1271 3.2. Mineralogical characterization "Bulk" mineralogical analysis by X-Ray Diffraction (XRD) is the most used technique in geometallurgical characterization; however, it is expensive and time consuming. Of course, alternative methods such as optical microscopy, QEMSCAN (Quantitative Evaluation of minerals by Scanning Electron Microscopy) and TESCAN are more expensive (Table 1). On the contrary, FTNIR analysis (Fourier Transform Near Infra-Red) is the more suitable because it is faster and cheaper (Canchaya 2016). FTNIR analysis is explained in Figure 2. 3.3. Structural and textural characterization In Table 2 is described the structural-textural characterization for every sampling domain at different scales; it is also mentioned the specific tools and main applications of every type of characterization. In all cases and scales, the performance of this analysis has been enhanced with the recent appearance of software for automated image analysis, which allows rapid qualitative and quantitative characterization of: fracture patterns and their frequency (fracture density); mineral and alteration assemblages, modal analysis of grains and particles (grain intergrowths); as well as mineral liberation. Anyway, MLA (Mineral Liberation Analyzer), QEMSCAN or TESCAN are the most evolved equipment; which provides virtually the entire service, that is to say: micro-chemical analysis, mineralogical analysis and intergrowth analysis; being the only capable to analyze “invisible Au” (as solid solution, nanometric or structural inclusions in other minerals or colloidal materials). 3.4. Physical-mechanical characterization After Canchaya (2012) and Canchaya et al. (2013), the most important and common physicalmechanical variables in a geometallurgical database are: bulk density and mechanical resistance (“hardness”). The traditional method for determining density is by pre-coating with paraffin, with recent more practical variations using lacquer-spray or plastic thin film; however, for a systematic sampling of the density, it is better the direct register of wells using gamma radiation. The mechanical competence should be
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