Buried in last week’s budget was money for rehabilitating the Rum Jungle uranium mine near Darwin. The exact sum was not disclosed.
The government’s second rehabilitation attempt is significant, as it recognises mine rehabilitation isn’t always successful, even if it appears so at first.
The quick and dirty history
The mine was owned by the federal government, but was operated under contract by a former subsidiary of Rio Tinto. Back then, there were no meaningful environmental regulations in place for mining, especially for a military project.
The waste rock and tailings (processed ore) at Rum Jungle contains significant amounts of iron sulfide, called “pyrite”. When mining exposes the pyrite to water and oxygen, a chemical reaction occurs generating so-called “acidic mine drainage”. This drainage is rich in acid, salts, heavy metals and radioactive material (radionuclides), such as copper, zinc and uranium.
Acid drainage seeping from waste rock, plus acidic liquid waste from the process plant, caused fish and macroinvertebrates (bugs, worms, crustaceans) to die out, and riverbank vegetation to decline. By the time the mine closed in 1971, the region was a well-known ecological wasteland.