What is In-Situ Recovery?
ISR is a method of extracting minerals by circulating solutions pumped into and out of the ground through drill holes, avoiding the need for traditional mine excavations.
It is described as a "closed circuit" operation because the solutions and dissolved uranium are contained in pipes and are controlled underground. ISR is a technique that is used widely to mine uranium in South Australia and around the world.
To achieve this, a pattern of holes is drilled, with one central hole, known as an extraction hole, surrounded by four to six other injection holes. An acid-based solution is delivered through the injection holes and is pumped back to surface through the central extraction hole.
As the solution passes through the ground from the injection holes to the extraction hole, it dissolves uranium.
The uranium solution is pumped back to the surface where the uranium is extracted. The extracted solution is conditioned again and delivered back down the injection holes to repeat the process as a closed circuit.
The natural chemistry of the rocks containing the uranium continually neutralises the solutions used in the process. During mining, monitoring holes are drilled surrounding the injection and extraction holes to confirm the solution is not escaping the targeted area.
The groundwater at Samphire is more saline than sea-water and a search of records shows that there is no use made of it within the region.
After uranium has been extracted from the solution, the solution is remediated and the ground is monitored to ensure it returns close to its natural condition.For more information about ISR visit www.ret.gov.au/resources