The textbook is intended for the economic geologist who deals with the evalution of deposits at an early stage of development. It offers rules for quick and easy calculations based on the application of application of approximate data. It provides both the students and the geologist in the field with a complete set of rules and methods enabling them to perform a quick intial evaluation of the deposit without the support of specialists or computers – even if he is left to his own resources, “ have been fully update in this second edition. New chapters discuss topics including the life time of deposits, derivation of interest rates for the net present value ( NPV ) calculation, the influence of poltical risk and the evalution of mineral prospects without know mineralization.