The 12th International Conference on Environmental ... - Events

Session 43-45 Abstracts
Canada and Saskatchewan are now funding the clean-up of these abandoned northern uranium mine and mill sites and have contracted
the management of the project to the Saskatchewan Research Council. <strong>The</strong> clean-up activity is expected to take about 8
years, followed by 10-15 years of monitoring activity before the sites are to be released into an institutional controls program that
will allow government oversight of a long term management and monitoring program. <strong>The</strong> Gunnar site, because of the magnitude
of tailings and waste rock, is subject to an environmental site assessment process regulated by both provincial and federal governments.
This process requires a detailed study of the projected environmental impacts resulting from the mining activities and an
analysis of projected impacts from remediation efforts. Prescribed environmental and land use endpoints will be made based on the
environmental assessment studies and remediation options analyzed and implemented based on expected results. Remediation
options range from deep lake disposal of tailings to disposal of tailings in the open pit which is now filled with water and fish (contaminated,
but which are reproducing successfully) to covering the tailings with a cap.
5) SUSTAINABLE COVERS FOR URANIUM MILL TAILINGS, USA: ALTERNATIVE
DESIGN, PERFORMANCE, AND RENOVATION - 16369
William J. Waugh, S.M. Stoller Corporation (USA); Craig H. Benson, University of Wisconsin-Madison (USA);
William H. Albright, Desert Research Institute (USA)
<strong>The</strong> U.S. Department of Energy Office of Legacy Management is investigating alternatives to conventional cover designs for
uranium mill tailings. A cover constructed in 2000 near Monticello, Utah, USA, was a redundant design with a conventional lowconductivity
composite cover overlain with an alternative cover designed to mimic the natural soil water balance as measured in
nearby undisturbed native soils and vegetation. To limit percolation, the alternative cover design relies on a 160-cm layer of sandy
clay loam soil overlying a 40-cm sand capillary barrier for water storage, and a planting of native sagebrush steppe vegetation to
seasonally release soil water through evapotranspiration (ET). Water balance monitoring within a 3.0-ha drainage lysimeter, embedded
in the cover during construction, provided convincing evidence that the cover has performed well over a 9-year period
(20002009). <strong>The</strong> total cumulative percolation, 4.8 mm (approximately 0.5 mm yr-1), satisfied a regulatory goal of