Bootstrapping: A fast way to simulate QTz curves

The aim of this paper is to present a fast method based on bootstrapping, f or simulating recoverable reserves for input to financial Monte Carlo simul ations. In mining, the three parameters defining recoverable reserves are t he cutoff grade, z, the ore tonnage above cutoff, T, and the metal quantity above cutoff, Q. After introducing the concept of 3-dimensional QTz curves , the statistical technique called bootstrapping is reviewed and applied to a set of South African gold grades. AS selective mining is carried out on blocks not points, these curves have to be calculated for blocks. The QTz c urves obtained by bootstrapping are compared to those obtained by condition ally simulating the same deposit. The procedure has been extended to incorp orate geologists' ideas of the likely size of the ore volume. Lastly, the r ecoverable reserves obtained by bootstrapping are compared with those obtai ned by traditional risk analysis (base case +/- 10% or 20%).