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. Extraction does not take place in the colder months and recently resumed in March 2019. Since then, about 27,500 gallons of groundwater were extracted through the interim action system. Over the life of the Project, extraction has prevented more than 919,000 pounds of ammonia and nearly 5,000 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 384,000 gallons of water has been injected in 2019.
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.