Miduk in one of the largest copper ore reserves in Iran that is situated in the north west of Kerman province. It consititues approximately 157 million tons of ore with an average grade of 85%. One of the most important elements of the open pit planning is the determination of the final pit limits. The simulation method (positive floating cone) is a commonly used method for this purpose in which the users design by grade blocks. In this presentation, geostatistic methods have been described and their application in open pit mine planning discussed.  Furthermore, computer programs of CSMINE and VARIOC have then been explained and parameters required for the application of the software programs obtained. Finally, the optimum design of the pit is determined by using two sets of real data and applying the above computer programs. The recommended pit will produce appropriate ore for the ore dressing plant with maximum average and the highest amount of economic gain mind.