"We are currently in the midst of an energy crisis, and it is generally recognized that a mineral crisis also looms on the horizon. Recent productivity trends in U.S. surface mining show the industry losing ground in comparison with other industries at home and abroad in competing for capital. This is primarily a result of the fact that increases in equipment handling capacity have been more than offset by the need to turn to lower-grade ores. This situation has been further complicated by inflation and other factors. Greater attention is, therefore, being focused on in situ processes for mineral recovery. Methods of in situ recovery fall into three categories. First, an ore body may possess sufficient native permeability for direct in situ recovery through boreholes. Secondly, if the natural permeability is low, stimulation by hydraulic fracturing, explosive detonation, or some other means will be necessary. Finally the formation may be so impermeable that a modified in situ process involving partial mining and the use of explosives will be required to generate permeability sufficient for processing. Considering the convenience and potential lower cost of borehole recovery, it would be very desirable to render as many deposits as possible amenable to this technique. For low-permeability deposits, an array of explosively loaded wellbores offers the possibility of creating a distribution of many fractures not achievable by other techniques. If fractures with sufficient porosity to create permeability can be generated, then a viable in situ recovery process may be possible. Explosives are often discussed in the context of in situ recovery. However, only recently have serious attempts been made to understand the mechanisms controlling enhancement of permeability by means of explosives."