The explosives like ANFO, despite low density and low VOD cause desired fragmentation if they’ve been used in a good pattern. Then it is necessary to present an independent classification criterion from density and VOD. For doing this, here, the explosive power was defined and calculated by a pre-existing definition in physical chemistry which hasn’t been common in mining. In according to this definition, the explosive power especially for a charge exploding in a confined space like a blast hole, is equal to the explosion obtained heat multiply by the explosion obtained gas volume. After calculating this power for conventional mining explosives, in order to have a good comparison criterion and for controlling the relation between calculated powers and desirability of fragmentation, all calculated power were divided by the power of ANFO as the most common explosive in mining which also causes good fragmentation. The dimensionless results were the based on ANFO power indices. Analyzing the power data showed that the explosives like ANFO and AL-ANFO in spite of their low VOD, have high power or in other words, the PI of ANFO is close to the PI of a dense and high VOD explosive like nitroglycerin, and the PI of AL-ANFO is even more than the power of TNT. It means, in an unidirectional statement, if an explosive causes good fragmentation, it has high power whereas by now the good fragmentation of ANFO accounted as an exception. In addition the correlation coefficient study of the power to density data didn’t show any dependency for power to density. Therefore this study recommends the mentioned PI as a criterion for explosive selecting in blast design instead of density and VOD.As an application and confirmation, the basic equation for ANFO specific charge on the basis of blast ability INDEX were modified with using the calculated PIs whereas conventionally it was modified by relative weight strength. By observation of the graphs were developed by the equations come from PI modification, it was seen that the graph of black powder as a weak explosive completely became detached but RWS modification couldn’t do so.