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
64 5.3.4 Risks associated with dam failure The risk assessments carried out above refer to a contingency situation in which the accumulated runoff from the catchment of the water storage pond at Jabiluka exceeds the capacity of the pond. It has been assumed that contingency measures are in place to ensure that, in these circumstances, water from the TCZ is diverted and allowed to flow freely to Swift Creek. In this way, overtopping of the pond itself would be avoided and the structural stability of the pond would, therefore, not be threatened. In this section, the risk to the environment associated with structural failure of the water storage pond is assessed. Such a failure could arise from overtopping of the pond if the above contingency procedures fail, static failure of the constructed embankment or the occurrence of a severe earthquake. So far in this review, the water storage pond has been considered as a single entity with an area of 9 ha. This has been adequate for all issues considered previously. In reality, however, the water management system for the JMA Original Concept included two ponds. Storm water runoff from the stockpiles, washdown, crushing plant and the mine would be contained in a 4 ha raw water pond. Better quality water running off from the mill area would be contained in a 5 ha containment pond. This water would be transferred to the raw water pond on demand. During extended periods of low rainfall, water would be transferred from the bore field to the raw water pond to maintain operation of the mill. It has been pointed out in section 5.2.4 that pond evaporation will probably need to replace enhanced evaporation in the ventilation system, at least to a significant extent and that, to provide control of pond evaporation, the water retention pond could be partitioned into three or four compartments with connecting spill ways and a water pumping system. In these circumstances, the water quality in each compartment will be similar because of the exchanges of water between compartments. For this reason, the risk of structural failure of the pond will be based upon the assumption of a single pond. Table 5.3.3 Estimates of the maximum concentrations of the principal constituents in the water retention pond at Jabiluka Chemicals Concentration mg/L Radionuclides Concentration Bq/L Uranium 0.8 238U 10 Magnesium 5 234U 10 Sulphate 20 230Th 0.03 226Ra 3.4 210Pb .2 210Po 0.03 Water inputs to the pond will arise from direct rainfall on the pond area, runoff from the ore stockpile, runoff from other areas of the TCZ (most of which will produce good quality water) and water pumped from the mine. Water from the mine may contain concentrations of uranium and magnesium sulphate at higher than background values but, because this water will have been exposed mainly to inert material rather than ore, these concentrations will be very small compared to runoff from the ore stockpile. The concentrations of uranium, magnesium, sulphate and the long-lived radionuclides of the uranium series in the retention pond have, therefore been estimated on the basis of the concentrations in runoff from the ore stockpile divided by a dilution factor determined by the ratio of the total TCZ catchment to