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
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
Supervising Scientist Report; 138
1 volume (various pagings) : illustrations, maps
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
32 However, the power consumption of such a system could be considerable. The power consumption of a humidifier designed to provide the latent heat of evaporation will be determined by the operating conditions in the Dry season when the maximum evaporative capacity exists. To estimate the power required, the data presented in table J.2 of Appendix J of the draft EIS have been used. For the period August to November, the total evaporation rate is R = 35 m3/h. Hence the power required (assuming 100% efficiency) is MWmkgkgJLsmRW 24)/()/()/( 33 == The capital cost and the operating costs for the humidifier will, therefore, be considerable. In addition the relative environmental advantages and disadvantages associated with the establishment of the required generator capacity at Jabiluka would need to be assessed. The latter would need to be compared to the alternative option of increasing the area of the retention pond. The area of the retention pond would need to rise from 9 ha to approximately 13 ha to provide the required evaporative capacity if no evaporation occurs in the ventilation shafts. This area is small compared to the total area of retention and tailings ponds proposed in the original JMA proposal and is only 2% of the disturbed area at the nearby Ranger mine. The environmental impact arising from such an increase, should it need to be part of the project, is, therefore, not considered to be significant. In summary, The observation by Wasson et al (1998) that the latent heat of evaporation needs to be supplied is correct. The conclusion that this results in a major error is, however, invalid because the energy required can be supplied externally, and it was the intention of the design engineer that the optimum way of doing this would be assessed at the detailed design stage once approval for the project to proceed had been given. The capital and operating costs of a humidifier system designed to meet the evaporation energy needs would be high and a cost benefit analysis of various water management options will be required before a final decision on the installation of a humidifier system is made. If it is decided that the cost of installing and running a humidifier system is too high or that the environmental impact is unacceptable, the retention pond at Jabiluka would need to be increased in area from 9 ha to about 13 ha. Given the experience of the Ranger Mine, which has a disturbed area of about 500 ha, this 4 ha increase is not expected to give rise to any detectable environmental impact. 3.5 Summary of findings on hydrological modelling issues The conclusions and recommendations of the Supervising Scientist on the hydrological modelling issues raised by Wasson et al (1998) are as follows. Estimate of the 1:10,000 AEP annual rainfall It is recommended that the Oenpelli rainfall record for the years 1917 to 1998 should be used for estimating the 1:10,000 AEP annual rainfall and for other hydrological modelling for the Jabiluka project because it is much more extensive than that at Jabiru and is consistent with the Jabiru record in the period of overlap.