"The definition and classification of mineral reserves and resources are discussed, and the factors which control their magnitudes and values analyzed. The reasons for the confusion in the use of these terms are explained. The extent to which reserves and resources of minerals can be as leading indicators of future mineral production is examined and examples of the dangers of over-reliance on this factor are described. Key aspects, such as confidence limits, differences in the economic exploitability, the dynamic nature of reserves, and their variability in grade, are examined in some detail."