico alleged that the agency and the contractors “neglected to perform the necessary engineering analysis to properly assess the level of water and the pressure built up inside the mine.” EPA and Environmental Restoration "then operated heavy machinery to excavate the area at the Gold King Mine, which caused the blowout,” the complaint contended, adding that emergency response procedures or plans were inadequate if a blowout occurred.

But the court found that Weston Solutions did not have the authority to direct or control the work of the other contractors performing the excavation, providing technical support but not in a supervisory capacity. EPA was the sole decision maker and excavation was the purview of other contractors and subcontractors, the judge said.

A Weston Solutions spokeswoman declined comment on the ruling.

US, Mine Company Settle Claims

In late 2021, Sunnyside and its parent, Canada-based Kinross Gold Corp., reached a $90-million settlement with EPA, under which it will pay $45 million to the U.S. government and to Colorado for future cleanup. The federal government will contribute another $45 million to the cleanup of the Gold King Mine site and nearby abandoned mines, as part of a Superfund site designation.

Also in an out-of-court settlement, Sunnyside agreed to pay $10 million to the Navajo nation, which claimed that toxic water flowed through 200 miles of river on its lands.

“The Gold King Mine blowout damaged entire communities and ecosystems in the Navajo Nation,” tribe President Jonathan Nez said in a statement at the time. But claims by individual tribal members remain in separate lawsuits.

Also earlier this year, New Mexico reached an out-of-court settlement with EPA. The U.S. will pay the state $32 million as a result of the toxic spill. Utah also settled separately with EPA in 2020, resolving legal claims against it and against the contractors, with the agency agreeing to fund $220 million for abandoned mine remediation projects and separate water projects in the state.

Sunnyside also settled with New Mexico, but the status of Utah's claims against it and Gold King mine owners could not be determined.

The agency said in a statement at the time that it has spent more than $75 million on cleanup work “and expects to continue significant work at the site in the coming years.”  Sunnyside said it has spent more than $40 million in mine site cleanup over 30 years.

Third-party defendant Harrison Western Construction Corp. on Nov. 10 reached a settlement-in-principle with EPA contractor Environmental Restoration and the two are currently preparing a settlement agreement, the company said.