THE LONG-TERM STABILITY OF ENGINEERED LANDFORMS OF THE RANGER URANIUM-MINE, NORTHERN-TERRITORY, AUSTRALIA - APPLICATION OF A CATCHMENT EVOLUTION MODEL

There is a need to assess the long-term stability of engineered landfo rms associated with the rehabilitation of Ranger Uranium Mine, Norther n Territory, Australia, as it is a requirement that mill tailings must be contained for periods in excess of 1000 years. The geomorphic mode l, SIBERIA, is calibrated on hydrologic and erosion data collected by a combination of monitoring and rainfall simulation experiments on the waste rock dumps of Ranger. Preliminary analysis of Ranger's preferre d above-grade option suggests that erosion of the order of 7 to 8m wil l occur on the structure in a period of 1000 years. This depth of eros ion may be sufficient to compromise the integrity of containment. It i s shown that SIBERIA has significant advantages over steady-state eros ion models. Suggestions are made for the design that will enhance the stability of the structure and extend the structural life of the conta inment. (C) 1998 Reproduced with permission of the Commonwealth of Aus tralia.