Application of geostatistical techniques to exploitation planning in slate quarries

When planning workings of slate extraction by mechanical means, it is important to know the quality of the rock mass to optimize the results of the cuttings in the extraction bank, because techniques to be used depend on relative percent of first quality or second quality slate. In this paper, a methodology for quality evaluation applied to slate extraction is developed in three phases, as a tool of support to the planning. The first phase consists of defining the geotechnical parameters that affect the bank and to appraise them in the visible faces. The second phase consists of applying multivariate statistical techniques related to discriminant analysis data to evaluate a quality function. This function can be seen as a recovery index of the slate mass, being its variance intervals established in the analyzed faces. The third phase consists of a forecast of the values of the index from visible faces to the inside of the extraction bank, using geostatistics to evaluate the quality of the mass and to plan the mechanical cutting works, in order to get the best results.