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
1999
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.
English
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
Environment Australia
Canberra (A.C.T.)
Supervising Scientist Report; 138
1 volume (various pagings) : illustrations, maps
application/pdf
642243417
Copyright
Environment Australia
https://www.legislation.gov.au/Details/C2019C00042
https://hdl.handle.net/10070/264982
https://hdl.handle.net/10070/462402
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
29 reason, it is recommended that a linear relationship between evaporation and rainfall is incorporated in future water management modelling because this will yield conservative results under high rainfall conditions and more realistic results under drought conditions than would be obtained using the long-term monthly average evaporation. The Supervising Scientists conclusions on the claims of Wasson et al (1998) on the deficiencies of ERAs estimates of evaporation from open water at the Jabiluka site are: All of the suggestions made by Wasson et al (1998) to check the validity of the evaporation pan factors used by ERA had already been taken into account in the evaporation calculations presented by ERA in its hydrological modelling of the water management system for the Jabiluka project. Based upon two recent independent reviews, it is recommended that, in all future hydrological modelling of the Jabiluka water management system, the pan factors proposed by the Supervising Scientist in 1987 be used. The difference in annual pond evaporation arising from the use of the pan factors recommended by the Supervising Scientist compared to that obtained using the factors adopted by ERA in the PER for Jabiluka is small (about 2%). This difference is well within current expectations of the accuracy of water management modelling. The volume of the retention pond at Jabiluka would need to be increased by about 3% to take into account the inter-annual variation in evaporation and the inverse relationship relationship between evaporation and rainfall. This estimate is, however, considered to be an overestimate because the relationship between evaporation and rainfall is not linear. Rather, evaporation during the main months of the Wet season tends towards a constant value at high rainfall values. It is recommended that a linear relationship between evaporation and rainfall is incorporated in future water management modelling because this will yield conservative results under high rainfall conditions and more realistic results under drought conditions than would be obtained using the long-term monthly average evaporation. 3.4 Evaporation in the mine In both the Environmental Impact Statement and the Public Environment Report, ERA proposed the use of enhanced evaporation in the exit stream of the ventilation system to remove water from the Total Containment Zone at the Jabiluka mine. Air passing through the underground workings and stopes will evaporate free water which will subsequently be discharged via the ventilation exhaust system. The company plans to maximise this form of enhanced evaporation in years in which there is surplus water in the system by transferring excess water from the TCZ water storage pond for subsequent evaporation in the ventilation system. Disposal of this excess water would be by the use of sprays or misting devices near the exhaust ventilation vents with monitors to maintain humidity of the exhaust air below 85% (or any other designated safe level) to avoid the emission of droplets from the vents. The calculations presented by ERA in the EIS and the PER show that disposal of 40,000 m3 per annum should be possible in the ventilation shafts, with this value increasing to a total of 90,000 m3 when evaporation from all underground sources is taken into account. For the Jabiluka Mill Alternative (original proposal) in extremely wet years, this figure represents about 20% of the total losses in the water balance model (table B.1.8 in Appendix B of the PER). This percentage will not be greater in a system that meets the requirements of the