Copper oxide ores are not as attractive an exploration target as copper sulfide ores due to their lower grade. However, low-grade copper ore of this type can still be economically mined because they can be processed at a lower cost than copper sulfide ores.
Oxidized copper ore bodies may be treated several ways. For instance, hydrometallurgical processes are used to treat oxide ores dominated by soluble minerals, such as copper carbonate minerals. These oxide ores are usually leached using sulfuric acid to liberate the copper minerals into a solution of sulfuric acid laden with copper sulfate solution.
The copper sulfate solution (the pregnant leach solution) is then stripped of copper via a solvent extraction and electrowinning (SX-EW) process. Alternatively, the copper can be precipitated out of the pregnant leach solution through a process called cementation, whereby the copper is contacted with scrap iron. Copper produced through the cementation method is usually less pure than SX-EW copper.
For more information on copper ore types, see Copper Ore Types: Sulfides vs. Oxides.