View of the evaporation pond (right center) on the tailings pile with the forced-air evaporators running. The extraction wells are between the pile and the Colorado River, which can be seen in the lower left.
Grand Junction, CO ― The Department of Energy (DOE) announced today that it has extracted 200 million gallons of contaminated ground water from the Moab site in Utah as part of the Moab Uranium Mill Tailings Remedial Action Project. Actively remediating the contaminated ground water is part of the project’s scope, which also includes relocating a 16-million-ton uranium mill tailings pile away from the Colorado River.
Ammonia was used in the milling process to extract the uranium from the ore. The mill tailings, what remained after the ore was processed, were pumped to an unlined impoundment at the Moab site that accumulated over time, creating a pile more than 80 feet thick and covering 130 acres. Excess water from the pile drained into underlying soils, contaminating the ground water.
Elevated concentrations of ammonia can affect endangered fish species in backwater channels of the Colorado River. Uranium is the other main contaminant of concern in the area ground water. In 2003, DOE began an interim action system that currently includes eight extraction wells. The system is designed to protect surface water quality and to recover contaminants prior to discharge to the river.
Today, 200 million gallons of ground water has been extracted through the interim action system, preventing more than 785,000 pounds of ammonia and almost 3,900 pounds of uranium from reaching the river. Extracted ground water is pumped to a lined 4-acre pond on top of the tailings pile where it is sent to forced-air evaporators.
“Our interim action system efficiently and cost-effectively protects the river, which is a drinking water source for millions of downstream users,” said Federal Project Director Donald Metzler. The project estimates that it costs less than 10 cents per gallon to extract and eliminate the water.
The project has relocated more than 38 percent of the tailings pile to a U.S. Nuclear Regulatory Commission-approved disposal cell located 30 miles away from the river. Active remediation of the contaminated ground water is anticipated to finish concurrent with completion of removing the tailings pile, which is currently estimated to take 12 more years.