Simulation of mineral grades with hard and soft conditioning data: application to a porphyry copper deposit

• Published in: Computational geosciences Vol. 13; no. 1; pp. 79 - 89
• Main Authors: Emery, Xavier, Robles, Lucía N.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.03.2009; Springer Nature B.V
• Subjects: Algorithms; Copper; Earth and Environmental Science; Earth Sciences; Geotechnical Engineering & Applied Earth Sciences; Hydrogeology; Mathematical Modeling and Industrial Mathematics; Minerals; Original Paper; Rocks; Simulation; Soil Science & Conservation; Statistics; Studies; Gibbs sampler; Conditional simulation; Spatial trends; Soft conditioning data; Geostatistics
• ISSN: 1420-0597; 1573-1499; 1573-1499
• DOI: 10.1007/s10596-008-9106-x

This work deals with the geostatistical simulation of mineral grades whose distribution exhibits spatial trends within the ore deposit. It is suggested that these trends can be reproduced by using a stationary random field model and by conditioning the realizations to data that incorporate the available information on the local grade distribution. These can be hard data (e.g., assays on samples) or soft data (e.g., rock-type information) that account for expert geological knowledge and supply the lack of hard data in scarcely sampled areas. Two algorithms are proposed, depending on the kind of soft data under consideration: interval constraints or local moment constraints. An application to a porphyry copper deposit is presented, in which it is shown that the incorporation of soft conditioning data associated with the prevailing rock type improves the modeling of the uncertainty in the actual copper grades.