On an international level, economic assessment of deposits is done through dynamic methods which take the time factor for investments and returns, i.e. the time value of money, into account and are based on compound interest formulae. The economic benefit of mining enterprise and investment's attractiveness indicated by net present value and internal return rate in dynamic investment forecast model. This study will only deal with simple cash flow calculations a geologist or mining engineer will have to make in the prefeasibility stage of a project in order to establish whether an exploration project worth pursuing.