Sungun copper mine is one the most important mines in Iran. It is in the final stage of development. The rate of productions of this mine is 7 and 14 Mt in the first and second phase, respectively. Average grade of the deposit is 0.6 percent and the grade of mill concentrate would be 30%. Feasibility study and mine design are carried out on the basis of several techno-economical and financial variables. Estimation of these variables is made under uncertainty conditions and therefore, sensitivity of economical indexes should be evaluated. In this research work, firstly, with the help of Excel and Comfar softwares, a model was developed and run considering scenarios for a certain variation of expected value of variables. It was observed that internal rate of return (IRR) is affected more by concentrate price comparing to other relevant factors. In this regard, mill recovery plant, exchange rate, capital costs, mine overall slope angle and operating costs can be ranked in the next degrees of importance. Secondly, for economic and financial risk analysis, Mont Carlo technique was applied for estimation of most probable economical indexes of the project. It was concluded that with a 90 percent level of confidence, range of IRR is more than 9.32 percent and less than 19.56 percent. In feasibility studies several factors are evaluated; technical factors, economical factors and financial factors. These studies are made on the basis of limited, often purely subjective, information. Uncertainties are associated therefore with both the input estimates and corresponding economical indexes such as net present value (NPV) and internal rate of return (IRR). For decision-making purposes, it is necessary to analyze the effects of these uncertainties on the DCF criteria. To fulfill this, various methods including sensitivity analysis, scenario analysis, decision tree, root sum of squares (RSS) and Mont Carlo method can be utilized.
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