Solution mining is the subclass of aqueous mining in which minerals are recovered by leaching, dissolution, melting, or slurrying processes. Some of these methods have been developed for underground use. Solution mining uses chemical relationships between desired metals/minerals and the appropriate solvents. These solvents break the ore from the surrounding country rock and create a “pregnant” solution that contains a mixture of solvent and ore. This solution is then collected and processed to extract the ore. There are many forms of solution mining, including borehole or in situ leaching, evaporite mining, and heap leaching.

Figure: Above is the chemical equation for the solution mining of zinc ore using sulfuric acid.

Figure: In-situ or borehole leaching involves pumping solvents into the ore body and then processing the "pregnant" solution.