Print7.4.3: Solution Mining
Solution mining is the extraction of the ore through a dissolution process, i.e., we pump a solvent through the ore, the solvent dissolves the constituent of interest, and then we recover and process the resulting liquid, which is known as the solute or pregnant liquor. We can apply this method to in-situ deposits using a borehole mining method, or to mined material using a heap leaching method. In-situ, which implies “in-place” “in-the-seam”, and using an in-situ method, means that we extract, i.e., dissolve, the material of interest within the deposit and leave behind the gangue or waste minerals. In-situ recovery has the advantage of not disturbing the surface with a mining activity and of eliminating surface piles of processing plant tailings or waste. It has the disadvantage in some applications of creating a potentially hazardous environmental situation if the solvent or solute can migrate into the environment. Let’s talk about the in-situ methods first.