Environmental remediation efforts are gearing up at the closed Questa Molybdenum Mine site in New Mexico, which operated for almost a century before shutting down in 2014. Declared a federal Superfund site in 2011, the cleanup is expected to take decades and cost the U.S. Environmental Protection Agency (EPA) over $1 billion.

The site's nine waste rock piles are currently being regraded to prevent erosion and reduce stormwater and snowmelt runoff. Don Bush, Chevron's lead engineer at the mine site, told the Tao News, "We've completely changed the shape," and added that eventually, "all the rock piles will be graded, covered and seeded." Workers have completed regrading one waste rock pile and are preparing to seed ground cover as early as later this year.

The wastewater treatment plant at the site treats around 750 gallons per minute of contaminated water from wells, springs, and former mine workings. The plant can treat around four million gallons per day and is considered "likely the largest wastewater treatment plant for mine sites in the state of New Mexico," according to a spokesperson for the New Mexico Environment Department. The treated water released into the Red River has a cleaner composition than upstream water, often contributing up to 30% of the overall river volume.

Gabriel Herrera, public affairs adviser for Chevron Environmental Management Co., said that after going through a four-stage treatment process to remove harmful metals, "what's actually produced is cleaner than the water coming upstream from the mine." It was also noted that any waste material produced during treatment is stored safely, with leachate returned to the wastewater treatment plant for additional processing.

Currently employing around 270 people in various roles related to mine site remediation or offsite support activities, 40% of their workforce is local. Tito Duran, the supervisor of the wastewater treatment plant who was previously employed at the mine, said, "My goal is to make sure this is running all the time."