Abstarct: Drilling and blasting are the main activities of mining operations in mines and special attention should be paid to them. Failure to pay attention to the design parameters in the explosion will lead to unwanted consequences. In Davaran iron ore mine, taking into account that after every heel explosion, boulders and improper crushing of stones are observed, the necessity of secondary crushing is justifiable as this work increases the costs and reduces the productivity of the machines. In this research, in order to better reduce explosions, improve the performance of loading and unloading machines, and reduce costs, a suitable model of drilling and blasting has been presented. A total of 28 drilled blocks with diameters of 3.5, 4 and 5 inches were evaluated, first 15 blocks (including six blocks with a diameter of 3.5 inches, five blocks with a diameter of 4 inches and four blocks with a diameter of 5 inches) for Examination of the reduction, performance of loading and unloading machines, as well as examination of costs, were carried out. In the next step, the model was modified for each diameter using experimental methods. Then using a modified pattern of 13 blocks (including five blocks with a diameter of 3.5 inches, four blocks with a diameter of 4 inches and also four blocks with a diameter of 5 inches) it was fired. After each stage of blasting, by image analysis method, with Split-Desktop software, the distribution and distribution of crushed stones resulting from blasting was done. Thus, by setting D80 of each block as a criterion, in order to check the decrease or increase of the heel and boulders of the block from the hammering time (including the hammering time of the heel and boulders of each block), to check the performance of the loading machines, the loading time of the machine cup And to check the performance of the trucks, the filling percentage of the truck room was used, and also for the economical check of the blocks, the cost of drilling and blasting each ton of crushed stone was used. By calculating the percentage of changes from the average block hammering time, before and after pattern modification, 3.5 inch diameter 17.8%, 4 inch diameter 28.1% and 5 inch diameter 17.9% hammering time after modification The pattern is reduced. In other words, the amount of heels and boulders in the blocks has been reduced. In order to check the performance of loading machines by comparing D80 and one cup loading cycle of the machine, a linear relationship was obtained for each diameter, which shows that with the increase of D80, the time of one cup loading cycle of the machine increases. In order to check the performance of trucks, by comparing D80 and truck room filling percentage, a linear relationship was obtained for each diameter. This relationship shows that as D80 decreases, truck filling percentage increases. In the economic analysis of the blocks, the average cost of drilling and blasting per ton of crushed stone from the blocks before and after the modification of the pattern was calculated. It was observed that this cost has decreased for 3.5 and 4 inch diameter, and in 5 inch diameter due to the slight changes in D80 blocks before and after pattern modification, the cost of drilling and blasting per ton of rock has also changed slightly.