Multifractal Modeling of the Sizes and Grades of Giant and Supergiant Deposits

The high-value tails of the sizes and size-grade distributions for sets of mineral deposits often can be modeled as Pareto distributions plotting as straight lines on log-log paper. The multifractal model for size-grade distributions proposed here reflects self-similarity (approximate scale independence) of the underlying spatial distributions of the deposits. It predicts that the majority of deposits of the same type can be described by a lognormal distribution, but the largest deposits in the tail are controlled by a hyperbolic instead of the lognormal law. This topic is important, because most ore comes from the relatively few giants and supergiants in a population of mineral deposits of the same type.