In 2003, DOE implemented the first phase of an interim action system at the Moab site to address concerns regarding elevated ammonia levels in ground water discharging to the Colorado River. Uranium is the other main contaminant of concern in ground water. 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.
Ground water extraction is through Configuration 5 wells, which are located closer to the tailings pile. Extracted ground water is pumped to a storage tank for use as dust control on the pile. To date, 236.1 million gallons of ground water have been extracted through the interim action system, preventing 884,800 pounds of ammonia and 4,700 pounds of uranium from reaching the river.
Freshwater (diverted river water) is injected through wells in Configurations 1 and 4 as an additional way of minimizing the discharge of ammonia to the Colorado River. More than 2,749,000 gallons of freshwater have been injected in 2017. The injection system was shut down on May 9 due to the high river flows. Injection will be restarted when the river flows drop below 15,000 cubic feet per second.
DOE continues to evaluate the effectiveness of the interim action system, which will likely become part of the final ground water remedy. See the Surface Water and Ground Water web page for project documents associated with the interim action.