Territory Stories

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

Details:

Title

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

Creator

Johnston, A.; Prendergast, J. B.; Bridgewater, Peter

Collection

E-Publications; E-Books; PublicationNT; Supervising Scientist Report; 138

Date

1999

Location

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.

Language

English

Subject

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.)

Series

Supervising Scientist Report; 138

Format

1 volume (various pagings) : illustrations, maps

File type

application/pdf

ISBN

642243417

Use

Copyright

Copyright owner

Environment Australia

License

https://www.legislation.gov.au/Details/C2019C00042

Parent handle

https://hdl.handle.net/10070/264982

Citation address

https://hdl.handle.net/10070/462402

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

8 If a properly engineered spillway were installed in the wall of the retention pond, the dam would be protected from destruction under overtopping. This would result in the loss of much lower volumes of water over a longer period and would fully protect both Swift Creek and the Magela floodplain under the conditions considered here. It is recommended that such a spill-way be incorporated in the design of the retention pond. Risks associated with slope failure of the embankment of the water storage pond The probability of slope failure is estimated to be less than the probability of overtopping which was estimated above to be about 5 in 10,000. Since slope failure would only arise under circumstances similar to those considered for overtopping, the estimates of environmental impact derived above for overtopping would also apply to slope failure. Risks associated with a severe earthquake Over the period of the mine life, the probability of structural failure of the water retention pond arising from a severe earthquake has been estimated to be approximately 5 in 10,000. In deriving this estimate, only local and regional earthquakes were considered. The frequent but distant large earthquakes in the Banda Sea, Indonesia, should be considered in the design of a water retention pond since they give rise to many cycles of ground motion. It is recommended that ERA commissions such a study at the detailed design stage of the Jabiluka project. The risk of radiation exposure of members of the public resulting from such an earthquake would be extremely low. At the 1 in 10,000 level of probability, the estimated radiation exposure is about 30 Sv. The highest calculated exposure, which is less than one tenth of the internationally accepted limit, has an extremely small exceedence probability. For an earthquake that occurs in the Wet season, the maximum area of the Magela floodplain in which adverse effects on some aquatic invertebrates might be expected is about 1.5 km2 but the probability of this occurring is extremely small. The area affected at the 1 in 10,000 level of probability is less than 0.5 km2 which is less than 0.3% of the floodplain area. At the same level of probability, residual effects may occur for some species of invertebrates out to an area of about 5 km2. Even within these areas, the impact would be small (for example, fish should not be affected) and the system would fully recover following flushing by the natural waters of the Magela system. If an earthquake occurs in the Dry season, the area of impact would be greater. Nevertheless, the probability of such effects occurring remains very low and the system would recover during the following Wet season. Contingency measures It is recommended that runoff from the ore stockpile should be isolated from runoff from the remainder of the Total Containment Zone so that it is always directed to the water retention pond while, under extreme conditions, runoff from the rest of the TCZ is diverted away from the storage pond. This measure would reduce still further the risk associated with exceeding the capacity of the storage pond. It is recommended that the water retention pond be constructed with a properly engineered spillway to ensure that, even if diversion contingency measures fail, the pond structure would not fail when the overtopping height is reached. This would reduce substantially the impact arising in the event of overtopping because only a small volume of water would be released to the environment rather than the full volume of the pond.


Aboriginal and Torres Strait Islander people are advised that this website may contain the names, voices and images of people who have died, as well as other culturally sensitive content. Please be aware that some collection items may use outdated phrases or words which reflect the attitude of the creator at the time, and are now considered offensive.

We use temporary cookies on this site to provide functionality.
By continuing to use this site without changing your settings, you consent to our use of cookies.