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Assessment of the Jabiluka Project : report of the Supervising Scientist to the World Heritage Committee



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

Table of contents

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

Publisher name

Environment Australia

Place of publication

Canberra (A.C.T.)


Supervising Scientist Report; 138


1 volume (various pagings) : illustrations, maps

File type






Copyright owner

Environment Australia



Parent handle


Citation address


Related items

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

Page content

45 5 Storage of uranium on the surface 5.1 Introduction The issues to be addressed in this chapter relate to the risks associated with the storage of uranium in a stockpile within the Total Containment Zone at Jabiluka. The risks are, essentially, twofold; (a) the risk to the environment arising from a sufficiently intense weather event that the capacity of the water retention pond for the catchment of the uranium ore stockpile is exceeded, and (b) the risk to the environment associated with the failure of the pond structure itself. Assessment of the first issue will bring together the hydrological information in the previous two chapters to enable a detailed assessment of the probability of exceeding the available storage capacity for a given design of retention pond. The risk to the environment will then be assessed using site specific information on water chemistry, ecotoxicology and radiation exposure. Assessment of the second issue will rely upon estimated risks of dam failure for the type of design proposed by ERA for the retention pond followed by a risk assessment that again uses the above site specific information. It must be recognised that the hydrological modelling described in this chapter does not apply to the actual design of the facility that may be constructed at Jabiluka. This is because the Minister for the Environment did not approve the project as proposed by ERA in the Public Environment Report for the Jabiluka Mill Alternative. As stated earlier, the Minister required the disposal of all tailings in the mine void and additional stopes/silos and required ERA to prepare an amended proposal for the approval of the authorities. ERA is currently preparing the amended proposal. The Supervising Scientist has chosen to assess the Jabiluka Mill AlternativeOriginal Concept as described in the PER but with the exclusion of the tailings ponds in that proposal. The reason for this choice is that the modified Original Concept is likely to be very similar to the amended proposal from ERA and because the results of modelling in this review can be compared quantitatively with the results obtained by ERA in the PER. Thus, this chapter does not provide a detailed design of the water management system at Jabiluka. However, the results obtained should be taken into account in such a detailed design by ERA. 5.2 Probability of exceedence of retention pond capacity 5.2.1 Design criterion The design criterion proposed by ERA in the EIS (p 467) for the water management system at Jabiluka was that, to maintain a policy of no release of water from the Total Containment Zone, the retention pond system should be designed to contain runoff from a theoretical extreme Wet season with a 1 in 10,000 annual exceedance probability. This would give a probability for exceeding the retention pond capacity of 0.01% in any single year of operation and an exceedence probability over the 30 year life of the mine of approximately 0.3%. However, the EIS goes on to state that the system should also include a residual volume of water from the previous year and the water balance modelling considered a sequence of Wet seasons including the 1:10,000 AEP rainfall year. Thus, the pond volume exceedence