Operations chain of mineral supply in a mine starts with blasting in most cases. Therefore, blasting optimization is a prerequisite for optimization of the whole mining complex. Blasting operation is mainly carried out for breaking rock masses into small fragments. There are two important results in operational blasting. The first is the rock fragmentation and the size distribution of fragments which is referred as the seen result of blasting. The second result is related to the inner damage exerted on the fragments which is known as the unseen effect of blasting. In fact, blasting can reduce the rock fragments strength by generating microcracks inside them. This reduction in strength, facilitates the crushing and grinding of the materials and in other words prepares the materials further for the comminution processes. This phenomenon is known as the conditioning or preconditioning effect of blasting. In mining projects, it is desired to reduce the strength of fragments as much as possible by changing the blasting design. Changing the explosive type is one of the possible blasting design changing options. It is assumed that proper selection of explosives may conduct the microcrack generation and strength reduction processes in the desired direction. In other words, to use an explosive which can reduce the strength as much as possible. The objective of this study is to characterize and compare the performance of different types of explosive in generating microcracks in rock fragments and reducing their strength, as well as the subsequent influences on the behavior of fragments in comminution processes. In order to implement this study, first 10 homogenous granite blocks were provided from a quarry. Then, three types of explosives, namely ANFO, emulite and pentolite, which have totally different detonation velocities, were selected for blasting. Applying each explosive, 3 granite blocks have been blasted in a blast chamber with the same blasting parameters and one block was kept unblasted. After each blast, the resulting rock fragments have been collected and their size distribution were assessed by sieve analysis. In the next step, some rock fragments from each batch were prepared and their strengths were determined by point load index and P-wave velocity experiments. Then, by preparing several thin sections of each blast, microcrack network of rock fragments has been studied in two separate stages. In the first stage, the microcrack density of rock fragments were quantified by fluorescent microscopic examinations. In the next stage, the number of each type of microcrack (intragranular, boundary and intergranular) were determined by polarized light microscopy. As the next phase of the study, the performance of fragments were examined in comminution processes. For this purpose, by preparing the same size distribution from each blast, the crushing experiments were performed on a representative sample of each blast and the performance of each batch of fragments in crushing operation was examined. The ball mill Bond work index of each sample was determined by conducting separate standard experiments. Then, by feeding the same size distribution of each batch to a ball mill, the milling throughput for each sample was studied, as well. The results showed that rock fragments strength is totally influenced by explosive types, so that blasting with pentolite causes a 16.5 % reduction in rock strength. Besides, it was found that the rock fragments strength is highly correlated with explosives detonation velocity (VOD). Furthermore, microcracks studies results showed that different types of explosive have dissimilar influences on rock microcrack network, so that the use of pentolite instead of ANFO increases the microcracks density more than 300%. It also was found that microcracks density is correlated with explosives’ VOD. Comminution studies concluded that the blasting process can reduce the Bond work index of fragments as much as 18% and enhances their crushability by 9.5%. Moreover, using different explosives brought about sensible changes in results, so that substituting ANFO with pentolite or emulite decreased the Bond index by 9.2% and 6.7% respectively, and increased the crushability index by 6.3% and 4.9% respectively. Besides, all results indicated that any increase in velocity of detonation (VOD) is followed by reduction of Bond work index and increase of crushability and milling throughput. Also some analysis regarding to energy consumption showed that alteration of fragments performance in comminution circuits can bring some saving benefits in total mining energy consumption as much as 4.5, 6.4 and 7.1 percent, in case of using ANFO, emulite and pentolite.