Measurements of mineral grades of an industrial mineral deposit (talcum) are used in a geostatistical case study. The data available come from a quality sampling scheme of the operating mine and can be assigned to two stoping layers each 3 m thick. The aim of the study is to establish a quality model on the basis of the mined blocks of the deposit. This will be used in the direct control of the extraction sequence of the blocks to guarantee certain average grades in the raw material for further treatment. A structural analysis (variogramming) shows certain trends, high nugget eect and high variances in the classi®ed data sets. By removing a certain trend and introducing a multiplication factor, a consistent model for both stoping layers can be established. This is further used to calculate extrapolated point values by kriging at the known sampling points in the second layer for validation of the model. To establish the quality model for planning the extraction sequences, block values on grid nodes according to the extraction scheme also have been extrapolated for the second and third stoping layers.