Valuation of an ongoing business

I was hired by one of the owners of a company that operated a gold mine to make a valuation of the company and of his share of it; this with the purpose of selling his shares to a third party. The valuation involved forecasting the firm´s future cash flows which, in turn, involved forecasting the price of gold. This latter part was done using a Montecarlo simulation to determine the probability of a given price range with which to calculate the company´s value. The client approved the valuation and successfully sold his share of the company at the price determined by the valuation.