Modelling the factors of mine production planning considering the risk free valuation and new cut-off grades algorithm Afshin Akbari , Islamic Azad University, Central Tehran Branch, Petroleum, Mining and Metallurgy dpt Abstract The average grades of copper mines are dropped by extracting high grade copper ores. Based on the conducted studies in mine field, it is observed that the uncertainty of economic calculations, insufficiency of initial information. This matter has drawn considerations to processing methods which not only extracts low grade copper ores but also decreases adverse environmental impacts. In this research, an optimum cut-off grades modeling is developed with the objective function of Net Present Value (NPV) maximization. The costs of processing methods are also involved in the model. In consequence, an optimization algorithm was presented to calculate and evaluate both the maximum NPV and the optimum cut-off grades. Since the selling price of the final product has always been considered as one of the major risks in economic calculations and designing of mines, it was included in the modeling of the price prediction algorithm. The results of the algorithm performance demonstrated that the cost of the lost opportunity and the prediction of selling price are regarded as two main factors directed into diminishing most of the cut-off grades in the last years of mines production. Keyword: NPV maximization, cut-off grade, Selling price, price prediction.