A finite-element computer program, unsat2, that simulates unsaturated flow is described and applied to a tailings pond near East Gas Hills, Wyoming. Information necessary to run the program are tables of relative conductivity versus moisture content and capillary pressure versus moisture; porosity and saturated conductivity; and initial pressures, boundary conditions, and spatial coordinates for each nodal point. A 10-year simulation is made of the tailings pond based on existing field data and assumptions and interpolations where field data are lacking. The final phreatic surfaces through the cross section are similar but higher than measured values, probably due to limitations in assigning boundary conditions. Unsat2 program results simulate actual conditions much better than saturated flow analysis. Limitations of applying the program to typical tailings ponds are lack of historical data, cost, and difficulty in obtaining representative data to determine relative conductivity--capillary pressure--moisture content relationships, and assigning realistic boundary conditions compatible with the program.
Proc. 1st Int'l. Conf. on Uranium Mine Waste Disp., Vancouver, May 1980, AIME, PP. 445-455