Discrepancies in raw materials properties informed by both producer and consumer are a common problem in most areas of the industry. Commercial contracts in the mineral industry normally penalize the producer, if contaminants in the ore exceed established limits. Differences in lab analysis are due many sources of error, such as distinct practices used in two laboratories for sampling, preparation or analysis. Sampling theory provides the tools to analyze errors involved in sampling, preparation and analysis. This paper proposes a methodology to check the precision and accuracy of a given sampling protocol emphasizing the application of Gy's sampling theory to broken ore. The results show the applicability of the method and its relevance to audit sampling procedures aiming at error minimization. The methodology is illustrated in a case study at a major coal producer in Brazil.
sampling; error; precision; protocol
