ABSTRACT
Three applications of geostatistics to geological modeling are presented. The first one refers to a simple geometry and calls into question the use or not of geostatistics. The second and third applications focus on the modeling of mineralized breccias and of the surrounding facies, a characteristic of porphyry copper deposits. Mining started in 1905, and the deposit is currently exploited from underground by panel caving with more than 3,000 km of galleries. About 4,500 drill holes crossing the pipe from side to side with different orientations are available, each of which has been split into composite samples of 6 m length. An alternative to the use of local facies proportions is to model the non-stationarity of the facies through the random fields to be truncated. A final comment refers to the preferential nature of the drill-hole sampling, where the low-grade copper facies – volcanic pipe, porphyry and granitoids – are clearly undersampled.
