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. In 2018, more than 7.4 million gallons of groundwater was 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. In mid-November, the Project shut down extraction for the remainder of the year and will resume those operations in mid-March when the risk for freezing temperatures subside.
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. The injection system has been operational through most of the year affected only by low river stage. More than 5.5 million gallons of water was injected in 2018.
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.