Uranium Mining

In-ground Acid Leaching

In-ground acid leaching involves pumping a corrosive acid solution through the ore body.  The solution  dissolves uranium along with other elements, many of which are highly toxic. The solution is then pumped  to the surface where it is treated to remove uranium. This process is also known as acid in situ leach (acid ISL) or acid solution mining.

In South Australia a sulphuric acid solution is used. In the USA only alkaline solutions are used for in-ground leach mining of uranium. The uranium at South Australia's two in-ground acid leach mines - Beverley and Honeymoon - is contained in aquifers whose water is neutral or slightly alkaline.

The acid leach method dissolves much more toxic material than the alkaline method. Restoration of the groundwater after acid leach mining has proven to be much more difficult and expensive than alkali leach mining.

In South Australia the acidic toxic radioactive liquid wastes are disposed of into the underground water and the underground water is not rehabilitated.

In-ground acid leaching is preferred by mining companies for small uranium deposits contained in underground water systems at Beverley and Honeymoon. This is because they are lower cost and have less visual impact. Uranium is extracted at the expense of the underground water, which becomes polluted with a range of toxic and radioactive substances.

As with all uranium mining and processing there are risks from ionizing radiation especially if there is an accident.

• Smaller, lower grade ore bodies can be mined. 
• There are shorter lead times to production.
• There is less dust.

• The mines are cheaper to build and operate.
• There is much less solid waste. There are no evaporation ponds at these mines in South Australia, only holding ponds where liquid wastes are held prior to being pumped into the underground water.
• There is much less surface disturbance. The real damage is being done out of sight in the ground.

• It destroys the underground water body (aquifer) being mined.
• It produces radioactive toxic wastes, which pollute the underground water.
• The large network of pipes through which corrosive, radioactive, toxic solution is pumped under pressure provides the potential for a catastrophic accident involving many kilograms of radioactive material.