A newly constructed facility to clean potentially contaminated water at the shuttered molybdenum mine east of Questa began releasing water into the Red River July 5.
Though water from the mine's water treatment plant has been flowing into the river for three weeks, the plant will not be commissioned - that is, fully operational - until the Environmental Protection Agency gives it a final sign-off.
The EPA cannot give a "hard and fast" date for when the water treatment plant will be fully commissioned, according to Gary Baumgarten, remedial project manager with the EPA.
Chevron, which owns the mine, is currently in a "shakedown period" for the plant, when contractors work out bugs and kinks in the various water treatment systems and test different scenarios to ensure all equipment and procedures are effective, according to Baumgarten.
Chevron has submitted operation and maintenance plans for the plant. The EPA will review them to determine the parameters for "stable operations" in the future of the plant. As a matter of procedure, Chevron will pass the final commissioning milestone once the company submits a "project construction completion report" to the agency, Baumgarten said.
Tommy Lyles, Chevron spokesperson, told The Taos News the commissioning process took longer than anticipated due to delays in delivering certain parts and equipment, though he did not disclose what equipment.
"There's lots of moving parts [in commissioning the plant] that didn't always fit together as well as we'd expect," Lyles said.
While engineers continue to toil over the long-term plans for the water treatment plant, water that meets state and federal standards will continue discharging into the river.
The new water treatment plant works with a network of six "collection stations" that gather all the surface runoff and groundwater at the mine site, which once had both open-pit and underground mining.
Three dewatering pumps that are about 1,200 feet deep pull water from the underground mine, which was flooded and capped following the shutdown of operations in 2014. Three shallow wells collect water at the base of the rock piles surrounding the mine.
Once collected, water is moved through a series of filters that clean it of "big chunks" of elements, such as aluminum, before smaller particles are captured, according to Steve Leach, facilities manager with Chevron.
The Questa facility is the only water treatment plant associated with mining that Chevron operates, said Lyles. Chevron did not disclose the overall cost of the water treatment plant.
As the plant comes online, construction crews and plant design contractors will leave the mine, reducing the overall workforce at the site, Lyles said. About 300 jobs were lost three years ago when Chevron announced it was closing the mine that for generations had sustained the economy of the remote Northern New Mexico village.
However, as Chevron ramps up other remediation activities - including the removal of the tailings pipeline that once moved waste material from the mine to the "ponds" west of the village of Questa - the number of contractors will increase, Lyles said.
Golder Associates, the Albuquerque-based firm in charge of long-term operations and maintenance of the plant, will have about 20 personnel and a management team on-site going forward, according to Lyles.
While Chevron had no official deadlines to have the water treatment plant up and running, there was a firm October 2016 deadline to switch off the tailings pipeline, which the water treatment plant is replacing. Chevron met that deadline, but wind damage to a temporary, stopgap water treatment plant forced the company to restart the tailings pipeline until earlier this month.