The textbook is intended for the economic geologist who deals with the evaluation of deposits at an early stage of development. It offers rules for quick and easy calculations based on the application of approximate data. It provides both the student and the geologist in the field with a complete set of rules and methods enabling them to perform a quick initial evaluation of the deposit without the support of specialists or computers even if he is left to his own resources. To support the 'how to do'-approach all rules for calculations are illustrated with examples and also points out mistakes and pitfalls the authors encountered during their careers. The case histories, exercises, metal prices and terminology, especially concerning 'reserves and resources', have been fully updated in this second edition. New chapters discuss topics including the life time of deposits, derivation of interest rates for the net present value (NPV) calculations, the influence of political risk and the evaluation of mineral prospects without known mineralization.