The Ranger Mine

Rainfall records used to estimate the total annual rainfall at the Ranger mine site were inaccurate. They provided an underestimation of actual rainfall. Data used to estimate the rate at which water would evaporate from the retention ponds overestimated the evaporation rate. More rain and less evaporation have resulted in an overall accumulation of polluted water in the mine site. What to do with this contaminated water is a constant problem at Ranger.

The cheapest way to deal with excess water is to dump it. Consequently in above average rainfall seasons, ERA regularly applies to release water into the Magella Creek system and from there, into the Kakadu National Park wetlands. To date no release has been permitted. In the 1994/95 wet season ERA went to court to override the concerns of the downstream traditional owners and could legally have released contaminated water into the Magella. ERA has refused to rule out the possibility of releases in the future and indeed considered it again in the 1995/96 wet season.

Uranium concentrations 100 times the original levels have been recorded in the Magela wetland system downstream of the mine. Sulfate, manganese, magnesium, copper and zinc concentrations have also been rising steadily. If this is happening while ERA are battling to keep the pollutants within the mine boundary, what is the future of Kakadu when ERA are gone?

The proposed development of the Jabiluka mine will involve considerable de-watering of the underground tunnels as the ore is situated below the water table. This contaminated water will need to be disposed of, adding to the already critical water management problems.