A Summary:Heap Leach Mining of Uranium and associated risks (in layman’s terms).
Not unlike in-situ leach mining, heap leach mining is a process whereby Uranium, Copper and other precious metals are extracted from ore with a chemical solution.
Ore is mined, crushed and dumped onto a “leaching pad” made from impermeable membrane with a minimum thickness of 1.5mm, often on a bed of clay.
There are four types of leach pads:
*Conventional Leach Pads are used on flat terrain for lighter layers of crushed ore.
*Dump Leach Pads are used on less flat terrain and hold ore which is extracted straight from the mine without crushing and dumped onto the pad. Slower extraction of minerals.
*Valley Fill Leach Pads are situated at the bottom of valleys and hold everything dumped in.Higher potency chemical solution.
*On/Off Pads are for larger loads which are moved and relocated after each cycle.
Once the Ore has been dumped on a leach pad it is then irrigated with a leach solution of dilute sulphuric acid, this can be done with a sprinkler system but more frequently a drip system is used. The solution percolates through the Ore leaching the target minerals into a leach pond. This s called pregnant solution. Once the minerals are harvested from the pregnant solution it becomes barren and is re introduced into the heap. The percolation process can take from 30 to 90 days.
In the case of Uranium heap leach mining produces yellow-cake which requires significant further processing to produce fuel grade feed. Once it is processed into yellow-cake it can then be enriched for use in nuclear reactors from which the spent nuclear fuel can be re purposed for use in nuclear weapons being one of the primary concerns of producing yellow-cake.
According to the Medical Association for the Prevention of War (MAPW) Australia’s uranium exports have resulted in the production of over 80 tonnes of ‘reactor grade’ plutonium