Abstarct: Regarding to that the drilling process in mines is a costly step and technically it is considered a critical step in blasting operation, this process requires a lot of optimization and studies, and in each mine, according to its specific conditions, this process must be done separately and the results are specific to the same place. According to the research carried out from 1946 to 2020 in the field of rock mass engineering classification, the drillability and the relationships presented in this field were examined and finally the RDi index considering that it includes all the parameters affecting the rock properties. It was considered as the selected index to evaluate the prediction of drilling rate. In this research, the drilling process was investigated baxsed on the field observations and rock mechanical affecting tests it in the Gehrzamin iron ore mine, and in the following, the data obtained according to the efficient empirical method of RDi to predict the drilling rate of the rock mass in this mine was used. In this study, 30 samples were taken from 14 areas in the mine pit, and then according to the results obtained from the tests and investigations, the number of 4 zones influencing the drilling rate was determined, according to the RDi index, the zones of Gehrzamin iron ore mine are divided into two categories. It is divided into: 1) medium drilling rate zone and 2) slow-medium drilling rate zone.