Weathered mafic is the primary waste from an iron ore mine (Carajas Province, Brazil). Due to its mineral composition, it can be used as a mineral addition to the cement industry. Analysing the properties of these materials adds value to projects and promotes regional circular economic initiatives, optimising the use of mined resources. This study aimed to infer the mineralogy of weathered mafic, focusing on kaolinite proportions in all samples from a geological database. The normative mineralogical calculation was performed using an alternative method based on Least Squares (LS) to determine the proportions of constituent minerals, minimising the quadratic error between the analysed chemical contents and the chemical contents calculated from the mineralogical norm. The method does not require prior knowledge of the mineralogical sequence, relying solely on the mineralogical context of the analysed samples. The methodology was validated by comparing X-ray diffraction (XRD) results using the Rietveld method, showing correlations above 0.8 and average relative differences below 5 per cent. After validation, the approach was applied to drill hole databases and block models, proving crucial for predicting kaolinite distribution in mining scheduling. Additionally, absolute density was calculated, which can be used as a weighting variable in mineral resource estimation.