Assessment of the Jabiluka Project : report of the Supervising Scientist to the World Heritage Committee
Johnston, A.; Prendergast, J. B.; Bridgewater, Peter
E-Publications; E-Books; PublicationNT; Supervising Scientist Report; 138
Alligator Rivers Region
Main report--Appendix 2 of the Main Report. Submission to the Mission of the World Heritage Committee by some Australian Scientists ... --Attachment A. Johnston A. and Needham S. 1999. Protection of the environment near the Ranger uranium mine--Attachment B. Bureau of Meteorology 1999. Hydrometeorological analysis relevant to Jabiluka--Attachment C. Jones, R.N., Hennessy, K.J. and Abbs, D.J. 1999. Climate change analysis relevant to Jabiluka--Attachment D. Chiew, F and Wang, Q.J. 1999. Hydrological anaysis relevant to surface water storage at Jabiluka--Attachment E. Kalf, F. and Dudgeon, C. 1999. Analysis of long term groundwater dispersal of contaminants from proposed Jabiluka mine tailings repositories--Appendix 2 of Attachment E. Simulation of leaching on non-reactive and radionuclide contaminants from proposed Jabiluka silo banks.
Uranium mill tailings - Environmental aspects - Northern Territory - Alligator Rivers Region; Environmental impact analysis - Northern Territory - Jabiluka; Uranium mines and mining - Environmental aspects - Northern Territory - Jabiluka; Jabiluka - Environmental aspects
Supervising Scientist Report; 138
1 volume (various pagings) : illustrations, maps
https://hdl.handle.net/10070/462403; https://hdl.handle.net/10070/462400; https://hdl.handle.net/10070/462405; https://hdl.handle.net/10070/462406; https://hdl.handle.net/10070/462408; https://hdl.handle.net/10070/462409; https://hdl.handle.net/10070/462411
54 by about 4 ha, thus increasing its evaporative capacity. If this suggestion were to be implemented, then the full additional evaporative capacity of 90,000 m3 would be available as soon as water covers the base of the retention pond. By year 5 of operation, the difference in accumulated water losses from the water management system between this scenario and that outlined in table 5.2.4 is about 300,000 m3. Hence, the maximum storage capacity required in the simulation illustrated in figure 5.2.2 would be reduced by about 50%. Similarly, it is likely that if the full simulation of the water management system were repeated using pond evaporation rather than evaporation in the ventilation system, the capacity required to achieve an exceedence probability of 0.01% over the life of the mine (see section 5.2.3) would be reduced by about 30%. This 30 % reduction in the required water storage capacity of the Jabiluka retention pond far outweighs the increase of about 10% that arises from consideration of refinements in the hydrological modelling that were addressed in the previous section. It is recommended that ERA, in its detailed design of the Jabiluka water management system, uses increased pond evaporation rather then enhanced evaporation in the ventilation system to minimise the volume of the water retention pond. In making this recommendation, it is recognised that some enhanced evaporation in the ventilation system as a result of dust suppression procedures is inevitable. This will need to be modelled carefully by ERA to achieve the optimum water management system. One advantage of the original ERA proposal to use enhanced evaporation in the ventilation system was that its use would be under control and, for example, in drier years or sequences of years, pond water levels could be controlled by switching off the enhanced evaporation system and minimising the need to import water from the bore field. If only pond evaporation is used, this level of control is lost. One way of retrieving control would be to partition the water retention pond into three or four compartments with connecting spill ways and a water pumping system. In this way evaporative losses in dry spells could be minimised by pumping all remaining water into one of the compartments and could be maximised in wetter periods by using the full evaporative capacity of all of the compartments. It is recommended that ERA consider this approach in the detailed design of the water management system at Jabiluka. Table 5.2.4 Water losses assumed in the hydrological model of the Jabiluka water management system (annual volumes in m3). Data from JMA Public Environment Report, Appendix B1. Year 1 Year 2 Year 3 Year 4 Year 5 Year 6 Year 7 Year 8 Year 9 Year 10 Year 1130 Evaporation Variable (see section 3.3) but approximately 170,000 Mill requirement 0 180000 Ore wet-down and plant wash-down 800 1200 3500 7000 10000 Mine ventilation and dust suppression 0 15000 30000 45000 60000 75000 90000 5.2.6 Effect of climate change on the required water storage capacity In section 4.4.2, the principal conclusions on the effect of possible climate change over the next 30 years were that: The projected temperature increase in the region of Jabiluka is expected to be in the range 0.350.8C.