Chemical additives can be used to improve the performance of standard drilling methods. The term chemical fragmentation is defined as the breakage, fracture, or comminution of rock or mineral materials by mechanical forces, aided by the presence of chemical solutions. The latter are usually in the form of the aqueous pulp of a ball-mill grinding circuit, or the flushing and cooling fluids pumped down the hollow drill stem to the drill bit. Grinding and drilling are, therefore, the two most important processes benefiting by chemicals in solutions. Although these processes are the chief ones discussed, other chemically induced changes in rock toughness, as determined by special laboratory tests, are also noted.