Abstarct: According to high costs and expensive machines, understanding all of the parameters effective in drilling and optimizing them, make the condition suitable for optimized exploitation. Realization the drilling environment and rock mass properties contribute to selection of drilling type, determination of drilling machines, assessment of mine production rate and prediction of drilling speed. Many factors have hand in drilling. Some of them have direct relationship with drillability and some have inverse. Sangan iron ore mines locate in southeastern of Khorasan-e-razavi province. To determine the drillability in these mines, two of active mines of this complex named Baghak and Dardway have been selected. To do the research in these mines, at first level contours of each mine have been classified according to parameters of RDi classification system, so that Baghak mine divides into 31 zones and Dardway mine divides into 22 zones. Thus, in each mine, 4 zones have been selected for sampling and recording of drilling speed. Uniaxial compressive strength, point load strength, density and porosity of each sample have been determined. Moreover, texture, Mohs Hardness, Schmidt hardness, spacing, slope and filling of the joints have been determined in all zones. Since one of an important parameters in RDi classification system is uniaxial compressive strength and determination of this parameter for all 53 zones is so expensive, so in this study Schmidt hardness at first has been determined for all zones and then after making relationship between uniaxial compressive strength and Schmidt hammer and between point load strength and Schmidt hammer in 4 selective zones in each mines, it was obtained that correlation coefficient between point load strength and Schmidt hammer in both mines are higher than correlation coefficient between uniaxial compressive strength and Schmidt hammer in determined zones. By relationship between point load strength and Schmidt hammer, compressive strength of all zones that is one of the input parameters of RDi classification system, has been calculated. Moreover, after calculation of the Rock Drillability Index (RDi) and recoding the drilling speed in selective zones, relation between RDi and drilling speed in each mine has been obtained separately. Finally, after calculation of the RDi for all zones and by relation between RDi and drilling speed, speed in all zones of both mines has been obtained. According to the results, drilling speed can be determined before drilling by RDi classification system in terms of quality and quantity and by information of each zone condition, drilling should be started.