Uranium in situ leach mines can cover huge areas

The thousands of bore-holes on an ISL mine can be drilled in different patterns, either parallel lines of injection and production boreholes or patterns of adjoining squares or hexagons with a production borehole in the centre of the pattern and injection boreholes at the corners.

A large mine is divided into smaller mine units (MUs) that are mined one after the other over a period that can last from a quarter to half a century or more. An example is the Lost Creek Mine in the United States of America. This covers 1700 hectares (about half the size of an average SAB farm) and is divided into 19 MUs. With about 1400 ISL boreholes in each MU spaced between 20 and 30 meters apart, the total number of boreholes on the mine will eventually exceed 26 000.

Surface pipelines and electric cables connect every borehole to control rooms and the processing plant. Alarms are set off if there is a sudden change in pressure, but slow changes - possibly caused by slow leaks or escaping mine solution - are not easy to detect.

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