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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



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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

63 The Institution of Engineers Australia makes recommendations (Pilgrim 1987) for the values of depth-area ratios to be applied in estimating the effect of the worst case assumption that the storm is centred on the TCZ and that the intensity of the storm reduces in magnitude as a function of distance from the TCZ. For a 40 km2 catchment the ratio for a five hour event is about 0.97. However, the Water Division of the NT Department of Transport and Works (Water Division 1982) also derived depth-area curves for the storm of 4 February 1980. The depth-area data and the best fit to these data for the 5 hour period of greatest rainfall intensity are shown in figure 5.3.4. From these data, the rainfall over the whole catchment of Swift Creek could be less than that on the TCZ by up to 20%. Using this more conservative figure, the dilution available in Swift Creek could be as low as 720. Figure 5.3.4 Rainfall depth versus catchment area from the centre of the storm for the most intense 5 hour period of the storm at Jabiru on 4 February 1980 The constituent concentrations that would occur in Swift Creek under this extreme dilution model are also presented in table 5.3.2. The Mg and SO4 concentrations are still well below the concentration at which any biological impact could be expected to occur and the calculated increases are comparable with the naturally occurring concentrations of these chemicals in Swift Creek, about 0.4 and 0.3 mg/L for Mg and SO4 respectively. The uranium concentration is intermediate between the safe and the effects concentrations for uranium. Hence, under this scenario adverse effects may occur in some species, particularly invertebrates, but effects on fish would not be expected. It is worth noting that the concentration in Swift Creek would only remain at the indicated value for a matter of hours. This period should be compared with the 6 day period of the toxicological test. In addition, the uranium concentration adopted for runoff from the ore stockpile is considered to be a worst case estimate and is higher than that estimated by ERA by a factor of about 10. The conclusion of this analysis is that, under normal circumstances, no effect on aquatic animals living in Swift Creek downstream from the Jabiluka mine would be expected to occur even when the volume of excess water discharged is that with an exceedence probability of 1 in 50,000 over the life of the mine. If the discharge results from an extreme rainfall event with an exceedence probability much greater than 1 in 100 at the end of a wet season in which the rainfall has an exceedence probability of greater than 1 in 1000, some adverse effects may occur in invertebrates, but adverse effects on fish would not be expected. Any adverse effects on invertebrates would be very short-lived. Catchment Area (km2) 10 100 1000 R ai nf al l d ep th ( m m ) 100 150 200 250 300 350