In 2003, DOE implemented the first phase of an interim action system at the Moab site to address concerns regarding elevated ammonia levels in groundwater discharging to the Colorado River. Uranium is the other main contaminant of concern in groundwater. This first phase consisted of 10 extraction wells (called Configuration 1). Four additional configurations of wells have been added since then, for a current total of 42 wells that are designed to reduce the amount of ammonia and uranium that discharges to the river.
Groundwater extraction is through Configuration 5 wells, which are located closer to the tailings pile. Extracted groundwater is pumped to a storage tank for use as dust control on the pile. Nearly 5.7 million gallons of groundwater was extracted through the interim action system in 2019. In mid-November, the Project shut down extraction for the remainder of 2019 and will resume those operations in mid-March 2020 when the risk for freezing temperatures subside. Over the life of the Project, extraction has prevented more than 930,000 pounds of ammonia and more than 5,100 pounds of uranium from reaching the river.
Freshwater (diverted river water) is injected through wells in Configuration 4 as an additional way of minimizing the discharge of ammonia to the Colorado River. More than 3.1 million gallons of water has been injected in 2020.
DOE continues to evaluate the effectiveness of the interim action system, which will likely become part of the final groundwater remedy. See the Surface Water and Groundwater web page for project documents associated with the interim action.