Resumo

VON WIELLIGH, M.H.M.  e  MINNITT, R.C.A.. Geostatistical techniques for improved management of brickmaking clays. J. S. Afr. Inst. Min. Metall. [online]. 2017, vol.117, n.2, pp.143-148. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2017/v117n2a5.

Brick manufacturers supply a variety of uniquely coloured facebricks to the building industry, which requires a high level of colour consistency in the products. Colour variation in bricks is influenced by the composition and consistency of the white clay raw material. By blending varieties of naturally occurring white clay the manufacturers produce a unique range of facebrick products. Homogeneity of the white clay raw materials mined at Lenasia is crucial for producing bricks of consistent colour. Geostatistical investigations of the major element distributions (SiO₂, Al₂O₃, Fe₂O₃, and K₂O) and loss on ignition (Lol) were conducted. An analysis of the spatial continuity of these variables followed by ordinary kriging indicated that the upper white clay layer at Lenasia is richer in K₂O and Fe₂O₃ than the lower layer. Consistency in the colour of facebricks depends critically on careful management of the variability in the K2O and Fe₂O₃ content of the clays. The geostatistical approach to understanding the distribution of elements in the clay allows miners to construct clay stockpiles of consistent quality for feeding the brick-making process. Geostatistical investigation of the chemical contents in other clay domains within the deposit is recommended, and could be extended to all facebrick manufacturers to assist in improving the colour consistency of their products.

Palavras-chave : geostatistics; facebrick clay; chemical composition; colour consistency.

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