Ranger (Image: Dr Snafu)
Energy Resources of Australia (ERA) has applied to the Australian and Northern Territory governments for approval to establish a heap leach operation at its Ranger uranium mine.
A feasibility study into the viability of the project, to treat 10 million tonnes of low-grade uranium ore per year, will be complete by mid year. The project gives the prospect of recovering up to 20,000 tonnes of uranium oxide in total. Column leach trials have so far been encouraging, yielding extractions of greater than 70% at low rates of acid consumption, hence using less energy and producing less waste compared with conventional processing.
The facility would consist of fully lined heaps of crushed ore about five metres high and covering about 60-70 hectares. They would be built and removed on a regular cycle with the residues stored after leaching is completed. The acid leach solutions would be treated in a process similar to that used in the existing Ranger plant and recycled after the uranium is removed from the pregnant leach liquor. In many respects the process is similar to in-situ leaching, though obviously not in situ.
Heap leaching is a well-proven technology commonly associated with gold and copper mining, and was used at Australia's Rum Jungle uranium mine for copper recovery 40 years ago. The proposed heap leaching facility at the Ranger mine would incorporate global best practice, ERA said.