The world demand for mineral and energetic commodities is rising strongly in the last years due mainly to the growth of the Chinese economy. In the iron ore industry movements of merger and acquisition are more frequent therefore steel producers groups are looking to, by means of acquisition, guarantee their iron ore supply and to protect against the huge volatility of price in the market. On the other hand mining companies are protecting their business against these threats by merger operations. In this context, the valuation of new mining projects is essential to identify the enterprise value, considering that a mining company is a portfolio of projects. Given the characteristics of some mining projects, the use of the Real Option Theory allows a more efficiently valuation be done in presence of flexibilities and market uncertainties. This thesis intent to apply the concepts of real option, considering the risk neutral probability and stochastic process with growth drift of the variable of uncertainty, thru a hypothetic mining project, which holds a capacity expansion option that can be exercised in the five year time.