Poisoning Kakadu
By Grusha
If its gets to mine uranium at Jabiluka, Energy Resources of Australia plans to leave 10,770,000 cubic metres — that's 100m X 100m X 1km — of radioactive waste (tailings), and more than that again in non-radioactive (or not so radioactive) waste.
The tailings would be around 90% as radioactive as the original ore and would be ground to a fine sludge with an acid-forming potential. Acid mine drainage is the process whereby the sulphur present in rock is exposed to the air for some time and turns water it comes into contact with acidic. Acid drainage has been widely documented at mine sites.
Apart from the damage caused by the acidity itself, a further problem is created as the many toxic heavy metals that exist naturally are broken down by the acid and made more bio-available, poisoning the food chain.
At Jabiluka, ERA plans to return some of the mining waste underground in pits, put some of it in above-ground dams and leave some in mounds. In each case, acid seepage will result in ground water and creek water contamination. It may take a few years, but gravity and erosion will ensure that this dispersion does happen.
Swift Creek, nearby Jabiluka, currently has the purest wild water river rating. It flows straight to Kakadu National Park and joins the magnificent Magela flood plain. It will probably be among the first water sources to be contaminated through acid drainage.
To control the potential problem, ERA plans to add concrete to the tailings at a rate of about 1%. This is a new technology, still being tested. If ERA's plan is allowed to proceed, half of this toothpaste-consistency gunk will be deposited back in the hole where the ore came from, while the other half will be deposited in four huge tailings dams or two large pits.
These pits will also be expected to hold the wet season rainwater. If there is a high-rainfall wet season when either pit is almost full of tailings, the containment of the contaminated water will be a major problem.
Water containment problems have already occurred at ERA's other uranium mine and mill in Kakadu, the Ranger mine. In fact, the water management crises became such bad publicity for ERA at Ranger that, although it says it has a "no release policy", it is reported that the company releases excess contaminated water into the bush, bulldozing, scraping and burying when it finished.
A further problem is the presence of aquifers (underground lakes) at Jabiluka, as there are at Ranger, which are vulnerable to contamination. While ERA says the concrete will stabilise the waste as it dries, both the ground water and the aquifers will work to keep the tailings paste wet and seeping.
If the tailings are dumped in huge piles above ground (one dump proposed is a kilometre long!) ERA's sediment control devise, which it says can withstand a one-in-20-year flood, will be inadequate since the mine will operate for 29 years. That possible bigger one-in-29-year flood would wash above ground sediment directly into Swift Creek. Worse, there is no seepage control plan for the piles.
Kakadu is no place for a radioactive waste dump. If the mine must go ahead, the kilometre-high pile of tailings should be sent direct to Parliament House, Canberra.